Solar Power Coming to a Boil

January 31, 2009 

USA Today; New York
After emerging in 2006 from 15 years of hibernation, the solar
thermal power industry is experiencing a resurgence, with plenty of new capacity coming online worldwide. During the 1990s, cheap fossil fuels,
combined with a loss of state and Federal incentives, put a damper on solar
thermal power development However, recent increases in energy prices, escalating
concerns about global climate change, and fresh economic incentives are
renewing interest in this technology. Considering that the energy in sunlight
reaching the Earth in just 70 minutes is equivalent to annual global
energy consumption, the potential for solar power virtually is unlimited.
With concentrating solar thermal power (CSP) capacity expected to double  every 16
months over the next five years, worldwide installed CSP capacity
will reach 6,400 megawatts in 2012 - 14 times current capacity.

Unlike solar photovoltaics (PVs), which use semiconductors to
convert sunlight directly into electricity, CSP plants generate electricity
using heat Much like a magnifying glass, reflectors focus sunlight onto a
fluid-filled vessel. The heat absorbed by the fluid is used to
generate steam that drives a turbine to produce electricity. Power generation
after sunset is possible by storing excess heat in large, insulated tanks
filled with molten salt Since CSP plants require high levels of direct solar
radiation to operate efficiently, deserts make ideal locations.

Two big advantages of CSP over conventional power plants are
that the electricity generation is clean and carbon-free and. since the sun is the
energy source, there are no fuel costs. Energy storage in the form
of heat also is significantly cheaper than battery storage of electricity,
providing CSP with an economical means to overcome intermittency and deliver
dispatchable power.

The U.S. and Spain are leading the world in the development of
solar thermal power, with a combined total of more than 5,600 megawatts of
new capacity expected to come online by 2012. Representing over 90% of the
projected new capacity in that span, the output from these plants
would be enough to meet the electrical needs of more than 1,700,000 homes. The
largest solar thermal power complex in operation today is the Solar
Electricity Generating Station in the Mojave Desert in California.
Coming online between 1985 and 1991, the 354megawatt complex has been
producing enough power for 100,000 homes for almost two decades. In June 2007,
the 64-megawatt Nevada Solar One plant became the first multi-megawatt
commercial
CSP plant to come online in the U.S. in 16 years.

Today, more than a dozen new CSP plants are being planned in
the U.S., with some 3,100 megawatts expected to come online by 2012. Some
impressive CSP projects in the planning stages include the 553- megawatt Mojave
Solar Park in California, the 500-megawatt Solar One and 300-megawatt
Solar Two projects in California, a 300-megawatt facility in Florida, and the
280-megawatt Solana plant in Arizona.

In Spain, the first commercial-scale CSP plant to begin operation
outside the U.S. since the mid 1980s came online in 2007: the
11megawatt PS10 tower. The tower is part of the 300-megawatt Solucar Platform,
which, when completed in 2013, will contain 10 CSP plants and produce enough
electricity to supply 153,000 homes while preventing 185,000 tons of
carbon dioxide emissions annually. All told, more than 60 plants are in the
pipeline in Spain, with 2,570 megawatts expected to come online by
2012.

Economic and policy incentives partly are responsible for the
renewed interest in CSP. The incentives in the U.S. included a 30% Federal
Investment Tax Credit (TTC) for solar through the end of 2008, which
has good prospects for being extended. Moreover, the Renewable Portfolio
Standards hold sway in 26 states. California, for instance, requires
that utilities get 20% of their electricity from renewable sources by
2010, and Nevada requires 20% by 2015, with at least five percent from solar
power. In the Southwest, the cost of electricity from CSP plants (including the
Federal ITC) roughly is 13 to 17 cents per kilowatt-hour, meaning
that CSP with thermal storage is competitive today with simple-cycle natural
gas-fired power plants. The Department of Energy aims to reduce CSP
costs to seven to 10 cents per kilowatt-hour by 2015 and to five to seven
cents by 2020, making CSP competitive with fossil-fuel based power sources.

Outside the U.S. and Spain, regulatory incentives in France,
Greece, Italy, and Portugal are expected to stimulate the installation of
3,200 megawatts of CSP capacity by 2020. China anticipates building 1,000
megawatts by that time. Other countries developing CSP include
Australia, Algeria, Egypt, Iran, Israel, Jordan, Mexico, Morocco, South Africa,
and the United Arab Emirates.

A study by Ausra. a solar energy company based in California,
indicates that more than 90% of fossil fuel-generated electricity in
the U.S. and the majority of U.S. oil usage for transportation could be
eliminated using solar thermal power plants - and for less than it
would cost to continue mipotting oil. The land lecjuirement for the CSP
plants would be roughly 15,000 square miles (the equivalent of 15% of the
land area of Nevada). While this may sound like a large tract CSP plants use
less land per equivalent electrical output than large hydroelectric dams when
flooded land is included, or than coal plants when factoring in land used for
mining. Anotiier study, published in Scientific American, proposes
using CSP and PV plants to produce 69% of U.S. electricity and 35% of total U.S.
energy, including transportation, by 2050.

Copyright Society for Advancement of Education Jan 2009