IMPROVED SCHOTT RECEIVER TECHNOLOGY WILL REDUCE MAINTENANCE COSTS AND ENABLE NEW SOLAR THERMAL POWER
SCHOTT Unveils New Solar Receiver Tubes At GroundBreaking for the Largest u.S. Solar Thermal Power Plant To be Built In 15 Years
February 11, 2006 (Boulder City, NV) - As Solargenix/Acciona executives and federal, state, and local officials broke ground nearby to symbolically start construction on the 64MW Nevada Solar One solar thermal power plant, SCHOTT officially introduced to the public its new PTR 70® solar receiver, which will lie at the heart of Solargenix's new power plant.
The SCHOTT receivers convert energy from the sun into electricity by using concentrated solar radiation from the plant's parabolic mirrors to increase the temperature of the thermo-oil Heat Transfer Fluid (HTF) flowing through the receiver to over 750° F [Figure 1]. This heated fluid is then used to turn water into steam, which drives a turbine and generates electricity [Figure 2]. Solargenix plans to use 19,300 of SCHOTT's PTR 70 receivers at Nevada Solar One.
Nevada Solar One 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 nation's highways.
"Solargenix's decision to use SCHOTT's new PTR 70 receivers at the Nevada Solar One power plant strengthens SCHOTT's position as a global leader in the solar receiver market," said Dr. Udo Ungeheuer, Chairman of the SCHOTT Management Board. "We are pleased to contribute a key component to this solar thermal power plant, which will be a shining example to the world of how advanced technologies can be used to generate clean electricity."
Technological Advancements Lower Costs, Improve Efficiency
SCHOTT 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 receiver's bellows and glass-to-metal seals so that the amount of the tube's active area, used to capture energy from the sun, has been increased to 96%.
"Solar thermal power plants have become a real alternative to conventional fossil fuel power plants because they are able to generate clean electricity in a dependable and cost-effective manner," said Steve Russo, head of SCHOTT's Solar Thermal business in North America. "By using our glass and advanced material expertise to make solar thermal power plants more efficient and reliable, SCHOTT is part of the reason why communities in sunbelt areas around the world are increasingly exploring the use of solar thermal power to satisfy their growing energy needs."
"The advancements that SCHOTT engineers have made in solar receiver technology are one of the key reasons we are able to break ground on this new power plant today," said Solargenix President John Myles. "Their work demonstrates how human ingenuity will enable the world to meet its growing demand for energy in an environmentally friendly manner."
SCHOTT has increased the efficiency and reliability of its new PTR 70 receivers by developing:
· New anti-reflective glass coatings: Previous glass coatings failed to adhere to solar receivers' borosilicate glass outer envelope tubes over time. 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 penetrate the receiver and heat the heat 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. SCHOTT's 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.
· 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 as possible needs to be used to heat the HTF that flows within. By positioning the receiver's 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 plant's 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. "The advancements that SCHOTT has made in solar receiver technology will enable Nevada Solar One to spend less money to make more electricity, benefiting the plant's owner Solargenix, the plant's utility customers, and ultimately Nevada's energy consumers."
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, SCHOTT's holding companies SCHOTT Corporation and its subsidiary SCHOTT North America, Inc. employ about 2,500 people in 16 operations.
The company's technological and economic expertise is closely linked with its social and ecological responsibilities.
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 future technology for centralized power generation along the Earth's sunbelt.
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