For the first time in 20 years, state energy regulators have approved construction on a solar thermal farm.

The California Energy Commission gave the Beacon Solar Energy project a unanimous go-ahead Wednesday. The installation, set to unfurl across 2,012 private acres in Kern County, is one of a group of solar proposals hustling to break ground before a federal grant expires at the end of the year.

Beacon Solar, a subsidiary of Florida-based NextEra Energy Resources, will build and manage the 250-megawatt Beacon site on the western edge of the Mojave Desert. Beacon first applied for approval in 2008.

The installation will use parabolic trough solar thermal technology. Long rows of curved mirrors will collect energy from the sun, heating tubes filled with fluid to help run a steam turbine generator.

The energy commission last approved a solar thermal project in February 1990, when it allowed a plant in San Bernardino County to move forward. But smaller arrays, which don’t require a license through the energy commission, have emerged since then.

Before the Beacon project breaks ground, however, it will probably have to secure a power purchase agreement with a utility. Chances aren’t looking good for California’s investor-owned utilities to meet a state mandate to get at least 20% of their electricity from renewable sources by the end of 2010.

-- Tiffany Hsu

Photo: Mirrors reflect sunlight onto water-filled pipes, which creates steam and, ultimately, electricity at AREVA Solar's 5-megawatt Kimberlina demonstration plant near Bakersfield. Credit: Robert Gauthier / Los Angeles Times