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Dow Chemical Rolling Out Solar Shingles Next Year
Several users wrote to tell us that Dow Chemical plans on selling solar shingles as early as next year. The solar version can be integrated with normal asphalt shingling and will be introduced in 2010, with a wider roll-out scheduled for 2011. "The shingle will use thin-film cells of copper indium gallium diselenide (CIGS), a photovoltaic material that typically is more efficient at turning sunlight into electricity than traditional polysilicon cells. Dow is using CIGS cells that operate at higher than 10 percent efficiency, below the efficiencies for the top polysilicon cells -- but would cost 10 to 15 percent less on a per-watt basis."
It seems unlikely that these will weather very well, so we'll have to see how they cope with thermal cycling and storm stresses. Nice to note that things have moved along since I worked on Si photovoltaics - it's taken longer than I expected, though
They say these can be installed by standard roofing techniques... I don't know if anyone else has ever nailed down asphalt shingles but it's about as low-tech as it gets. So the question is how do these interconnect electrically?
I could imagine a couple ways - perhaps there are contacts that need to be aligned prior to nailing. Either that, or they intend for an electrician to come in after the roofers and attach a bus bar or something. Anyone got the full story?
The future for residential solar is not in the highest-tech, highest efficiency panels. Rather, it will be the system which gives the lowest $/W after ALL costs, including installation, depreciation, and in this case, savings because it also serves as your actual roof. Sounds like a great idea to me.
What happens when the CIGS cells wear out?
Are they toxic? Can they be recycled?
The traditional mono- and polysilicon panel makers catch hell for using things like lead (leading to RoHS solder being used and etc)... what's the plan for recycling these puppies?
(don't get me wrong, I'm loving the idea, but you know someone's gonna bitch about it...)
Also, since there are places that see annual windstorms which tend to rip the occasional shingle off of the roof, err, how much would it cost to repair/replace?
It'll be hammered out eventually (err, s'cuse the pun), but it's something I hope that someone is thinking about all this today, instead of the being blinded by the whole 'gee-whiz' factor that may come around to bite the whole renewables movement in the butt later on.
(disclosure - I work IT in this industry - take it as you will).
Quo usque tandem abutere, Nimbus, patientia nostra?
TFA says "thin film" cells, so I'd imagine they're fairly flexible.There's also a known pattern to how they'll be installed (overlapping horizontal rows that are each offset by about half the length of one shingle), which could probably be used to print wires on the upper part of the top side and the lower part of the back side such that they'll make fairly good contact.
http://www.newscientist.com/article/dn16550-why-sustainable-power-is-unsustainable.html
"Politicians and diapers must be changed often, and for the same reason."
Wouldn't it be easier to just paint the roof white so that the building reflects more heat and needs less cooling in the summer? (In the winter, insulation will keep the heat inside.)
And wouldn't it also help to use lighter pavement to reduce the urban heat island effect?
It just seems like photovoltaic shingles are pretty low on the net-payback list.
Agreed.
I highly doubt that two guys with a case of beer, a couple of utility knives, and a nail gun can lay these down and have them work as they are supposed to. Shingling a roof really doesn't require any skills, other than doing the peaks and valleys. If you can put down a shingle, and nail it to the roof, you're golden. If you can hack the excess off that hangs over the side with a knife, you can shingle 95% of a house.
Ignoring any interconnections between the shingles that must be lined up, (because, that's beyond a roofer's knowledge base) you still have to tie it into the house electricity. And you have to be able to slap the roof down in the beating sun, while standing on it, and driving nails through it. How exactly does that work if the roof is generating electricity as you do so?
Velociraptor = Distiraptor / Timeraptor
The CIGS PV cell is called "thin film" because the photoelectric sandwich is deposited as thin layers on top of a GLASS plate. Oh, and they apparently are (very) moisture-sensitive, so having them last 20-25 years will be difficult.
The substrate isn't necessarily glass. Flexible metal substrates have been used already by other companies. They do bend, and they're encased in a flexible moisture barrier and offered with a warranty that lasts as long as the lifetime claims. I don't think that the companies selling these would be willing to offer the warranty without a reasonably good expectation that the cells would actually last that long.
"I zero-index my hamsters" - Willtor (147206)
I am not a roofer, nor electrician... But using some sense, I could hypothesize a good edumacated guess...
If I designed something like this, I'd have a band of separate material at the top. And mark on the package somewhere that you're only supposed to nail that part. I'm sure a contract roofer shouldn't have a problem nailing above some dotted line on a solar shingle. Thus no nails would go through the actual solar panel part. Then they sit on the roof loose other than the nailed down part. Then the guy doing the wiring comes along after the roofers with some flat romex. And he finishes the job that secures the shingles on the bottom half in the process of electrically connecting them. I'd make the part at the top flexible enough that it's OK to fold back the shingles, and they'd have a peel-away with adhesive foam tape on the backing side. And also on the back a groove for the wire with two prongs that you would push through the insulation on the flat romex to make an electrical connection. It would just be a matter of running your wire along the bottom of each row, then going back over while peeling something off the back of the shingles and pushing them down so they're glued in a way that secures them and the wire in place. It wouldn't be that complicated at all. The process seems obvious that they'd be wired in parallel, so the voltage would be determined by the panel design. So each panel would add to the amount of current available to a system that is designed for a known voltage. That would simplify the work on the electrical end. (You won't have voltage leak problems this way, or random system voltages because of a half-assed job. A qualified electrician should be doing this part, as he should be aware that despite a seemingly low voltage there's possibly enough current available in the daytime to seriously zap his ass.)
Now I'm curious as to how far off such a guess is. It seems simple enough to be obvious the way I picture it, but I wouldn't be surprised at all if there was a patent on this idea already.