Thin-film solar is back in the news as Solexant, a company that’s been hiding out for the past two years, recently resurfaced, likely with the goal of raising more funds (see “Thin-Film Solar with High Efficiency”). A few years ago, thin-film solar was all the rage in Silicon Valley. It was supposed to be a cheaper alternative to conventional silicon solar panels, promising costs as low as a jaw-dropping $1 per watt. It fell out of fashion as conventional silicon solar panels first approached, and then dropped below that cost. Thin-film solar companies started failing, or being acquired for pennies on the dollar, or dropping off the radar, lurking at a low burn rate in the hope that the solar market will surge, creating demand for their product.

But they haven’t all died, and a few may yet survive to cash in on good times—if the solar market ever takes off again. Here’s the argument: 1) Thin-film solar can actually beat $1 a watt (as First Solar has shown). 2) Low price solar panels are opening up new markets, which could lead to a surge in demand. 3) The fastest, cheapest way to meet that demand could be building thin-film solar factories, since you can build those factories for a third as much as silicon solar panel factories (see “Is Thin-Film Solar Dead?”).

Here, however, is the main argument against thin-film. 1) Where we really need to reduce costs now is not in solar panels, but in everything else that goes into the final cost of solar power, including installation costs, which are now higher than the cost of the panels themselves. 2) One of the best ways to reduce installation costs is to use higher effiency solar panels—that way you can install fewer panels. 3) Thin-film solar panels are actually less efficient than silicon ones, so who would buy them?

Solexant has this going for it: it is switching from cadmium telluride to CIGS semiconductors, which can be more efficient. But the technology still won’t beat conventional silicon panels. And the company is going to have to keep treading water for years until the market picks up. It’s best hope might be getting acquired by a big company with the funds to keep it alive until the technology is needed.