Solar One is concentrated solar power project in the Mojave Desert, California. This project was based on the solar power tower technology where reflective mirrors are placed in a field and track the sun, bouncing the sun energy into a central receiver point. These mirrors are known as a heliostat and the heat generated was the working energy for turbine electricity. This project produced 10 MW of electricity.

Solar Two used a molten salt storage to help adjust for cloudy days. The salt storage was 60% sodium nitrate and 40% potassium nitrate. The molten salt also allowed the energy to be stored in large tanks for future use such as night time.

Known also as Central Receiver Systems, these this project is well documented in http://www.powerfromthesun.net/Chapter10/Chapter10new.htm

The nine SEGS plants built in California were constructed in less than one year each, and the final pair of plants each had a capacity of 80 MW. Previously demonstrated production capacity of 200 MW per year could be reestablished in two years, providing local jobs and a boost to the manufacturing economy, rather than the continuing drain of having to buy fuels for conventional plants. Expensive, special-purpose semiconductor or comparable manufacturing plants are not required for CSP, substantially limiting investment in production capacity and the time required to scale up. As few as five developers implementing the technology would have the capability to put more than 20,000 MW online in the southwest United States by 2020.

Since these plants are operating reliably, why haven’t more plants been built in the last few years? The field of mirrors in a concentrating solar power plant delivers the thermal energy that is provided by fossil fuels in a conventional power plant. Because the sunlight is free, the initial capital expenditure for the collectors is equivalent to buying a lifetime supply of fuel. To recover this high first cost, plant operators need to be able to sign long-term power purchase agreements. However, the current environment favors low first-cost, gas-powered plants, with ratepayers bearing the risk of escalating fuel costs. Other factors, including risks associated with
building new technologies, tax equity with conventional technologies, and cost reductions needed from technology advances and economies of scale, are also important. Sunlight is intermittent.

How can we count on solar energy to supply power when needed? Concentrating solar power technologies can employ cost-effective thermal storage, which sets aside the accumulated heat energy for later conversion to electric power.

Concentrating solar power plants also can be hybridized with fossil fuels. Both options allow these plants to generate electricity even when the sun is not shining (for example, at night or during cloudy weather).

Do concentrating solar plants require a lot of land? Relatively speaking, no. Consider the Hoover Dam. Lake Mead covers nearly 250 square miles. A concentrating solar power plant occupying only 10 to 20 square miles of land could generate as much energy on an annual basis as the Hoover Dam did last year. Taking into account the land required for mining, concentrating solar power plants also use less land than coal power plants.

What is the benefit of continuing federal support for concentrating solar power research and development? Concentrating solar power is on the brink of commercial viability, and U.S. industry is actively seeking commercial projects. To ensure the success of these initial plants and thus enable large-scale construction of additional plants, U.S. industry requires continuing access to the research base on which these plants will be designed. Eliminating federal support for concentrating solar power at this critical stage could disrupt plans to build critically needed commercial plants. The benefit of U.S. investments to date would be lost, and foreign competitors would provide future U.S. solar power plant capacity.

Sandia National Laboratories and the National Renewable Energy Laboratory (working together as SunuLab) provide technical expertise and
research and development support to the Department of Energy Concentrating Solar Power Program and the CSP industry.

This information in its entirety is from: http://www.nrel.gov/csp/troughnet/

TroughNet is developed by the National Renewable Energy Laboratory’s Solar Energy Technologies Program under the Center for Buildings and Thermal Systems.

Learn more about NREL’s concentrating solar power research.

Parabolic Trough Technology Parabolic trough solar technology offers the lowest cost solar electric option for large power plant applications. To learn more, read our technology overviews: Solar Field Thermal Energy Storage Power Plant Systems

Parabolic Trough Data and Resources

Industry Partners Solar Data

Power Plant Data Models and Tools

System and Component Testing

This information in its entirety is from: http://www.nrel.gov/csp/troughnet/

TroughNet is developed by the National Renewable Energy Laboratory’s Solar Energy Technologies Program under the Center for Buildings and Thermal Systems.

Learn more about NREL’s concentrating solar power research.

Parabolic Trough Technology Research and Development

Parabolic trough R&D efforts focus on improving the technology’s performance and cost competitiveness.

Learn more about these efforts, including parabolic trough technology R&D today, the organizations involved in research and development, and its R&D history.

R&D History

Since Luz built the first commercial parabolic trough power plant in 1994 (SEGS I), parabolic trough technology has been constantly evolving and improving. Luz made significant progress during the seven year period when the nine SEGS (solar electric generating station) plants were built. Following 1991, the operators of the SEGS plants, government research laboratories, and industry continued to develop the technology.

R&D Today

The parabolic trough technology of today has significantly improved from the last SEGS plant built 15 years ago. However, substantial opportunities remain for further improvement in efficiency, improvement in component reliability, or reduction in cost.

R&D efforts focus on all aspects of parabolic trough solar power plant technology.

Solar Field

The research and development of parabolic trough collector technology has focused on the following:

• Receiver — Development of improved more reliable receiver designs with improved selective coatings, and able to operate at higher temperatures
• Concentrator Structure — Development of lower cost structures that maintain the optical performance of LS-2 collector.
• Reflectors — Lower cost and higher performance reflectors that are more durable, with improved solar reflectivity, and that reduce mirror washing requirements.
• Balance of Collector Systems — Improved drives, controls, and collector interconnects.

Thermal Energy Storage and Heat Transfer Fluid

R&D activities have focused on development of the indirect two-tank, molten-salt thermal energy storage (TES) option for near-term applications. The longer-term R&D efforts focus on new storage or process designs that could substantially reduce the cost of parabolic trough technology, including moving to a higher temperature heat transfer fluid (HTF), or direct steam generation in the solar field.

Other advanced thermal energy storage options include advanced heat transfer fluids in a single-tank thermocline storage system, concrete thermal energy storage, or phase-change thermal energy storage.

Power Plant Technologies

R&D activities have focused on the best approaches to integrate parabolic trough technology into combined-cycle power plants, how to optimize the design of parabolic trough plants utilizing an organic Rankine cycle, and how to minimize the impact of dry cooling. Additionally, some work has focused on how to reduce the O&M costs of solar power plants.

Systems Integration

One of the key R&D efforts has been to develop the tools and testing capabilities to characterize the performance of the various parabolic trough components. Additionally many new models have been developed for evaluating systems or specific components.

R&D Organizations

The U.S. Department of Energy Solar Technologies Program administers its research and development of parabolic trough technology through SunLab — a partnership between NREL and Sandia National Laboratories.

Other organizations involved in parabolic trough research and development include:

• Ciemat
• German Aerospace Center (DLR)
• Italian National Agency for New Technologies, Energy and the Environment (ENEA)
• SolarPaces

For more information, see our list of publications on parabolic trough research and development.