Monday, August 18, 2008

Solar Efficiency Record Broken

Written by Hank Green

When it comes to eeking another fraction of a percentage point of power out of a solar panel, we're pretty good at not paying attention. I mean, what's the difference between 40.7% and 40.8% anyway?

Generally these efficiency gains aren't all that important to the future of the solar economy. Yes, it's a new world record, but the photovoltaic modules that are most economical are only like 20% efficient. They're better because they're cheaper...and these record-breaking panels are NEVER cheap.

But this one is worth talking about.

Scientists at the National Renewable Energy Laboratory in Colorado eeked that extra fraction of a percent out using a few very interesting techniques. Highly efficient solar cells have to split light into segments and then capture each hunk of wavelengths separately. This lets the panel be efficient across a wide spectrum.

This new chip uses an entirely different system to split the wavelengths (gallium indium arsenide and gallium indium phosphide...if you're curious.) The result is a much thinner and lighter solar cell that could even possibly be flexible.

The chips is also optimally efficient under concentrated sunlight. Concentrated sunlight is preferable because large areas of light can be concentrated on small areas of photovoltaic material. And since the PV material (especially this ultra-efficient stuff) is extremely expensive, using less per unit of sunlight captured is way better.

In short, this isn't just another tiny bump in efficiency, it's an entirely new solar cell, and one that could be very useful not just for satellites, but also for utility scale solar. Though, to be fair, the path to the commercial market is always pretty arduous for these new solar technologies.

Original here

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