View Full Version : Is now a good time to invest in solar?
My state (NJ) is offering rebates of $1.75 per solar watt installed up to 10000 watts ($17,500 max) Feds are giving 30% tax credit (approximately $18,000 after state rebate is subtracted), utilities in NJ are forced to purchase SRECs to show they are complying with regulations to use green energy sources. These are at current market values of $680 per 1000 kWh solar electricity produced they will be issued for 15 years (a system can produce electricity 6.5 hours a day in my area so 10 kWh will produce about 23 SRECs a year or about $15,640 a year at current market value). Solar is a home improvement that is exempt from property taxes in my state. All the incentives add up to paying off the investment in just a few years not even counting the electricity saved.
My wife and I are considering installing a grid tied system of somewhere between 6.5 and 10 kW (cost will probably be between $60,000 and $80,000). What do you think, is now a good time to go solar?
FredGarvin
Jul9-09, 03:50 PM
Just in our local news last night was a fight that is going to court because a homeowner purchased solar cells but his subdivision association won't let him put them up. He already has permission by the county but apparently homeowner associations here carry some clout. It may be something you want to look into if this could affect you.
Thanks FredGarvin. I have been considering the effect on my neighbors. I am considering a ground mounted system as my roof faces the wrong way and I have a lot of land around my house. That could be an issue.
russ_watters
Jul9-09, 06:24 PM
Well you tell us Artman - what kind of payback can you expect? Anything under 5 yrs is probably worth doing.
mgb_phys
Jul9-09, 06:35 PM
Payback is still >10 years now.
There are a few companies that will rent you the panels and even some deals where they install an over capacity for free, sell the power back to the grid and you just pay your existing electric bill but at todays power prices guaranteed for the next 20years.
They are betting on being able to replace the panels with more efficient ones in the future or being able to sell premium 'green' power to the power companies.
The trouble is that people putting in solar panels are normaly interested in being green - so they also go around adding insulation, efficient appliances and CF lamps - then having halved their power consumption they find the panels will take 50 years to pay back!
Well you tell us Artman - what kind of payback can you expect? Anything under 5 yrs is probably worth doing.
My wife and I went to a seminar held by Home Depot on solar power. They claim that the incentives will cover 100% of the cost through the rebates, tax credit and sale of SREC's for at least $475.00 each. Above that the power saved is gravy, amounting to approximately $51,000 from a 10kWh system over 15 years (assuming price of electric to double in fifteen years). Payback should be about 5 - 6 years, I estimate because the federal tax credit will have to spread out over that long.
In NJ you can only sell back to the Electric utility 5% over-production per billing cycle, so they are pretty careful to not exceed 100% design of the solar system (except for future additions such as an electric car or converting to a heat pump from oil or gas heat, etc).
I guess what I am mostly wondering is, is there a paradigm shift coming in solar electric generation in the near future that I should wait for? Will my system be obsolete long before it pays back, if I buy now? Incentives are probably at their peak for my area right now, with bailout money funding many of the government programs.
gmax137
Jul10-09, 07:16 AM
...These are at current market values of $680 per 1000 kWh ...
How much do you pay for a kw-hr in NJ? Is it really 68 cents?! The utility companies can buy a megawatt hour on the spot market for about $75 (or 7.5 cents per kw-hr).
I will be the first to admit ignorance on the financials of solar, but something doesn't look right in your numbers.
mgb_phys
Jul10-09, 09:54 AM
The srecs aren't really the price of the power they are also a sort of tax - the power company only has to buy a small amount of power at these prices to make up it's 'green' requirements.
The price varies, $680 is at the top of the range for winter months - it can go down to $100 - you also don't know if the scheme will be in place next year or next president.
The srecs aren't really the price of the power they are also a sort of tax - the power company only has to buy a small amount of power at these prices to make up it's 'green' requirements.
The price varies, $680 is at the top of the range for winter months - it can go down to $100 - you also don't know if the scheme will be in place next year or next president.I think tax or penalty for not using green energy describes the SRECs pretty well. State of NJ promises that SRECs will be available for 15 years, but there is no guarantee they will hold their value. They are a commodity and are traded as such. Yes they do swing in price, but they can be held for a couple of years and some brokers will lock in an average rate of say $475 over several years hoping to cash in by selling them when they are high. I was told other states are beginning to buy these as well, NJ residents can register to sell theirs in these other states. I think it costs the government very little to issue these, so there is a good chance they will be available the full 15 years.
Electric charges in my area are about 15 cents per kWh, but expected to double within the next 5 years.
russ_watters
Jul11-09, 08:32 PM
My wife and I went to a seminar held by Home Depot on solar power. They claim that the incentives will cover 100% of the cost through the rebates, tax credit and sale of SREC's for at least $475.00 each. Above that the power saved is gravy, amounting to approximately $51,000 from a 10kWh system over 15 years (assuming price of electric to double in fifteen years). Payback should be about 5 - 6 years, I estimate because the federal tax credit will have to spread out over that long. Considering all the incentives you listed, I'm surprised it is that bad. But if that includes covering it with a home equity loan, it might be worth doing. But considering the condition that the US economy is in right now, a better place for your money over those 5 years is probably the stock market, though obviously the risk is greater. However: I guess what I am mostly wondering is, is there a paradigm shift coming in solar electric generation in the near future that I should wait for? Will my system be obsolete long before it pays back, if I buy now? Incentives are probably at their peak for my area right now, with bailout money funding many of the government programs. No, you shouldn't expect a major revolution in solar technology in the near future. Enough money has been spent in researching it over enough time that it just doesn't seem likely to me that something obvious has been missed.
But the more important question is probably the political one: can you expect those incentives to get better or worse over the next few years? And that's a difficult question. With a democratic president and congress, you can expect them to be friendly toward such things for a while. For NJ, I don't know your politics or budget situation, so I can't help you there....
But it is important to remember that right now residential solar is such a small potatoes energy concept that the government can afford to throw absurd amounts of money at it without many people realizing how rediculous it is to do that. If a lot of people start to take advantage of this, I think people will start to realize just how bad the return on investment is for the government and these incentives will go away. So you may want to consider how long these incentives will actually be around and get while the gettin's good.
russ_watters
Jul11-09, 09:17 PM
I've been looking over your numbers.... Feds are giving 30% tax credit (approximately $18,000 after state rebate is subtracted)... Sounds about right to me. (a system can produce electricity 6.5 hours a day in my area so 10 kWh will produce about 23 SRECs a year or about $15,640 a year at current market value). That sounds high to me. What is the 6.5 hours based on? Is this a single axis tracking system? I would expect an average of about half that if it isn't due to the angle of the sun varying and clouds.
Anyway, continuing, I get a capital cost of $44,500 for an $80k system minus those first two incentives. Then subtracting the SREC at your rate gives a payback of just under 3 years, not including the energy you generate. So it doesn't sound to me like you've actually run the numbers. You really need to if you want to be able to make an educated decision here. And you really need to include the energy generated, since that is a big part of the benefit! It is also critical for sizing the system. Start by checking your electric bills and seeing both how much energy you use per year and what the summer and winter usage is. You probably want to size the system at around 50-75% of your summer months peak (I'm assuming you are going to use storage to cover you at night). If you produce/use 10,000 kWh per year, that's about $1500/yr.
Anyway, the SREC number is the critical number here. If it really is that high (and does that get bought every year at that year's market rate?), this is a rediculously good mid-term investment. Including the energy produced, you get your $44,500 investment back in 2.5 years and have it doubled after 5...$125k profit after 10 years, and $210 k after 15. That's an average of a 32% profit per year over 15 years. Note that since the return is constant dollars per year and not constant percentage per year, it doesn't compound like interest and so loses ground to an interest based investment - but over 15 years, that's extremely good.
If you're financing it with a home equity loan, of course, you'll need to subtract that from the return.
If the SREC is half what you think, the payback is about 5 years.
That sounds high to me. What is the 6.5 hours based on? Is this a single axis tracking system? I would expect an average of about half that if it isn't due to the angle of the sun varying and clouds.
Thanks Russ, You're right, my SREC's number was too high. The 6.5 is the approximate number of hours that a fixed South facing solar panel will produce a high percentage of output at my latitude. This number is available on several websites, I think it is pretty accurate and even a little conservative. I have a large open field where the panels are planned to be, but they are still talking about removing some trees to get better unobstructed light.
I tallied my electric bills yesterday for the year and we used around 11,000 kWh, that would be 11 SREC's, now at 680 apiece that that would be more than 600 per month, which should cover the payments on the loan, then we pocket the electric bill money saved (or more likely kick it back into paying off the investment as soon as possible.
The sales people have been saying things like "a conservative return of $50,000 profit over 15 years," "make $3 for every $1 spent over the life of the system," "pocket $90 per month after all incentives."
Thanks everyone for your responses. I appreciate the thoughts. It is a very large investment.
Well, we're signed up. We will be installing an 8.8 Kw ground mounted panel grid system made of 40 panels rated at 220 watts per panel. Payback is estimated at 5-10 years (there are a lot of variables, hours of direct sunlight, SREC prices, rising cost of electricity, availability of taxable income to take as credit). It should be online by November 30th. I'll let you know more later.
russ_watters
Aug10-09, 06:16 PM
Congrats. That's a neat project. Keep us informed about how it works out. Does the system include any type of monitoring that will tell you total kWh generated and differentiate it from kWh from the grid for consumption in your house? If so, by June 21st of next year (after 6 full months of generation, covering every conceivable sun angle), you'll be able to pin down your payback almost exactly.
mheslep
Aug10-09, 09:49 PM
....
Electric charges in my area are about 15 cents per kWh, but expected to double within the next 5 years.Wow, double? That's aleady 50% above the national average at 15. Any idea about the main reasons for such an increase in NJ? EIA shows NJ is half old nuclear (that is, bought and paid for). Oyster creek is old but small. Then there's 16% coal, 31% gas, and there's a large gas glut now.
http://www.eia.doe.gov/cneaf/nuclear/page/at_a_glance/states/statesnj.html
This must be due to some governmental regulation or tax interference if true.
Topher925
Aug10-09, 10:53 PM
Well, we're signed up. We will be installing an 8.8 Kw ground mounted panel grid system made of 40 panels rated at 220 watts per panel. Payback is estimated at 5-10 years (there are a lot of variables, hours of direct sunlight, SREC prices, rising cost of electricity, availability of taxable income to take as credit). It should be online by November 30th. I'll let you know more later.
Make sure you check with your electric company to see if they support sharing. The way it works out here is that for every kwh you put in, you can take a kwh out free of charge. Unless of course you have a surplus of power for a month, then the power company will only give you something like 2 cents per kwh you supply.
My university has solar powered apartments that were built almost 10 years ago I guess and from what I hear they have almost paid for themselves.
russ_watters
Aug11-09, 10:11 PM
Wow, double? That's aleady 50% above the national average at 15. It is often said in the media that the removal of rate caps will cause the rate to double, but what might double is just the generation portion of the rate, which accounts for perhaps 30% of the total. So it is more likely that rates for states where rate caps are about to come off would go up by 30%....
....but no one really knows just what's going to happen.
[edit] Wait, have rate caps already come off in NJ? This link implies they have: http://www.mwn.com/files/FileControl/fb610dc7-4655-4e58-b89c-9edccee9eace/7483b893-e478-44a4-8fed-f49aa917d8cf/Presentation/File/RATE%20CAP%20FAQ.pdf
If they have and the increase has already been seen (which would explain why they are already so high), and future rate increases won't be as dramatic.
ktech311
Aug13-09, 10:23 AM
Artman--- You are correct inn that your SREC numbers are way too high. Look to the OCE's website on the 8 year legislated schedule of SREC values based upon the Solar Alternative Compliance Penalty. Currently SREC ceiling are set to go down 3%/year---There is currently a shortfall in the RPS standard which should be made up for in the next few years. When we quote customers we use 500-511 for the next 8 years which is the weighted average. There are also a number of securitization efforts going on and we have been pushing our LSE's to commit to long term contracts at halfway decent numbers.
For SREC gen you can use a multiplier of 1.1-1.2 on the total KW of your system.
For reporting your inverter should have reporting capability but there are also aftermarket services that provide web based reporting for additional cost.
As the first company to be approved by the OCE back in 98' we have provided design and installation for 5-10% of all systems in NJ. This is a great time to go solar.
On a side note I'm pretty confident that HDs numbers are pretty high. I hope you got a couple quotes. They also 100% subcontract.
Any questions let me know.
Thanks Russ, You're right, my SREC's number was too high. The 6.5 is the approximate number of hours that a fixed South facing solar panel will produce a high percentage of output at my latitude. This number is available on several websites, I think it is pretty accurate and even a little conservative. I have a large open field where the panels are planned to be, but they are still talking about removing some trees to get better unobstructed light.
I tallied my electric bills yesterday for the year and we used around 11,000 kWh, that would be 11 SREC's, now at 680 apiece that that would be more than 600 per month, which should cover the payments on the loan, then we pocket the electric bill money saved (or more likely kick it back into paying off the investment as soon as possible.
The sales people have been saying things like "a conservative return of $50,000 profit over 15 years," "make $3 for every $1 spent over the life of the system," "pocket $90 per month after all incentives."
Thanks everyone for your responses. I appreciate the thoughts. It is a very large investment.
ktech311
Aug13-09, 10:29 AM
Energy Year SACP (SREC ceiling price)
2009 $711
2010 $693
2011 $675
2012 $658
2013 $641
2014 $625
2015 $609
2016 $594
My state (NJ) is offering rebates of $1.75 per solar watt installed up to 10000 watts ($17,500 max) Feds are giving 30% tax credit (approximately $18,000 after state rebate is subtracted), utilities in NJ are forced to purchase SRECs to show they are complying with regulations to use green energy sources. These are at current market values of $680 per 1000 kWh solar electricity produced they will be issued for 15 years (a system can produce electricity 6.5 hours a day in my area so 10 kWh will produce about 23 SRECs a year or about $15,640 a year at current market value). Solar is a home improvement that is exempt from property taxes in my state. All the incentives add up to paying off the investment in just a few years not even counting the electricity saved.
My wife and I are considering installing a grid tied system of somewhere between 6.5 and 10 kW (cost will probably be between $60,000 and $80,000). What do you think, is now a good time to go solar?
mheslep, The reason for doubling in five years is that the electric utilities facilities in NJ are nearing their capacity for production of electricity, unless they expand by building new generating plants they will have to purchase electricity from other sources, either scenario could raise prices quite a bit.
Russ, our system is supposed to have a real time meter on the solar to tell us our production and a connection to the installer to let them know if there is a drop in production so they can check it.
ktech311, thanks for checking in. Yes, they have all used a figure of $475 for calculating the SRECs value. I think the price is a little high because we are a ground mount system, about a hundred feet of trenching is required, and we need five large trees taken down. They are going to use Schott Solar 220 watt panels, which seem pretty nice from what I read. They told us we could expect higher than rated production that is part of the reason for the meter, we can give exact numbers for SRECs based on actual production. Our installer suggested we find a decent long term price for the SRECs and lock in. I like that idea as well. I suspect as more people go solar this value will drop.
Thanks for replies all.
Just in our local news last night was a fight that is going to court because a homeowner purchased solar cells but his subdivision association won't let him put them up. He already has permission by the county but apparently homeowner associations here carry some clout. It may be something you want to look into if this could affect you.I asked our contractor about this. He said in NJ there are laws protecting our right to use solar energy, but he said they will check with the local officials as well.
Topher925, it is my understanding that in NJ, because of the SRECs, the utilities are only required to purchase 1 kwh to 1 kwh plus about 5% overproduction at regular rates. Beyond that they pay nothing for any overproduction. So the idea is to size the systems as close as possible or slightly below the annual electric load. Ours was sized slightly below (about $11 a month worth at current electric rates), with hope we can conserve the difference or the system will produce better than expected.
The project is almost finished. Construction is complete and the system is functional, but we're now waiting for Local then State inspections.
It's been a long time coming (August till now). The array is huge, 56 feet long 12 feet high diagonally, 4 rows of 10 columns for a total of 40 panels at 220 watts each. We had to have about twenty trees removed because our local codes require 30 feet of setback from property lines, which moved us up into shade from several of our large trees. Rain put us back about two weeks because our tree removal service kept getting their equipment stuck.
mheslep
Dec16-09, 05:35 PM
Artman - So you used Home Depot for the install?
I see Lowes is selling do-it-yourself panels now along w/ everything needed: integrated racking, wiring and grounding.
http://www.sustainablebusiness.com/index.cfm/go/news.display/id/19397
The project is almost finished. Construction is complete and the system is functional, but we're now waiting for Local then State inspections.Thanks for the update. Let us know when you start generating to give us an idea of how well it's doing.
Brian_C
Dec16-09, 10:22 PM
I wouldn't invest in anything right now.
Artman - So you used Home Depot for the install?
I see Lowes is selling do-it-yourself panels now along w/ everything needed: integrated racking, wiring and grounding.
http://www.sustainablebusiness.com/index.cfm/go/news.display/id/19397
No, I didn't use Home Depot. I found they were not competitive in either price, quality or service. Among other things, I was told they charge for the solar survey, which other contractors do for free.
I considered the do it yourself option and I am fairly sure I could have managed the tasks involved, but I think in order for me to qualify for State rebate and certificate programs, the installation has to be performed (or at least certified) by a licensed professional.
I used a company that was just starting into the field. I've been very happy so far with their staff and their work. The two owners of the company are a Mechanical engineer who used to work on submarines and his brother who is a CPA. They seem very good at the design and describing the financial benefits and they are a branch of a plumbing and heating outfit that has been in business forty some years.
