The largest series of solar installations in history, more than
1,300 megawatts, is planned for the desert outside Los Angeles,
according to a new deal between the utility Southern California Edison
and solar power plant maker, BrightSource.
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 technology isn't the familiar photovoltaics — the direct
conversion of sunlight into electricity — but solar thermal power,
which concentrates the sun's rays to create steam in a boiler and spin
a turbine.
"We do see solar as the large untapped resource, particularly in
Southern California," said Stuart Hemphill, vice president of renewable
energy and power at Southern California Edison. "It's barely tapped and
we're eager to see it expand in our portfolio."
BrightSource is the reincarnation of Luz International, which built
the only currently operating solar thermal facility during the 1980s in
the Mojave Desert. After natural gas and energy prices plunged in 1985,
that operation became unprofitable. The group's engineers and founders
moved the business to Israel, where they continued to work on their
technology.
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.
"Coupled with our earlier partnership with PG&E, this agreement
proves that the energy industry recognizes the important role that
solar thermal will play in the energy future," John Woolard, CEO of BrightSource, said in a press conference with reporters.
While Brightsource is a leader in the field, a variety of other
companies compete in the solar thermal space. Google.org and other
investors have backed eSolar's with $130 million funding. Abu Dhabi's clean-tech fund, Masdar, has funded a $1.2 billion solar thermal company called Torresol. Yet another player, Abengoa, recently signed a $4 billion deal with Arizona Public Utilities, and Stirling Energy Systems, a
company that has adapted the Stirling Engine, a 200-year-old invention,
for concentrated solar power, even pulled in a $100 million investment.
The first of the seven installations will be in Ivanpah,
California and will be rated at 100 megawatts of peak power. The
companies expect it to produce 286,000 megawatt hours of electricity
per year. When all the installations are finished, they'll stretch over
10,500 acres of land.
Southern California Edison's Hemphill said that the new plants would
provide a valuable hedge against volatile natural gas prices, noting
that his company had seen natural gas prices as low as $4 per thousand million
cubic feet (a standard industry measure) and as high as $16. Given the
variability of natural gas pricing, Hemphill said that his company did
not expect the solar thermal electricity to exceed the market cost of
electricity in California.
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.
Solar thermal is seen as a promising source of energy for city-scale
power because it works on very well established principles.
Photovoltaics have come down in price — and thin-film plastic solar
cells could get even cheaper — but the conversion of sunlight to
electricity remains a novel source of energy. The first working cells
were only built half a century ago, and they were truly something new
in the world.
Steam-driven turbines, on the other hand, make almost 90
percent of the world's electricity and their ancestry stretches back to
the start of the Industrial Revolution. Solar thermal engineers, then,
can use the knowledge gained from more than a century of tinkering at
coal, natural gas, and nuclear fission plants.
