GM Installs World's Biggest Rooftop Solar Panels

By Graham Keeley
The Guardian
July 9, 2008

The world's largest rooftop solar power station being built by General Motors at
their factory in Zaragoza, Spain

The largest rooftop solar power station in the world is being built in Spain.
With a capacity of 12 megawatts of power, the station is made up of 85,000
lightweight panels covering an area of two million square feet.

Manufactured in rolls, rather like carpet, the photovoltaic panels are to be
installed on the roof of a General Motors car factory in Zaragoza, eastern Spain.

General Motors, which plans to install solar panels at another 11 plants across
Europe, unveiled the €50m (£39.73m) project yesterday. The power station should
be producing energy by September.

The panels will produce an expected annual output of 15.1m kilowatt hours (kWh)
- enough to meet the needs of 4,600 households with an average consumption of
3,300kWh, or power a third of the GM factory. The solar energy produced should
cut CO2 emissions by 6,700 tonnes a year.

Energy Conversion Devices, the US company producing the panels, said it would be
the largest rooftop solar array in the world. Energy Conversion will supply the
equipment to two other companies, Veolia Environment and Clairvoyant Energy,
which will lease the rooftop space from General Motors and operate the
installation. The rooftop power station is also supported by the regional Aragón government.

Carl-Peter Forster, GM European president, said: "GM's Zaragoza plant will
become home of the biggest rooftop solar power station worldwide. This has
significant potential to reduce costs at the plant."

Solar panels on houses usually produce a few kilowatts of power. On large
commercial buildings, installations of one or two megawatts are now common. A
one-megawatt installation could run about 1,000 air-conditioners while the sun is shining.

The Solar Energy Industries Association, a trade group based in Washington, said
the largest installation planned in the US was in Atlantic City, where a
convention centre will produce 2.36mW of power. Another US solar panels company,
Southern California Edison, is to install 250mW of rooftop solar arrays spread
over 100 or more roofs.

Blessed with almost year-round sunshine, Spain's socialist government is trying
to capitalise on this natural resource. In an effort to encourage private
individuals and companies to install solar power, Spain introduced subsidies of
€0.42 per kilowatt per hour.

But the Spanish government is considering reducing this subsidy in September, a
move which is likely to face opposition from within the solar energy industry.


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