Did PV solar power just become affordable?

[hitssquad]

This can't be right... doesn't anyone else see this as absurd or did i slip into the twilight zone.

Similar ratios of system cost to system size are available at the Homepower Magazine site. Find one that is lower than $200 per installed kwh-month and post it here, if you like. Your figure of $100,000 up-front cost works out to $40 per installed kwh-month. That is not so much lower that the $200 figure is in the twilight zone, is it?

 

[Pengwuino]

Wait wait awiatjaklsdjflafjla

I see what's going on here. That $8000 figure is for a house that uses 1kwh a day. Normal residential houses with an air conditioner and washer/dryer are talking about 1kwh an HOUR. I think i understand what's going on here. If you take out the non-scaled equipment (basically everything but the panels and batteries), we're talking about the ability to create roughly .5kwh's per hour for $3500. For a home like mine at 50kwh/day, we're talken about the need to create about 8kwh's per hour (at the equivalency of 6 hours peak-power production which is based on a real-time generation report from a local resident who had his generator hooked up to a website to display his own statistics) which means around $56,000 in panels and not much more then $10,000 extra in batteries and a better inverter

 

[loseyourname]

It is interest or opportunity cost at an arbitrary 5% discount rate. If you borrow it from a bank, it is interest. If you borrow it from yourself, it is opportunity cost.

Cool. Your calculation is saying exactly what I thought it was saying. It's counting the money you could have made by investing elsewhere - at a 5% compound interest rate - in the cost of the system.

The only real problem I see with this is that you can make the same argument against any $500,000 purchase. In fact, you can say that you should never purchase anything (regardless of the price) aside from what the minimal things you need to survive because that money is better spent investing in something that yields a 5% compound interest rate.

Then again, it seems at this point that Pengwuino is only concerned about how to make the most money. It certainly isn't by installing solar panels in the house. There is one more thing, though. If they're simply taking the money they would have spent on electricity each month and applying that toward mortgage payments for the panel purchase, then the only way they can take that money and apply it toward any other form of investment would be to live without any electricity. That doesn't seem a very feasible option. The real question here should be: If I'm going to spend $500/month on electricity, am I better off paying that money to the local utility provider or paying that money to the bank that gives me a loan to buy and install solar panels. The latter seems the better option. Of course, that's an idealized situation in which you spend the same amount of money either way, when in reality I would imagine you pay less powering your home with electricity from the local provider. That seemed to be his initial question, though: At what point does the price of the local utility become so high that it is feasible to go solar instead?

 

[Pengwuino]

Well its not about making any moeny, its about losing money. I can obviously put $50,000 into an investment that immediately makes a profit but I am wondering if putting a large amount of money like that, or any amount for that matter, will pay itself off in a decent amount because the last thing i want to do is actually lose money on the solar panels or end up breaking even in 20 or 30 years.

Its become more obvious that an investment in bonds or real estate is much smarter because whether or not you pay $50,000 for solar panels or you pay PG&E for electricity, you end up paying large amounts of money over time that you could probably invest with much better returns.

 

[hitssquad]

The utility kwh price breakeven for homepower; negawatts; thin-shell construction

At what point does the price of the local utility become so high that it is feasible to go solar instead?

I very roughly guestimate that the breakeven would be somewhere around $1.00 per kwh.

This would only be for someone who refuses to invest in any energy saving technologies or techniques, though. The cost per kwh saved (also known in the homepower world as the cost per "negawatt") might be a lot cheaper for investing in energy-saving appliances such as front-loading washers or in energy-saving construction such as http://www.monolithic.com/pres/alt-energy/ .

 

[loseyourname]

I very roughly guestimate that the breakeven would be somewhere around $1.00 per kwh.

This would only be for someone who refuses to invest in any energy saving technologies or techniques, though. The cost per kwh saved (also known in the homepower world as the cost per "negawatt") might be a lot cheaper for investing in energy-saving appliances such as front-loading washers or in energy-saving construction such as http://www.monolithic.com/pres/alt-energy/ .

