Is now a good time to invest in solar?

[Artman]

Artman - what kind of daily kWh are numbers are you producing now that we are into 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]

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?

... .. .

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.

 

[Artman]

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).

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]

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).

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, , but with the gulf spill going on, I'd say your timing was impeccable.

 

[Artman]

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.

I can understand their answers, my best days were days with snow on the ground and a clear solar array.

 

[Artman]

Not to politicize the engineering forum, , but with the gulf spill going on, I'd say your timing was impeccable.

Wow, yes that could have an impact.

 

[mheslep]

Not to politicize the engineering forum, , 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]

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?

 

[Artman]

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]

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]

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%.

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.

 

[blimkie.k]

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]

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]

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.

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.

https://www.youtube.com/watch?v=WAp08b9_EuU
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.

 

[OmCheeto]

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 https://www.physicsforums.com/showpost.php?p=2571575&postcount=67":

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 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.

Leaf

Not yet

My laptop sounded like a pachinko machine the day they started taking reservations:

All were announcing they'd put in reservations.

Volt

Not yet

True, but there are plenty of hybrids out.

Roadster

$109k

S

Not yet

Good timing:

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.

https://www.youtube.com/watch?v=WAp08b9_EuU
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.

I want one of those.

 

[mheslep]

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/vehicle

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.

I want one of those.

Me too

 

[OmCheeto]

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:

[PLAIN]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?

 

[mheslep]

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]

Another 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.

 

[Artman]

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]

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 )
d. the albedo of my lawn is ~11.4%(8.76% output, fully shaded, @ ~56.3' angle from horizontal)

 

[mheslep]

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]

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...




water systems.html]Solar hot water[/url]

 

[Artman]

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.

http://www.gotohallowell.com/Acadia™-Products/the-acadia-30.html"

 

[marcos248272]

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]

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]

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 :)


http://www.googlesniperrevealed.com//

 

[mheslep]

http://www.googlesniperrevealed.com//

Advertising/Spam:
Advertising for personal gain of any kind is not permitted in any forum. Commercial spam will result in an immediate ban. Posting science website links will be permitted occasionally, but will be dealt with on a case by case basis. Linking to obviously "crank" or "crackpot" sites is prohibited.

https://www.physicsforums.com/showthread.php?t=414380

 

[Artman]

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.

 

[Artman]

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.

 

[donbcg]

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]

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

 

[Artman]

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]

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]

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]

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]

Artman - heads up:
http://www.technologyreview.com/energy/25963/

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]

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]

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]

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 going to 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.

 

[Artman]

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]

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.

 

[Artman]

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]

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?

 

[Artman]

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]

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]

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]

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]

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...

 

[Artman]

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.