"Spray-On" Photovoltaic Windows

New Energy Technologies, a solar energy startup here in the US, has developed a technique to manufacture “spray-on” photovoltaic windows. The technique should ramp up production speed and bring down costs.

First of all, what’s meant by a spray-on window? New Energy Technologies gives a good run-down of the product, which they call SolarWindow, on their site. The tech uses an organic solar array made up of extremely small solar cells–they measure about a quarter of the size of a grain of rice.

The Christian Science Monitor, in a story back on Earth Day, futher explains that NET developed plastic polymers that, when sprayed on a window, would produce electricity. The stuff is so effective as to harvest light even from northern exposure, and indeed even from indoor fluorescent lighting. “It will generate electricity even in low light conditions,” John Conklin, NET’s CEO, told the Monitor. NET teamed up with the National Renewable Energy Laboratory and the University of Florida to develop the tech.

The Engineer, which reported on the manufacturing breakthrough, says that the film can be sprayed on in an ultra thin, sub-micrometer layer. The breakthrough is important for American industry, because as the Monitor pointed out in April, while American firms experimenting in spray-on solar had the technical edge, Chinese companies were so far able to produce the stuff more cheaply.

And spray-on solar is more than just an eye-catching innovation. It’s potentially a revolution in solar power, a move away from the traditional rooftop solar array. “It puts energy harvesting everywhere,” said Ken McCauley of Konarka, an NET competitor, to the Monitor.

Everywhere, that is, assuming the cost of production could come down. The traditional method to make spray-on solar panels was something called vacuum deposition, which was time-consuming and expensive. But NET found a way to do what the Engineer calls “high-speed roll-to-roll and sheet-to-sheet manufacturing,” and it made the process possible at low temperatures and at ambient pressure.

At the end of the day, a major logjam in the ascent of solar power comes down to finance and cost-cutting. New Energy Technologies’ manufacturing innovation is a step in the right direction.