(Hat tip: Peak Energy) The bright prophecy of solar in America's southwest is just starting to bear fruit. The largest solar deal ever inked: a deal between the utility Southern California Edison, and solar power plant maker, BrightSource, for 1.3 gigawatts of solar installations - more juice than even the largest nuke plant. The deal calls for solar thermal power as opposed to conventional photovoltaic; solar thermal concentrates the sun's rays to create steam in a boiler to turn a turbine.
More detail from the Wired magazine article:
The momentous deal will deliver more electricity than even the largest nuclear plant, spread out among seven facilities, the first of which will start up in 2013. When fully operational, the companies say the facility will provide enough electricity to power 845,000 homes — more than exist in San Francisco — though estimates like that are notoriously squirrely.
The new deal breaks the company's own record for the largest ever solar deal. The new installations, when completed, will produce 3.7 billion kilowatt hours of electricity per year. Previously, they'd cut a deal to deliver 900 megawatts of power to the Northern California utility, PG&E.
The 1980s-era solar thermal plants use the oldest solar thermal technology around, known as a parabolic trough. Mirrors shaped like a paper-towel roll cut in half concentrate the sun's rays on a liquid. That heat can be transformed into various types of energy. The Luz fields made electricity, but Frank Shuman built a plant based on this principle to pump water in Egypt in the first decade of the 20th century.
The new design sounds more exciting. Mirrors that track the sun — heliostats — sit in a massive field around a tower with a boiler. All those mirrors concentrate the sun's heat on the boiler, which makes steam and drives a turbine.