Awesome. You seem to be pretty knowledgeable about this topic. Should the price of solar panels be going down any time soon? Have the prices been pretty stable (adjusting for inflation) since the invention of solar power?

 

[hypatia]

http://http://www.partsonsale.com/
The price of the panels, is and has been dropping for several years.

 

[pattylou]

Its become more obvious that an investment in bonds or real estate is much smarter because whether or not you pay $50,000 for solar panels or you pay PG&E for electricity, you end up paying large amounts of money over time that you could probably invest with much better returns.

Eureka! The best way to make money is to reduce our consumption in the first place.

 

[pattylou]

The real question here should be: If I'm going to spend $500/month on electricity, am I better off paying that money to the local utility provider or paying that money to the bank that gives me a loan to buy and install solar panels. The latter seems the better option. Of course, that's an idealized situation in which you spend the same amount of money either way, when in reality I would imagine you pay less powering your home with electricity from the local provider. That seemed to be his initial question, though: At what point does the price of the local utility become so high that it is feasible to go solar instead?

This is not the case. We paid up front and over the life of the panels will *save* around 10,000 dollars (that *would* have gone to SoCal Edison with traditional energy.)

A friend of ours is getting panels with a home equity loan. He will come out ahead the first year (by about a hundred dollars) and come out further and further ahead every year following - and over the life of the panels will save (if I recall) about 5000 dollars.

So at present, the local utility is so expensive as to make solar worth it.

This *may* only be the case in California, where we have lots of sunshine and solar panel rebates.

 

[hitssquad]

How solar PV panels are rated

So i started calculating and based off this meter this one company has online that shows one of their residential 2.5kw generators (actually 2.5kw so it must be like 10 square feet of panels)

We got our 2.5 kW system installed in February. It's much more than 10 square feet - I think more like 50 but I'd have to measure it and its outside.

Pengwuino meant square meters when he said square feet. Solar panels are rated by multiplying their efficiency at 20 degrees celsius by a standard solar insolation value of 1000 watts per square meter (the maximum that could be expected at the absolute optimum spot on Earth at the absolute optimum time; solar insolation is at best never more than a fraction of that at any point in the continental United States). 25% efficiency * 1000 w/sqm = 250 w/sqm. 10 square meters of 25% efficient panels gives us 2.5kw.

10 square meters = 108 square feet. Your 2.5kw PV array, Pattylou, probably measures more in the neighborhood of 150 to 200 square feet, since consumer-grade solar panels are much less efficient than 25%.

 

[pattylou]

You're right. And I saw Pengwuino's previous correction about feet/meters.

I actually thought when I measured them several months ago, that they were 148 square feet, but didn't think Pengwuino would have been off by a factor of 15 so scaled back my suggested correction to spare his feelings a bit. (I indicated that the number might not be right by saying "I think," and made a small joke about not wanting to take the time to measure them accurately.)

The manufacturer we used has reportedly improved the efficiency some, since, just in the few months since we've been generating. The ... crystals? cells? are now arrayed slightly differently to capture more energy.

 

[hitssquad]

The manufacturer we used has reportedly improved the efficiency some

Which manufacturer is that, Pattylou?

 

[Pengwuino]

The manufacturer we used has reportedly improved the efficiency some, since, just in the few months since we've been generating. The ... crystals? cells? are now arrayed slightly differently to capture more energy.

Doesn't sound like you gained much. Although re-adjusting angles is a key in gaining increased generation, it normally has to be done on a continual basis (solar tracker setups)

 

[Pengwuino]

Eureka! The best way to make money is to reduce our consumption in the first place.