Brian_C, oops. Now you tell me. :rolleyes: It's in now. Time for it to start paying back.
concaveup
Dec24-09, 10:52 AM
I don't live in NJ, but I hear that New Jersey solar (http://www.getsolar.com/new-jersey-solar-power-panel-installation-professionals.php) power has one of the most progressive incentive plans in the US. Personally I'm not sure about investing in solar right now. But if you have calculated it to return in 10 years, and already have funds available I think it could be a good idea to save on energy prices when they go up. I would just make sure that you can sell your excess energy back to the grid at least for the 10 years to breakeven. If you want to install solar panels, there are breakthroughs coming, but the technology hasn't actually changed much in decades. I wouldn't count on new panels coming out any time soon. Of course you risk that they might come out, but you can't be sure. Like the phrase goes, "the best time to plant a tree is twenty years ago, the second best time is now." I think the same applies to solar panels, except maybe 10 years. If you installed them 10 years ago you might be getting free energy already.
jtesttubes
Dec25-09, 02:16 AM
US government is giving some benefits to those people who use solar energy. I have not decided on it, but sure in another 5 year yes i might go for solar energy.
Latest update is that the local inspector has passed the system. This was the technical inspection. The state interest is more in bookkeeping. It waits until after the local inspector has passed the system, then they just look to see that it was installed and write down serial numbers and performance data from the installed equipment. The state is mainly looking to see that it is not a fake installation designed to collect SREC certificates without producing electricity, or that it is duplicating installation details from another location (the State is looking that there is no evidence of fraud).
I don't live in NJ, but I hear that New Jersey solar (http://www.getsolar.com/new-jersey-solar-power-panel-installation-professionals.php) power has one of the most progressive incentive plans in the US. Personally I'm not sure about investing in solar right now. But if you have calculated it to return in 10 years, and already have funds available I think it could be a good idea to save on energy prices when they go up. I would just make sure that you can sell your excess energy back to the grid at least for the 10 years to breakeven. If you want to install solar panels, there are breakthroughs coming, but the technology hasn't actually changed much in decades. I wouldn't count on new panels coming out any time soon. Of course you risk that they might come out, but you can't be sure. Like the phrase goes, "the best time to plant a tree is twenty years ago, the second best time is now." I think the same applies to solar panels, except maybe 10 years. If you installed them 10 years ago you might be getting free energy already.
SRECs are supposed to be available for at least the next 15 years. That is the maximum projected payback, more likely 10 or less years, with a good SREC rate. Also, I want to install a heat pump to allow me to heat my house with electricity through much of the winter. I am going to have a State energy audit performed. If the audit suggests a heat pump be installed I can get half of the cost of a heat pump rebated to me from NJ. This can decrease my payback period by reducing my fuel oil consumption.
The reason I invested now are all the incentives are so high from state and federal governments and utilities through SRECs, rebates and tax credits. Payback through electrical savings alone would be in excess of 30 years for my system, depending on the rise in cost of electricity and that would not have been practical.
markjkirk
Jan14-10, 11:08 AM
PSEG launched a new loan program .. Solar Loan II .. here is an interview with the Program Lead, Andres Salas, at SolarPanelReporter.com (http://solarpanelreporter.com/public-utility-interviews/pseg-solar-loan-program-lead-andres-salas) where he gets into the specifics of what makes their program useful for private and commercial projects.
Also key is a link in that article that goes straight to their complete Solar Developer package. That has the present NJ SREC rates and shows what PSEG SREC rates are going to be in the coming years. - the link is in the article at SolarPanelReporter.com - above
What I like best was that they work through a homeowner solar panel project example and a medium sized commercial solar panel installation with (what looked like) fairly realistic costs and revenues.
They make a strong case for investing as early as possible. But then again, it is their own business interest to make those loans.
Yeah! :approve:
Threw the switch on Thursday the 21st! We are harvesting solar electric power now.
The state inspector took a good look at the project and was very impressed with the quality of materials and workmanship. He said our installers used top shelf equipment even where other installers frequently might skimp. Such as metal for backer boards instead of pressure treated wood, lightning arresters, and temperature sensors on the panels where they are not required, but make a better job.
So far we've had some cloudy weather, but on a couple of nice sunny days it has produced admirably at about 7200 watts at the inverter at almost 12 noon, about 81.8% of its 8800 watt rated capacity and so far about 27 kwh per day average.
mheslep
Jan25-10, 05:33 PM
at almost 12 noon, about 81.8% of its 8800 watt rated capacity ...That's 82% at noon on 21 January, a month from the Winter solstice. No doubt it will improve substantially later in the year.
Yeah! :approve:
Threw the switch on Thursday the 21st! We are harvesting solar electric power now.
The state inspector took a good look at the project and was very impressed with the quality of materials and workmanship. He said our installers used top shelf equipment even where other installers frequently might skimp. Such as metal for backer boards instead of pressure treated wood, lightning arresters, and temperature sensors on the panels where they are not required, but make a better job.
So far we've had some cloudy weather, but on a couple of nice sunny days it has produced admirably at about 7200 watts at the inverter at almost 12 noon, about 81.8% of its 8800 watt rated capacity and so far about 27 kwh per day average.
Outstanding. Keep the data coming.
That's 82% at noon on 21 January, a month from the Winter solstice. No doubt it will improve substantially later in the year.
Thought I would post the effect of snow on the ground in front of our ground mount solar array. The panels were clear of snow, there was a solid layer of 3"-4" of snow on the ground in front of them creating a nice reflective surface, and the sky was sunny, pretty much cloudless. The 8800 watt system produced 8200 watts (measured by the inverter) at 1:30. That's 93.2% efficient under those conditions. I wasn't able to check it at noon, but I'll bet it was nearly 100% because the system produced a total of 43 kwh during its operation that day. The snow seemed to help because the following day was equally sunny, but some of the snow had melted off the ground in front of the panels and they only produced a total 39 kwh (still, not bad for middle of winter). I think the wattage was around 7800 at 1:00 that next day.
Thought I would post the effect of snow on the ground in front of our ground mount solar array. The panels were clear of snow, there was a solid layer of 3"-4" of snow on the ground in front of them creating a nice reflective surface, and the sky was sunny, pretty much cloudless. The 8800 watt system produced 8200 watts (measured by the inverter) at 1:30. That's 93.2% efficient under those conditions. I wasn't able to check it at noon, but I'll bet it was nearly 100% because the system produced a total of 43 kwh during its operation that day. The snow seemed to help because the following day was equally sunny, but some of the snow had melted off the ground in front of the panels and they only produced a total 39 kwh (still, not bad for middle of winter). I think the wattage was around 7800 at 1:00 that next day.
It might be interesting to hook up an instantaneous amp meter, ie a scope with a current probe. I read that the power can vary substantially second to second on partially cloudy days, or due to bird and aircraft overflights, and that fast variation at larger scales can be a problem for grid operators.
mgb_phys
Feb2-10, 04:05 PM
(still, not bad for middle of winter).
The panels are more efficient when they are cold - not sure how much difference there is summer-winter but it all helps
Just so
http://www.solarpower2day.net/images/9t.png
It might be interesting to hook up an instantaneous amp meter, ie a scope with a current probe. I read that the power can vary substantially second to second on partially cloudy days, or due to bird and aircraft overflights, and that fast variation at larger scales can be a problem for grid operators.We're getting an instantaneous meter as part of the package. The installer is contracted to monitor through the internet to see if there is a problem and we can monitor also. Not sure if it can do trending, or if I just have to log in and check it out from time to time. They are supposed to put it in next week.
dr dodge
Feb4-10, 12:41 PM
so, with install, solar panels and controls and gound construction, what the total cost?
sounds like its putting out some nice power
good job in doing what many only talk about
jr
The latest development is that the installer came to put in a real time monitor yesterday. It took a few hours for us, and a service tech, to discover that MAC filtering on my network was blocking the signal from reaching their server. Got it straightened out and now I can monitor my solar output from any computer with internet capability.
so, with install, solar panels and controls and gound construction, what the total cost?
sounds like its putting out some nice power
good job in doing what many only talk about
jr
Installed price $74,020
NJ Buy down rebate -$15,400
Subtotal $58,620
Permit fees $500
Subtotal $59,120
Federal Tax credit -$17,736
Total $41,384
Sounds like a lot left, but with an estimated savings from electricity production, SREC sales, the payback should be less than ten years, with near zero cash outlay to make the payments. Also, it's a nontaxable $74,000 increased value improvement to my property.
russ_watters
Feb5-10, 09:30 AM
Taking a swag at your energy savings, if you get 43 kWh on a sunny winter day, you'll probably get more like 80 on a sunny summer day. Figure though a 60 average and 60% clearness, you get 13,140 kWh per year. What's your all-up energy cost? $.15 / kwh? At that, you save $1971 per year (can you sell excess back to the grid at the same price?). How much money will you get for SRECs?
rewebster
Feb5-10, 11:59 AM
sounds great artman--I'd love to do the same
I wouldn't doubt that they'll be even more state and federal tax credits in the future, and it may even come to pass that putting solar panels up may be a requirement someday
Yes the excess sales to the grid must be part of this plan, no? Otherwise it sounds like you have too much panel at ~8kW, $74k.
What's your all-up energy cost? $.15 / kwh? At that, you save $1971 per year (can you sell excess back to the grid at the same price?). How much money will you get for SRECs?
Average all-up cost is about $.15 to $.17/kwh.
We can sell excess of about 5%. We have a new digital net meter on the house, so far we haven't caught up to our night/cloudy day usage because of all the cloudy days, but I think we will if given a few clear days in a row.
We should get 11 or 12 SRECs a year they are currently selling for around $670 each. We may try and lock in to a lower long term deal for a guaranteed rate of about $500 each for a contract period of several years, if we can find a buyer. I think the Life Cycle Cost analysis was based on only $460 per SREC for 10 year payback at 11 SRECs per year.
great discussion...I looked into this about six months ago...and decided the payback looked like it would be too long...8 or 10 years....but a lot depends on assumptions and actual performance.
Good to see your electrical production is robust...when I looked into a few solar panels for use aboard my boat, perhaps six or eight years ago, the assumptions were ridicuously optimistic and the investment not even worth considering....at that time unicellular panels were the most efficient and most expensive...that's perhaps more important where space restrictions are really limited.
Glad to see solar now makes marginal sense, but not glad that my tax dollars are supporting application of an inefficient and uneconomical technology.....
good luck with all your efforts!!
Average all-up cost is about $.15 to $.17/kwh...What, that is the rate you sell energy to the utility, or your internal expected rate amortizing the $42k out of pocket?
russ_watters
Feb5-10, 04:17 PM
That's the cost of buying a kWh from the electric company. He didn't say what he can sell them for....
russ_watters
Feb5-10, 04:26 PM
We should get 11 or 12 SRECs a year they are currently selling for around $670 each. We may try and lock in to a lower long term deal for a guaranteed rate of about $500 each for a contract period of several years, if we can find a buyer. I think the Life Cycle Cost analysis was based on only $460 per SREC for 10 year payback at 11 SRECs per year. 12*$670= $8040
$8040+$1971=$10,011
$41,384/$10,0011 = 4.1 years
If that's what it really works out to, 4.1 years is an excellent payback.
Gotto admit though, I really don't understand the logic behind SRECs. From the wiki, it sounds like the point is to have electric companies subsidize private solar production by paying them 4x what the power is worth just for producing the power (ie, not actually buying the power). That seems like bad economics to me, but they are a great deal for you.
Glad to see solar now makes marginal sense, but not glad that my tax dollars are supporting application of an inefficient and uneconomical technology.....
Actually, each year it will reduce greenhouse gases equivalent to those generated running a car for 19,000 miles, the efficiency approaches 100% of rated capacity on a very sunny day, placing it well over many forms of power plant electrical production efficiencies And the panels will continue to create electricity from sunlight for the next 20-40 years with only some additional maintenance to the inverter.
As a use of stimulus money, it begins by putting the money in the hands of those who will use it, myself, my contractors, their employees, the local bank that financed the project, their employees, the solar component companies, and if enough people take advantage of the opportunity, it will prolong the time till there is a need for increased power utility infrastructure.
Or, you could give the stimulus money to wall street and see how much works it's way down to the people.
Russ, as far as I know, I can sell the excess kwh for what I buy it for in NJ up to 5% overproduction.
This got me curious as to how much you can sell electricity back to the utility company here in Kansas. Here's what I found:
House Bill 2844, passed in 2006, established net-metering rules for Kansas utilities. Net-metering is available for systems that generate 10kW or less. Net excess generation is credited to the customer’s next bill until the end of a 12-month billing cycle. After 12 months if you generate more than you use, you’ve just made a donation to your utility company (but it’s for a good cause since you’re using clean power). Reimbursement is however capped at 1% of the total number of kilowatt hours sold by the utility. This means that up to that 1%, customers are credited at the retail rate for the power they generate. Beyond the 1% cap, the utility reimburses customers at 150% of the wholesale rate.
http://www.solarpowerrocks.com/kansas/
russ_watters
Feb5-10, 06:50 PM
...the efficiency approaches 100% of rated capacity on a very sunny day, placing it well over many forms of power plant electrical production efficiencies Not sure what you mean by that - all types of power plants can produce their rated capacity, that's why they call it "rated capacity". And the panels will continue to create electricity from sunlight for the next 20-40 years with only some additional maintenance to the inverter. Of course (assuming the panels don't degrade), but at what cost? These vast subsidies make it viable for an individual to do, but for the economy as a whole, it's a huge loser. It's one of those things that works only as long as almost no one takes advantage of it, akin to the idea that "if everyone got phd's, who would pick up trash?"
Russ, as far as I know, I can sell the excess kwh for what I buy it for in NJ up to 5% overproduction. Just to clarify, you can sell it for the "all-up" cost of $.15-$.17? Or for the generation portion of the electrical cost (typically half to a third of the cost). Ie, a good fraction of an electric bill is paying for the maintenance of the distribution infrastructure. Since obviously you aren't building or maintaining any power lines, it wouldn't make sense to pay you to do that....though I could see lawmakers forcing the power company to pay the all-up price.
Also, I don't understand that 5% of production issue - I always thought the electric copmany was required to buy whatever you sold it. I guess that may be to prevent people from building plants just to get the subsidies, since most of the profit possibility is in the subsidies.
...And the panels will continue to create electricity from sunlight for the next 20-40 years with only some additional maintenance to the inverter...Is that from the panel manufacturer? Off the top of my head 20 years out I believe silicon PV panels degrade to something like 80% of rated.
Edit: yeah, 0.71% per year.
http://www.nrel.gov/docs/fy02osti/31455.pdf
russ_watters
Feb5-10, 07:01 PM
FYI, here are the rates for southeastern PA:
VARIABLE DISTRIBUTION SERVICE CHARGE:
SUMMER MONTHS. (June through September)
5.20¢ per kWh for the first 500 kWh per dwelling unit (I)
5.96¢ per kWh for additional kWh. (I)
WINTER MONTHS. (October through May)
5.20¢ per kWh (I)
COMPETITIVE TRANSITION CHARGE:
SUMMER MONTHS. (June through September)
3.42¢ per kWh for the first 500 kWh per dwelling unit
3.97¢ per kWh for additional kWh.
WINTER MONTHS. (October through May)
3.42¢ per kWh
ENERGY AND CAPACITY CHARGE
SUMMER MONTHS. (June through September)
6.10¢ per kWh for the first 500 kWh per dwelling unit
6.81¢ per kWh for additional kWh.
WINTER MONTHS. (October through May)
6.10¢ per kWh
As you can see, the actual generation of the electricity costs about 1/3 of the $.15 per kwh all-up cost (in which I didn't include the sales tax).
FYI, here are the rates for southeastern PA:
VARIABLE DISTRIBUTION SERVICE CHARGE:
SUMMER MONTHS. (June through September)
5.20¢ per kWh for the first 500 kWh per dwelling unit (I)
5.96¢ per kWh for additional kWh. (I)
WINTER MONTHS. (October through May)
5.20¢ per kWh (I)
COMPETITIVE TRANSITION CHARGE:
SUMMER MONTHS. (June through September)
3.42¢ per kWh for the first 500 kWh per dwelling unit
3.97¢ per kWh for additional kWh.
WINTER MONTHS. (October through May)
3.42¢ per kWh
ENERGY AND CAPACITY CHARGE
SUMMER MONTHS. (June through September)
6.10¢ per kWh for the first 500 kWh per dwelling unit
6.81¢ per kWh for additional kWh.
WINTER MONTHS. (October through May)
6.10¢ per kWh
As you can see, the actual generation of the electricity costs about 1/3 of the $.15 per kwh all-up cost (in which I didn't include the sales tax).3.4¢ in the Winter. That's cheap, even before taxes. I though electricity was getting expensive in Pa.
russ_watters
Feb5-10, 08:08 PM
3.4¢ in the Winter. That's cheap, even before taxes. I though electricity was getting expensive in Pa. You misread: It's 5.2+3.42+6.10=14.72¢
There are three separate per kwh charges to every residential electric rate:
Distribution charge (upkeep on the grid)
Transition charge (other, basically)
Energy charge (the cost to actually generate the electricity)
You misread: It's 5.4+3.42+6.10=14.92¢
There are three separate per kwh charges to every residential electric rate:
Distribution charge (upkeep on the grid)
Transition charge (other, basically)
Energy charge (the cost to actually generate the electricity)
ouch
I've been trying to find in writing what NJ's policy is on the subject of overproduction. What I am finding seems that the net metering (meter that rolls forward and back) allows a customer generating system to run the meter backward during production and forward during nighttime and days when the sunshine is outrun by the house usage, at full retail rates. The net difference can be carried from month to month, like "rollover minutes." I haven't been able to find if they are carried from year to year, but that may be the case. Any credit is in the form of just that, basically saving for a rainy day.
Net metering helps customers make the most of their renewable energy investments. It enables customers to obtain full retail credits on their utility bill for each kWh of electricity their renewable system produces, in excess of the amount of electricity used over the course of a year.
When a customer's renewable energy system produces more electricity than the customer actually uses, the customer will be compensated with credits at the full retail value of the electricity for the production over and above what they use.
Net Metering and Interconnection NJ OCE Web Site (http://www.njcleanenergy.com/renewable-energy/programs/net-metering-and-interconnection)
Not sure what you mean by that - all types of power plants can produce their rated capacity, that's why they call it "rated capacity".
