When a penny stock outfit working with a University of South Florida professor announced it had a clear solar window last year – a solar cell you could spray onto a backing that would provide power but still let you use the window – I was more than a little skeptical.
But now MIT has announced a prototype of a completely clear solar cell http://web.mit.edu/newsoffice/2011/transparent-solar-windows-0415.html and I’m a little less skeptical.
Vladimir Bulovic and Richard Lunt have published a paper on their finding in Applied Physics Letters. The cell has a maximum efficiency of 1.7%, using mainly light in the near-infrared spectrum while remaining 55% transparent. (Think tinted glass.)
This picture of Lunt holding a prototype, photographed by Geoffrey Supran of MIT, is all over the Net. The key, says Energy Harvesting Journal, is that these cells would have very low installation costs, adding only marginally to the price of installed glass (when you add in the frame and the normal installation).
This could create markets among mainline window companies, both residential and commercial. As many homeowners are looking to replace old windows and frames purely to save on heating and cooling costs, the extra juice could clinch a lot of deals – even if you’re just powering the flat panel TV and the home PC.
Lunt’s own view is that these windows could find their way into skyscrapers or greenhouses. An office tower couldn’t power itself with solar windows at the present efficiency, he admitted, but greenhouses could easily be net sellers of electricity. He also thinks that the cells could be stacked, multiplying their efficiency.
What’s exciting about this, to me, is that this is coming from respected researchers at a major institution, who have published their theoretical work in a real journal, and who aren’t flogging stock, who are admitting the hurdles they still have to cross.
This is not to say that MIT doesn’t have an agenda. Just that its agenda is MIT. (As you may be able to see from the seal, the institution turns 150 this year.)
MIT seems to have released this news in line with Earth Day, alongside separate research from the Biomolecular Materials lab of Angela Belcher, published in Nature, demonstrating how viruses can help align carbon nanotubes so they’re finally useful in solar structures, not only delivering increased efficiency to panels but self-repair capabilities.
The Belcher team thinks this can increase the efficiency of current panels by up to one-third, and maintain that efficiency for much longer.