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Model rendering of ISEGS, the world's largest solar power tower being built in California
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Google has chipped in a US$168 million investment in what will be the world's largest solar power tower plant.
To be located on 3,600 acres of land in the Mojave Desert in
southeastern California, the Ivanpah Solar Electric Generating System
(ISEGS) will boast 173,000 heliostats that will concentrate the sun's
rays onto a solar tower standing approximately 450 feet (137 m) tall.
The plant commenced construction in October 2010 and is expected to
generate 392 MW of solar energy following its projected completion in
2013.
Although
solar power tower development is currently less advanced than the more
common trough systems, they offer higher efficiency and better energy
storage capabilities. Parabolic trough systems consist of parabolic
mirrors that concentrate sunlight onto a Dewar tube running the length
of the mirror through which a heat transfer fluid runs that is then used
to heat steam in a standard turbine.
Solar
power tower systems such as the ISEGS on the other hand focus a large
area of sunlight into a single solar receiver on top of a tower to
produce steam at high pressure and temperatures of up to 550 ° C (over
1,000° F) to drive a standard turbine and generator. The ISEGS also uses
a dry-cooling technology that reduces water consumption by 90 percent
and uses 95 percent less water than competing solar thermal
technologies. Water is also recirculated during energy before being
reused to clean the plant's mirrors.
Overshadowing the 20 MW PS20 solar power tower plant in
Spain, the scale of ISEGS can't be overstated. It will be the first
large-scale solar power tower plant built in the U.S. in nearly two
decades and will single-handedly almost double the amount of commercial
solar thermal electricity produced in the U.S. today and nearly equal
the amount of total solar installed in the U.S. in 2009 alone.
The entire complex will consist of three separate plants developed by BrightSource Energy that
will be built in phases between 2010 and 2013. The energy generated
from all three plants will be enough to supply more than 140,000 homes
in California during peak usage hours, with the project contracted to
provide 1,300 MW to Southern California Edison and 1,310 MW to Pacific
Gas and Electric Company.
Google
says it has now invested over $250 million in the clean energy sector
but its $168 million investment in the ISEGS is the company's largest
investment to date. The size of the investment reflects Google's faith
in the technology and it hopes that other companies will follow its
example and make similar investments in renewable energy.