There are efficiency losses due to the inverter that place the production on an average day at about 80% of the panel's rating. On a sunny day with snow on the ground in front of the panels for instance, the output of the inverter after efficiency loss might equal the panel nominal rating (220 watt panel might produce 225 or 230 watts).
Of course (assuming the panels don't degrade), but at what cost?
They do degrade. The process is destructive to the panels. We were told there are BP panels that have been in operation nearly 40 years.
These vast subsidies make it viable for an individual to do, but for the economy as a whole, it's a huge loser. It's one of those things that works only as long as almost no one takes advantage of it, akin to the idea that "if everyone got phd's, who would pick up trash?"
True enough, but there is little fear of that. These systems are not for everyone. They require a lot of space on the ground or a roof, the initial money outlay to install the system is high for an average homeowner. Fossil fuel subsidies way outrace solar incentives.
More than $54 billion of that was in the form of 23 different tax credits for oil, coal and natural gas producers, including those overseas, most of which are permanent provisions of the U.S. Tax Code. Just $18.3 billion was grants and other direct cash for research and development and other pursuits, such as the Strategic Petroleum Reserve.
Renewables such as wind, solar and hydropower received nearly $29 billion in all, much of it also in the form of tax credits although, in this case, credits that expire after set durations. And more than half of the renewable subsidy—$16.8 billion—went to the production of ethanol from corn, a controversial biofuel that can cut into food supplies and has significant environmental consequences, including greenhouse gas emissions and expanded dead zones from fertilizer runoff.
"The vast majority of federal subsidies for fossil fuels and renewable energy supported energy sources that emit high levels of greenhouse gases when used as fuel," the report's authors write. "These figures raise the pressing question of whether scarce government funds might be better allocated to move the United States toward a low-carbon economy."
Scientific American subsidies fossil fuel (http://www.scientificamerican.com/blog/post.cfm?id=how-much-in-subsidies-do-fossil-fue-2009-09-18)
I concur with Russwatters comments above.....
Actually, each year it will reduce greenhouse gases equivalent to those generated running a car for 19,000 miles, the efficiency approaches 100% of rated capacity on a very sunny day, placing it well over many forms of power plant electrical production efficiencies And the panels will continue to create electricity from sunlight for the next 20-40 years with only some additional maintenance to the inverter.
This is totally irrelevant as Russwatters has pointed out. If I have a system that is 100% efficient and costs a million dollars to produce a KWH, it's irrelevant how "efficient" it is. If you look up the efficiency of silicon solar cells, you'll find that are about 30-35% efficient...see the chart at http://en.wikipedia.org/wiki/Solar_cell#Solar_cell_efficiency_factors
.but this has nothing to do with economics.
No matter how you slice it investing about $8400 to produce a kwh of electricity part time (when there is sun) cannot in any way compete economically with a large power plant...and no one knows the environmental damage,if any, associated with the production of silicon based products...and all the other components of a solar system//////silicon is NOT lying around on the surface to be scooped up.
As a use of stimulus money, it begins by putting the money in the hands of those who will use it,
By this logic, we could also give $100 to every street alcoholic in the country...they,too, would "use it"....
I spent some years doing economic studies for projects at AT&T and I guarantee home solar power, on an economic basis, would have been laughed right out of consideration. The real issue here is that the tax money that goes to support this uneconomic investment. If everybody did this we'd go bankrupt....
Artman, my comments are an idictment on a policy and governmental level, not directed at you. I AM installing energy efficient windows and WILL be taking advantage of the 30% tax credit for those; so we all get wrapped up in bad government policies....
If you look up the efficiency of silicon solar cells, you'll find that are about 30-35% efficient...see the chart at http://en.wikipedia.org/wiki/Solar_cell#Solar_cell_efficiency_factors
.but this has nothing to do with economics. No the type of solar crystal silicon, single band (single junction) PV for use in the majority of residential rooftops are ~17-20% efficient, with the higher end ones hitting 22%. Multiband, very expensive solar PV like that use on space vehicles can hit ~40%.
No matter how you slice it investing about $8400 to produce a kwh of electricity part time (when there is sun) cannot in any way compete economically with a large power plant...The $8400 was the govt rebate for six New Jersey SRECS. The interesting question here is when solar might compete with larger power plants.
and no one knows the environmental damage,if any, associated with the production of silicon based products...and all the other components of a solar systemOf course they do, but whatever the environmental impact obviously there's no comparison to damage done by a coal plant.
//////silicon is NOT lying around on the surface to be scooped up. The source material, SiO2, largely is. Making Si from SiO2 is energy intensive. An interesting point is that it requires about two years of energy production from the panel for it to produce the energy used in making the it. Of course that number used to be six years, then four ...
Artman, my comments are an idictment on a policy and governmental level, not directed at you. I AM installing energy efficient windows and WILL be taking advantage of the 30% tax credit for those; so we all get wrapped up in bad government policies....
No problem Naty1. I know the economics of solar electricity means it has to be subsidized to be feasible at this point in time. That's why I did it now, lot's of incentives. I still say that as a use of economic stimulus money it is a wise use as are incentives for insulated windows, and other energy saving device incentives. There is at least some benefit to the populace, be it marginal, from decreasing carbon footprint, decreasing dependence on foreign oil, and getting money back into the economy.
As far as giving $100 to every street alcoholic in the country, I see no benefit to the general populace from that and I struggle to see how giving stimulus money to wall street benefits the general populace as these people are extremely adept at manipulating the financial world to their own advantage, which is IMO what got us here in the first place.
OmCheeto
Feb7-10, 05:10 PM
No problem Naty1. I know the economics of solar electricity means it has to be subsidized to be feasible at this point in time. That's why I did it now, lot's of incentives. I still say that as a use of economic stimulus money it is a wise use as are incentives for insulated windows, and other energy saving device incentives. There is at least some benefit to the populace, be it marginal, from decreasing carbon footprint, decreasing dependence on foreign oil, and getting money back into the economy.
As far as giving $100 to every street alcoholic in the country, I see no benefit to the general populace from that and I struggle to see how giving stimulus money to wall street benefits the general populace as these people are extremely adept at manipulating the financial world to their own advantage, which is IMO what got us here in the first place.
As an ardent supporter of solar energy, I kneel before you, and bow in awe.
ps. My 1981 Kyocera panels are still operating at 100% rated capacity. Trust in quality, not statistics from the 1950's.
My 1981 Kyocera panels are still operating at 100% rated capacity.Good to know. Thanks.
ps. My 1981 Kyocera panels are still operating at 100% rated capacity. Trust in quality, not statistics from the 1950's. Yep, trust in quality. Let's also trust in physics. How do you know the panels are still 100%? Have they been in daily use since 1981?
Yep, trust in quality. Let's also trust in physics. How do you know the panels are still 100%? Have they been in daily use since 1981?There are monitors and meter readings that will give this information. My real time monitor said my system produced 52 kwh yesterday (brilliantly sunny and snow on the ground). At one point in time, after the inverter it was producing 8650 out of 8800 nominal rating for the panels. That is 98% after inverter efficiency losses, which means the panels had to be producing above their rating.
OmCheeto
Feb9-10, 11:27 AM
Yep, trust in quality. Let's also trust in physics. How do you know the panels are still 100%? Have they been in daily use since 1981?
Ah! I need new glasses. They are labeled 1991, 1992, 1993. Stupid fat font.....
I actually never saw them installed for their first 16 years. They belonged to my father, who lived half way between Flagstaff and Phoenix Arizona. He lived off the grid for much of that time. Looking at the solar flux maps, I'd say it was a good test of their durability.
You would have to ask me about their efficiency on a Tuesday in the dead of winter.... :grumpy:
But I'm fairly certain that they were supplying full rated amperage when I did my "replace the alternator" experiment.
Let's look at a couple of examples from the net:
http://home.europa.com/~garry/Kyoncera_LA36151_5p5_yr.jpg (http://www.docstoc.com/docs/9641834/PV-Performance-Tests)
Looks pretty bad after only 5.5 years.
Though as the author says, the panels were run at 220% of their rated temperature, which according to the following, cuts their output significantly:
http://www.reuk.co.uk/OtherImages/solar-panel-power-temperature-relationship.gif (http://www.reuk.co.uk/Effect-of-Temperature-on-Solar-Panels.htm)
x axis is 'C, y axis is watts, ignore T < 30'C per the author.
Hmmm..... Interpolating the two graphs, it appears the panel was actually operating at 98.5% of it's rated capacity after 5.5 years. Not bad.
But I'll get back to you in August when the sun comes out again with proper documented values for my 4 panels.
There are monitors and meter readings that will give this information. My real time monitor said my system produced 52 kwh yesterday (brilliantly sunny and snow on the ground). At one point in time, after the inverter it was producing 8650 out of 8800 nominal rating for the panels. That is 98% after inverter efficiency losses, which means the panels had to be producing above their rating.Sounds like the mfn (BP?) is derating the panel a little. You mentioned up thread it was a 220W?
http://www.bp.com/liveassets/bp_internet/solar/bp_solar_usa/STAGING/local_assets/downloads_pdfs/pq/BP3220N_lowres.pdf
The data sheet lists 220W as rated for 1000W/M^2; obviously you are not getting 1000W/M^2 solar irradiance in NJ on Feb 8 at low elevation.
The BP 220 is a 1.68M^2 panel, including frame.
more later...
ramonegumpert
Feb10-10, 10:59 AM
will solar panel reflection cause glare problems for pilots? just curious. thanks.
dr dodge
Feb10-10, 11:05 AM
I have often wondered that. I live basicly right under final approach for Bush. They fly over all day and night, pretty high up. With my luck, they'd create a new law limiting panels right after I dropped the $$$
dr
russ_watters
Feb10-10, 11:09 AM
I haven't looked too closely at a solar panel, but I'd think they'd be coated to reduce glare. After all - if they are reflecting light, it isn't being absorbed and converted to electricity!
I haven't looked too closely at a solar panel, but I'd think they'd be coated to reduce glare. After all - if they are reflecting light, it isn't being absorbed and converted to electricity!The surface is low iron "solar" glass material over the bluish-black PV cells. Not much glare.
mheslep, mine are Schott Poly 220 panels.
Schott Solar Poly 220 (http://www.schottsolar.com/us/products/photovoltaics/schott-poly/)
Just saw my monitor show me 8.811 kw output after the inverter. That's over 100% of the panel nominal capacity of 8.8 kw. Not too shabby. :approve:
I wonder if studies have been done on the effects of snow reflectance on solar panel output? The ground is covered with snow, the panels are in cool ambient air and under very clear sunny skies. I really think the snow must help.
mheslep
Feb12-10, 05:27 PM
Clear day solar insolation on a perpendicular ground surface is ~1000W/m^2 x cos(zenith angle) (http://edmall.gsfc.nasa.gov/inv99Project.Site/Pages/science-briefs/ed-stickler/ed-irradiance.html).
For NJ at Noon in Feb,
cos(zenith) = sin(φ)*sin(δ)+cos(φ)cos(δ) = 0.61,
where δ=solar declination (Feb) ~ -10 deg, φ=latitude = ~40.3 deg.
Note for June 21 with δ=+23.5, cos(zenith) = 0.96 at Noon.
So received peak power in Feb for a panel facing South at latitude should be ~610W/m^2.
Given 40 panels at 1.67 M^2, total received power by the surface of the array is 41.1
kW. If measured power today was 8811 Watts, then the conversion efficiency of the panels, assuming 94% efficiency for the inverter, is
eff = 8811W / (1.67M^2 * 40 panels * 610W / M^2 * 0.94) = 20.3 %. That's extremely high for a polycrystalline panel.
In June output power after the inverter should hit 12.2kW
mheslep
Feb13-10, 12:14 AM
From Monday's MIT TR:
U.S. Solar Market to Double in the Next Year
Government incentives and lower solar prices are starting to pay off. (http://www.technologyreview.com/energy/24498/?a=f)
According to Harry Fleming, the CEO of Acro Energy Technologies in Oakdale, CA, these changes mean that the cost of a typical five-kilowatt rooftop solar system has dropped from $22,000 after state incentives are applied ($40,000 without them) to $16,000 in the last 18 months. Prices are expected to fall to $13,000 by the end of the year ($25,000 without incentives). "This is going to make solar a middle-class product," he says.
Scaling their 5kW typical system to Artman's 8.8kW system gives
with (without state incentives)
$39k ($70k without) - more than 18 months ago [in the ballpark with post #41 (http://www.physicsforums.com/showpost.php?p=2565045&postcount=41)]
$29k ($51k without) - last 18 months,
$23k ($44k without) - end of 2010.
a 40% price drop, giving $2.6 per Watt-peak for a theoretical 2011 residential system.
Clear day solar insolation on a perpendicular ground surface is ~1000W/m^2 x cos(zenith angle) (http://edmall.gsfc.nasa.gov/inv99Project.Site/Pages/science-briefs/ed-stickler/ed-irradiance.html).
For NJ at Noon in Feb,
cos(zenith) = sin(φ)*sin(δ)+cos(φ)cos(δ) = 0.61,
where δ=solar declination (Feb) ~ -10 deg, φ=latitude = ~40.3 deg.
Note for June 21 with δ=+23.5, cos(zenith) = 0.96 at Noon.
So received peak power in Feb for a panel facing South at latitude should be ~610W/m^2.
Given 40 panels at 1.67 M^2, total received power by the surface of the array is 41.1
kW. If measured power today was 8811 Watts, then the conversion efficiency of the panels, assuming 94% efficiency for the inverter, is
eff = 8811W / (1.67M^2 * 40 panels * 610W / M^2 * 0.94) = 20.3 %. That's extremely high for a polycrystalline panel.
In June output power after the inverter should hit 12.2kW
Thanks for working that out for me (math is not my strong suit). :cool:
(Does this mean over the following ~34 year lifespan of the system, Artman will make $241,026? Hmmm... Even without the SREC's that's $71,026. Wow. Seems the answer to the original question is: not only yes, but ......)
I was told as part of the sales pitch (so take it for what that's worth) that solar electric generation systems purchased with the current level of incentives will payback $3 for every $1 spent over about 25 years given escalation rates of electricity and expected rise and eventual fall of SREC values. Of course this is just speculation, much of it hinges on the weather. So far it has been the snowiest winter on record where I am. This means lots of cloudy days. Fortunately we have had a few sun on snow days to go with them and the output goes way up then.
OmCheeto
Feb14-10, 06:17 PM
I was told as part of the sales pitch (so take it for what that's worth) that solar electric generation systems purchased with the current level of incentives will payback $3 for every $1 spent over about 25 years given escalation rates of electricity and expected rise and eventual fall of SREC values. Of course this is just speculation, much of it hinges on the weather. So far it has been the snowiest winter on record where I am. This means lots of cloudy days. Fortunately we have had a few sun on snow days to go with them and the output goes way up then.
I'm very interested in your system voltage vs. temperature. I learned yesterday that most solar panel manufacturer's under-rate their panels, knowing that they have a certain degradation over time. (I'm still trying to figure out how to gracefully retract my "100%" claim from the other day)
I have to admit that I've learned more about solar panels in the last two weeks than I have in the last 4 year. It's easy to ignore the scientific facts when these little buggers appear to be the ultimate "Energizer Bunnys".
But mheslep and I both posted graphs that indicate that ratings on the panels start at 25'C and voltage output degrades as temperatures go up. So my questions are: Do the graphs continue linearly in the opposite direction? Does a panel operating at 0'C give a 6 to 7 % increase in power output? Was it the solar reflection from the snow, or the temperature that are giving you increased power output? Or was it both?
I'm very interested in your system voltage vs. temperature. I learned yesterday that most solar panel manufacturer's under-rate their panels, knowing that they have a certain degradation over time. (I'm still trying to figure out how to gracefully retract my "100%" claim from the other day)
I have to admit that I've learned more about solar panels in the last two weeks than I have in the last 4 year. It's easy to ignore the scientific facts when these little buggers appear to be the ultimate "Energizer Bunnys".
But mheslep and I both posted graphs that indicate that ratings on the panels start at 25'C and voltage output degrades as temperatures go up. So my questions are: Do the graphs continue linearly in the opposite direction? Does a panel operating at 0'C give a 6 to 7 % increase in power output? Was it the solar reflection from the snow, or the temperature that are giving you increased power output? Or was it both?I understand both low temperatures and reflectance can add to performance. I was told that my ground mount system will perform better than a roof mounted system (everything else being equal) because it will be better arranged for air movement to transfer heat away from the panels, since the backs are wide open on a metal rack angled 40 deg up to 12' in the air at the high end from 3' above the ground in the front. Where roof mounted panels lying flat on racks against the angle of the roof tend to gain heat from attic spaces and trap heat between the panels and the roof, driving down performance.
russ_watters
Feb15-10, 12:54 AM
I'm very interested in your system voltage vs. temperature. I learned yesterday that most solar panel manufacturer's under-rate their panels, knowing that they have a certain degradation over time.... That's not quite right. Manufacturers rate their panels according to a set 3rd party standard. Like any other device, mechanical or electrical, performance will vary based on test conditions, so *someone* has to decide on a standard set of conditions unless the industry is to be a free-for-all. The rating point is then based on a set of conditions near the top of what is likely to be seen, but there is no such thing as perfect conditions, so there is no real set maximum.
Here's an article about the Standard Test Conditions for rating panels (on which, Artman's panel's 220W nominal rating is based). 1.Irradiance (sunlight intensity or power), in Watts per square meter falling on a flat surface. The measurement standard is 1 kW per sq. m. (1,000 Watts/m2)
2.Air Mass refers to “thickness” and clarity of the air through which the sunlight passes to reach the modules (sun angle affects this value). The standard is 1.5.
