This page provides a brief overview of concentrating solar power (CSP) technologies supplemented by specific information to apply CSP within the Federal sector.
Concentrating solar power technologies produce electricity by concentrating the sun's energy using reflective devices, such as troughs or mirror panels, to reflect sunlight onto a receiver. The resulting high-temperature heat is used to power a conventional turbine to produce electricity.
There are three types of CSP technologies:
Linear concentrator systems collect the sun's energy using long rectangular, curved (U-shaped) mirrors. The mirrors are tilted toward the sun, focusing sunlight on tubes (or receivers) that run the length of the mirrors. The reflected sunlight heats a fluid flowing through the tubes. The hot fluid is then used to boil water in a conventional steam-turbine generator to produce electricity.
Dish/engines use a mirrored dish similar to a very large satellite dish. The dish-shaped surface directs and concentrates sunlight onto a thermal receiver, which absorbs and collects the heat and transfers it to the engine generator, which is used to produce electricity.
Power towers use a large field of flat, sun-tracking mirrors, known as heliostats, to focus and concentrate sunlight onto a receiver on the top of a tower. A heat-transfer fluid heated in the receiver is used to generate steam, which is then used in a conventional turbine generator to produce electricity.
CSP systems are used to generate a large amount of electricity and require large amounts of land to deploy. These technologies are typically not applicable under other circumstances.
Visit the Department of Energy's (DOE) Solar Technologies Program for in-depth information about solar energy basics and technologies. An Energy 101 Video on Concentrating Solar Power is also available on the EERE multimedia site.
Before conducting an assessment or deploying CSP systems, Federal agencies must evaluate a series of questions. Concentrating solar power systems are viable for large-scale electricity production in the Federal sector.
What are my energy goals?
Energy goals range from meeting regulatory requirements to powering remote applications to increasing energy security.
Regulatory Requirements: Electricity produced by solar energy falls under the Energy Policy Act (EPAct) of 2005 definition of renewable energy and can be used to meet EPAct 2005 renewable energy requirements.
Remote Power: CSP systems are a major investment and generate large amounts of electricity. The systems are typically not appropriate or cost-effective for remote power applications.
Energy Security: Solar energy is natural and renewable. The energy source is found in abundance across the U.S. and can be leveraged to increase energy continuity.
What kind of energy do I use?
Federal agencies must understand what type of energy is needed before determining if concentrating solar power is applicable. CSP systems generate electricity and are not appropriate for mechanical or thermal power.
When do I need the energy?
Due to their large size, most CSP systems are tied into the utility grid. This combination provides accessible electricity around the clock to meet agency load requirements.
CSP power towers
How much power do I use/need to produce?
CSP systems generate large amounts of electricity and are applicable for campus size deployments or larger.
Is open land available?
Concentrating solar power systems require a large, open area of land to accommodate sprawling collector and tower equipment. According to SolarPACES, CSP trough systems require an average of 5.5 acres per megawatt of electricity produced. If large, open areas are not available, CSP may not be the best solution. It is important to consult an expert to determine whether CSP systems are a good fit for your Federal facility.
Where am I located?
For a broad overview of your facility's solar resources, the National Renewable Energy Laboratory (NREL) provides solar energy resource maps of the U.S. Before initiating a project, solar resources in your area must be measured and verified. Resource maps are a good start, but resources vary at a micro level. It is important to consult an expert for a professional evaluation before implementing energy projects.
What is my budget?
CSP systems are a large investment with varying costs depending on application and location specifics. It is important to consult an expert to determine whether CSP systems are a good fit for your budget.
What resources are available for operations and maintenance?
The operation and maintenance (O&M) of a parabolic trough power plant is very similar to conventional steam power plants that cycle on a daily basis. Staffing is needed to operate and maintain them 24-hours per day. CSP systems also require additional labor to maintain the solar fields. Experience shows that solar field mirrors must be washed frequently during the summer, but the increase in solar output pays for the cost of labor and water. Current power plants may wash mirrors weekly during the peak solar times of the year and every few months during the winter.
Visit the project planning section for detailed information on planning and deploying renewable energy projects. Federal case studies are available to provide specific examples of viable solar energy projects.
Detailed information on solar energy resources and technologies is available through:
DOE Solar Technologies Program: Program providing information and resources on solar energy resources and technologies.
American Solar Energy Society: Leading association of solar professional and grassroots advocates.
Solar Electric Power Association: Compilation of more than 560 electric utilities, solar companies, and other industry stakeholders to form a central resource for unbiased and actionable solar intelligence.
Solar Energy Industries Association: Organization working to expand the use of solar technologies, strengthen research and development, remove market barriers, and improve education and outreach for solar.