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Solar at Home

Solar at Home


The trials, tribulations and rewards of going solar
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Stories from solarland: What’s it like to install a solar array?

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Editor’s Note: Scientific American ‘s George Musser will be chronicling his experiences installing solar panels in Solar at Home (formerly 60-Second Solar). Read his introduction here and see all posts here.

I’ve gotten some great responses to my call for stories about solar installations. In this post, I’ll describe the grid-tied photovoltaic arrays that people told me about, and in a subsequent one, I’ll mention other approaches such as solar thermal. I’m struck by the commonalties among our experiences. People report comparable subsidies and payback periods.

Don Cruse, Orange County, Calif.

We have a 6.6 kW system, and maximum instantaneous generation I’ve observed is 5 kW. It has generated power for two years and covers all our household needs and one plug-in hybrid car (an A123 Systems/Hymotion); it generates about 15 days/yr more than I need (currently, the utility just keeps the excess). We converted our house space heating to electric space heaters and have seen significant savings in electricity (blower in furnace) and natural gas.

We had some installer problems (design). The electric utility wasn’t going to approve such a "large" system. We received a $2k tax credit and $20k rebate over 5 yrs.

Joseph Cullen, Exeter, England

I live in a sixteenth-century thatched cottage in the South West of England. The cottage faces almost exactly due south but is a listed historical building, so I cannot put panels on top of the thatch. However the garage is separate with a pitched roof facing 190 degrees (see photo above). As I write 1.8 kW panels are being fitted. This is the biggest array that will fit. In UK money, there is a government grant of 2,500 pounds towards the installation and a 0.39 pounds per kW-hr "feed in tariff". This should give me about 8% return on investment assuming 1,000 kWh per kW installed. That is reasonably conservative for this part of the UK. I costed purchasing the individual components and fitting it myself. It did not make sense for the saving compared to paying for the installation. In addition the grant requires use of an approved contractor. Because of the historic status of the house, officially described as grade 2 listed, I had to get planning permission to put in the panels (even though they were not on the house itself). This took two months, to allow for objections. The planning department were very helpful and other than the delay and a small fee it is not an onerous requirement.

Generally the climate is warm by UK standards though rather on the wet side as we get the first taste of Atlantic weather, so it’s not the best place for solar but not that bad either. In the first two days we’ve got just over 6 kW-hr, about as much as we could expect for this time of year. At 1330 UTC on a November afternoon we have a clear sky with the sun already quite low in the West (we are 51 degrees North, 3.5 West here). Nevertheless I’ve got an output of 1.15 kW from my 1.8 kW installation. I have attached some photographs of the installation on the roof, the inverter installation in the garage and for good measure the house. I hope you will recognise why putting panels on the house roof is not permitted under our historic-buildings legislation!

I don’t believe in doing eco things unless the economics adds up. The UK government changed its incentives recently, coming into line with Germany, to encourage take up. The theory is that this will generate enough economies of scale to do away with the subsidy. We’ll have to see how that pans out. I’m quite happy to update you on how we get on with this.

Ken and Linda Ossman, Rochester, N.Y.

Our home solar installation could not have been easier. I believe the key is to find a knowledgeable installer. We have a 5,100 W roof-mounted, grid-connected system that went into operation in January 2009. Our installer, Rochester Solar, knew exactly what to do with the paperwork as well the actual construction. After a site survey they wrote a descriptive estimate for the system. Then we went to our town hall and got a building permit with absolutely no hassles. The installer did all the applications for the New York State incentives. This size system costs over $40k. NYS paid half that amount in incentives directly to the installer.

We did have to wait a few months for the state approval. That was because New York ran out of rebate funding and had to have the legislature renew it. Because Rochester Solar was confident of the approval, they pre-ordered materials. When constriction did begin it went smoothly and quickly. Less than two weeks after final approval, all the parts were installed and functional. The installer arranged for independent electrical inspection and we then informed the town to do their inspection to close out the building permit.

The system has now been operating for 10 months and has given us about 6,000 kW-hr of power. Our home is all-electric with a ground-coupled heat pump, so the PV system gives us about half our total electrical needs.

The final, great part of the story is yet to come. When we file our State and Federal income taxes in 2010 we expect to get credits of $5K and $6K respectively. That means our entire cost is under $10K. A simple calculation of the "pay-back" period is less than 13 years at our current electric rate. This is for a system we expect to last more than 25 years!