3.Cell temperature , which will differ from ambient air temperature. STC defines cell testing temperature as 25 degrees C.
http://www.altestore.com/howto/Electrical-Characteristics-of-Solar-Panels-PV-Modu/a87/
Because of #2, #1 seems to me that it should be the irradiance at the top of the atmosphere. The real value varies from 1.321-1.412 kW/sq m, so I would think if you mounted one of these on the top of Mt Everest, it would put out a good 285W. I'm not really sure of what #2 means in terms of real-world conditions, though.
#3 is significantly cooler than what you'll actually get in summer, so that one works against you.
....speaking of which, does anyone make a combo solar water heater and power panel? I'd think that you could collect nearly as much heat as with a regular solar water heater while also significantly improving the electrical output of the panel.
....speaking of which, does anyone make a combo solar water heater and power panel? I'd think that you could collect nearly as much heat as with a regular solar water heater while also significantly improving the electrical output of the panel.
Not sure about water, but a company called Solarwall makes a combination PV panel and air preheater duct. Air is ducted behind the panels to cool them while simultaneously preheating fresh air for roof mounted Air handling units.
Solarwall PV and roof mounted solar air heating. (http://solarwall.com/en/products/solarwall-pvt/solarduct-pvt.php)
At 11:45 yesterday, sunny, clear, with snow on the ground temps in the upper 30's deg F, the system monitor showed 9.34 kw output after the inverter. Around 106% of the panels' kw rating. The inverter is only rated for 10 kw. Anyone know what happens should the panels go over that? It's beginning to look like a possibility.
mheslep
Feb16-10, 01:14 PM
At 11:45 yesterday, sunny, clear, with snow on the ground temps in the upper 30's deg F, the system monitor showed 9.34 kw output after the inverter. Around 106% of the panels' kw rating. The inverter is only rated for 10 kw. Anyone know what happens should the panels go over that? It's beginning to look like a possibility.The panels will go well over that - to 12kW come a clear day in June/July. I doubt you'll have any problems with the panels themselves, but the inverter concerns me if it is indeed rated 10kW. It must have a breaker or fuse, e.g. UL safety, but it's likely have a shorter life if its run at full or over capacity all the time. Doesn't make sense that an experienced installation company would have given you an inverter underrated for the job.
The panels will go well over that - to 12kW come a clear day in June/July. I doubt you'll have any problems with the panels themselves, but the inverter concerns me if it is indeed rated 10kW. It must have a breaker or fuse, e.g. UL safety, but it's likely have a shorter life if its run at full or over capacity all the time. Doesn't make sense that an experienced installation company would have given you an inverter underrated for the job.I looked up my inverter and checked the ratings. The maximum output is 9995 watts. The maximum input current is 46.7 amps nominal input amps is 27.6 amps. I think my system is wired for 480 volts DC. 12,000 watts/480v = 25. Should be fine. I'm breathing better again.
mheslep
Feb16-10, 07:23 PM
Hold on, I didn't account for the temperature coefficient before. The SCHOTT data sheet gives a -0.47% / deg C coeff, 20deg C as the rating point. Assuming your Noon temperatures lately have been 5 deg C outside, the panels would run 15*0.47%=7% better than rated. In the Summer, assuming 30 deg C on the roof, the panels would run 10*0.47=4.7% worse, an 11% decline due to temperature from now. So the peak June solstice power for the Artman array declines to ~10.7kW at 30 degC, better when the odd clear cold front comes through.
russ_watters
Feb16-10, 10:08 PM
I looked up my inverter and checked the ratings. The maximum output is 9995 watts. The maximum input current is 46.7 amps nominal input amps is 27.6 amps. I think my system is wired for 480 volts DC. 12,000 watts/480v = 25. Should be fine. I'm breathing better again. All motors have a "service factor" of 1.15 that means the true rating is actually 15% higher than nameplate - I suspect your inverter has such a saftey-factor built into its design.
Topher925
Feb17-10, 03:19 PM
All motors have a "service factor" of 1.15 that means the true rating is actually 15% higher than nameplate - I suspect your inverter has such a saftey-factor built into its design.
There's no doubt a factor of safety, but often operating a device outside of its specified range wont damage it but it may shorten its lifespan.
Latest update, the Electric Company estimated our last bill so even after the solar array saved us 750 kwh we got a bill for $160.00. To be fair, there was still a foot of snow on the ground around here, so I didn't expect them to read the meter. My wife called and told them the reading I took on meter reader day and they are going to amend the bill and send out a new one. The Electric Company has been very reasonable through this whole process.
I was anxious to see the difference in the bill after nearly a month of solar power generation. It was an odd month anyway because of snow, clouds, some time left from the old meter, and a few days on the new without solar assistance.
Currently the system has generated over 900 kwh, should earn us our first SREC soon. Then we get to see how that works.
We had our first non-estimated bill this weekend. $47 and change for 281 kwh. $15 of that was distribution and connection fees. We are still ending up paying more than expected (the design was for an average bill of $11.00), but it has been unusually cloudy. The hope is that the summer months will help reduce the actual average bill to meet the design.
System has been functioning well with several sunny days just after the last meter reading. We are still waiting for the SREC number to come through. It is tied to the rebate which is tied to the home energy audit, which has to be submitted to the state still (waiting for a computer program code of some sort). The whole energy audit part of the process came as a surprise to me. I hadn't realized at first that a home energy audit was required to get the rebate and the SREC number, but it is.
More later as it happens.
The meter-reader came yesterday and found the reading over 300 kwh below the previous month (good sunny month). He said "System failure." I asked him what that meant, he said it kicks out any results too far below the expected average reading. It should be interesting to see the bill. I'll post the outcome.
The meter-reader came yesterday and found the reading over 300 kwh below the previous month (good sunny month). He said "System failure." I asked him what that meant, he said it kicks out any results too far below the expected average reading. It should be interesting to see the bill. I'll post the outcome.
On a month with a negative meter reading we got a bill for +- $2 (not sure of the exact amount, it's home, I'm not, my wife told me the total). There are a couple of charges that are based on days tied to the grid rather than kwh used. Those amounted to the +- $2 charge. I can stand that. :wink:
mheslep
Apr27-10, 02:57 PM
On a month with a negative meter reading we got a bill for +- $2 (not sure of the exact amount, it's home, I'm not, my wife told me the total). There are a couple of charges that are based on days tied to the grid rather than kwh used. Those amounted to the +- $2 charge. I can stand that. :wink:By this time of year the utility/panels should be paying you substantially for your excess kWh produced, I would think? No summer air conditioning running yet, and we are <60 days away from summer solstice. I would think May might be your biggest pay off month, unless you don't use air conditioning in the summer.
By this time of year the utility/panels should be paying you substantially for your excess kWh produced, I would think? No summer air conditioning running yet, and we are <60 days away from summer solstice. I would think May might be your biggest pay off month, unless you don't use air conditioning in the summer.Because of the SREC program, I can only sell back a small portion of the excess at this time (about 5% I think). We had about 300 kWh under the last meter reading. We can carry it to the next month, but we won't get back any money for it.
mheslep
Apr28-10, 02:18 PM
Because of the SREC program, I can only sell back a small portion of the excess at this time (about 5% I think). We had about 300 kWh under the last meter reading. We can carry it to the next month, but we won't get back any money for it.
So you are supplying free power to the grid?
dr dodge
Apr28-10, 02:25 PM
So you are supplying free power to the grid?
thanks, we all appreciate that...lol
this (IMHO) is why a seperate off grid system is all I would invest in. Somehow the power company still wins
Glad your system is working good, and your thread is a great source of info for all
dr
thanks, we all appreciate that...lol
this (IMHO) is why a seperate off grid system is all I would invest in. Somehow the power company still wins
Glad your system is working good, and your thread is a great source of info for all
drThanks dr. It's doing really good. The main problem right now is that the state still hasn't issued us our SREC code and instructions yet. It is in the works. However, I still think grid tied was the way to go. Our overproduction last month was around 300 kWh.
300 kWh is 30% of 1 SREC. They are selling for about $700 in NJ right now. So a third of an SREC = $210 in NJ.
Electricity is selling for approximately $.17 right now in NJ. so 300 times .17 = $51 in NJ.
Grid tied still looks the best to me. And we carry the credit for the 300 to this month should it be cloudy.
Another update. I received my SREC registration number from the NJ Board of Public Utilities. Now I can start selling SREC's. It took about 5 months for the registration to come through from the date of system activation at the end of January. From what I understand, all of the SREC's produced prior to the registration number being issued are still credited to my account and can be sold. It's produced almost 5 now, right about on schedule to make 11 by the anniversary date at the end of January.
mheslep
Jun15-10, 04:13 PM
Artman - what kind of daily kWh are numbers are you producing now that we are in to June?
From what I understand, all of the SREC's produced prior to the registration number being issued are still credited to my account and can be sold.
Are the SREC's value seasonal dependent? i.e. Can you sell them back on peak times. I would guess not.
Artman - what kind of daily kWh are numbers are you producing now that we are in to June?
Well, the hot air does do quite a hit on efficiency, our better days are around 49 or 50 kwh (down from 55 or 56 in the early Spring), but we seem to be able to eek a decent output from a longer cloudy day, getting up around 25 or 30 kwh.
Are the SREC's value seasonal dependent? i.e. Can you sell them back on peak times. I would guess not.
Y 04:13 PM
They can be held to be monetized (sold) for the current year plus two years for a total of three years in NJ, so you can wait a while for the price you are trying to get.
I've just began an arrangement to allow an online company SRECTrade.com handle the sales. They charge 3% of the selling price, deal with the buyer and send me a check. I set a low limit (in my case $500.00 per SREC) and they try and get me as high a price above that limit as they can find. If I want, I can handle the sales myself and they only charge the buyer a percentage, but I think 3% to watch the market and find a good buyer is a reasonable charge.
OmCheeto
Jun16-10, 11:39 PM
Artman, you do realize that it has taken all of my willpower not to flood this thread with little smileys every time you make a post, don't you?
:smile: ... :smile: .. :smile: .
No! Don't do it Om! This is the engineering section! They'll give you an infraction!
So, please. Given the SRE's, the cut in your electric bill, and the original cost, what is your current payback time for your investment?
And give us the answer. Was this the right time to invest in solar?
snicker, snicker.
So, please. Given the SRE's, the cut in your electric bill, and the original cost, what is your current payback time for your investment?
And give us the answer. Was this the right time to invest in solar?I'll run the numbers again and let you know. I think with a decent SREC rate, it should be around 5-7 years, worst case about 10 years.
My original question wasn't really so much about the payback as it was the technology. I wanted to know if anyone here knew of any breakthrough technology that would make the old panels obsolete and very much more expensive. If the world was on the cusp of a breakthrough that would drive solar array prices way down or solar efficiency so good that fewer panels could do the same job. If the cost comes too far down, the market will become flooded and SREC prices will drop. Then payback would become an issue. Payback from electricity savings +rebate and tax credit, but with no SRECs is about 20 years.
Was this the right time to invest in solar?My honest answer is "no." I wish I had done it sooner (when rebates were higher). :approve:
I attended an energy symposium where I had to answer questions about residential solar. there were several others there who had solar arrays as well and, from what they have said, all of them are very pleased with their investments. I'll post more about this later, some issues to be aware of came up out of that day.
OmCheeto
Jun17-10, 10:05 AM
I'll run the numbers again and let you know. I think with a decent SREC rate, it should be around 5-7 years, worst case about 10 years.
My original question wasn't really so much about the payback as it was the technology. I wanted to know if anyone here knew of any breakthrough technology that would make the old panels obsolete and very much more expensive. If the world was on the cusp of a breakthrough that would drive solar array prices way down or solar efficiency so good that fewer panels could do the same job. If the cost comes too far down, the market will become flooded and SREC prices will drop. Then payback would become an issue. Payback from electricity savings +rebate and tax credit, but with no SRECs is about 20 years.
My honest answer is "no." I wish I had done it sooner (when rebates were higher). :approve:
I attended an energy symposium where I had to answer questions about residential solar. there were several others there who had solar arrays as well and, from what they have said, all of them are very pleased with their investments. I'll post more about this later, some issues to be aware of came up out of that day.
Not to politicize the engineering forum, :rolleyes: , but with the gulf spill going on, I'd say your timing was impeccable.
One of the questions asked of the residential panel made up of home owners with solar arrays was: "Knowing what you know now, what would you do differently?"
A man with a huge 28 kw ground mounted array said he would have had it set slightly higher. His is only 6" above the ground at the low end (mine is about 30"). He said snow bunched up around the bottom and he had to clear it.
A man with a 9.5 kw array mounted on the roof of a pole barn said he would ride past mine (he lives close by me) during those days following the heavy snows and see my solar array was clear of snow while his went for weeks with snow on it because the angle was too small (30 deg over horizontal, mine is 40 deg) and the roof was too high for him to clear them. He said If he had it to do over, he would put it on the ground at a steeper angle, similar to mine.
I said I would have done it sooner. :approve:
I can understand their answers, my best days were days with snow on the ground and a clear solar array.
Not to politicize the engineering forum, :rolleyes: , but with the gulf spill going on, I'd say your timing was impeccable.Wow, yes that could have an impact.
mheslep
Jun17-10, 04:42 PM
Not to politicize the engineering forum, :rolleyes: , but with the gulf spill going on, I'd say your timing was impeccable.Not sure how solar PV will help Artman to use any less oil in his next truck/car/airplane/train trip.
mheslep
Jun17-10, 04:44 PM
I can understand their answers, my best days were days with snow on the ground and a clear solar array.Really? More kWh on snow days than the Spring months? How do your sky facing arrays get ray line from the snow?
Really? More kWh on snow days than the Spring months? How do your sky facing arrays get ray line from the snow?
I'd have to draw that out myself, but they did. One of our highest instantaneous outputs that I saw on our monitor was 10.15 kw at 1:20 on Feb 18th a day with snow on the ground. Other snow days also did over 9 and 10 kw peak instantaneous outputs. On no-snow-sunny days the highest it goes is about design 8 to 9 kw. Today was a screaming sunny day and the best I saw was about 7.6 kw, but it held that longer and will probably end up around 50 kwh today. March did have one of our highest daily outputs of 57 kwh and earlier that week it had a peak day over 10 kw. But the snow on the ground days do appear to be good performers.
mheslep
Jun17-10, 06:46 PM
I'd have to draw that out myself, but they did. One of our highest instantaneous outputs that I saw on our monitor was 10.15 kw at 1:20 on Feb 18th a day with snow on the ground. Other snow days also did over 9 and 10 kw peak instantaneous outputs. On no-snow-sunny days the highest it goes is about design 8 to 9 kw. Today was a screaming sunny day and the best I saw was about 7.6 kw,
Part of that is because of the 30-40 degree C temperature difference between then and now, but that still doesn't explain a nearly ~30% power swing, from a lower in the sky sun (then) to a higher one (now). Perhaps the panels have gotten a little dirty? A little banged up (from ice, blown debris)?
OmCheeto
Jun17-10, 09:37 PM
Part of that is because of the 30-40 degree C temperature difference between then and now, but that still doesn't explain a nearly ~30% power swing, from a lower in the sky sun (then) to a higher one (now). Perhaps the panels have gotten a little dirty? A little banged up (from ice, blown debris)?
Might be the fact that fresh snow has an albedo of almost 90%.
http://upload.wikimedia.org/wikipedia/commons/thumb/1/18/Albedo-e_hg.svg/220px-Albedo-e_hg.svg.png
Not sure how solar PV will help Artman to use any less oil in his next truck/car/airplane/train trip.
Leaf, Volt, Tesla Roadster or Model S.
Airplanes will have to wait for Ivan and his green slime fuel. :smile:
:smile:
blimkie.k
Jun29-10, 11:41 AM
Artman,
First off, congrats on the successful installation of your system, sounds like its running great!
I am looking into building a 10 kilowatt system. We have submitted an application to the Ontario Power Authority to get a contract in there microfit program. They pay 82 cents a kilowatt over a 20 year period. Still doing the research but submitted the application because it takes about 3 months to be processed.
Well, the hot air does do quite a hit on efficiency, our better days are around 49 or 50 kwh (down from 55 or 56 in the early Spring), but we seem to be able to eek a decent output from a longer cloudy day, getting up around 25 or 30 kwh.
So are you saying on days were its pretty much overcast all days and really no direct sunlight you get about 25 to 30 khw per day with your 8.8 kilowatt system? Have you ever got anything lower then 20 khw in a day?
One of the questions asked of the residential panel made up of home owners with solar arrays was: "Knowing what you know now, what would you do differently?"
A man with a huge 28 kw ground mounted array said he would have had it set slightly higher. His is only 6" above the ground at the low end (mine is about 30"). He said snow bunched up around the bottom and he had to clear it.
Have you worked our a rough average daily kwh generation rate yet for the 5-6 months you have been operation, or are you just happy with its performance now and letting it do its thing?
A man with a 9.5 kw array mounted on the roof of a pole barn said he would ride past mine (he lives close by me) during those days following the heavy snows and see my solar array was clear of snow while his went for weeks with snow on it because the angle was too small (30 deg over horizontal, mine is 40 deg) and the roof was too high for him to clear them. He said If he had it to do over, he would put it on the ground at a steeper angle, similar to mine.
.
I have been doing some calculations using declination and determining the the max and minimum angles of the suns position at noon. (with a little help from in another thread on this forum). I'm trying to work out a good angle to have them tilted at.
You say yours is about 40 degrees. Does it ever change or is it always angled at 40 degrees?
Artman,
So are you saying on days were its pretty much overcast all days and really no direct sunlight you get about 25 to 30 khw per day with your 8.8 kilowatt system? Have you ever got anything lower then 20 khw in a day?We had 3 days below 30 kWh in June the lowest of those was 7.64 kWh, probably raining. The other 2 low days were above 20 kWh. In May we had 7 days below 30 kWh, the lowest of those was 8.16 kWh, one was 11.59 kWh the rest of the low days were above 20 kWh.
I have been doing some calculations using declination and determining the the max and minimum angles of the suns position at noon. (with a little help from in another thread on this forum). I'm trying to work out a good angle to have them tilted at.
