PG&E contracts solar thermal-biomass hybrid power

LOS ANGELES (Reuters) - California utility PG&E Corp said on Wednesday it has contracted with a renewable energy unit of Portuguese conglomerate Martifer for 106.8 megawatts (MW) of solar thermal-biofuel hybrid power.

Two projects, which will provide enough power for nearly 75,000 homes in northern and central California, combine solar thermal technology with steam turbines powered by gas produced by local agricultural waste and livestock manure.

"This hybrid technology combines two renewable resources abundant in California -- solar energy and biofuel," Fong Wan, vice president of energy procurement for PG&E, said in a statement.

The plants will be located near Coalinga, California, in the center of the state, and will help PG&E reach the state-mandated goal of increasing the amount of electricity it produces from renewable sources. The projects are expected to begin operations in 2011.

Solar thermal power plants use the sun's heat to run steam turbines that produce electricity and are mostly located in sun-drenched states such as California. Advocates say the technology is a viable replacement for fossil-fueled power plants due to their large scale, but detractors argue the power produced is too inconsistent because it requires the sun to be shining.

Martifer's hybrid technology attempts to solve that problem by using biomass gas to allow the solar thermal plants to keep running even when the sun is not shining.

"When the sun is shining during peak hours, it will just be the solar facility," said Andrew Byrnes, one of the project's developers. "As the sun sets, biomass will be available to support the solar generation, and then at night the biomass will run purely on its own."

Ricardo Abecassis, president of Martifer Renewables Solar, said in the statement that power generated by the solar thermal-biofuel hybrid plants would be cost-competitive with energy from conventional power plants, such as those fueled by natural gas or coal.

(Reporting by Nichola Groom; editing by Jeffrey Benkoe)