We think the governments are doing the right thing to promote everyone’s better heath, economic growth, and energy source security.

Robert Spreeuw, Breukelen, Netherlands

It’s been almost one year since I installed six panels on my roof and I have now proudly produced close to 1 MW-hr of electrical energy and fed it into the power grid. My six panels are rated for 170 W each, so 1,020 W total. These are connected to two converters, each taking a string of three panels.

The system is subsidized by the Dutch government by a payment per kW-hr fed into the grid. The subsidy has been designed so that the payback time for the investment should be around 13 years. The amount of paperwork was not too bad, although it took a long time before I finally received the first payments. The maximum amount of subsidy is based on multiplying the peak power by 850 equivalent hours per year (our country is not known for its sunny climate). Based on this I was expecting to produce about 870 kW-hr per year and I am actually delighted to see that I will end up at around 1,000 kW-hr. Perhaps this is due to the favorable orientation of my roof, which is almost perfect south with a slope of about 45-50 degrees.

Out of personal interest I read out the converters with my laptop PC once a week, and type the numbers into a spreadsheet. It yields an interesting record of the hours of sun per day and the generated energy during the various seasons. At some point when the year is complete, I will produce a few graphs.

Joseph Cullen’s solar installation in Exeter, England

 





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  1. 1. Bops 6:46 pm 11/10/2009

    You don’t know how nice it is to hear Good Solar News from everyday people. Thank you very much.

    Link to this
  2. 2. Soccerdad 7:20 pm 11/10/2009

    Good news? Not if you are a taxpayer or ratepayer.

    Let’s take a look at the Rochester NY project. They state that they have produced 6000 kwh in 10 months, which would be about 7200 kwh annualized. A commercial power plant could produce this amount of electricity for about $400 per year, or $10,000 over the estimated 25 year life of the solar installation (it would be less if discounted for the time value of money). For this $10,000 worth of power, the state of NY has paid the homeowner / installer around $25,000 and the feds have kicked in $6,000. And today we heard from the Governor of NY that the state will run out of money in 4 1/2 weeks. Gee, with brilliant ideas like this, I can’t understand why!

    http://gothamist.com/2009/11/10/governor_paterson_issues_depressing.php

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  3. 3. gmusser 10:12 pm 11/10/2009

    I discussed this at http://www.scientificamerican.com/blog/post.cfm?id=are-we-freeloaders-if-we-install-so-2009-03-13. There is no doubt that solar is more expensive than fossil fuels, even when environmental externalities are taken into account. The subsidies are an investment in the technology — a way to jumpstart the industry. They are not a permanent crutch that perpetuates an inherently uneconomic activity, but a temporary measure. And they appear to be working: solar power is getting cheaper as panel prices come down and installers achieve economies of scale. When it reaches grid parity, the subsidies can be phased out, solar will provide a net benefit to the economy, and we taxpayers will reap the rewards.

    Link to this
  4. 4. Soccerdad 11:00 pm 11/10/2009

    I disagree. There are world scale solar plants being built as we speak (enabled by the subsides) based on the same uneconomical designs. These designs, like the subsidies, will be the norm for some time.

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  5. 5. Michael Hanlon 1:19 am 11/11/2009

    Thogh I’m in favor of all efforts to self generation to meet our needs, some that have invested are perhaps too gaga over their outlay? How can a 5KW system provide 6KW? How can a 1KW system produce a 1 MW in a year? If a system costs $40,000, how does it take 13 yrs to get ROI at a tax break of $11,000 per yr (was a millage factor on property value omitted?) and 15.4West and 55 north at 1.8kw has returned and they’re installing them as I write? And what’s a "feed-in-tariff"? Is that to be paid out of grid contribution or is it what you pay even off the grig or is it what you get to charge the Power Co for what you supply? If the point is ROI, then that term needs explaining, please.
    But Soccerdad, how’re you battling our change to the climate? Do you walk the kids to the games? Do you allow the grass to grow taller so no gas mower is needed? Or, have you figured a way to harness these free electrons the www brings us?
    I know. I’ a jackass and often offend in my verbage. Please, I’d like to see both sides agree on something, even if it’s "Well, he’s an idiot".