You say yours is about 40 degrees. Does it ever change or is it always angled at 40 degrees?
Ours has a fixed position. Always due south, always 40 deg tilt.
Good luck with it if you decide to go ahead. Ours has worked out well so far.
Thanks for the comments all.
mheslep
Jun29-10, 02:20 PM
Might be the fact that fresh snow has an albedo of almost 90%.Of course, but the panels are not pointed at the snow. Is there significant flux in atmospheric scatter? I dunno.
Leaf,Not yet
Volt,Not yet
Tesla Roadster$109k
or Model S.Not yet
Airplanes will have to wait for Ivan and his green slime fuel. :smile:
E-planes are certainly years away, but I think they're coming. Maybe fuel cells for awhile, but definitely e-motors. Just too many advantages.
WAp08b9_EuU
DS-94 Fan (http://www.schuebeler-jets.com/index.php?option=com_content&task=view&id=102&Itemid=1), about 4KW per Kg power density.
http://www.electraflyer.com/gallery/videos/pure_electric.swf
Of course Artman's panels would have to put in some overtime to charge the full size version. :wink:
OmCheeto
Jul4-10, 01:45 PM
Of course, but the panels are not pointed at the snow. Is there significant flux in atmospheric scatter? I dunno.
At 40 degrees from horizontal, the panels will be 140 degrees from the plane of snow. They would still catch light at that angle.
Also, as I noted back in February (http://www.physicsforums.com/showpost.php?p=2571575&postcount=67):
http://www.reuk.co.uk/OtherImages/solar-panel-power-temperature-relationship.gif
x axis is 'C, y axis is watts, ignore T < 30'C per the author.
The temperature of the panels changes their output significantly. I know that when I set mine up in the summer to water the volley ball courts at the beach, you could fry eggs on them.
450 watts/750 watts = 60%
I'd say Artman's panels must be better than my old Kyoceras with only a 30% reduction in output.
Ah ha! You could almost interpolate the panel temperatures from his panel's data sheet (http://www.schottsolar.com/fileadmin/media/us/data_sheets/SCHOTT%20POLY%20220-235%20Data%20Sheet%20US%200510.pdf):
NOCT 25'C
Power %/'C -0.45
30%/0.45% + 25'C = 92'C
Yup. Probably could have fried eggs on them.
LeafNot yetMy laptop sounded like a pachinko machine the day they started taking reservations:
http://home.europa.com/~garry/leafreservations.jpg
All were announcing they'd put in reservations.
VoltNot yetTrue, but there are plenty of hybrids out.
Roadster$109k
SNot yet
Good timing:
http://home.europa.com/~garry/Tesla_goes_public.jpg
With a little cash on hand, maybe they can ramp up production = economies of scale <> $109k/vehicle
E-planes are certainly years away, but I think they're coming. Maybe fuel cells for awhile, but definitely e-motors. Just too many advantages.
WAp08b9_EuU
DS-94 Fan (http://www.schuebeler-jets.com/index.php?option=com_content&task=view&id=102&Itemid=1), about 4KW per Kg power density.
http://www.electraflyer.com/gallery/videos/pure_electric.swf
Of course Artman's panels would have to put in some overtime to charge the full size version. :wink:
I want one of those. :biggrin:
At 40 degrees from horizontal, the panels will be 140 degrees from the plane of snow. They would still catch light at that angle. Yes, but only diffuse light. Nothing normal to the plane of the panel. So the question is what is the impact of diffuse light. I dunno. Per Artman's results there likely is some impact.
True, but there are plenty of hybrids out.Not Plug In Hybrids. Solar panels don't help regular hybrids at all, can't plug them in.
With a little cash on hand, maybe they can ramp up production = economies of scale <> $109k/vehicleThe cost is in the very large, custom cooled battery pack they're using (220 miles worth at full charge). The li ion laptop style batteries used by Tesla are already made in very large quantity.
I want one of those. :biggrin:Me too
OmCheeto
Jul4-10, 09:42 PM
Yes, but only diffuse light. Nothing normal to the plane of the panel. So the question is what is the impact of diffuse light. I dunno. Per Artman's results there likely is some impact
Two words: Skiers Tan:
http://www.skinet.com/ski/files/imagecache/gallery_image/_images/200909/Okemo_Goggle_Tan.jpg
Not Plug In Hybrids. Solar panels don't help regular hybrids at all, can't plug them in.
Hymotion can convert a Prius into a plug in hybrid in two hours. Why can't auto manufacturers do that? Is there a patent?
The cost is in the very large, custom cooled battery pack they're using (220 miles worth at full charge). The li ion laptop style batteries used by Tesla are already made in very large quantity.
Good observation. Why are we powering cars with batteries designed for laptops?
Two words: Skiers Tan:I always thought that was from being above 2/3 of the atmosphere at high elevation and loosing UV protection. I don't see skiers tans close to sea level no matter how much or how long the snow's on the ground, but maybe I'm not looking.
Hymotion can convert a Prius into a plug in hybrid in two hours. [...]Expensive toy I expect ($10k for the conversion?) Small battery, takes up the cargo room, etc.
http://www.popularmechanics.com/cars/news/4215681
Good observation. Why are we powering cars with batteries designed for laptops?Tesla was the first out of the gate 5-6 years ago. That's all that was available then.
mheslep
Jul15-10, 03:14 PM
Another price update (http://www.technologyreview.com/energy/24498/):
According to Harry Fleming, the CEO of Acro Energy Technologies in Oakdale, CA, these changes mean that the cost of a typical five-kilowatt rooftop solar system has dropped from $22,000 after state incentives are applied ($40,000 without them) to $16,000 in the last 18 months. Prices are expected to fall to $13,000 by the end of the year ($25,000 without incentives). "This is going to make solar a middle-class product," he says.i.e. $2.6 per peak Watt installed, with incentives. About 15 years payback given average US electric rates, even without SRECs.
Compared to last year's cost for a 8.8KW system in NJ:
[...]
Installed price $74,020
NJ Buy down rebate -$15,400
Subtotal $58,620
Permit fees $500
Subtotal $59,120
Federal Tax credit -$17,736
Total $41,384
Or $4.7 / peak Watt installed. That's a 44% cost decline in 2 years. I smell some kind of Moore's law effect here.
Sold our first SRECs for $665.04 each. We had 3 qualifying so we made $1995.12 (minus the 3% service charge to SRECTrade for selling them) for a total of $1935.26.
That's more than a year's worth of our old electric bills ($1800).
OmCheeto
Jul15-10, 03:38 PM
Yes, but only diffuse light. Nothing normal to the plane of the panel. So the question is what is the impact of diffuse light. I dunno. Per Artman's results there likely is some impact.
I am quite certain that I am reverting back to my nerd-like childhood.
Yesterday I did experiments on my solar panels whilst I could have been sitting at the beach.
a. Solar panel output is, not surprisingly, directly proportional to the face area of direct sunlight.
b. Nerdish fact that I'd forgotten: One must place a plane 60' out of perpendicular with the sun before area drops to 1/2.
c. at an angle of 40', Artman's panels would be absorbing 64.3% of the full energy reflected by the snow. (assuming an infinite backyard :wink:)
d. the albedo of my lawn is ~11.4%(8.76% output, fully shaded, @ ~56.3' angle from horizontal)
mheslep
Jul15-10, 04:20 PM
c. at an angle of 40', Artman's panels would be absorbing 64.3% of the full energy reflected by the snow.
There you are then; I suppose that explains the power boost w/ snow on the ground. That, and the cold temperatures which improve efficiency.
morris99
Jul22-10, 01:50 AM
It is definitely a good time to take a solar heater.Since they already announced that you need to use the things like green energy sources this would be the best time...
Solar hot water (http://www.coastalsolarsolutions.com.au/hot water systems.html)
We just signed up to increase insulation in our attic, replace our AC unit with a High performance HP that can heat effectively down to 30 below 0, and install a Heat Pump Domestic Water Heater with resistance backup. The insulation, higher efficiency HP equipment, and switch to Heat pump water heater should allow for zero impact on our electrical usage and allow us to eliminate most fossil fuel use in our our house (Oil fired boiler would remain as a backup, but probably won't ever run.) Basically, we are soon to be all solar powered.
This all happened as a result of the required energy audit that was performed as part of the solar installation process. There is an Energy Star NJ rebate program that will pay $3000 towards the changes and another NJ State program that will give a $10,000 no interest loan for 10 years.
Conservative payback estimates are for 20 years, I would guess closer to 10 years just from our oil savings potential and more efficient AC. The Acadia Air-to-Air Heat Pump is supposed to be almost as efficient as geothermal, without the cost for wells.
Acadia Heat Pump (http://www.gotohallowell.com/Acadia%E2%84%A2-Products/the-acadia-30.html)
marcos248272
Jul31-10, 09:43 AM
I have work in the big company and I'd like to propose to use this solar energy. Can you help how to make a proposal. Do you have a study that this is now a good time to switch into solar ? Please help.
russ_watters
Aug1-10, 08:18 PM
I have work in the big company and I'd like to propose to use this solar energy. Can you help how to make a proposal. Do you have a study that this is now a good time to switch into solar ? Please help. There is no blanket answer to that question. Every case must be considered on an individual basis.
shilpaam1
Aug2-10, 10:55 AM
Today the demand is so strong for electricity.We have to find other ways how to produce it.Solar Energy is the solution to this problem :)
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http://www.physicsforums.com/showthread.php?t=414380
I have work in the big company and I'd like to propose to use this solar energy. Can you help how to make a proposal. Do you have a study that this is now a good time to switch into solar ? Please help.
My experience is with residential solar, but I agree with Russ:
There is no blanket answer to that question. Every case must be considered on an individual basis.
I can tell you this though, incentives in the USA are probably the best they will be, compared to the future, right now. They are already dropping and not as high as when I installed my system, less than a year ago. My state is considering doing away with their rebate program because of the incentive value of the SREC program. Also, the SREC prices are going to drop as more and more people install solar arrays (the predicted price for an 2011 SREC in NJ is $600, currently, 2010 SREC's in NJ are selling for $664).
You more than likely won't "Switch to Solar." Solar is an intermittent energy source, it needs to be added as a redundant system to conventional energy sources, such as a power grid for photovoltaic or fossil fuel for solar thermal or have some form of energy storage (batteries, heated water tanks, etc). Also, arrays designed to offset 100% of industrial loads could be very large and very costly (my 8.8 kW array is 12'x56' and made of 40 panels and cost approximately $74,000). "Supplement with Solar" would be a better way of phrasing what you would more likely be proposing.
Today the demand is so strong for electricity.We have to find other ways how to produce it.Solar Energy is the solution to this problem :)
Solar helps offset the demand for electricity during daylight hours only. Say a house with a solar array produces 3x what it uses, you might think that the power grid could be reduced in capacity by that amount, but what about cloudy days? Or nighttime? What it does do is to reduce the amount of energy used to create the electricity that powers the grid during the hours they are producing. Solar helps, but it is not currently the solution.
The difference lies in cost benefit ratios.
A solar panel is by far the least economical in terms of power production. They can only generate at a 12% - 18% efficiency. The rest is lost to heat. Secondly, the amount of panels to create such a system would be in the nature of 1200 sqft. Lastly, they break. Not frequenly, but when they do it's very expensive to repair. And most systems are built with series circuits. If one goes down, they all go down.
I suggest that you do it understanding one thing, they are toys at best for now. It takes over 10 years for ROI, and by then you money and investment may be obsolete. The technology is such that it could very well be similar to computers. Some parts are interchangable, but the parts you need most are not.
Just my opinion. Alternative energy is what it says, alternative. Not replacement.
mheslep
Aug11-10, 07:59 PM
The difference lies in cost benefit ratios.
A solar panel is by far the least economical in terms of power production.By far? ~20 cents / kWh in sunny climates, large scale.
They can only generate at a 12% - 18% efficiency.17-22%
The rest is lost to heat.Some is lost to heat in the panel, some is reflected.
Lastly, they break. Not frequenly, but when they do it's very expensive to repair. And most systems are built with series circuits. If one goes down, they all go down. They're built with both: parallel chains of panels in series. And everything breaks.
I suggest that you do it understanding one thing, they are toys at best for now. It takes over 10 years for ROI, and by then you money and investment may be obsolete. The technology is such that it could very well be similar to computers. Some parts are interchangable, but the parts you need most are not.Flawed comparison. For products with low or zero cost to operate that generate a commodity (energy in this case) obsolescence doesn't matter much - the PVs still produce energy and cash flow.
Just my opinion. Alternative energy is what it says, alternative. Not replacement.Not yet. Five years, ten at the outside my guess PV probably becomes cost effective with coal up and until PV would cut into baseload needs, and that's a way to go yet.
http://www.1366tech.com/v2/company-mainmenu-1/reaching-coal-parity
Not yet. Five years, ten at the outside my guess PV probably becomes cost effective with coal up and until PV would cut into baseload needs, and that's a way to go yet.
Still, it will be alternative energy until storage becomes feasible.
I suggest that you do it understanding one thing, they are toys at best for now.Solar yard lights are toys. My solar array is an 8.8 kW generator that can produce enough kWh in 6.5 hrs of decent sun to power my house all day. Agreed solar is not for everyone, requires a lot of space for serious capacity, and the technology is still in its infancy, but I know people who have been using it for years and are very happy with the results and so far, so am I.
It takes over 10 years for ROI, and by then you money and investment may be obsolete. The technology is such that it could very well be similar to computers. Some parts are interchangable, but the parts you need most are not.There is zero ROI on using the grid for all of your electrical power. It's like renting a house instead of buying one. In ten years, my electricity will be free. True, the current technology will probably be obsolete, but the panel warranty is for twenty-five years and the panels are said to last for 40 years. That's long enough for me.
In fact because of incentives, my electricity is free now. The SREC sales are beginning to pay off my loan and my meter is 600 kWh to the negative.
mheslep
Aug13-10, 02:38 PM
Still, it will be alternative energy until storage becomes feasible. Well that depends on what you mean by alternative. Is wind alternative now, with a US capacity ~40 GW by the end of this year (highest in the world)? If you mean solar can't replace base load, 24/7 power without storage, I agree, but I suspect solar or wind can make up 20-30% of all US electrical power before the intermittent limitations of non-backed up solar/wind become intractable problems.
mheslep
Aug13-10, 02:43 PM
Artman -
Regarding breakage from hail/tree limb/kids baseball, do you have some idea of how to handle replacing the panel? I would think with all the structure and wiring in place that you could easily replace one panel yourself by accessing half a dozen fasteners.
russ_watters
Aug13-10, 04:03 PM
Well that depends on what you mean by alternative. Is wind alternative now, with a US capacity ~40 GW by the end of this year (highest in the world)? If you mean solar can't replace base load, 24/7 power without storage, I agree, but I suspect solar or wind can make up 20-30% of all US electrical power before the intermittent limitations of non-backed up solar/wind become intractable problems. Plus, since solar's peak output corresponds well with the peak grid load, the types of power plants used for for meeting the peak demand are the ones being displaced: and those are almost exclusively fossil fuel plants. So it dovetails nicely with the type of energy we most need to displace.
mheslep
Aug16-10, 07:47 PM
Artman - heads up:
http://www.technologyreview.com/energy/25963/
http://www.technologyreview.com/files/45091/fusion_x220.jpg
The power output of solar panels can be boosted by 10 percent just by applying a big transparent sticker to the front. Developed by a small startup called Genie Lens Technologies, the sticker is a polymer film embossed with microstructures that bend incoming sunlight. The result: the active materials in the panels absorb more light, and convert more of it into electricity.
[...]
Tests at the National Renewable Energy Laboratory showed that the film increases power output on average between 4 percent and 12.5 percent, with the best improvement under cloudy conditions, when incoming light is diffuse. Adding the film--either in the factory, which is optimal, or on solar panels already in use--increases the overall cost of solar panels by between 1 percent and 10 percent....
blimkie.k
Aug17-10, 02:27 PM
Artman, are you planning on testing out the transparent sticker?
If you do let me know how it works for you. My boss and I are planning on putting a 10 kw system on one of the companies properties. Were just waiting for the ontario micro fit application to pass. However they are saying the kwh rate might be lowered from 88 cents to 55 cents so we may not go ahead with it.
I would also have to check whether or not the panels we would be getting allready have the transparent sheet attached or not.
mheslep
Aug17-10, 04:17 PM
Were just waiting for the ontario micro fit application to pass. However they are saying the kwh rate might be lowered from 88 cents to 55 cents so we may not go ahead with it.
.Aside - electricity costs 88 cents per kilowatt hour in you area? Where may I ask? More to the point, why?
blimkie.k
Aug18-10, 10:03 AM
Aside - electricity costs 88 cents per kilowatt hour in you area? Where may I ask? More to the point, why?
Sorry, electricity only costs labout 8 or 9 cents a kw/h from Ontario Hydro. The rate they pay per kw/h with a 10 kw system or less is 80.2 for rooftop and 64.2 for ground mounted. It used to be 88 and they were gonna change it to 55 so they must have settled on those numbers.
http://microfit.powerauthority.on.ca/microFIT-Program-Rules/microFIT-Program-pricing/index.php
They lowered the ground mounted rate because its cheaper to do a ground mounted system because of extra engineering costs and possible roof reinforcement.
I believe they want to be able to say so many percent of Ontario's power comes from renewable energy so by paying people higher rates its compensating them for installing solar 10 systems for the government. If you build a system for microfit you are not harvesting power from it for your home it all goes to the grid. Unless you want to build a 20 kw system and have 10 for you and 10 for the grid.
