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I am interested in residential solar. My home is in central Arizona and we have LOTS of sun. I have thermal solar on the home's roof (for the pool) and there is no room left for solar PV up there. I have a lot of property and would like to have a carport anyway in order to protect some equipment and a car from the sun. I'm thinking that maybe a carport could do double duty and provide a structural base for solar PV. Solarcity has teamed up with Zep to do commercial solar carports but they are not interested in even discussing a residential solar carport. I have an appointment with a local vendor tomorrow to discuss this and have sent them a photo of the Orion Saturn solar carport as an exemplar. Problem is, I have no idea what such a carport would cost and I'd like to be prepared a bit for the meeting tomorrow. Anybody with any experience regarding residential solar carports and what I should know, be care of, and any idea on what the cost should be? Also, would the cost of a residential solar carport qualify for the 30% federal tax credit?
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Tax questions are beyond my ken, but see e.g.
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My reading of it is the solar part (panels, wiring, inveter, etc) would qualify.
The structure of the carport would not (just like a garage or house would not)
IMO $3/W for the solar plus the cost of a regular carport with that much roof area is the neighborhood I'd expect the price to be in.
Maybe a little more because of bigger steel needed, and more for engineering costs (not spread across 100s of carports)
Because no roof material is needed, maybe you save a bit - probably not enough to fully offset the above would be my guess..Comment
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I believe my research indicated that if the structure is for the solar it could qualify for the 30% tax credit, but if it is an ancillary use it would not. If the "side walls" were open I'd be looking to convince my accountant. If enclosing, I think you have a garage that should not be claimed. Let us know what you decide.Comment
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I was thinking of something like this (Orion Saturn scalable):
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Well, I tried to post a photo of what I have in mind but it was not approved. There would be no side walls.Comment
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I think the question would be:
"Is it a carport that has solar modules on top? Or is it a ground mounting system for solar modules and is providing some shade to a parking area?"
I think your initial post said that it's the former, which IMO means it's a carport and would be treated just like any other structure (ie. not eligible for 30% credit)
But if you can convince your accountant that it's the latter, then by all means go for it. Then it's not tax fraud - it's following the advice of a tax professional, and it's (mostly) the tax professional's problem.
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If (big if) you get audited, and the solar credit is targeted, the auditor will take a look at the construction and determine, in his opinion, what the costs for the structure were for: infrastructure for panel support that you happen to park under vs carport that you installed panels on.Comment
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FWIW, The roof real estate may well get a better ROI with PV on it than the pool heaters.
Do you have a goal as to how much of your current electric load you want to offset ?
A 5 kW PV system will produce ~ 8,000 -8,500 kWh/yr. and need about 300 ft^2 of surface when tilted about 20-30 deg. off horizontal, and probably about 15-20 % more if horizontal.
Horiz. panels will need a fir amount more cleaning as stuff collects and doesn't run off as easily when it rains. Carport solar seems a good idea until the details come out and fades some in brilliance when education brings some of the drawbacks to light.Comment
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The solar representative (Harmon Solar) was ill and did not show up. My home is in central Arizona on about 10 acres and has a pool with a separate pump for the thermal solar. So, the pool pump runs to clean the pool and the solar pump runs to heat the pool. The pool has a sliding cover that I use at night and often during the days as well. My APS energy bill varies from the mid $200/month to the mid $400/month depending on season. The home is all electric -- no natural gas available where I live. Water is off a well (well pump). My home has a two car garage but I was considering having a separate free standing garage built to provide extra storage. On that, I would be able to put solar PV if I want. But, the estimate for the garage (without solar) came in at $55K and I considered that ridiculous. That got me to thinking smaller and I wondered about a carport for shade plus use as foundation for solar PV. Bouncing around the web I discovered that I am hardly the first to consider this and there are companies that make kits for solar carports (but I cannot seem to find much in the way of cost information regarding that). The Harmon folks do build solar carports for schools and industry here in AZ but do not seem totally prepared to deal with a residential inquiry. They now want to send out an analyst to review the area that I have in mind for a carport to determine soil composition, how much steel would be required, and so forth -- in order to give me a firm bid. I will get that arranged and see what they have to say.Comment
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Back to my questions/comments on my 07/06 post: How much of your electricity load do you want to offset ? Knot that panels tilted at ~~ latitude will produce the most output, but will require a sawtooth arrangement to avoid shading from the more southerly rows of panels. Also, low slope/horizontal panels most often need more cleaning as dus/dirt will cake on more easily. Horizontal panels can turn into mud flats.
