Windows that Work as Solar Cells

The biggest problem with solar panels is that they're expensive. Solar power is actually the most expensive type of renewable energy. But a Swiss professor has just received the Millennium Technology Prize for developing low-cost solar cells that can be built into glass windows. So instead of installing solar panels on your roof; you'd just install them as windows, which you need anyway.

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Michael Gratzel spent two decades developing a revolutionary type of dye-sensitized solar cell called a Gratzel cell (guess where he got the name for it). The group that presented the award, the Technology Academy Finland, says this invention is a huge leap forward for solar technology.

In a prepared news release, the group says, "The price/performance ratio of Grätzel's dye-sensitized solar cells is excellent. [It] is a promising alternative to standard silicon photovoltaics."

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Gratzel says his technology was inspired by photosynthesis, the process whereby plants obtain energy from the sun. The natural process also inspired the inventors of a type of car that absorbs carbon dioxide and emits oxygen.

In a YouTube video, Gratzel says, "I was always intrigued with natural photosynthesis, the way the plant uses molecules to generate charges and separate those changes," he says. "Nature then uses those charges to make chemicals out of water, oxygen and out of CO2."

This technology was first built into consumer products in 2009. A company called G24 Innovations developed a backpack that uses Gratzel cells to charge the batteries in portable electronics. 

These cells are part of a growing trend to use low-cost solar energy to power small devices like the iPhone. Even General Electric has hopped on the thin-film solar cell train.

Gratzel wants his solar cells to go big time, and dreams of the windows in New York high-rise buildings being transformed into electricity-generating panels. That sure beats sticking solar energy facilities in the middle of the desert and transporting that energy to places where people actually live. Progress!