Efficiency of solar cells doubled (and they now look beautiful too)
Currently, the most advanced commercial solar cells are around 25% efficient, converting a quarter of the suns free energy into useable power. We use silicon, which is cheap to manufacture and brings solar down to a cost point where it can now feasibly compete with fossil fuel (barring power storage). But, it’s still a way off from completely trumping fossil to become the dominant power source on planet Earth. But things may be about to change.
John Rogers, of the University of Illinois and his company, Semprius have devised a way of converting up to 50% of the sunlight into useable energy. How? He’s stacked them. Where there would be one solar cell, there’s now four, piled on top of each other, drastically increasing it’s power yield. The Economist wrote;
Semprius’s panels are now being tested at 14 sites around the world. How much they will cost to make when manufacturing is running at full tilt is not yet clear, but Dr Rogers said that Siemens, a big German firm which is one of Semprius’s investors, reckons that they have the potential to produce cheaper electricity than coal-fired generators can. Solar energy obviously cannot replace fossil fuels completely until the problem of banking some of what is collected during the day, for use at night, is solved. But at this sort of cost it can make a useful (and unsubsidised) contribution.
The new panels have aesthetic advantages, too. The 99.9% of them not covered by stacks can be used for art. Seen from the sun’s point of view (ie, straight ahead), they appear black because the lenses are focused on the stacks, which absorb all the light falling on them. Viewed obliquely, however, their foci are on other parts of the panel. The result, as the picture shows, can be quite pleasing—and certainly prettier than a coal-fired power station.
You can read more about the science behind this discovery and exactly how Dr Rogers got around some of the fundamental design and production problems by reading the full report from The Economist. The technology is still not totally cost efficient due to the use of certain materials (arsenic, gallium and indium) but while current PV has to cover the entire panel, Dr Rogers system is made up of a matrix of dots, covering a mere 0.1% of the surface and saving costs. With a whole host of other technology such as Solar 3D about to make it mainstream, this is, as ever, a very exciting time for solar.
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