Plus, since solar's peak output corresponds well with the peak grid load, the types of power plants used for for meeting the peak demand are the ones being displaced: and those are almost exclusively fossil fuel plants. So it dovetails nicely with the type of energy we most need to displace.This is very true. I did an HVAC project for a coal fired generating station that was used specifically for peak demand loads only.
blimkie.k and mheslep, more than likely, I won't be using the new sticker technology unless they pass legislation allowing me to sell back the excess energy at retail rates. There is some question as to longevity effects of the product (collection of dirt, scratching, discoloration, etc). However, I may consider it if switching to a heat-pump for heat makes my usage rise significantly, but it shouldn't, we hope, since we are also switching to a heat-pump water heater from a resistance electric type, increasing insulation, and the cooling efficiency is higher in the new heat-pump than in my old AC unit. Right now my solar array meets my house usage and a little over.
mheslep
Aug20-10, 06:10 PM
blimkie.k and mheslep, more than likely, I won't be using the new sticker technology unless they pass legislation allowing me to sell back the excess energy at retail rates. There is some question as to longevity effects of the product (collection of dirt, scratching, discoloration, etc). Yes, though there may be another side to the deterioration of the the sticky film, in that in protects the underlying surface panel. As an uncoated panel surface degrades from the elements you are stuck with it. With the film, maybe you replace it every ~7 years and return to a higher power output, cost basis permitting.
Yes, though there may be another side to the deterioration of the the sticky film, in that in protects the underlying surface panel. As an uncoated panel surface degrades from the elements you are stuck with it. With the film, maybe you replace it every ~7 years and return to a higher power output, cost basis permitting.Yeah, I thought that too. As a further layer of protection they may have some value, however, my panels are pretty tough. They are supposed to be able to withstand a 1" diameter projectile (like hail) at 40 mph. My main point is that I don't currently need it to meet my load, so the the extra cost isn't warranted. Should switching to a heat-pump push us over our electric production, it might be worth the investment.
mheslep
Aug21-10, 08:03 PM
Yeah, I thought that too. As a further layer of protection they may have some value, however, my panels are pretty tough. They are supposed to be able to withstand a 1" diameter projectile (like hail) at 40 mph.I'm not referring to breakage. We know that panel output degrades at something like 0.5-2% per year. Part of that may be due to a degradation of the panel surface from simple abrasion over time, I don't know, and maybe a simple polishing would remove that effect. But if not, in 15 years, if your system is down 30% from today (extreme worst case), will that still be sufficient?
I'm not referring to breakage. We know that panel output degrades at something like 0.5-2% per year. Part of that may be due to a degradation of the panel surface from simple abrasion over time, I don't know, and maybe a simple polishing would remove that effect. But if not, in 15 years, if your system is down 30% from today (extreme worst case), will that still be sufficient?I hadn't thought about that as a possibility. I'll ask my installer what he thinks about the film.
OmCheeto
Aug23-10, 08:55 PM
I hadn't thought about that as a possibility. I'll ask my installer what he thinks about the film.
I'd also contact the manufacturer to see if it would void your warranty. It strikes me that a film on glass would restrict heat flow. And you know how hot they get already.
And I doubt the reduction in panel efficiency over time has anything to do with the glass.
mheslep
Aug23-10, 10:16 PM
I'd also contact the manufacturer to see if it would void your warranty. It strikes me that a film on glass would restrict heat flow. And you know how hot they get already. Yes, if the film increases the infrared trap then maybe so. I doubt conductive heat flow is changed on the surface.
And I doubt the reduction in panel efficiency over time has anything to do with the glass.Well we know this much:
A dust layer of 4 grams per square meter can decrease solar power conversion by 40 percent, [...] To put this in perspective, dust deposition in Arizona is about 17 grams per square meter per month[...]I don't know how much transmission might be typically lost in the surface glass (or polymer?) over time, but obviously surface impairment matters.
http://www.scientificamerican.com/blog/post.cfm?id=self-cleaning-solar-panels-could-fi-2010-08-22
mugaliens
Aug25-10, 01:22 AM
Its interesting reading through this, as I designed a simple 4'x8' solar water heating system for my parent's place to be connected to a radiator in the basement. It's just supplemental, tied into the central air thermostat for activation. I tilted it to our latitude less 23 degrees for maximum influx during the winter.
Total cost is less than $400, not including labor. I estimate it'll take me about 20 hours for the install, but Dad's a little hesitant. I calculate it'll save him $400 a year, and the system should last 5 to 10 years with little or no maintenance.
One question I have is whether or not it needs a pump. Obviously, an appropriately-sized pump would increase its efficiency and heat output signficantly. My question is whether there's enough thermal expansion of heated water alone to power at least basic movement of the water. It sports about 100' of black hose in the collector, which is turned sideways, so only 4' tall. Entry is at the bottom and exit at the top, the reverse of the radiator. Line runs between the collector and the radiator are approximately 50', total, with standard 1/2" PVC piping. It's insulated only on the outside, as the purpose once inside is to heat, so if it heats, it heats.
Back to the question? Do I need a pump?
Mech_Engineer
Aug25-10, 10:06 AM
One question I have is whether or not it needs a pump. Obviously, an appropriately-sized pump would increase its efficiency and heat output signficantly. My question is whether there's enough thermal expansion of heated water alone to power at least basic movement of the water.
The only method of natural flow of the water would be through natural convection, and for that to work the heat source has to be below the radiator. Convection flow also wouldn't work very well in a piped system. Just get a small pump, they aren't THAT expensive...
If it's a closed loop you may need a few things. It should have a small expansion tank for expansion compensation, over-pressure/temperature relief valve, and freeze protection (propylene glycol or some other antifreeze), depending on possible temperatures at nights and cloudy days. These may not be required with a plastic pipe loop like you described, but you should consider them.
It may work without a pump by placing the return connection at the top of the panel and the inlet supply at the bottom, but in a closed loop I'm not sure it will help. You could try that first.
Since you describe this as supplemental, you could put in a solar powered DC pump to circulate the system only when the sun is out heating the water. That will add to the cost of the system, however it might make back enough in electric savings over non solar pump over time to pay it back, should you find a pump is necessary.
OmCheeto
Aug25-10, 11:09 AM
Back to the question? Do I need a pump?
Yes.
I did an experiment last summer using 1/2 inch 100' long black irrigation hose and a $22 bilge pump (http://www.cabelas.com/link-12/product/0001519012155a.shtml?cmCat=perf&rid=0987654321&cm_mmc=Performics-_-CSE-_-GoogleBaseUSA-_-0001519012155a&mr:trackingCode=DB6184C8-958E-DF11-A0C8-002219318F67&mr:referralID=NA). The system collected ~2.3 kwh of thermal energy in about 3.5 hours.
With no pump, you are just going to heat the water in the hose.
Some numbers:
flow: 1.6 gpm (~ 24 watts pump)
area of hose: 0.27 m^2
system fluid capacity: 32 gallons
max delta T / hr: 11 'F
To = 61.7'F
Tf = 90.9'F
Eek! Late for work. BBL.
OmCheeto
Aug26-10, 10:25 AM
.....to be connected to a radiator in the basement. ......
It sports about 100' of black hose in the collector......
You also have to remember that if the system is unpressurized, the weight of the water will draw a vacuum on your black hose. It had better be a robust hose, otherwise it will collapse.
(been there, done that. Black garden hose on the roof to the rubbermaid at ground level experiment. FAIL! Hose collapsed.)
mugaliens
Sep8-10, 01:29 AM
The only method of natural flow of the water would be through natural convection, and for that to work the heat source has to be below the radiator.
(slaps forhead) For some reason I was forgetting the fact the collector is about 4' above the radiator. You're right, of course. A pump is definately required. This brings to mind some sort of passive system, though, much like a hammer pump... heh-heh... Perhaps a waterfall pump?
Just get a small pump, they aren't THAT expensive...
I've checked with Home Depot and Lowes, but aside from sump (bilge) pumps, all I get from them are blank stares, so I went to two pool places, but their pumps are way too big and designed to be used in pump houses (they leak). I need a small, non-leaking pump.
Does anyone have any links to pumps between 0.1 gpm to 5 gpm with which they've worked, are cheap, and are long-term reliable?
Eek! Late for work. BBL.
Lol - thanks for the numbers! Between your factors on kW-hr, time, and area, I can calculate some better estimates for here, but I'd need to know some measure of your area's solar influx on a median basis, either annual, seasonal, or monthly basis (I don't need to know your area).
You also have to remember that if the system is unpressurized, the weight of the water will draw a vacuum on your black hose. It had better be a robust hose, otherwise it will collapse.
(been there, done that. Black garden hose on the roof to the rubbermaid at ground level experiment. FAIL! Hose collapsed.)
Only about 4' to 6' of head. Shouldn't collapse a heavy-duty rubber garden hose (which I'm using for the collector). Besides, most of these systems are pressurized. I won't need much. The gas/water/radiator system in my home in Germany was pressurized at about 35 psi, but the green range was something like 20 to 45 psi. The landlord said "keep it around 30." I'd increase system pressure by means of the attached faucet to 35 psi, then check it once a month. About once every eight months I'd use the faucet, and walla!
Question is - where'd missing water go?? ! I never saw any leaks... Perhaps several micro-leaks which simply evaporated before they became puddles?
Anyway, this very modern and very efficient system did have its pump in the closet, along with a drain. I never saw a drop of water which might go down the drain, but that re-raises the question of microleaks. Who's a plumbing expert, here? Are microleaks (those which leak, but evaporate before they drip or puddle) common? I know such leaks can be avoided altogether in plumbing via well-executed materials and construction techniques. I also know of certain leak-sump systems which are effectively closed, but they're not cheap. Other, more exotic systems involving ferrofluids make effective zero-breach seals, but only up to between 3 and 4 psi (http://en.wikipedia.org/wiki/Ferrofluidic_seals).
Is there any way I can seal this system in toto, without resorting to such exotic measures? Perhaps by enclosing the pump in a pressurized environment equaling that of the fluid pressure? Symbiotic stacks* would do, but may lead to the encroachment of fluid on the pump body, and pose serious cooling issues with most pumps, which are air-cooled.
Pump supply system pressure itself is used to provide fluid to a a simple pipe column (or same-head air pressure vessel) which maintains pump housing pressure, thereby equaling the exit pressure at the bearings. Still - how does one continue to air-cool the pump? I'm thinking one might need a second system, a cooling system for the pump housing, but then... How does one seal that?
OmCheeto
Sep10-10, 10:22 AM
(slaps forhead) For some reason I was forgetting the fact the collector is about 4' above the radiator. You're right, of course. A pump is definately required. This brings to mind some sort of passive system, though, much like a hammer pump... heh-heh... Perhaps a waterfall pump?
I've checked with Home Depot and Lowes, but aside from sump (bilge) pumps, all I get from them are blank stares, so I went to two pool places, but their pumps are way too big and designed to be used in pump houses (they leak). I need a small, non-leaking pump.
Does anyone have any links to pumps between 0.1 gpm to 5 gpm with which they've worked, are cheap, and are long-term reliable?
Lol - thanks for the numbers! Between your factors on kW-hr, time, and area, I can calculate some better estimates for here, but I'd need to know some measure of your area's solar influx on a median basis, either annual, seasonal, or monthly basis (I don't need to know your area).
Insolation, kWh/m²/day 1.15 1.99 3.01 4.05 4.89 5.27 5.59 5.08 3.92 2.34 1.34 1.01
January through December
Only about 4' to 6' of head. Shouldn't collapse a heavy-duty rubber garden hose (which I'm using for the collector). Besides, most of these systems are pressurized.
I've changed my mind about your hose collapsing.
My prototype had the pump at ground level.
If your system is open to atmosphere above the level of the collector hose, then it shouldn't collapse. And I can think of no good reason why your system should be pressurized, other than by the head provided by your expansion tank. And that's where I'd put my pump.
I would answer your other questions, but I'm late for work again. :grumpy:
mheslep
Sep10-10, 02:49 PM
Insolation, kWh/m²/day 1.15 1.99 3.01 4.05 4.89 5.27 5.59 5.08 3.92 2.34 1.34 1.01
January through December
In NJ? Tilted to latitude or flat? There's a difference in result.
OmCheeto
Sep10-10, 09:53 PM
In NJ? Tilted to latitude or flat? There's a difference in result.
Jersey? I'm an Orygoonian. You've obviously mixed me up with Artman.
And what the hell is MHD?
Astronuc
Oct30-10, 08:11 AM
Solar Power Projects Face Potential Hurdles
http://www.nytimes.com/2010/10/29/business/energy-environment/29solar.html
BrightSource Energy has a $2 billion project in the Mojave desert in S. California. The project, Ivanpah, is the first large-scale solar thermal power plant to be built in the United States in two decades. Apparently this is one of nine projects planned for California and Arizona. However, they seem to need substantial financial support from the federal government in the form of loan guarantees, tax credits and/or subsidies.
And even then the economics is still questionable.
The competitiveness of large-scale solar thermal plants in California also depends on the cost of natural gas, the state’s dominant source of electricity. According to Mr. Bullard, gas-fueled plants can produce electricity for about 10 cents a kilowatt-hour. After including the government subsidies, solar thermal plants are expected to generate power at 13 to 17 cents a kilowatt-hour, which the industry says is close enough in price to be competitive.
. . . .
Tessera Solar, based in Houston, has received federal approval to build two solar power plants that together would generate nearly 1,400 megawatts from 54,900 large solar dishes installed on 10,000 acres of government land. The company is seeking loan guarantees to help finance more than $4.6 billion in construction costs.
. . . .
mheslep
Oct31-10, 05:13 PM
Solar Power Projects Face Potential Hurdles
http://www.nytimes.com/2010/10/29/business/energy-environment/29solar.html
BrightSource Energy has a $2 billion project in the Mojave desert in S. California. The project, Ivanpah, is the first large-scale solar thermal power plant to be built in the United States in two decades. Apparently this is one of nine projects planned for California and Arizona. However, they seem to need substantial financial support from the federal government in the form of loan guarantees, tax credits and/or subsidies.
And even then the economics is still questionable.
I find it difficult to ever cut the government involvement away from energy projects, so that one can see at last the thing just for what it is. Yes the solar projects get subsidies, but then a major recurring cost for solar plants is property taxes - the government giveth and the government taketh away. Property taxes are less out the middle of nowhere, but that then requires expensive transmission, once again requiring negotiation with every town, country, and state government the lines pass through.
knickick
Nov13-10, 09:38 PM
Hi Artman. I think this will help you in your question http://www.sunpowerport.com.
Time for another report. With Winter fast approaching and the days getting shorter, I've noticed a definite decline in energy production from the system. On what we would call a "Screaming Sunny Day" which is a cloudless, haze-less day our production is only about 30 (down almost 20 from Spring and Summer). It still peaks at a decent level during the height of the day about 7.5 kW to 8.0 kW out of 8.8 kW design.
The system has produced overall 10.582 MWh for around 11 months of operation (Started mid Jan) and the design was for 11.000 MWh per year. So, with 1 month still to go, I think we will finish above design levels.
SREC sales have been good at around $600 as well.
One of the big benefits that I have noticed is that we could live more comfortably without it costing us more money for energy. We ran our AC on days that were a bit too humid for comfort in the Summer where we would have maybe just used fans before, and we've been using electric space heaters now to supplement the fossil fuel heat. Our meter is still about 750 kWh below 0.
Small digression: I wonder if the EV/PHEV makers will eventually accommodate direct DC battery charging given the proliferation of residential solar panels. Avoiding the DC/AC inversion improves efficiency, and certainly reduces capital cost if the the panels were dedicated to only DC loads so that no inverted is required.
Fish4Fun
Dec11-10, 12:49 PM
Small digression: I wonder if the EV/PHEV makers will eventually accommodate direct DC battery charging given the proliferation of residential solar panels. Avoiding the DC/AC inversion improves efficiency, and certainly reduces capital cost if the the panels were dedicated to only DC loads so that no inverted is required.
Really it has more to do with the Solar installation & the car. If there were a "standard" battery voltage (12V, 24V, 36V, ..... , 275V, 375V) then the task might be simply a matter of matching your grid tied inverter input voltage to your car's charging voltage, but you would still require a "charge controller" to regulate the current into your car's batteries, and really, an AC to DC charger is not much more or less efficient than a DC to DC charge controller.
Artman,
I find your story and this thread fascinating. I have been researching Renewable Energy for quite some time, but have never been able to make Solar PV work on paper. The Federal Tax Credit of 30% combined with my State's (NC) $10,500 Tax Credit Maximum are not quite as attractive as NJ's SRECs. NC has started a 10% Renewable Energy Tax paid by all consumers of Grid Power, and created mandates for the percentage of grid power that has to come from renewable sources, but there are as of yet, no real incentives to consumers other than what local POCOs might offer. Net Metering is available only if the POCO decides to offer it, and the State treats renewable energy savings as income! By law, only 20% of any Renewable Energy Improvements are added to the property tax assessment; however, the property tax assessment process is so subjective in my area that the State law is meaningless.
The POCO in my immediate area will grudgingly allow you to sell excess power back to the grid only @ wholesale. Wholesale prices are to be determined by them, but the excess cannot exceed your monthly bill. You of course have to pay for all of the equipment/inspections/permits etc, and there is a monthly maintenance fee for having the equipment you purchased connected to their lines.
So, for ME the "Time is Not right" for solar PV. Essentially left to stand on it's own merits, as it is here in NC, the "break even point" is ridiculous. Assuming I installed a 20kW PV array, and could average 60kW a day, and assuming I could actually use 20kW's of that power rather than sell it back to the grid, I would "save" ~$60/month (our current rate is $0.09675/kWh) off my power bill. I would also receive "credit" for the surplus ~1200kWh/month @ ~$0.04/kWh = $48, for a total "savings" of $108/month.
If I could install the 20kW array for $5/W (I don't think this can currently be done), I would have an investment of $100,000. Assuming I could get 0% 15 year money, and received $30,000 in Federal Tax Credits and Managed to get ALL of the $10,500 State Tax Credits (virtually impossible), I would have $330.56 a month loan service on the $59,500 minus my $108 "savings", for a net loss of $222.56/month, or $40,600 over the course of 15 years. 31 years after the initial 15 year period (46 years total), the system would have "paid for itself". Obviously this bleak outlook would improve if electricity prices doubled or tripled over the term.
