Dow Chemical readies easy-to-install solar roofs.

[bik0]

Solar Shingles See the Light of Day
Dow Chemical readies easy-to-install solar roofs.

By Phil McKenna

Wednesday, January 20, 2010

Dow Chemical is moving full speed ahead to develop roof shingles embedded with photovoltaic cells. To facilitate the move, the U.S. Department of Energy has backed Dow's efforts with a $17.8 million tax credit that will help the company launch an initial market test of the product later this year.
Sunny future: Dow Chemical hopes to transform the solar power industry by integrating solar cells with conventional roofing shingles .
Credit: Dow Chemical

In October 2009, the chemical giant unveiled its product, which can be nailed to a roof like ordinary shingles by roofers without the help of specially trained solar installers or electricians. The solar shingles will cost 30 to 40 percent less than other solar-embedded building materials and 10 percent less than the combined costs of conventional roofing materials and rack-mounted solar panels, according to company officials.

Dow isn't the first company to incorporate solar cells into building materials. In recent years, a number of leading solar manufacturers have launched small lines of solar shingles, tiles, and window glazes. But as Dow looks to bring its shingles mainstream, other solar manufacturers are backing away from the products. Suntech Power, the Chinese solar maker, and the largest crystalline silicon photovoltaic manufacturer in the world, has several integrated solar systems on the market, but with the recent downturn in new housing construction, the company has focused instead on ramping up conventional photovoltaic panel output, says Jeffrey Shubert, Suntech Power marketing director for North and South America.

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http://www.technologyreview.com/business/24383/

[Old Codger]

1. I'm not sure

What the real cost of going full solar panels is but I am pretty sure that the 10% less than a new roof and solar panels is still way too expensive for most people also you still need to live somewhere that solar makes sense... I am in Oregon and even if not sunny enough in the winter to work well I would seriously consider solar if costs ever get down to a price that actually makes sense,. Hopefully if they really work well and demand rises enough prices will come down enough to be within range.

[kristopher]

2. ^^+

[joshcryer]

6. The cost will go down and those guys you see in the summer knocking on doors...

...asking if you want a new roof (they pay for shingles, then install, then you pay) get a hold of 'em. I don't have raw stats but you're looking at hundreds of thousands of new roofs installed yearly.

[progressoid]

3. Another ass backward tax credit.

Why not give US a tax credit so we can afford to install them.

[kristopher]

4. Install what?

The products that didn't get built?

Not to mention the fact that there ARE homeowner tax credits for energy efficiency and renewable energy investments.

[Old Codger]

5. A problem

With those tax credits is I have no tax liability so a credit is useless for my purposes...

[garybeck]

7. 10% better upfront price isn't worth it if they degrade.

Amorphous solar cells have shown to degrade over time compared to crystalline solar panels. I would pay 10% more for crystalline and just attach them to my roof.

[kristopher]

8. I don't disagree but...

Would you expand your comments a bit? Especially as to what you see as the cause of the degradation.

[garybeck]

9. I can't do that

I can barely explain to you how amorphous panels are made, let alone why they degrade more than crystalline cells. I would imagine that simply the crystalline form is more stable. but beyond the how and why, we know from years of testing that amorphous silicon solar panels degrade significantly more. There is a new technology called CIGS however, which is not made from crystalline cells, and is more like amorphous panels. The thing is, it's so new we don't know what its degredation curve is like. Same thing with the new "nanosolar" panels. If the savings were 50% or more I would go for it, but 10%? not a chance.

another problem with the roof panels is that if you have a problem, it's much more expensive to tear up your roof, than it would be to simply replace a broken panel.

another thing, the article incorrectly says that roofers will be able to install the systems without help from electricians. That's pure bull. sure maybe they can install the panels, but that is only part of the system. The inverter, disconnects, monitoring system, etc all has to be installed by a qualified electrician.

for years people have been talking about roof panels, like they're the answer to everything. I don't see the real value of combining a your roofing system with your electric system. Think of your kitchen... would you want to combine your blender with your wall? Then if your blender ever craps out on you, you have to replace your wall AND your blender. why not just keep them separate?

we should stop focusing on the roof panels and strive to bring down the cost of solar panels, with tax incentives on retail purchases and research grants for new technologies that lower price (much more imporatant than increasing efficiency). we are already at a tipping point where the payback is becoming reasonable in some areas.

[kristopher]

10. You can't take this as an indication of where the technology is across the board.

I think the problem is related to flexing of the substrate. So the shingles might be subject to it or they might not. Nanosolar is selling their panels for $1/w and their production cost (a secret of course) is thought to be about $0.30.

Solyndra has a unique thin film product that doesn't have the problems with degradation. It also dramatically reduces the criticallty of the angle of installation and wind drag - thus dramatically reducing installation costs. They aren't selling on the retail market yet as their production can't keep up. In spite of a brand new factory they are sold out 3 yrs in advance to commercial clients and utilities.

Things are coming along apace. (How often do you get to use that word?)

[garybeck]

11. flexing the substrate

that's not the reason for degredation. rigid amorphous panels have the same degredation as flexible.

not familiar with Solyndra, but i'm always ready for something new! I just like to be objective and a little skeptical. I've seen a lot of "new promising technologies" come and go, while the crystalline panels continue to go up and put out power.

cheers

[kristopher]

12. Please define specifically what you mean by "amorphous solar cell". nt

[garybeck]

13. there are two main types of solar panels, crystalline and amorphous.

crystalline is when they grow silicon crystals and slice them into wafers. you can easily tell these because you see a bunch of squares or circles on the panel that are all wired together. the other type, amorphous, is made without growing crystals. there are various methods, but a material is attached to a substrate and this creates a uniform, usually black, solar collector. If it is on a flexible substrate, the solar panel is flexible. but many times the material is rigid, like glass or plexiglass and this creates an amorphous solar panel that is rigid. You can tell these because there are no individual cells on the panel. here's an example:





to compare the two, crystalline panels:

1) degrade less
2) are always rigid
3) have individual cells
4) are made from crystals
5) generally cost less per watt if you get ~50 or more watts
6) are more efficient (watts per square meter)
7) are generally a little more affected by partial shading than amorphous panels

hope that helps

[kristopher]

14. I think we are talking about different types of cells.

Amorphous silicon and CIGS thin film.

The CIGS cells are stable except as they are subject to degradation due to flexing. You are back in the 90s.

[garybeck]

15. no i'm not stuck in the 90s :)

I'm not stuck in the 90s, but you blew my cover, I have been doing this for quite a while. i mentioned CIGS several posts up and I said that they are fairly new and we don't know about the longevity, as much as we do with traditional amorphous. Yes, I do sometimes (incorrectly) interchange "amorphous" with "thin film" because for many years what we call "amorphous silicon" was basically the only type of thin film technology available. to clarify, amorphous (a-Si), CIGS, and CdTe are three types of of the broad category, thin film.

CIGS is still fairly new, and while it seems promising, I have yet to see a CIGS product that I would put on my roof because the price is still better with the more proven crystalline technology.

[kristopher]

16. Dear Gramps,

:) Enjoyed the dialog and learned some things, thanks. I came across this and thought the last 2 paragraphs made it worth sharing.

http://techon.nikkeibp.co.jp/article/HONSHI/20091029/177088/