PV’s bright future?

Window coating could be low-cost solar breakthrough Price is still a real barrier to household-level photovoltaic power. But a special coated window glass, developed at the Massachusetts Institute of Technology, could help crack that problem. As a spin-off benefit, it could make colourfully tinted panes a new badge of honour for switched-on microgen homes.

What the MIT experts have done is work out how to use a special paint on the glass surface to trap sunlight in the pane, and emit it at different wavelengths, so the light travels to the edge of the window. Solar cells located around the edge can then convert it to electricity.

It’s an “exciting” technology, agrees Richard Guy, advanced PV research accelerator manager for the Carbon Trust.
 
The crucial point, he says, is that the expensive solar cells only coat the edge of the glass, so fewer are needed. Other approaches use lenses or large optics to direct the light towards clusters of solar cells, but these techniques require precision engineering and funding. The paint coating promises to be much cheaper to install – and can also make existing solar panels more efficient.
 
“This technology has been talked about for 20 years or so,” says Guy, “so if someone can chip away at the practical side and make it cost-effective, so much the better. What's also interesting is that you can re-emit the light at whatever wavelength you like, so you can make your windows fluorescent green or blue – which could have some exciting applications.” – Louise Vennells

5 September 2008

Louise Vennells

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