Experts Seek Cells That Soak up More Sun
SYDNEY (Agencies via Xinhua )-Scientists in sun-drenched Australia are improving the efficiency of solar cells, offering hope that solar power will be cheaper than coal-fired electricity within a few years.
Researchers at the University of New South Wales (UNSW) in Sydney are perfecting techniques using lasers to make the most efficient solar cells in the world.
"We're aiming to reduce solar power production costs to about half the level of coal-fired plants, and we think this is achievable in the next 10 years. There are certainly no technical impediments." said Professor Martin Green, group leader at UNSW's Centre for Photovoltaic Devices and Systems.
Unlike coal-fired power, solar energy does not pollute the air or contribute to global warming. Solar collectors have no moving parts and can produce power continuously for 30 years before needing maintenance. Excess solar energy can be stored in batteries for use at night or on cloudy days.
But solar power has remained largely untapped because it is significantly more expensive than coal or hydroelectric power.
Photovoltaic cells use the sun's energy to dislodge electrons from atoms of silicon or other materials. The electron, with a negative charge, and the atom that released it with a positive charge, migrate to separate terminals, generating an electric current.
UNSW scientists say their cells have the world's highest efficiency — the ratio of the energy deposited as sunlight to the electricity produced — at 24.2 percent.
Scientists in the United States and Japan have recorded slightly higher efficiency rates, but these were attained with concentrated, not natural, light and were not independently confirmed, they said.
Ian Lowe, Griffith University scientist and former member of Australia's National Energy Research Council, said the UNSW cells would almost halve the cost of producing solar power.
Existing cells generate power for between 20 and 40 US cents per kilowatt hour, about the same as diesel generators, he said.
UNSW scientists believe they can eventually boost their efficiency to 26 percent, or nearer to what is considered the theoretical limit of 30 percent. This would cut costs to around five US cents per kilowatt hour.
If this was achieved, Lowe said, solar power would be a viable aJternative to existing energy sources, allowing utilities to lessen their reliance on oil as a source of power. "Oil is a very dodgy basket to put all of your eggs in." he said.
UNSW scientists are boosting their cells’ efficiency by using lasers to remove defects that impede the flow of sunlight into the electric contacts.
The cells are composed of tiny crystalline pyramids that capture and direct light energy into contact leads. The concept was invented at UNSW and is now used by researchers World-wide.
Group leader Green believes his team will be able to streamline the process and make it easier for mass production.
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