Pff, you come over here and live with 20 straight days of 103+ temperatures :P. See how much reduction you can handle. Our air-conditioner never even makes it to 76 degrees during the daytime and sometimes can't even get under the 80 degree mark till around 7pm

 

[Pengwuino]

A friend of ours is getting panels with a home equity loan. He will come out ahead the first year (by about a hundred dollars) and come out further and further ahead every year following - and over the life of the panels will save (if I recall) about 5000 dollars.

Thats impossible. What system did he get, how much can he generate and what costs did he incur in setting it up and how much did he normally pay in electricity bills. The math can't add up

 

[hitssquad]

The manufacturer we used has reportedly improved the efficiency some, since, just in the few months since we've been generating. The ... crystals? cells? are now arrayed slightly differently to capture more energy.

Doesn't sound like you gained much.

She said the manufacturer changed its formula after she purchased.

 

[Moonbear]

Pff, you come over here and live with 20 straight days of 103+ temperatures :P. See how much reduction you can handle. Our air-conditioner never even makes it to 76 degrees during the daytime and sometimes can't even get under the 80 degree mark till around 7pm

Maybe you need a more efficient air conditioner instead, and better insulation on your home. Sometimes insulation is the best investment for cutting energy costs. What temperature are you aiming for? Lower than 76 with A/C? No wonder you're paying so much! I never set my thermostat lower than 78 in the summer. What's the point of living in a warm climate if you're going to refrigerate yourself?

 

[Pengwuino]

What's the point of living in a warm climate if you're going to refrigerate yourself?

Because i don't want to move and switch universities and leave all my friends to stay 2 degrees cooler :P

 

[Pengwuino]

She said the manufacturer changed its formula after she purchased.

Ohh ok. Wonder how much they got. Has there been any recent noticable improvements in the cells?

 

[loseyourname]

Because i don't want to move and switch universities and leave all my friends to stay 2 degrees cooler :P

You can change your living arrangements, though. It's been as high as the mid-nineties around here, but our apartment has stayed cool for several reasons. We face north and don't receive any direct sunlight, plus we're surrounded by trees. Both of these factors played into my choosing this apartment. The downside is that it's always fairly dark in here, but I prefer that to being terribly hot.

 

[pattylou]

Ohh ok. Wonder how much they got. Has there been any recent noticable improvements in the cells?

I can get some info if you want - but not til monday --- the company we went with doesn't have a website (!) and aktough they told us by phone that the technology had mproved (marginally, not a lot) in the last few months, I don't know the manufacturer.

 

[pattylou]

Thats impossible. What system did he get, how much can he generate and what costs did he incur in setting it up and how much did he normally pay in electricity bills. The math can't add up

He figured it out with the solar calculator at the california energy commission, and it only pays off with the rebates.

I googled and couldn't find the calculator (the Ca.ec site is huge and the search engine didn't bring up the calculator - I spent 15 minutes looking for you!) but *might* see this guy at church tomorrow in which case I'll get more details for you.

p.s. he's an engineer that used to work with the electric company in pennsylvania. I think his math is right!

 

[Pengwuino]

Well I'd still love to see his math. We're tlaken about systems that cost $10,000's with monthly savings only in the hundreds it would seem so it doesn't sound like it makes any sense unless the rebates are ginormous.

 

[Pengwuino]

You can change your living arrangements, though. It's been as high as the mid-nineties around here, but our apartment has stayed cool for several reasons. We face north and don't receive any direct sunlight, plus we're surrounded by trees. Both of these factors played into my choosing this apartment. The downside is that it's always fairly dark in here, but I prefer that to being terribly hot.

Well we even have trees surrounding our house... fairly new windows... slowly switching to CF bulbs...

We also need to get rid of these 15+ year old washer/dryer and refrigerator and get some new ones. Theres also a freezer in the garage that practically pre-dates electricity :P

 

[Moonbear]

Well we even have trees surrounding our house... fairly new windows... slowly switching to CF bulbs...

