Big Solar Project Planned for Arizona Desert

By Marianne Lavelle
US News and World Report
February 15, 2009

$1 billion installation would use parabolic mirrors to generate power southwest of Phoenix

It's a big week for mirrors in the desertówith two big southwestern projects
putting a spotlight on a form of big-scale solar energy that its most ardent
advocates believe has the best chance of expanding the nation's share of
electricity from renewable sources.

The Nevada Solar One solar power plant located near Boulder City, Nevada.People

Today, Arizona's largest utility, Arizona Public Service, is announcing plans
to build the world's largest "concentrating solar power" plant, a $1 billion
project to spread parabolic mirrors over a 3-mile-square stretch of desert 70
miles southwest of Phoenix. To be designed and built by the Spanish firm
Abengoa, it would generate 280 megawatts of electricity, or enough to power 70,000 homes.

That makes it four times as large as Nevada Solar One, near Boulder City, Nev.,
which last summer became the first CSP plant to open in the United States in
more than 17 years. Tomorrow, Nevada Solar One's developer, a rival Spanish
company, Acciona, plans a star-studded dedication ceremony for the facility,
with speakers including former astronaut Sally Ride, Apple cofounder Steve
Wozniak, and actor/activist Ed Begley Jr. The dedication, says Acciona Energy
North America chief executive Peter Duprey, is meant to get the word out that
concentrating solar "is a reality today, and we need to be developing it and exploiting it."

Unlike the solar energy that most people know, CSP doesn't use expensive
semiconductor material to transform the sun's energy into electricity. CSP
relies on mirrors to focus sunlight onto a heat transfer fluid, which in turn
heats water into steam, which turns turbines to generate power. The big Arizona
plant, which will be called Solana Generating Station, will take the technology
an exciting step forward by using molten salt to store solar energy for up to
six hours. "When the suns sets, this plant keeps on ticking," says Arizona
Public Service President Don Brandt. "We'll have solar energy in the dark."

The big issue with solar energy has been the cost. Brandt says the Solana plant
is expected to generate electricity at 12 cents to 14 cents per kilowatt-hour,
which is about 20 percent more than the cost of the other electricity that APS
generates with its mix of nuclear, natural gas, and coal. But Brandt notes that
since the price of the fuel is free, it's a 30-year contract with one big source
of risk eliminated. If natural gas prices increase or if coal-fired power is
made more expensive because of climate-change legislation, the CSP power could
end up being one of the lowest-priced forms of electricity in the utility's
portfolio. "Any business wants to diversify its sources of supply," Brandt says.
"That's why we feel right now the price is attractive. And you factor in the
possibility of natural gas prices rising or any carbon legislation, and I think
we'll look back in five years and think this was an absolute grand-slam home run."

In the late 1970s, it was the U.S. government that spurred research and
development of CSP technology through a series of experimental projects in the
Mojave Desertóone of which has been generating power for years, operated by
Florida Power & Light. But in recent years, European companies have taken the
lead in big-scale renewable energy projects, spurred by aggressive government incentives.

Duprey of Acciona says his company is building four more CSP plants in Spain and
has a number in development in the United States. He says all will be two or
three times the scale of Nevada Solar One, which was a $226 million project.
"This plant is on the smaller side, because we wanted to see how it would work,"
he says. "We had to start out with all new suppliers and build out this
industry. It's like an infantówe have to nurture it and bring it along.

"We believe the technology is proven, it's a matter of getting more suppliers
and getting competition among suppliers and driving the cost down," he says.


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