The race to bring the high efficiency solar cells used in space down to earth has intensified. The Rochester Institute of Technology’s NanoPower Research Lab just announced $846,000 in new funding from the Department of Defense to advance its development of nanotechnology structures in space solar cells.
These multijunction cells achieve efficiencies close to 40 percent by using expensive III-V semiconductor materials that are not economical in terrestrial applications. There are many researchers experimenting with the application of novel nanotechnologies to photovoltaics—carbon wires, tubes etcetera. RIT and a number of others are applying quantum dots to the existing space technology—triple-junction cells consisting of gallium arsenide, indium phosphide and geranium layers—to increase the absorption efficiency and light spectrum.
The incumbent space applications suppliers are gearing up for a terrestrial market. Emcore recently joined the Defense Research Projects Agency’s (DARPA) Very High Efficiency Solar Cell (VHSEC) program, which aims to double the efficiency of terrestrial solar cells over the next 50 months. VHSEC is providing $53 million in funding to program participants over the next few years, the largest commitment to solar research to date. The semiconductor component maker has reached 36 percent efficiency and plans to be in production this year. SpectraLab, the leading developer of solar cells used in space, holds the efficiency record at 39 percent. It says the terrestrial market is still a few years off.
A few stealth startups hope to get there sooner. Cyrium Technologies, which closed $3 million in venture capital financing in December, plans to reach 45 percent efficiency levels in 2007. The high price of silicon is making the semiconductor III-Vs more attractive, but the real challenge of bringing the material and fabrication costs down remains.
Space Island Group (SIG) has a bigger and bolder idea—producing solar energy with space satellites and beaming the power down to earth. In a press release out this month, SIG says it hopes to secure a $200 billion, 20-year energy purchase agreement with China or India to cover 5 percent of the project costs. SIG may also have to find some otherworldly project backers. The largest project financing to date, the channel tunnel, at $15 billion, involved a global syndicate of 220 banks.
Lien: EcoLog :: High Efficiency Solar Cells Coming to Earth.
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