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  6. 6. Joseph Cullen 4:51 am 11/11/2009

    Very roughly

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  7. 7. Joseph Cullen 5:01 am 11/11/2009

    Sorry about the previous post; a problem registering. Feed in tariff is a government subsidy. This is in addition to what the power company pays for energy supplied to the grid. Effectively fossil fuel generation is subsidising solar. In this area 1 kWh of installed solar will generate on average 1 MWh of electricity a year. There are 8760 hours in a year and the sun doesn’t shine all the time. The ROI is simply revenue divided by capital investment. Conservatively, I will get 800 pounds a year revenue on 10000 pounds investment that gives me 8% which is much better than the bank will give me!

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  8. 8. Soccerdad 8:49 am 11/11/2009

    Michael,

    I am not battling climate change. Like about 90% of Americans, I save energy to save money – period. Studies have shown that though Americans may profess to care about the environment, they are not willing to pay significantly more money to do it. I’m just honest about it, unlike most. Most of those installing solar are doing it only because someone else (government) is willing to waste money to make it economical for the homeowner.

    If I were worried about GW, I would be deregulating nuclear energy as quickly as possible since, in a reasonably regulated environment, it will be much more cost effective than solar.

    Link to this
  9. 9. gmusser 9:40 am 11/11/2009

    This is precisely why public policy needs to provide incentives.

    As for nuclear, I personally agree that it should be part of the mix. We shouldn’t put our eggs in any one basket.

    Link to this
  10. 10. Joseph Cullen 12:33 pm 11/11/2009

    If the discussion is going to move on to the overall mix of energy sources, one of the best analyses comes from Prof. David MacKay of Cambridge (our Cambridge!). "Sustainable Energy – without the Hot Air" is available, free, online here:
    http://www.withouthotair.com
    An American perspective comes from Amory Lovins "Winning the Oil End Game" can be found here:
    http://nc.rmi.org/Page.aspx?pid=269&srcid=269

    Both repay study, there are a lot of numbers in them. In brief they conclude that we can have a less carbon intensive energy infrastructure if we are more efficient in our use of energy and use all available sources including both nuclear and renewables. The USA with your enormous land area has more options in this than the UK with 60 million people on an island "slightly smaller than Oregon" according to the CIA! We can do this without seriously reducing our living standards and without draconian government controls. However we do need to get on with it.

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  11. 11. Michael Hanlon 3:04 am 11/12/2009

    So, joseph, if I may?, are you saying you get (or spend less) 10,800 of whatever monetary system as a result of a 10,000 investment? Well, at that rate I’d recommend you rip up some of that driveway in front of the garage and install some more at ground level. Do you get 10,800 per year or just 800 per year? (see why I nit-pick, there’s a big difference in those numbers) At the 800/yr number that would mean it will take you 12.5 years for payback/break even on money outlayed now. That is how we usually calculate a good or bad return rate on inveatment over here. But if you are indeed getting in your hand your inveatment plus 800 each year, that means next year you will have realized to date: 10,800 for this year and 10,800 for next year which comes out to 21,600 returned on a 10,000 investment. that’s a two hundred sixteen percent return on investment after just two years.
    .There are only 8736 hours in our year here (maybe the bermuda triangle eats a few of them?) Half of that time and it has nothing to do with clouds, are unavailable to solar generation because the sun is down (I’ll actually later give you some time because at full moon the pv’s trickle) leaving 4368 possible generating hours per year. Since the sun is too low at dawn and dusk for full generation that reduces your equivalent exposure time to two thirds of that timet (two hours less than peak at each dusk and dawn) (maximum) or 2912 peak generating time. Considering clouds and inefficiencies of both generation and storage I’ll grant you 2,500 hours a year. meaning a 1KW /hr system should be giving you 2.5 MegaWatts per year!! I you guys are only getting credit for 1 MW, well……., and remember that little extra that gets kicked in 12 times per year at full Moons!
    You state yours is a 1.8KW system meaning you should get 9/5 times that generation of 2.5 MW for a 1 KW system or, are you ready for this :
    4.5 MW per year See why I need to know if you are being paid or are required to pay that "feed-in-tariff" and you didn’t actually state which way the money flows. If you are paying 0.39/ KW out that’s 1,755 in monetary system. If you are getting that good for you , it’ll help pay for those new panels at ground leve. Or, is that just a figure the gov and the PoCo toss back and forth? We once went to war over here over British tariffs!