We also need to get rid of these 15+ year old washer/dryer and refrigerator and get some new ones. Theres also a freezer in the garage that practically pre-dates electricity :P

I cut costs quite a bit just by installing a programmable thermostat. During the hottest part of the day when I'm not home anyway, it adjusts the temperature several degrees warmer (80), then I program it to cool the house down about an hour before I usually get home so I'm not too hot when I get home (78). I have it set a bit cooler for night sleeping (76), back up to 78 for morning showers, and then repeat the cycle. I think it helps for two reasons, 1) I don't have to remember to adjust the thermostat and 2) I don't have to get home to adjust it cooler, so am not tempted to run it very cold when I walk into a house that feels way too hot.

I also have two floors and the second floor is always warmer, so I adjust my habits by season. In the winter, I spend more time upstairs in my office where it's warmer, and in the summer, I stay downstairs in the family room where it's cooler...or on really hot days, in the basement. This way I don't have to overcool the first floor to sit around on the second floor comfortably. Of course I'm only here for another month, so won't have to deal with the winter again. A/C costs should go down a lot when I live in the mountains, though heat costs will probably go up!

 

[pattylou]

Well I'd still love to see his math. We're tlaken about systems that cost $10,000's with monthly savings only in the hundreds it would seem so it doesn't sound like it makes any sense unless the rebates are ginormous.

(You realize he is paying it with a loan so it doesn't touch his capitol or savings at all?)

My friend was very skeptical.

There is a five minute period in the service where congregants share "joys and sorrows." I decided "What the hell, I'm a green nut, I'll share my photovoltaic joy."

This fellow UU'er approached me after, and told me in no uncertain terms that he had worked the numbers and it made no financial sense to go with solar. I told him simply what I told you - that we paid X, and that we should have the panels paid off in five (to seven) years, and that the life of the panels was 20 years. We calculated 10,000 dollars savings, but not accounting for increasing oil costs. So, our savings could be more - (we won't pay "more" for sunlight in ten years.)

A barrel of oil costs 50% more than it did only one year ago. http://www.wtrg.com/daily/clfclose.gif Amazing.


Technically, the solar company says: "If the panels are working at less than 80% after 20 years, we'll replace them free."

My friend still maintained he was better off investing the money elsewhere.

Anyway, this guy came up to me about a month later beaming. He said he looked at the numbers again... and that he realized that we had passed the point where it was more economical to go with solar.

I'll try to get you the relevant sites, after services tomorrow.

 

[pattylou]

P.s. If you're a student and planning to move in the next few years - then it doesn't make financial sense to invest in solar. Because obviously - the panels stay with the house.

 

[Pengwuino]

P.s. If you're a student and planning to move in the next few years - then it doesn't make financial sense to invest in solar. Because obviously - the panels stay with the house.

Unless the panels add to the value of the house! (that is, if my parents move somewhere else once i leave). So far the general consensus is "pff, they'll tear them down! not pay more for the house" haha.

I still need to see the math to decide if this "instant" payoff is real. I suppose all your doing is getting an immediate, smaller savings in the short term then it would be if you payed cash up front minus any loans.

And where did oil prices get thrown in with all this? Do they have a lot of gasoline powered plants in your state?

 

[pattylou]

You're living with mom and pop? Great! Then they'll still benefit. Any new owners *might* keep the panels, but may as soon decide they're ugly. So if mom and pop are sticking around - the math should be good.

The electric company uses oil to make electricity. As the cost of a barrel goes up, so does the cost per kwh from Edison. At least, this is my understanding. But the increase is not immediate.

 

[Pengwuino]

Yah they use oil but typically, they only use oil at third tier peak-production facilities because its such an expensive thing. They do use it though because unlike nuclear, wind, solar, and hydro, they can turn it off and on and the equipment is cheap. Its pretty much a last resort generation method for hot summer days at like, 3-6pm. I don't think any base-production facilities use oil because its too expensive. So unless your state uses an unordinarily large amount of oil, it won't affect it much.