FWIW, I too have 10 acres in the desert with a climate almost identical to Phoenix. I designed/planned a home with, among other things solar PV. The design was not built, but used a ground mounted grid tie arrangement.
With 10 acres, I'd simply built a carport, and ground mount the array. Putting panels horizontal as part of, or an alternative to a roof is, IMO only, false economy and shortsighted thinking, particularly in a hot, dry, dusty climate.Comment
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J.P.M.: good comments. I will take that into consideration. As to how much electricity load I want to offset -- I don't know what would be most cost effective. More panels = more offset = more expensive build. I don't know where the sweet spot is. I was hoping to gain some of that information once the solar guy does show up. They have had temporary access to my APS account and should be in a position to provide me with options. You do have me thinking about a ground mount and a stand alone carport.Comment
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The solar guy will probably tell you >= 100 % offset will make the most sense. That of course is probably B.S. Vendors make money putting equipment on your property, not selling you the most cost effective size or equipment, or saving you the most money, which is the name of the game for most folks. No one I know of in any business ever got fired for selling too much.
Solar as an energy investment is characterized by generally high(er) up front capital costs and relatively low ongoing costs (low(er) electric bills). The sweet spot calculation involves some work with time value of money type stuff: Process economics, life cycle costing, and for residential solar, a subset or variation on those called Levelized Cost of Energy analysis (LCOE).
Often, ~~ 75+% is what seems to be a good target. Of course, opinions vary and situations change. Your money/house /life/etc. I see and talk to many folks who seem eager to talk themselves into oversizing in a way that sounds like backing into justifying a bigger system than needed. Emotion and ignorance always cause more problems than logic.
Any of those process economics methods, which have a lot of common elements, require some working knowledge of how you pay for energy, and some crap shoot guess as to how those rates may change in the future. That's a real, big PITA, and most folks balk at the task, but it is a necessary and worthwhile effort. Common misinformation and ignorance about rates, and how they have changed, and what the future may hold, is a favorite and fertile ground for peddlers to sow seeds of fear. Check the NREL website under "LCOE" and find the calculator. It's not a bad start. Also, on the net, see "NREL/TB-462-5173". It's an economic eval. manual.
Other things necessary for finding the most cost effective system size involve information about how much electricity any system will generate. Do not rely solely on vendors for that info. Find something called "PVWatts", also from NREL. Spend ~ 20 min. with the info help screens before doing a run or two. It's a rather steep, fast learning curve.
Before any of that, find and download free from the net an older version of "Solar Power Your Home for Dummies", or a newer version for ~ $25 at a bookstore or online.
After all that, come back here and get any knowledge gaps you can't fill on your own filled in.
Knowledge is power. Get one and the other will follow. Do not rely on vendors for answers. Know the answers before you ask the peddlers. You'll find out who knows what they're talking about and who's a con.
Get your roof inspected. Solar lasts a long time. give the roof under a proposed array the highest probability of lasting as long as any solar array. Cheap insurance.
Remember: everything is negotiable. Walk from any vendor who won't. The going rate in my area, San Diego, is probably below $3.50/Watt at this time. Your area is probably a bit different, but just as probably, not too much different. Much more than that and you're probably leaving money on the table. Spend more time on vendor selection than equipment. A good vendor is worth a slight, but fairly negotiated premium.
Sunpower equipment is some of the best, but probably not any better and probably a lot less bang for the buck than other quality equipment installed in a professional manner. Equal (electrical) size systems installed in the same location and orientation for the same duty, will produce about equal annual output for probably longer than you'll own it. Sunpower stuff costs about 20 % more up front and produce about the same as LG, SolarWorld, Canadian Solar, etc. etc. Sunpower comes with bragging rights, sort of like a Mercedes. Solar's an appliance, not a lifestyle. There are no pretty solar arrays. Deal with the uglies.
Finally, remember the common goal: The most cost effective way and methods to reduce an electric bill - not usually solar for its own sake. Know that solar PV is usually the most expensive way to reduce an electric bill. The cheapest is turning stuff off, or not using it in the first place. Turning an incandescent light off is more cost effective than replacing it with an LED, for example. Read the solar for dummies book for more on conservation. Do the conservation/use reduction before solar. Any resulting system will be smaller, less costly and more cost effective.
Take what you want of the above. Scrap the rest.Comment
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A carport does not qualify for tax credits, but a "solar support structure" does.....BSEE, R11, NABCEP, Chevy BoltEV, >3000kW installedComment
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