Current pricing on solar arrays is largely a function of "sub prime" silicone wafers purchased from the semiconductor industry. With modern IC makers' emphasis on higher and higher quality wafers, the price of "sub prime" keeps falling, and with it the price of solar cells. I think this trend will continue for some time into the future unless the growing of silicone crystals makes a giant leap forward, or the demand for sub prime wafers outstrips the secondary market. If the retail price /kWh reaches ~$0.25, and the cost of solar arrays drops to ~$2/Installed Watt, Solar becomes viable w/o subsidies.
Solar PV that is economically viable w/o subsidies is what I would truly like to see, sadly it pretty much requires electricity prices to double or triple. Right now, the only Home Owner Renewable Energy that has the potential to stand on its own is Solar Heat. I can make a good case for solar collectors & storage paying for itself in 10 years or less. When we built our house we oriented it with a 72ft x 25ft roof pointing due South. I had a heat exchanger installed in the HVAC system, and I have plans to install a solar collector array and a 2000 gallon Hot Water storage tank as soon as I have an extra $10,000. The system should supply 100% of DHW (Domestic Hot Water), 100% of the heat energy for my Hot Tub and >50% of our Winter Household Heat demand.
Our baseline consumption is 2200kWh/month, an estimated 1200kWh of which goes to generating heat. @ $0.10/kWh this is $120/month. (Obviously most of the savings is in the Winter). $10,000 @ 4% for 10 years ~ $100/month, leaving me +$20/month before any tax credits. Obviously a hot tub is a "luxury item" that makes the collection of heat a bit more viable (~$50/month average) in my case, but home heating alone in many areas may well make such a system worthwhile.
You mentioned looking into a heat pump, perhaps you should consider the addition of a solar heat collection system to go along with your solar PV array. If you augmented your heat pump with the solar hot water you could save as much as 1kW/M^2 of collector area (actual savings more likely ~500W/M^2). Evacuated Tube arrays cost ~$500/M^2 + Storage Tanks + Plumbing. Assuming 500W usable heat/M^2, this places the cost of solar heat @ ~$2/Installed Watt. That's a bargain!
If you went with a "Water Source" heat pump that used the solar heated water for its source in the Winter, and a well for its source in the summer, you could really save on heat/AC. Using 65F water for AC and 80F+ water for heat would make your heat pump SUPER efficient!
Sorry for the rambling, I just really enjoyed reading through this thread, and I obviously had a lot to say.... Again, congrats on your amazing story; I only wish my State were willing to pay me to put in a solar array! With the Tax Credits and other incentives available to you in NJ, I think you made a great investment! I look forward to reading your updates in the future.
Fish
mheslep
Dec11-10, 06:51 PM
Really it has more to do with the Solar installation & the car. If there were a "standard" battery voltage (12V, 24V, 36V, ..... , 275V, 375V) then the task might be simply a matter of matching your grid tied inverter input voltage to your car's charging voltage, but you would still require a "charge controller" to regulate the current into your car's batteries, and really, an AC to DC charger is not much more or less efficient than a DC to DC charge controller.
Yes I suppose the scheme I suggest only works with panels dedicated solely to vehicle charging, as there always has to be a converter in the loop somewhere, whether DC/AC or DC/DC. In the case of dedicate panels, there need be only one converter, the one that will always come with the EV. Still that would be less expensive than charging a EV from a traditional solar system like Artman's here, which would be: panels -> DC/AC inverter -> house circuit -> car AC/DC converter -> car battery.
Fish4Fun
Dec12-10, 12:27 AM
mheslep,
At the risk of hi-jacking this thread, AND arguing with someone who has invested over 2k posts on this forum, I would like to suggest that one of the "features" of EV's like the "Tesla" is the ability to charge "anywhere there is power". I cannot think of any way designing the car to be charged directly by a solar array would improve marketability of the vehicle.
The single largest problem I see with directly charging an EV from a solar array is the loss of any energy credits associate with the array (these are typically garnered from the inverter meter). The second major problem is that unless you primarily drive at night and sleep during the day, charging your car all day is not really practical. Ignoring these points, for the sake of argument, here is some data associate with the charging of the Tesla EV:
Figures for the Tesla taken from their website:
Battery Pack Specifications:
Nominal Pack Voltage: 375V
Storage Capacity: 53kWh (141 1/3 AH)
Maximum Discharge Rate: 200kW (533 1/3A)
(Taken from http://webarchive.teslamotors.com/display_data/TeslaRoadsterBatterySystem.pdf )
The High Power Wall Charger Specifications are as follows:
Maximum Current: 70A
Voltage: 208-240V, Single phase
Maximum Power: 16.8 kW
(Taken from: http://www.teslamotors.com/goelectric/charging/high-power-wall-connector )
A full charge is the energy equivalent of ~ 8 liters of gasoline, in today's market we will call that about $8. The charging time of the charger @ 16.8kW input is 4 hours (67.2kWh). We must assume the charging efficiency is 53kWh/67.2kWh = 78.9% and this efficiency likely represents a 88.8% converter efficiency and a 88.8% charging efficiency. At $0.10/kWh 67.2kWh = $6.72. I do understand your desire to cut the inverter out of the charging loop, but a grid tie inverter should be pretty close to 90% efficient, this would make the overall charging efficiency 78.9% * 90% = 71%.
Assuming 20k miles per year driving and the stated 245 miles/charge ~82 "full charges" would be required (obviously most charges would be "partial", and charging would occur daily) 82 * 67.2kWh = 5.5MWh/year. @ $0.10/kWh this = ~$550. The difference between 78.9% efficiency (a theoretical DC charge Controller + Battery Losses) and 71% efficient (Grid Inverter + Charger + battery Losses) would only amount to ($550/.71) - ($550/.789) = $77.56/Year. (Actually this number is a bit high, I should have used 53kWh, but the difference is trivial).
Compared to battery life (pessimistically 6 months, optimistically 3-5 years), any energy savings associate with charging would appear completely moot. @ ~$36,000, even a 36 year life span would place the cost of the batteries at almost twice the cost of charging.
Anyway, if you would like to continue this discussion, let's open a new thread to fully explore it rather than hijacking this very excellent thread on a Solar Installation. I certainly mean no disrespect to the thread starter, nor you.
Fish
mheslep
Dec12-10, 05:35 PM
mheslep,
At the risk of hi-jacking this thread, AND arguing with someone who has invested over 2k posts on this forum, I would like to suggest that one of the "features" of EV's like the "Tesla" is the ability to charge "anywhere there is power". I cannot think of any way designing the car to be charged directly by a solar array would improve marketability of the vehicle.
The single largest problem I see with directly charging an EV from a solar array is the loss of any energy credits associate with the array (these are typically garnered from the inverter meter).Yes, maybe so, but that's bookkeeping of subsidies problem, not a technical problem.
The second major problem is that unless you primarily drive at night and sleep during the day, charging your car all day is not really practical. Ignoring these points, for the sake of argument, here is some data associate with the charging of the Tesla EV:
Figures for the Tesla taken from their website:
Battery Pack Specifications:
Nominal Pack Voltage: 375V
Storage Capacity: 53kWh (141 1/3 AH)
Maximum Discharge Rate: 200kW (533 1/3A)
(Taken from http://webarchive.teslamotors.com/display_data/TeslaRoadsterBatterySystem.pdf )
The High Power Wall Charger Specifications are as follows:
Maximum Current: 70A
Voltage: 208-240V, Single phase
Maximum Power: 16.8 kW
(Taken from: http://www.teslamotors.com/goelectric/charging/high-power-wall-connector )
A full charge is the energy equivalent of ~ 8 liters of gasoline, in today's market we will call that about $8. The charging time of the charger @ 16.8kW input is 4 hours (67.2kWh). We must assume the charging efficiency is 53kWh/67.2kWh = 78.9% and this efficiency likely represents a 88.8% converter efficiency and a 88.8% charging efficiency. At $0.10/kWh 67.2kWh = $6.72. I do understand your desire to cut the inverter out of the charging loop, but a grid tie inverter should be pretty close to 90% efficient, this would make the overall charging efficiency 78.9% * 90% = 71%.
Assuming 20k miles per year driving and the stated 245 miles/charge ~82 "full charges" would be required (obviously most charges would be "partial", and charging would occur daily) 82 * 67.2kWh = 5.5MWh/year. @ $0.10/kWh this = ~$550. The difference between 78.9% efficiency (a theoretical DC charge Controller + Battery Losses) and 71% efficient (Grid Inverter + Charger + battery Losses) would only amount to ($550/.71) - ($550/.789) = $77.56/Year. (Actually this number is a bit high, I should have used 53kWh, but the difference is trivial).
Compared to battery life (pessimistically 6 months, optimistically 3-5 years), any energy savings associate with charging would appear completely moot. @ ~$36,000, even a 36 year life span would place the cost of the batteries at almost twice the cost of charging.Yes I grant that the efficiency savings is small. As above, my point is that the solar array to charge a DC charged EV can completely do without the capital cost of an inverter at all. There are already pilot solar arrays so dedicated - Google has solar arrays to charge pilot EVs in its parking lot. Given all EVs charge off AC power right now, that means Google must have expensed an inverter - uselessly if the EV's could also handle a DC charge.
Artman: Great project analysis and reports....
Time for another report. With Winter fast approaching and the days getting shorter, I've noticed a definite decline in energy production from the system. On what we would call a "Screaming Sunny Day" which is a cloudless, haze-less day our production is only about 30 (down almost 20 from Spring and Summer). It still peaks at a decent level during the height of the day about 7.5 kW to 8.0 kW out of 8.8 kW design.
Is this to be expected...or does it suggest a slightly different orientation of the panels might have been better.....or neither???
Artman: Great project analysis and reports....
Thanks. I'm trying to keep you guys up to date.
Is this to be expected...or does it suggest a slightly different orientation of the panels might have been better.....or neither???Yes, it was expected. Our panel angle was around 40 deg, which is close to our Latitude, making it optimized for Spring and Fall. We had a cloudy fall so we've been using our reserve kW from the meter (We've dropped from around negative 1000 to around negative 500 in two months).
I went out and checked our sunlight at off-peak hours and I noticed that the panels are getting a lot of shade from tree branches early and late in the day with the shallow angle of the sun right now. So I imagine until we get past the Solstice our ratings will just continue to drop a bit. Still, overall the system built up a nice reserve prior to heading into winter and we're hanging in there enough on production to allow us to use electric unit heaters to supplement for comfort heating.
Fish4Fun, too bad about NC programs. They don't sound very conducive to putting in a system.
The single largest problem I see with directly charging an EV from a solar array is the loss of any energy credits associate with the array (these are typically garnered from the inverter meter).
This is not the case with us. We are under 10 kW at which point our production is estimated. We also have a commercial meter as part of the system in addition to the inverter so a reading can be taken of that if the Authorities change their method of accounting.
Fish4: (our current rate is $0.09675/kWh)
You sure that's the total cost about 10 cents per KWH, not just "distribution" or "supply" ???
When I looked at homes in New Bern, almost 2 yrs ago, I found the local electric rates were like NJ...about 18 cents per KWH....
gmax137
Dec30-10, 06:57 PM
Oddly, just as I was reading the previous post, my wife handed me our current electric bill. Here in Connecticut, it's 13 cents for generation and 7 cents for distribution.
mheslep
Dec30-10, 07:20 PM
Oddly, just as I was reading the previous post, my wife handed me our current electric bill. Here in Connecticut, it's 13 cents for generation and 7 cents for distribution.Yep. What is going on up there? Virginia rates in cents/kwh are residential:10.6, commercial:7.5. and industrial:6.6. Connecticut's industrial rate is 2.15X higher than Va. How can Connecticut expect to have any kind of job base with power that expensive? I suppose having that new gas fired plant blow up (http://www.elp.com/index/display/article-display/3421342111/articles/electric-light-power/generation/natural-gas/2010/02/Deadly_explosion_hits_Connecticut_gas_fired_power_ plant_.html) back in Feb. didn't help.
http://www.eia.doe.gov/electricity/epm/table5_6_a.html
Edit: more curious. Since 2000 Virginia's power company Dominion Power bought and operates the last two reactors at Millstone. (http://www.eia.doe.gov/cneaf/nuclear/state_profiles/connecticut/ct.html)
gmax137
Dec30-10, 07:30 PM
...I suppose having that new gas fired plant blow up (http://www.elp.com/index/display/article-display/3421342111/articles/electric-light-power/generation/natural-gas/2010/02/Deadly_explosion_hits_Connecticut_gas_fired_power_ plant_.html) back in Feb. didn't help.
Well, the rates were high before that, I'm pretty sure they've been high for years.
http://www.eia.doe.gov/electricity/epm/table5_6_a.html
Thanks, that's an interesting table. I'd like to know more about the reasons behind the variation from state to state, but that should be another thread.
mheslep
Dec31-10, 08:38 PM
Interesting: this source shows New Jersey as the top ranked state for residential solar investment.
http://solarpowerrocks.com/reports/spr-report-card-2010-part-2-state-by-state-summary-grades/
Price of solar continues to fall sharply. PV silicon panels per Watt, not corrected for inflation.
http://www.solarbuzz.com/Photos/moduleprices11-1.jpg
Year: $price, (% from prior yr)
Jan 2011: 3.38 (-13.7%)
Jan 2010: 3.92 (-15.6%)
Jan 2009: 4.65 (-2.3%)
Jan 2008: 4.76
russ_watters
Jan4-11, 10:36 PM
"Continues to fall sharply" seems a little misleading to me. It looks to me like from that graph it went up for about 3 years in the mid-2000s. While I'm sure there is a general downward trend, it probably also reflects economic conditions, so I'd be shocked if the last two to three years of sharp downward trend continued.
"Continues to fall sharply" seems a little misleading to me. It looks to me like from that graph it went up for about 3 years in the mid-2000s. While I'm sure there is a general downward trend, it probably also reflects economic conditions, so I'd be shocked if the last two to three years of sharp downward trend continued.Maybe. But then looking at the full ten year period I'd be surprised if the -37% per decade declining trend didn't continue (5.4-3.4)/5.4. Also those prices are not corrected for inflation. So the 2001 price in 2011 dolars is ~$6.8/W (http://data.bls.gov/cgi-bin/cpicalc.pl?cost1=5.4&year1=2000&year2=2010), giving a 50% per decade trend in real terms.
russ_watters
Jan5-11, 06:30 PM
Maybe. But then looking at the full ten year period I'd be surprised if the -37% per decade declining trend didn't continue (5.4-3.4)/5.4. Also those prices are not corrected for inflation. So the 2001 price in 2011 dolars is ~$6.8/W (http://data.bls.gov/cgi-bin/cpicalc.pl?cost1=5.4&year1=2000&year2=2010), giving a 50% per decade trend in real terms. So a ten year interval is more useful than the 3 year interval from your previous post? Would the 10 year peariod from 1995-2005 give a similar figure? What was the decrease the previous decade? How long has this trend been going on?
I just get very antsy seeing stats and predictions like this because it's been an MO for enviro activists and bad reporters to misuse statistics to imply unlikely and even impossible advances in wind and solar power growth.....not so prevalent as it used to be as those trends have mostly broken, but the internet it still littered with bad claims about advances in solar and wind. When a market - any market - is tiny and changing so fast, it is easy to get caught-up in misleading or even meaningless percentage changes. For example: “Solar is now the fastest growing energy industry in the U.S., employing nearly 100,000 Americans and generating billions of dollars of economic growth for our economy,” President and CEO of the SEIA Rhone Resch writes.
By 2015, as you can see in the graph above, the solar industry is expected to grow several times over, perhaps even reaching a total of 10 GW of installed solar power capacity, enough to power 2 million homes.
“We can install so much solar energy that we will eliminate the need for any new coal or nuclear power plants in the U.S. ever again,” Resch writes. http://cleantechnica.com/2010/10/13/solar-power-blowing-up-in-the-united-states/
Just please don't get caught-up in the same type of fallacy.
Here's an article from August of 2008 that seems to have accurately predicted the past three years of drop and also predicts we've already seen most of the drop expected by 2015 (ie, the next 5 years won't see anywhere near the drop of the last 3). And it may even level off by 2015
FOR 40 years or so, the price of solar panels fell steadily, as volumes grew and technology improved. But in 2004 Germany enormously increased subsidies for solar power, prompting a surge in demand. The supply of pure silicon, the main component of most solar cells, did not keep pace. Its price rose from $25 a kilogram in 2003 to as much as $250 this year, abruptly halting the downward march in the price of panels. If making energy from sunlight is ever to become as cheap as burning fossil fuels, the price of silicon will have to fall.
New Energy Finance, a research firm, expects the output of silicon for the solar industry almost to double next year. It has asked big buyers and sellers what prices they have agreed on this year for silicon to be delivered in the future. The responses suggest that participants in the industry expect prices to fall by more than 40% next year, and over 70% by 2015 (see chart). http://www.economist.com/node/12010071?story_id=12010071
The accompanying graph shows the following silicon prices ($/kg):
2008 $200
2009 $120 -40%
2010 $90 -25%
2011 $80 -11%
2012 $70 -12%
2013 $60 -14%
2014 $55 -8%
2015 $53 -2%
Now I'm not sure what fraction of the cost is represented by the commodity but if the above ratios hold, it could be 40-50%. That means the overall drop in panel prices from 2010 to 2015 would be 13-17%, with prices going pretty much flat after that.