For example in California, according to the California Energy Commission...

http://www.energy.ca.gov/electricity/electricity_generation.html

Oil was used to generate only 0.17% of the states electrical needs. Besides "other", it was the least used resource. Solar even beat it out by about 50% in 2002. The "gas" is natural gas by the way. Ooo baby, look at that 23% imported energy. Yah, that's how you pay $.21 per kwh... you import your energy because everyoens too chicken to fix our energy situation.

 

[hitssquad]

And where did oil prices get thrown in with all this? Do they have a lot of gasoline powered plants in your state?

Pattylou lives in Southern California.

physicsforums.com/showthread.php?t=83532&p=694991

 

[Pengwuino]

haha wow... I just read "SoCal" and nothing popped into my head.

 

[hitssquad]

Homepower as a money pit

the world's leading homepower evangelism site says that it is impossible to make money with homepower.

Could you provide a specific quote and link to what you just said?

The Homepower Magazine site has a Rogues Gallery of 26 Guerrilla Solar activist profiles. These sometimes feature statements about not being able to make money doing homepower and that homepower should instead be done because it is a just cause.
http://www.homepower.com/magazine/guerrilla.cfm


From Profile 1:

--
Since we first fired up this system on April 10, 1998, we have put 208,827 watt-hours of solar-made electricity into the utility grid. At our utility rate, that means only about $20 towards paying for the system. So we can’t justify this project based solely on economics.
--


From Profile 2:

--
Short term costs suggest that green energy is less economic than the brown stuff. The reality is that today's brown energy "profits" come at the cost of tomorrow's generations.
--


From Profile 15:

--
Our main objective in using this system is to reduce our ecological footprint.
[...]
We will never see a financial payback on this investment.
--


From Profile 20:

--
What have I learned from my experimentation? I’ve learned that it is more cost effective to save electricity than it is to generate it.
--


From Profile 25:

--
The system components were very expensive. On the other hand, it’s my hobby, and it makes me happy.
--


Also please see:
http://www.aspencore.org/Solar_Power/solar_power.html

--
It's Not Cost-Effective[/color]

Gag me with a spoon. If I heard it once, I heard it a dozen times, "What's the payback?" I heard it from an architect, a rancher, an engineer, and an electrical inspector. Dividing my system's price by it's production gave my brother in law his bottom line: "It's not earning its keep."
[...]
Buying a grid connected PV system is folly. Why pay 25 cents a kWh for solar power when you can buy coal power for 7? Are you brain dead, a moon rock? PV is cost-effective for cannabis growers, dirt-poor Haitians, Soviet cosmonauts, Everest climbers, Indonesian peasants, and the Mars Rover. As for the rest of you, forget it.
--



Kenneth Adelman's 30.5kw (from 36.7kw of solar panels) system...
http://www.solarwarrior.com

...cost $360,000.
http://66.102.7.104/search?q=cache:...e/2004/06/03/solar/+Adelman+salon+solar&hl=en
http://66.102.7.104/search?q=cache:...3/solar/index1.html+Adelman+salon+solar&hl=en
http://66.102.7.104/search?q=cache:...alon+"fight+for+your+right+to+go+solar"&hl=en
http://66.102.7.104/search?q=cache:...alon+"fight+for+your+right+to+go+solar"&hl=en

I estimate that it produces an average of 3,000 kwh per month. That works out to an up front cost of $120 per installed kwh/month. The opportunity cost of that $360,000 over 30 years at a 5% discount rate and daily compounding is $1,253,242.33. Dividing that by 1,080,000 kwh produced over 30 years gives us a cost of $1.16 per kwh just for the interest alone.

You can see the Adelman's homepower system from space with Google Earth. The exact location of the array is 36^o59'56.28" N, 121^o47'05.61" W.

