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Solar thermal power plant in the Mojave Desert in California with glass envelopes from SCHOTT |
Electricity from the desert
SCHOTT Solar
DESERTEC is a concept that originated in the United States (US) in the 1970s. It is now becoming a reality. German companies are working with partners from Algeria and Spain with the long-term goal of satisfying up to 15% of Europe’s electrical power demand with solar energy by the year 2050. To do so, the consortium is planning to build solar thermal power plants linked by a high-performance network which will bring clean solar power from North Africa and Arabia to Europe.
SCHOTT Solar is one of the initiators of this project. “With DESERTEC, we are laying the foundation for a sustainable European energy supply,” says Professor Udo Ungeheuer, Chairman of the Management Board of SCHOTT AG. “And with the receiver, we supply the heart of solar thermal power plants. In fact, we even view ourselves to be the technology and market leader in this area. We are working intensively on a new generation of receivers. The goal is to increase the process temperatures to more than 500 degrees Celsius. Also, with the help of an improved structural design, we are seeking to reduce the costs of generating electricity rather considerably.”
The technology behind DESERTEC
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SCHOTT Solar Receiver |
The project is based on parabolic trough power plants like those already used successfully in the US for over 20 years. It uses mirrors with a parabolic shape, arranged in long rows, which magnify the rays of the sun by up to 80 times onto a receiver inside the solar field of a power plant. Oil flows through this receiver and is heated up to around 400 degrees Celsius. Steam, that drives a conventional steam turbine, is generated inside a heat exchanger and modern storage technology enables the heat generated in the day to be used at night. The transfer medium circulating inside the solar field is a reservoir capable of bridging gaps caused by brief cloudy phases. Salt-based storage units also guarantee a dependable power supply for longer periods of several hours when the sun is not shining and thus ensure reliability.
The receiver is the key component. The better its quality is, the higher the efficiency of the power plant will be. It is one of the most sensitive parts because it is subjected to severe thermal and mechanical stress. In order to achieve a high degree of efficiency, receivers must offer as long a lifetime as possible. They must be able to resist effects of more than 20 years of the most intensive solar radiation. The coating on a receiver, often only a few hundred nanometres thick, needs to withstand temperatures of up to 500 degrees Celsius over two decades, while the system cools down to temperatures below zero degrees at night. In the past, receivers have met the extremes of this challenge to a limited extent.
SCHOTT Solar devoted four years of research and development work to developing a product with previously unmatched properties in radiation optics, efficiency and long-term stability. The team broke new ground in the area of construction design and materials technology and developed a receiver with mechanical and optical properties ideally suited to the extreme operating conditions inside these plants. Today, this receiver is setting new standards and is largely responsible for the fact that solar energy can be generated much more economically. This development makes solar power plants a true alternative to conventional fossil fuel power plants.
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| Europe’s first commercial solar thermal parabolic trough power plant near Granada (Spain) “AndaSol 1”. With its receivers, SCHOTT Solar supplied the heart piece of the power plant. The “AndaSol 1” power plant will produce around 180 million kilowatt hours of climate-friendly solar electricity per year. This would cover the electricity needs of 50,000 Spanish households or 200,000 individuals |
An economic driving force
Solar power plants can provide entire cities with power or, in the case of DESERTEC, a large portion of Europe. The economically weak regions around the Earth’s Sun Belt offer excellent development opportunities. Quite often, these areas lack a broad-scale reliable power supply, yet have considerable solar radiation. Aside from solar power plants, photovoltaic installations can be used as insular systems securing the local power supply in rural regions or providing much-needed access to electricity in the first place. DESERTEC is not only an alternative for clean power for Europe, but a real opportunity for the population of North Africa and its sustainable development.
DESERTEC is a dynamic motor for renewable energy sources, industry and business. It supports an industry for the future and searches for solutions to the central future challenges, such as shortages of energy, water and food shortages or the reduction of CO2 emissions. For the regions in North Africa and the Middle East, this could accelerate industrialisation, create jobs and clean power and generate enough energy for the desalinisation of seawater for the fast-growing population. Renewable energy sources that are networked for international use and also a local source of power are not mutually exclusive, but rather complement each other. The plan is to use both to contribute towards climate protection and lower electricity prices.
SCHOTT Solar
W: www.schottsolar.com
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