GREEN EARTH Sinivasa Raghotham Around the world, governments and power utilities, struggling against skyhigh oil prices and global warming, are turning to solar power as the next big source. Here are some of the largest projects under implementation or planned. Gila Bend, Arizona 280 MW station, expected to cost $1 billion Expected completion date: 2011 A bengoa Solar is building a 1,900acre solar farm called Solana that will produce enough power to sup ply 70,000 homes. The project is based broadly on the same principles as the Stirling Energy Systems project in Mojave Desert. Some 2,700 sun-tracking mirrors will focus the heat to convert water into steam, which will drive turbines to produce electricity. The heated water can be stored, which enables turbine operation even after sunset and power can be supplied through the night. The Arizona Public Service company has contracted with Abengoa to buy the power produced for 30 years. Deming, New Mexico, USA 300 MW project, expected to cost $1.6 billion. Construction start: 2006; Projected completion date: 2011 G overnor Bill Richardson wants to make his state the "Saudi Arabia of renewable energy". The site chosen receives sun light 350 days a year. The Deming plant, being implemented by New Solar Ventures, is an integrated project that will feature a solar panelproducing factory and a billion-dollar solar farm in some 3,200 acres of land. The power produced will be supplied to 240,000 homes. Tres Cantos, Spain 300 MW plant being built by BP, expected to cost $400-470 million Construction start: 2007; Expected completion date: 2010 B ritish Petroleum, now known as BP, is big on renewable energy. Its solar division is building a 300 MW solar station at Tres Cantos in Spain which serves as its European headquarters. BP is putting its high-quality screen-printed photovoltaic cells to work to improve the efficiency of its solar panels. The company is said to have obtained a 25year contract with the Spanish government to supply electricity from the plant. Mojave Desert, California, USA 500 MW station being built by Stirling Energy Systems Construction start: Mid-2008; Expected completion date: 2011 A rnold Schwarzenegger is no more a "terminator". In fact, he should be called a "beginator" for solar power. Under his governorship, solar energy projects have got a huge boost, so much so that California is set to become the world leader in the production and use of solar power. Phoenix-based Stirling Energy Systems (SES) is building the world's largest solar power station in the Mojave Desert in southern California. It will comprise 20,000 dish-shaped mirrors, each 38-foottall, spread over 4,500 acres of the desert. It will produce 500 MW of power when completed, and could expand to 850 MW. Each dish, called the SES SunCatcher, consists of 82 curved glass mirror facets, each 3-foot-by-four-foot, that focus solar heat onto a heater with hydrogen gas inside, called the Stirling Engine. As the gas expands, it creates enough pressure to start the engine and drive an electricity generator to produce 25 kW of power. The dish is designed to automatically track the sun and focus the solar heat onto the engine. Stirling also plans to build a 300 MW station in California's Imperial Valley. Ashalim, Israel 250 MW project, expected to cost $700 million Expected completion date: Not known I srael wants to build two solar thermal plants spread over 1,000 acres in the Negev desert. It has called for bids from companies around the world and plans to sign a contract by the end of the year. The country wants to produce five per cent of its electricity from solar energy by 2016.