 

[pattylou]

Pengwuino: I goofed. My friend didn't take a home equity loan. He took bonds that were making 4.5% from his IRA, and put the money instead into solar and from this will come out ahgead. The home equity loan has a 7% rate...and you don't come out ahead that way.

He said he'd try to find the online worksheet for me, that I mentioned earlier - I still think you might enjoy plugging in different variables to decide when it pays off for you.

 

[Pengwuino]

He said he'd try to find the online worksheet for me, that I mentioned earlier - I still think you might enjoy plugging in different variables to decide when it pays off for you.

Thank you for inquiring about the data. I don't feel the need to plug in different variables because most of the numbers that need to be plugged in are pretty much set in stone or i can't see a reason why they would be changing anytime soon. For example, our rate wouldn't change and I can't see a whole lot of change with our energy requirements (unless of course we do finally get new appliances... but pff... dealing with these parents of mine is like... bleh).

 

[pattylou]

You can project different scenarios, like what you think the cost of electricity will do, what you think your investments will do, and so on, and figure out what the "break even" point is.

Sounds like you are happy with or without the additional info. ?? So I'll only post it if it ends up being easy for me (if the guy sends me an email with a web link, for example.)

 

[Pengwuino]

Its pointless to try to project different scenarios because now we're REALLY talking about things in terms of investment. This unfortunately doesn't fit the form of investment that can take into account variables like that because its a one time upfront deal. Once you do it, that's it, no 'pulling out' or switching to a different investment and so on. I can project a million reasons about why I should go solar and a million why I shouldn't. None of it helps me because I can't tell the future and once we plop the money down, there's no going back or pulling out. I can figure out a break even point but there'd be no use in doing so since figuring that would include energy cost variances which are beyond my knowledge as it is has yet to occur.

No matter how I crunch the numbers, it seems like the best thing to do is probably to just reduce useage with newer appliances and 'cost-saving devices'. They bring a quicker pay-off plus have a guaranteed return in the home-value and utilitarian benefit (our appliances suck :( ).

I wonder what kinda return we're looking at if we just make a business that sells solar power. Have the state force PG&E to buy solar power from us at an insane rate and get rebates and not have to deal with powering a home or anything. Probalby need a good quarter or half a million worth of panels to make a good return though...hmm.. time to calculate!

oops, nevermind. Not very easy to calculate when you have no clue how much they sell solar power at :(

 

[hitssquad]

Steam turbines, not PV panels, are used for commercial solar power

I wonder what kinda return we're looking at if we just make a business that sells solar power. [...] Probalby need a good quarter or half a million worth of panels to make a good return though.

Almost no one uses photovoltaic panels to generate commercial solar electricity. They use parabolic troughs (that heat oil that ultimately powers steam turbines).
rhlx01.rz.fht-esslingen.de/projects/alt_energy/sol_thermal/troughs.html

--
Parabolic troughs assembled in collector fields are responsible for almost all commercially produced solar thermal power.
--

 

[Pengwuino]

Wait wait... then what are those fields with big flat panels on them i always see??

I assume such a setup is too dangerous for at-home use...

 

[hitssquad]

The 22 commercial solar PV installations in California

Wait wait... then what are those fields with big flat panels on them i always see??

Commercial PV installations. There are 22 commercial PV installations in California. They are:
http://www.solarelectricpower.org/installation_inventory/Index.cfm?do=do&Orderby=Custom24&MaxCount=42&start=31

