Whatever happened to thin, adhesive solar panels?

I seem to remember reading in Outside that research was being done to create thin, adhesive solar "panels" that could be affixed to windows. Any progress on that front? y Minnesota


Yes, the exciting progress of creating thin, relatively inexpensive solar film that can be easily rolled onto a roof or sprayed onto a window has been covered in Outside and in my book, Greasy Rider .

In fact, there's so much buzz around the concept that one of its leading developers, Nanosolar, received more venture capital in 2008 than any other startup—in any industry—in the country, at nearly $300 million. Second place went to another thin film solar firm, Solyndra, at $219 million in funding. And it's safe to say that in these times, venture capitalists are looking for the surest bets possible.

Sadly, though, the era of thin film solar has not yet fully arrived, and there's no guarantee that it ever will. The challenge is economics—as it is for all solar power. To explain, I need to give you some background. The traditional silicon wafer-based photovoltaic cell that people generally put atop their homes today converts only about 20 percent of the sun's energy into electricity. On top of that, it's expensive to build and install. During its 25- to 30-year lifetime, the cost of the power generated by a rooftop system is about 30 cents per kilowatt hour. By contrast, a new coal-fired power plant delivers electricity at about 10 cents per kilowatt hour. To level the playing field for solar panels, the federal government and many state governments must offer generous tax incentives to people who install them.

Makers of thin-film solar technology think they can generate power closer to the 10-cent range by radically reducing manufacturing costs. Their methods generally involve using an alternative material to silicon that's sprayed onto glass or a thin film (like newspapers being run through a printing press). The challenge is that thin film solar technology is even less efficient at converting the sun's energy into electricity, at about 10 percent, and it tends to break down more quickly—irony of ironies—when exposed to the sun.

Proponents of thin film convincingly argue that their method will be the most economical for generating solar power. Others researchers believe the answer lies in dramatically boosting the efficiency of traditional photovoltaic cells, so that the energy they generate will become cheaper. Both camps say they're on the verge of a breakthrough, but the true proof will come only when one of them rolls out a real product available on a mass scale. Personally, I don't care who wins the battle, as long as someone shows us a way to churn out solar power more cheaply than coal. Hopefully someone will soon.

Filed To: Nature, Culture

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