US scientists unveil 15% efficient solar window

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Last year, a group from the University of Michigan published research suggesting that the United States could get 40% of its electricity from solar windows. Their projection suggested 5 to 7 billion square meters of usable window space existed, and that a 5% efficient solar window product applied across the area would get close that 40% number.

The Department of Energy’s (DOE) Solar Energy Technologies Office has awarded a team from the University of Michigan a $1.3 million grant to further develop its organic solar cell window technology from its current 8% efficiency to a goal of 15% efficiency. The project, Semi-Transparent, Reliable and Efficient Scalable Organic Solar Cells for Building Integrated Applications, hopes to produce their 50% transparent project on rolls at low costs and quickly.

The goal of the overall program from the Solar Energy Technologies Office, was to both support early stage research but also to help improve the pathway to move products from lab to commercialization.

While the specific technology to be researched in this grant wasn’t made available, a team lead by similar members at the University of Michigan did project back in April that they were already hitting 15% with their organic solar cells, and that they projected 18% soon.

The researchers estimated that at 15% efficiency and given a 20-year lifetime, organic solar cells could produce electricity at a cost of less than 7¢/kWh (there was no mention of subsidies, but the assumption is unsubsidized).

The group was able to make a jump from 11% efficiency, that they said the organic solar cell industry had plateaued at, by stacking two organic solar cells—one capable of absorbing light from the visible spectrum starting at 350 nanometers in wavelength, and another capable of absorbing near-infrared light up to 950 nanometers in wavelength. The team demonstrated that their new design, materials and process have a high fabrication yield of over 95%.

With building integrated photovoltaics (BIPV) starting to catch traction in a couple of limited spaces – for instance Onyx Solar:

And of course, there are new solar shingles coming – the Tesla Solar Roof, and the RGS Energy Powerhouse. And some of that solar roof stuff is being pushed by the California Residential Rooftop Solarmandate. What ought also be discussed is that the California mandate will move to government structures, and then commercial structures soon.

With 5 to 7 billion of glass space per the Michigan study, and the State of California moving toward requiring commercial solar – maybe this space has a lot going for it as we slowly replace and upgrade our building stock.