1. Buena Vista Elementary School, Kyocera panels, 30kWac
   
2. San Jose Campus, Siemans/Sanyo panels, 288kWac
   
3. school (unknown name), AstroPower panels, 5kWac
   
4. Pet boarding facility, BP Solar panels, 32kWac
   
5. school (unknown name), AstroPower panels, 5kWac
   
6. Fetzer Vineyards, PowerLight Corporation panels, 41kWac
   
7. Connecticut Transit (CTTRANSIT), PowerLight Corporation panels, 23kWac
   
8. City Fire Station, ASE panels, 22kWac
   
9. PWS Motion Control, Inc. Kyocera panels, 7kWac
   
10. Multi-Unit Apartment Complex, Kyocera panels, 43kWac
    
11. Solar port for electric vehicles, SMUD panels, 3kWac
    
12. City Hall, BP Solar panels, 6kWac
    
13. Domaine Carneros Winery, PowerLight panels, 120kWac
    
14. Neutrogena Corporate Offices, Powerlight panels, 230kWac
    
15. MTA Division, 15 RWE Schott panels, 213kWac
    
16. MTA Division, 8 RWE Schott panels, 213kWac
    
17. South Pasadena High School, Kyocera panels, 20kWac
    
18. Aquatics/Swimming Center, SMUD panels, 8kWac
    
19. Wesley Allen, Inc., Shell panels, 225kWac
    
20. City Centre, Fountain Valley 1, PowerLight Corp. panels, 116kWac
    
21. City Centre, Fountain Valley 2, PowerLight Corp. panels, 118kWac
    
22. Carlsbad Pointe, Carlsbad, PowerLight Corp. panels, 110kWac

I assume such a setup is too dangerous for at-home use...

All electricity generation facilities are dangerous. That is one reason people buy their electrical services from companies that specialize in providing them instead of providing their own electrical services (homepower). (Another reason is that commercial electrical service is always cheaper than homepower for homeowners near the grid. A third reason is that commercial electrical service is more reliable than homepower. A fourth reason is that commercial electrical service pollutes less than homepower).

 

[Pengwuino]

haha and 5 are schools... well i suppose if only places liek schools put em in, i guess they can't b very economical.

 

[russ_watters]

haha and 5 are schools... well i suppose if only places liek schools put em in, i guess they can't b very economical.

In some places, schools are eligible for a big grant for pv.

 

[Moonbear]

From Profile 2:

--
Short term costs suggest that green energy is less economic than the brown stuff. The reality is that today's brown energy "profits" come at the cost of tomorrow's generations.
--


From Profile 15:

--
Our main objective in using this system is to reduce our ecological footprint.
[...]
We will never see a financial payback on this investment.
--

Those statements seem pretty amusing when you look at the picture you posted below them. Looks like quite an ecological footprint there! How many trees, shrubs, bird and squirrel homes, etc., do you think they had to clear out of there to make room for those panels and avoid shadows on them from surrounding vegetation? I would only go for a system that could be rooftop mounted, in other words, don't clear any more land than you already needed to for your house. That is, unless you want to turn the entire planet into a desert.

...cost $360,000.
http://66.102.7.104/search?q=cache:...e/2004/06/03/solar/+Adelman+salon+solar&hl=en
http://66.102.7.104/search?q=cache:...3/solar/index1.html+Adelman+salon+solar&hl=en
http://66.102.7.104/search?q=cache:...alon+"fight+for+your+right+to+go+solar"&hl=en
http://66.102.7.104/search?q=cache:...alon+"fight+for+your+right+to+go+solar"&hl=en

I estimate that it produces an average of 3,000 kwh per month. That works out to an up front cost of $120 per installed kwh/month. The opportunity cost of that $360,000 over 30 years at a 5% discount rate and daily compounding is $1,253,242.33. Dividing that by 1,080,000 kwh produced over 30 years gives us a cost of $1.16 per kwh just for the interest alone.

You can see the Adelman's homepower system from space with Google Earth. The exact location of the array is 36^o59'56.28" N, 121^o47'05.61" W.

 

[hitssquad]

The Adelman's solar PV footprint

It is actually quite a distance from the house, Moonbear. (The angle of the picture distorts the distances.) The reason it was placed so far was to avoid cutting down any of those oak trees. Check out Part 3 of the Salon article:

--
They eventually ended up with a giant black array of panels, located well down the hill from their house. Next to the panels, one live oak casts a bit of shade on the huge array, but Gabrielle won't let Ken cut down that tree to make the system more efficient. In this, as with every other ecological choice, there are always trade-offs. But as their Web site brags: "No oak trees were harmed in the process."
--

As can be seen in the photo on the homepage of their website, the array is located at one end of a field used for farming. So, some farmland was lost.