So a ten year interval is more useful than the 3 year interval from your previous post? Yes. That's >3x more data over time, so we have more a similarly increased confidence in its prediction power, but of course no guarantee that the trend will continue. Would the 10 year peariod from 1995-2005 give a similar figure? What was the decrease the previous decade? How long has this trend been going on? I don't have older data from the same source, but there is this data set (http://www.1366tech.com/v2/) going back to the 70s from a long time PV technology (not a manufacturer) researcher/MIT prof and entrepreneur, PV energy cost not power this time. He also presented the information in Congressional testimony:
http://i52.tinypic.com/nz2jwp.giff
I just get very antsy seeing stats and predictions like this because it's been an MO for enviro activists and bad reporters to misuse statistics to imply unlikely and even impossible advances in wind and solar power growth.....not so prevalent as it used to be as those trends have mostly broken, but the internet it still littered with bad claims about advances in solar and wind. When a market - any market - is tiny and changing so fast, it is easy to get caught-up in misleading or even meaningless percentage changes.I agree there's hype surrounding the business and claims warrant skepticism. The solarbuzz industry survey is the best (ie oldest, continuous, best known) I know of; I'm certainly open to counter data.
Here's an article from August of 2008 that seems to have accurately predicted the past three years of drop and also predicts we've already seen most of the drop expected by 2015 (ie, the next 5 years won't see anywhere near the drop of the last 3). And it may even level off by 2015
http://www.economist.com/node/12010071?story_id=12010071
Thanks, will look at that later.
Edit: take another look at the article. The Si fall is from a bubble, caused by the German PV demand driven by their subsidies that kicked in 2004 which caught production unprepared. The year before, in 2003, the price of Si was $25/kg.
The accompanying graph shows the following silicon prices ($/kg):
2008 $200
2009 $120 -40%
2010 $90 -25%
2011 $80 -11%
2012 $70 -12%
2013 $60 -14%
2014 $55 -8%
2015 $53 -2%
Now I'm not sure what fraction of the cost is represented by the commodity but if the above ratios hold, it could be 40-50%. That means the overall drop in panel prices from 2010 to 2015 would be 13-17%, with prices going pretty much flat after that.Yes I read from some of the same sources that for Si PV panels, PV grade Si currently accounts for ~half of the cost of the total panel; perhaps it used to be much more. It's not clear from the Economist chart what form of Si they are pricing; semiconductors require very high (~99.9%) purity. Many of the historical technology improvements also correlate with the drop in price. Several of those impact the amount of Si required, or just increase PV cell efficiency (2X increase over ~20 years). For instance, the stock Si shipped to a PV mfn comes in the form of expensive high purity Si ingots (http://upload.wikimedia.org/wikipedia/commons/thumb/5/59/Polycrystalline_silicon_rod.jpg/220px-Polycrystalline_silicon_rod.jpg). The PV mfn then cut the ingots into PV cell wafers, wasting a substantial amount of Si as dust which can not be economically reused. Then came ultra thin wire saws (see the above PV energy chart), making the wafer cuts much more efficient, which would allow drop in the kWh per panel price, completely independent of stock Si prices.
On the the Cleantechnica piece on SEIA:
“Solar is now the fastest growing energy industry in the U.S., employing nearly 100,000 Americans and generating billions of dollars of economic growth for our economy,” President and CEO of the SEIA Rhone Resch writes.Don't know about fastest growing. Could be. The revenue in the billions must be correct, as the US market 2010 was market was that large in just panels alone, not including the fabrication machinery sales led by US giant Advanced Materials.
By 2015, as you can see in the graph above, the solar industry is expected to grow several times over, perhaps even reaching a total of 10 GW of installed solar power capacity, I assume this refers to solar PV only, which is now ~1GWp total in the US, as solar PV plus thermal was already 8GW total a couple years ago. That requires a ~35% annual US installation growth rate to reach 10GWp cumulative in five years from the current ~1GWp. Given the list of utility scale PV plants already planned or under construction (http://en.wikipedia.org/wiki/List_of_photovoltaic_power_stations#Large_systems_ in_planning_or_under_construction), along with residentials like Artman's here, I'd say 10GWp total by 2015 is likely.
enough to power 2 million homes.Bogus. Not by solar alone, even if source is concentrated solar thermal with storage.
“We can install so much solar energy that we will eliminate the need for any new coal or nuclear power plants in the U.S. ever again,” Resch writesBogus x 2.
Bogus x 2
Yup.
Solar is currently only a supplement and can reduce the need for auxiliary coal plant operation. If enough solar installations are placed in operation it may prolong the time until the need to add more nuclear or coal generating plants, but the grid needs to meet its demand, even at night and cloudy days.
As of today our system is at 11,100 kWh and has exceeded design expectations by 100 kWh for the year. Still a few weeks left to generate before the anniversary of putting it online. We went online on the 21st of January 2010.
It's been 6 months - does anyone have any updated info?
It's been 6 months - does anyone have any updated info?
He's probably partying with all his energy savings money. But yea. Update please. :biggrin:
David Morrow
Jul10-11, 05:06 PM
Hello all, first time here, am doing a research paper for undergrad degree. Renewable energy, here is my question, The power out of a small pv inverter is suppose to push its energy onto the grid past the net meter, how does this current get past the first step down transformer if that transformer has 7200 V coming into it from the other side?
mheslep
Jul10-11, 06:45 PM
Hello all, first time here, am doing a research paper for undergrad degree. Renewable energy, here is my question, The power out of a small pv inverter is suppose to push its energy onto the grid past the net meter, how does this current get past the first step down transformer if that transformer has 7200 V coming into it from the other side?The transformer can move energy in both directions. That is, the low voltage from you inverter is eventually stepped up the the HV side of transformer.
Wow, more than 6 months. Sorry about that. Time for an update.
It's been about a year and six months since we went solar. A few new things have happened: the electric company zeroed our meter on the anniversary date for our connection or there abouts. It's hard to tell from the records, we check our meter daily, but we apparently hooked up at a good time because we were nearly at zero then anyway, which is what you want. We were bouncing back and forth across the zero line for a few days.
We also put in a heat pump (more on that in a later post) and a heat pump water heater, and more insulation, so our house is all electric currently, with oil heat backup. With the addition of the more efficient HP and the HP H2O heater, we've been still gaining ground as we did last year through the year down at about 520 kWh below zero. Not bad, and comfort is great.
Got to go, more later.
Sorry it's been so long. :redface:
Wow, more than 6 months. Sorry about that. Time for an update.
It's been about a year and six months since we went solar. A few new things have happened: the electric company zeroed our meter on the anniversary date for our connection or there abouts. It's hard to tell from the records, we check our meter daily, but we apparently hooked up at a good time because we were nearly at zero then anyway, which is what you want. We were bouncing back and forth across the zero line for a few days.
We also put in a heat pump (more on that in a later post) and a heat pump water heater, and more insulation, so our house is all electric currently, with oil heat backup. With the addition of the more efficient HP and the HP H2O heater, we've been still gaining ground as we did last year through the year down at about 520 kWh below zero. Not bad, and comfort is great.
Got to go, more later.
Sorry it's been so long. :redface:
Thanks for the update. Can't wait to hear about your other improvements; especially the heat pump water heater.
mheslep
Jul12-11, 01:03 AM
I see the SREC price for NJ continues to hold above $0.60 / kWh, by far the highest in the US, while the price has collapsed elsewhere.
http://www.srectrade.com/new_jersey_srec.php
Thanks for the update. Can't wait to hear about your other improvements; especially the heat pump water heater.
Yes, what type of booster is on the water heater?
I just posted about a NJ alternative approach here:
http://www.physicsforums.com/showthread.php?p=3483872#post3483872
"I am having my home evaluatehttp by SunRun, Home Depot and bpsolar. There was a booth in a Home Depot store in NJ.
The "deal in brief": I supply the roof area for solar and they get permits, build, install, maintain and pay for the entire solar system. Then they sell me power under a 20 year contract at a discount to PSE&G power. Unless I have to modify my roof or replace shingles, there is no out of pocket expenditure for me."
I just posted about a NJ alternative approach here:
http://www.physicsforums.com/showthread.php?p=3483872#post3483872
"I am having my home evaluatehttp by SunRun, Home Depot and bpsolar. There was a booth in a Home Depot store in NJ.
The "deal in brief": I supply the roof area for solar and they get permits, build, install, maintain and pay for the entire solar system. Then they sell me power under a 20 year contract at a discount to PSE&G power. Unless I have to modify my roof or replace shingles, there is no out of pocket expenditure for me."
Are you replacing the roof now/first?
I have to be a preliminary site evaluation, be approved to participate, then an engineering evaluation.....I have no data yet so I am open.
I am going to post in the thread I started so as not to disrupt this great discussion....I am posting some interesting information as soon as I sign off here.
"Are you replacing the roof now/first?"
Depends on engineering evaluation and cost.....in theory, I can remove and replace just the upper portion,south facing side, of my four roof surfaces. Roof shingles should be good for another 15 years or so I guess.
I see the SREC price for NJ continues to hold above $0.60 / kWh, by far the highest in the US, while the price has collapsed elsewhere.
http://www.srectrade.com/new_jersey_srec.php
Can you explain your post....Looks like in September rates dropped to $167!!!!!, although I do not understand such a huge change.....
Can you explain your post....Looks like in September rates dropped to $167!!!!!, although I do not understand such a huge change.....
I'm glad you found this thread. I think you need to be careful with this: ...they sell me power under a 20 year contract at a discount to PSE&G power.
You will probably get very little savings. It might be better to rent a room.
You will probably get very little savings.
could be,,,the Home Depot rep mentioned 15% to 20%.....
I'm either "selling" anything here nor recommending anything, just posting whatever I learn.
The discount given to me must depend on the SREC rate the company gets from selling power to PSE&G. If I can save money over an extended time, I'm interested enough to check out the details but not whole heartedly enthusiastic at this point.
What happens for example if the company goes bankrupt or fails to maintain the installation?? I can easily visualize them disappearing as the life expectency of the installation approaches....
"It's all in the fine print."
could be,,,the Home Depot rep mentioned 15% to 20%.....
I'm either "selling" anything here nor recommending anything, just posting whatever I learn.
The discount given to me must depend on the SREC rate the company gets from selling power to PSE&G. If I can save money over an extended time, I'm interested enough to check out the details but not whole heartedly enthusiastic at this point.
What happens for example if the company goes bankrupt or fails to maintain the installation?? I can easily visualize them disappearing as the life expectency of the installation approaches....
"It's all in the fine print."
No doubt. Do they require a minimum average usage or a guarantee of usage?
OmCheeto
Sep4-11, 02:33 PM
"It's all in the fine print."
I would definitely scan in the contract and post it here. I can understand the tax incentive for businesses to own, and depreciate, their property, while selling you a commodity over a long term period.
Caveat emptor (http://www.youtube.com/watch?v=GVwWE_WOY0Q); from Peng's "Is the world messing with me" thread (http://www.physicsforums.com/showthread.php?t=526428).
ps. I traded a solar panel installation(50 watts) for an air conditioner last week. But the damn kid said it would take him years for the system to pay off when I told him he'd have to invest $60 for a deep cycle battery. I was like; "Dude. I'm trading you a $250 solar panel for a $100 beat up old air conditioner..... The sun shines during the day. You want to power your lights at night. You need a place to store all that energy. When the power goes out, due to a hurricane or something, you'll have the only house in the neighborhood with the lights still on. That's freakin' braggin' rights dude!". I'm still waiting on his response.
pps. don't know if you are a facebook kind of person, but the following made me smile yesterday:
https://www.facebook.com/oevadotorg#!/photo.php?fbid=10150280920073020&set=a.384838638019.165959.138510433019&type=1&theater
Can you explain your post....Looks like in September rates dropped to $167!!!!!, although I do not understand such a huge change.....Yes that was back in July. The new data does show a huge drop in SREC price as you say. I can't explain the drop, but it highlights a concern with SREC options - no guarantee on the future price at which you can sell your solar electricity. Actually I suppose it was bound to happen. That state could not afford to pay out at 4X the price of regular electricity for too long. This drop is a point in favor of the 20 year contract people. The SREC prices become their problem not yours.
There are a number of companies doing these deals in the US. Until recently, the big ones have been on the West coast.
Edit: Here's a backstory on PPA company SolarCity. There's been a lot of interest from commercial business in PPAs
http://www.technologyreview.com/tr35/profile.aspx?trid=970&mod=tr35_riverofnames
http://www.solarcity.com/commercial/portfolio/manufacturing/
I'm glad you found this thread. I think you need to be careful with this:
You will probably get very little savings. It might be better to rent a room.Why do you say this? His out of pocket is zero in a PPA, if he wants. Only concern that comes to mind is a turn over in the event of a house sale. But then, resale value needs to be considered for any modification done to the house, solar's no different.
Actually I suppose it was bound to happen. That state could not afford to pay out at 4X the price of regular electricity for too long.
Iagree: That's the major thing I could not understand when I considered my own solar installation several years ago....that and well over $5/watt first cost at the time....it makes NO sense for government to subsidize relatively wealthy individual homeowners via tax credits and paying higher rates for electricity for otherwise uneconomical solar energy...somebody has to provide money to do that...those who pay regular electric rates. It's another silly big government waste.
Can you explain your post....Looks like in September rates dropped to $167!!!!!, although I do not understand such a huge change.....
Yes that was back in July
Thanks, just wanted to check as I had not looked at rates in a long time....
Only concern that comes to mind is a turn over in the event of a house sale.
If a potential buyer gets an electric discount, it should be attractive; if not, I'm screwed. Another issue I posted in my own thread: any tax assesment on solar?? I don't remember...and that can always change.
I just went to the official NJ website on SREC rates and there is no decline in rates reflected there:
http://www.njcleanenergy.com/renewab...g/srec-pricing
??????????
Some interesting SREC background here:
http://en.wikipedia.org/wiki/Solar_Renewable_Energy_Certificates
"In addition to providing cash flow security and stability, long-term SREC contracts are often required by banks or other lending institutions unwilling to accept market and legislative risk associated with SREC markets..."
Why do you say this?
Because of this.
"It's all in the fine print."
You will probably get very little savings.
I got an initial estimate of 33%. More information in my separate thread.
Artman:
Are you able to utilize solar electricity during a commercial power outage with your system? If so, how is that achieved. Apparently most installations don't provide that and I'm trying to find out why. Thanks.
I got an initial estimate of 33%. More information in my separate thread.
Artman:
Are you able to utilize solar electricity during a commercial power outage with your system? If so, how is that achieved. Apparently most installations don't provide that and I'm trying to find out why. Thanks.
No, grid tied system inverters actually mimic the sine wave they get from the grid to convert to alternating current. When the grid is down we have no power.
I was considering looking into an emergency generator and automatic transfer switch to lock out the grid so we don't electrocute a lineman to allow the solar to supplement the generator during the daylight hours. Anyone know if this would work?
SREC prices are way down. I think the reason is the supply of SRECs has increased to a point where the demand has reduced. the last time we checked it was around $276.00 in August, down from $536.00 in July. Drastic change. I don't recommend going solar to anyone at this time. Although, I am actually able to live more comfortably without it costing us more. We kept our AC set on 75 deg F all summer and our meter still went backwards. We are down at about -944 kWh as of this morning.
Due to our conversion to heatpump water heater and improved insulation and high efficiency heat pump HVAC system, we have additional savings in oil costs, but we are also still out more first costs for this new equipment.
The heatpump water heater is a GE Hybrid:
http://www.geappliances.com/heat-pump-hot-water-heater/
Nice unit. No complaints at all about it so far. Noticed a drop in electric usage immediately after putting it into operation.
After the heatpumps and increased insulation, our electric usage is down from about 30 kWh a day to around 20 kWh a day average.
mheslep
Sep20-11, 04:16 PM
...
SREC prices are way down. I think the reason is the supply of SRECs has increased to a point where the demand has reduced. the last time we checked it was around $276.00 in August, down from $536.00 in July. ....
??? I see $167 in August. Isn't that below the grid rates in NJ?
http://www.srectrade.com/new_jersey_srec.php
Edit: yes, apparently grid rate is 18c/kwh
http://www.physicsforums.com/showpost.php?p=3484807&postcount=3
This is why SRECs have plummeted in NJ. (http://www.nj.com/salem/index.ssf/2011/04/construction_under_way_on_larg.html)
SRECs are issued once a solar facility has generated 1,000-kilowatt hours of energy, and then are sold to companies who lack solar energy production.
Electric producers are required to yield a certain amount of solar energy by the New Jersey Board of Public Utilities (BPU), and if they do not, they must buy SRECs.
The going rate for those certificates, which are traded on the open market, is around $400 to $450 each.
The Pilesgrove solar project is expected to generate about 27,000 certificates a year. So in addition to the energy that can be sold, the companies can generate around $11 million per year by selling the certificates.
Not at $167 they won't, that's only about $4.5 million.
Too many huge solar farms and communities with solar panels on every lightpost. They're killing the market for the little guy.
My numbers came from last month's email from SRECtrade. So, yeah, they're outdated, darn it.
mheslep
Sep20-11, 07:14 PM
Keep in mind that the little guy in the end pays for those SRECS. The electric producers don't buy SRECs using their hidden pot of gold, they pass the cost on via electric rates, or the state of NJ does via taxes.
What concerns me is the double dipping from the utility companies. The SREC program has restrictions imposed on the "little guy" that do not seem to be imposed on utilities.
Little guy can't sell their overproduction for retail rates.
The utilities can sell their overproduction for retail rates.
Little guy gets their meter's zeroed at their anniversary. This is because they can take advantage of the SREC program so the utilities supposedly have paid something for the solar power. If this benefit disappears (with a one year drop from near $700 to $166 disappearance is right around the corner), I don't want my meter zeroed.
The utilities can generate and sell as much as they want supposedly because they are the ones buying the SRECs.
Now the utilities are selling SRECs to their competition. How is that right?
Shouldn't their solar farms only count against their SREC requirements? Then perhaps any production in excess of those requirements be sold. Otherwise it's double dipping. Triple dipping if you consider that money gained from SREC sales to competition benefits them in straining their competition's income.
Perhaps I do not understand the SREC program, but I thought it is _only_ the utilities that buy the SRECs, as mandated by law; it is the utilities that make the market demand for SRECs and no one else. Also, the utilities can only sell as much power as the consumers use (the load). They can not, in effect, generate as much power as they like and zap it into the ether for a fee.
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