IBM makes solar energy child's play

The cost of developing high-capacity photovoltaic cells should fall significantly, as a result of a marriage between computer cooling techniques and solar power generation.

Researchers at IBM have developed a system that uses magnifying lenses to greatly concentrate the amount of solar energy reaching a cell. The technique allows a centimetre-square photovoltaic cell to capture 230 watts of energy and generate 70 watts of "usable" electricity. According to IBM, this is around five times' the output of a conventional solar cell.

The process, according to scientists at the company, is similar to the way a child might use a magnifying glass to concentrate the sun's rays on to a small surface such as a piece of paper or tinder for a camp fire.

But just as a child's magnifying glass creates temperatures high enough to start a fire, so the IBM lens creates the equivalent power of 200 suns. This in turn leads to temperatures of up to 1,600 degrees Celcius - hot enough to melt stainless steel.

However, cooling techniques developed for computer chips allowed IBM to reduce temperatures to a far more manageable 85 degrees. A liquid metal of gallium and indium compound to dissipate the heat.

"We believe we can drive big change for an entire industry, and advance the basic science of solar cells," said Dr Supratik Guha, lead scientist for photovoltaics at IBM.

Earlier this year, researchers at Cambridge University suggested solar and wind power should be used to run computers.