It is also possibly oversized so they can pump as much solar electricity into the grid as possible (they are solar electric activists). There are a couple of caviats here, though. Their house uses insane amounts of electricity, so that system may actually be about the right size for them. The second caviat is that a different kind of house -- such as a super-insulated thin-shell concrete dome; one for the pool and one or more for the living area -- would radically reduce the need for electricity while not impacting the living standard of the home; and therefore the Adelman's example cannot be taken to imply that all houses with that particular living standard would need a solar PV footprint that large.

I would only go for a system that could be rooftop mounted, in other words, don't clear any more land than you already needed to for your house.

Rooftop mounting is a bad idea. Up on a roof it is dangerous to install, clean and service solar panels because of the fall danger (falls constitute a leading cause of accidental injury and death in America), and most roofs are not engineered to have things mounted on them. People's roofs have been destroyed by solar panels catching the wind. Solar panel mounting hardware has caused leaks in roofs. As far as I am aware, insurance companies have refused to cover any of these solar-panel-related losses.

In other words, roofs are engineered to perform certain tasks and accepting the mounting of PV panels is not one of them.

 

[Pengwuino]

I remember a while ago wondering if you could reflect light into a reservoir of water to create steam to run a turbine just like in that setup you mentioned earlier. I thought i was insane and that it wouldn't work :(

 

[hitssquad]

Rankine cycle and Brayton cycle solar power towers

wondering if you could reflect light into a reservoir of water to create steam to run a turbine

The ones in operation use heliostats (fields of sun-tracking mirrors) aimed at the tops of towers:

http://www.tve.org/images/janus/uploaded/ACFC8.jpg

http://www.menzelphoto.com/images/gallery/big/environment/altenergy/gal_env_alt_02.jpg

They can create steam or heat gas. Gas turbines (Brayton thermal engine cycle) are more efficient than steam turbines (Rankine thermal engine cycle).

 

[pattylou]

"No oak trees were harmed in the process."
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My husband MIke freaks out every time I find a sprouted acorn, because it is illegal to remove Oak Trees here in "Thousand Oaks. " He is a little upset that I have a few oaks that are now three or four years old, in pots, because he doesn't want them going into the ground where they can't be cut down by law! Heheheh. I keep them because they are preferred host plants for several species of butterfly and I have a butterfly garden.

Rooftop mounting is a bad idea. Up on a roof it is dangerous to install, clean and service solar panels because of the fall danger (falls constitute a leading cause of accidental injury and death in America), and most roofs are not engineered to have things mounted on them. People's roofs have been destroyed by solar panels catching the wind. Solar panel mounting hardware has caused leaks in roofs. As far as I am aware, insurance companies have refused to cover any of these solar-panel-related losses.

In other words, roofs are engineered to perform certain tasks and accepting the mounting of PV panels is not one of them.

I hadn't heard of these... maybe you have a point. We clean the panels without going on the roof (hose spray/single story home.) The weight on the roof was offeset by removing the heavy tiles beforehand. Roof mounted is SOP around here...

 

[Pengwuino]

Your cleaning an electrical device with a hose?

I suppose there insulated... how else could they handle the rain.

 

[pattylou]

Your cleaning an electrical device with a hose?

I suppose there insulated... how else could they handle the rain.

yep. Rain. The pollen coats them pretty bad, and the installer said to hose 'em dwon - only thing is make sure they're not hot when that cold water hits.

I'm still curious about the effect of hail, like Moonbear asked.

 

[Pengwuino]

I doubt it would have much of an effect. I am sure they considered it when they designed the panels for sale where you live.