Shanghai engineers have found a way to cut noise pollution and reduce the types of emissions responsible for global warming at the same time.

In what is admittedly a small step in the bigger battle against pollution, the city is embedding solar cells in sound-proofing boards that will be placed along Metro Line 3.

The boards, fitted with photovoltaic cells that turn sunlight into electricity, are now being installed between Changjiang Road S. and Yingao Road W., an elevated Metro route, said Gao Guorong, manager of the technology and equipment department of Shanghai Metro Operation Co.

Gao said the pioneering program is supported by technical expertise from the Shanghai University of Electric Power.

The 360-meter-long stretch of boards installed between the two stations cost 600,000 yuan (US$87,889).

The technology may be used at more Metro stations if the cost can be reduced. About 200 square meters of boards fitted with solar cells can generate 5,000 kilowatt-hours of electricity every year, offsetting about 3,500 kilograms of carbon dioxide discharges from traditional power plants producing the same amount of electricity.

Electricity from the Line 3 cells will be used to light nearby Metro stations.

While solar energy is clean and renewable it is more expensive that power from coal-fired plants. Without government subsidies, there is little incentive to go solar, insiders said.

China's biggest solar power energy station is in Shanghai's Chongming County.

The station was tested and connected to the Shanghai power grid in September 2007. The government buys the electricity for 4 yuan per kilowatt hour.

Energy experts have urged the government to provide more support to solar energy so that more families will choose the renewable energy source.

(Shanghai Daily November 11, 2008)