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Nevada Solar Thermal Plant Breaks New Ground
350-acre solar power plant in Boulder City will be one of the largest
in the world, and one of the most efficient due to improvements in materials and
construction.
BOULDER CITY, NEVADA, USA -- Solar energy saw a
breakthrough this weekend with Solargenix's groundbreaking in Boulder City
Nevada for a 64 megawatt thermal power plant that will cover 350 square acres.
This marks the first Concentrated Solar Power (CSP) energy project in the U.S.
in more than 15 years.
Though other solar technologies look more promising in their cost per
kilowatt-hour, Solargenix President, John Myles, likes to think that this system
is "the lowest cost solar energy that can be produced today."
Named Nevada Solar One, the facility is expected to begin providing energy to
the grid in 2007 and will produce enough electricity to meet the energy demands
of about 40,000 households. The use of solar power to produce electricity at the
plant, rather than fossil fuels, will result in a reduction of greenhouse gases
equivalent to removing approximately one million cars from the nations
highways.
How it Works
At the heart of the array is a new PTR 70ฎ solar
receiver produced by Schott.
These receivers convert energy from the sun into electricity by using
concentrated solar radiation from the plants parabolic mirrored trough
reflectors, which increase the temperature of the thermo-oil Heat Transfer Fluid
(HTF) flowing through the receivers to over 750ฐ F. This heated fluid is then
used to turn water into steam, which drives a turbine and generates electricity.
Solargenix plans to use 19,300 of SCHOTTs PTR 70 receivers at Nevada Solar
One.
Improvements
Schott has developed new glass and steel coatings for the PTR 70 receiver,
making it more reliable and efficient than earlier models. In addition, Schott
redesigned the receivers bellows and glass-to-metal seals so that the amount
of the tubes active area has been increased to capture 96% of the maximum
possible energy from the sun.
Schott says that communities in sunbelt areas around the world are increasingly
looking to this technology to satisfy their growing energy needs.
The PRT70 receivers have the following improvements over earlier designs:
- New anti-reflective glass coatings: Previous glass
coatings failed over time to adhere to solar receivers borosilicate glass
outer envelope tubes. SCHOTT has developed a new anti-reflective glass
coating for its receivers that resists abrasion for years, while still
allowing more than 96% of solar radiation to reflect onto and penetrate the
receiver, heating the transfer fluid within.
- New absorptive steel coatings: In order to achieve
peak efficiency the steel absorber tube located inside the outer glass
envelope tube needs to absorb as much solar radiation as possible while
releasing as little heat as possible. SCHOTTs new absorptive steel
coating improves radiation absorption rates to 95%, while helping ensure
that no more than 14% of the heat from the steel tube is released
prematurely.
- Improved glass-to-metal seals: In other solar
thermal receivers, differences in the thermal expansion of the inner steel
tube and the outer glass envelope tube resulted in tube failure when there
were severe shifts in temperature. The new PTR 70 receiver uses a new
borosilicate glass with the same thermal expansion coefficient as steel. The
result is a receiver that can handle the changes in temperature that occur
as cool Nevada desert nights quickly become hot desert days. This
improvement was designed to reduce both maintenance time and the need for
replacement parts.
- A more efficient design: In order to maximize the
energy captured by the receiver, as much of the receiver tube as possible
needs to be used to heat the HTF that flows within. By positioning the
receivers bellows on top of its glass-to-metal seals, SCHOTT has been
able to expand the percentage of the length of the tube used to capture
solar radiation to 96%. An independent study by the German Aerospace Center
on the new PTR 70 tubes at the Plataforma Solar de Almeria testing site in
southern Spain has shown that this new design improves the receivers
overall efficiency by 2% over previous models and competitive products.
Even a small increase in a solar thermal power
plants efficiency and reliability can result in a large increase in kilowatt
hours of electricity generated or a significant reduction in plant downtime or
maintenance hours, said Alex Marker, SCHOTT Solar Thermal Research Fellow.
Many other companies are involved in other aspects of hardware and
construction. EPC of Houston is the main construction contractor.
Hydro, of Phoenix is building the aluminum tracking frames that suspend the
mirrors.
About SCHOTT
SCHOTT is a technology-driven, international group that sees its core purpose as
the lasting improvement of living and working conditions through special
materials and high-tech solutions. Its main areas of focus are the household
appliance industry, pharmaceutical packaging, optics and opto-electronics,
information technology, consumer electronics, lighting, automotive engineering
and solar energy.
SCHOTT has a presence in close proximity to its customers through highly
efficient production and sales companies in all of its major markets. It has
more than 17,000 employees producing worldwide sales of approximately $2
billion. In North America, SCHOTTs holding companies SCHOTT Corporation and
its subsidiary SCHOTT North America, Inc. employ about 2,500 people in 16
operations.
SCHOTT is one of the leading solar industry companies worldwide. The
international technology group supplies components for almost all photovoltaic
and solar thermal applications. PV solar electricity modules with various
performance ratings are used for decentralized power generation. Receivers are
the key components in solar thermal parabolic trough power plants, a mature
technology perfected over twenty years for centralized power generation along
the Earths sunbelt.
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Concept image of Nevada Solar One installation
SOURCES
ACKNOWLEDGEMENTS
See also
Page composed by Sterling
D. Allan Feb. 11, 2006
Last updated February 12, 2006
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