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  12. 12. choppam 6:21 am 11/12/2009

    The nukers never give up, do they? Nuclear generation is a form of solar power in the form of a very very primitive human cludge based on the uncontrollable (both long and short-term) use of very active poisons. This is a huge, and unacceptable externality. Fusion offers a more benign and more productive alternative but at unknown cost and unknown time of delivery.

    So let’s look at practical and proven clean real solar energy generation and get it available on a mass scale at viable mass pricing. Fossil fuels and nukes are just too dangerous for humanity and the planet. Perceived (but fictional) short-term benefits (for some) provide a criminal justification for burdening most of us now and all future generations of humanity with economically wasteful damage control for thousands of years.

    So Mussolini got the trains running on time and Hitler oversaw the construction of German motorways (interstate highways) and the Volkswagen beetle. Good short-term investments? Long-term benefits for humanity?

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  13. 13. Michael Hanlon 10:03 pm 11/12/2009

    Mr. Cullen, allow me to restate the idea of return on investment in a different light. I assume these facts as background, that you paid out L10,000 for your 1.8KW system and that through the use of that system you will come out of next year L800 ahead of what you spent for electricity last year (Meaning you didn’t get the money it’s just further money you didn’t have to spend).
    For the first 12 years you can only balance those monies against what you outlayed until the whole L10,000 is gotten back. That 13th year you get your L800 and that is for sure now callable as ‘profit’. But to arrive at a return rate on your investment, you must divide out that L800 over the previous 12 yrs calculating to 1/12 of L800 or L67 or 00.67% ROI.
    Another way: You have L100 to invest. There’s me or the bank going to pay you back. The bank offers 5%/yr meaning next year you have L105. The next year: L111, then L122 what’s termed exponential or compound growth (The formula is in any economics or statistics text) From me you get just L8 back the first year, (I still keep your principal)next year I only give you another L8 and Keep the L100 for myself and on until 12.5 yrs have gone by and all you’ve gotten back is your principal (0% ROI) It would still be a good investment any way you total it if you roll over that saved money into increased generation, because after 12.5 years, that is all , ALL, money in your pocket and will in the long run be more than the bank offers now.

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  14. 14. caliman 2:03 pm 11/13/2009

    Those who continue to promote the use of coal or other fossil fuels because of their low cost, are not taking into consideration all the externalities that fossil fuels entail. Fist there is the cost of treating all the health care issues such as asthma caused by the burning of fossil fuels including loss of work. There is also the cost of the multiple wars we have fought in the middle east, not because we don’t like dictators but because we are trying to protect our source of oil. And not the least of these is the cost to our economy when we are selling off huge parts of our country to pay for foreign energy sources.

    Link to this
  15. 15. Soccerdad 3:19 pm 11/13/2009

    So, if we switch to solar, asthma and wars will be a thing of the past? Dream on caliman.

    Link to this
  16. 16. Michael Hanlon 11:25 pm 11/14/2009

    Soccerdad, I think you’ll get a rise out of this one. The Power Co’s want the government to invest 1 TRILLION dollars to upgrade and rebuild the electric distribution grid! Fight that subsidy why dontcha! Better to get us all off the grid. along those trains of thought, I went to the article here about a new metamaterial that some Chinese scientists havve developed which absorbs 100% of the incident Microwave frequecy put to it. If this were developed to work in the visible light range it would improve the efficiency of PV collectorsfour-fold. That I think ’tis a wiser investment. And now a copy of my last posting there.

    But you will find that the material absorbs a very small range of microwave frequencies, meaning the use if it as a stealth coating would be a waste of money and add weight to something you’d like to go faster. No, it’s surprising that the Power industry hasn’t squashed tis science in its infancy. If we replaced only our southfacing windows with a material that changed 100% of the incident energy into electrons, we could get off the grid. Oh, yeah the gtid that is expecting to have an infusion of a trillion dollars of taxpayer dollars to upgrade it. The other use of a trillion, i.e., develop the metamaterial, would be a wiser investment but comes with no margin or shareholder profit.(from "…Electromagnetic Black Hole The Size of a salad plate" blog postings.)

    Link to this

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