Concentrating solar power systems make use of the sun’s limitless energy first by concentrating solar radiation and then by converting it to thermal energy for use in steam generation. The steam drives a standard turbine to generate electricity. Customers include electric utilities and those involved with a growing number of industrial processes, such as enhanced oil recovery. Although varied in design, all CSP technologies are based on proven engineering principles and built using common materials and accommodate energy storage.

Power Tower


An array of heliostats – large mirrors – focuses light on a solar receiver located at the top of a tower hundreds of feet high. Large, sun-tracking mirrors (heliostats) focus sunlight on a receiver at the top of a tower. A heat transfer fluid heated in the receiver is used to generate steam, which, in turn, is used in a conventional turbine generator to produce electricity.

Of the 36 operational CSP power stations worldwide, five are power towers.

Parabolic Trough


A long parabolic mirror, aligned north-to-south, rotates to track the sun and reflects heat onto a fluid-filled tube that runs its length. The sun’s energy is concentrated by parabolically curved, trough-shaped reflectors onto a receiver pipe running along the inside of the curved surface. This energy heats oil flowing through the pipe, and the heat energy is then used to generate electricity in a conventional steam generator.

Of the 36 operational CSP power stations worldwide, 23 are parabolic troughs.

Fresnel Reflectors


A series of long, narrow, shallow-curvature mirrors focus light onto one or more linear receivers positioned above the mirrors. The technology is unique from other CSP processes such as parabolic troughs in that it uses modular flat reflectors to focus the sun’s heat onto stationary receivers consisting of a system of water filled tubes. The concentrated sunlight boils the water, which generates high-pressure steam without the need for costly heat exchangers or intermediate heat transfer fluids such as oil or salt.