Nine Concentrated Solar Power (CSP) plants, totaling over 350 MW, have been in daily operation near Kramer Junction, Calif., for over 20 years.

Concentrating solar power (CSP) plants use mirrors or lenses to concentrate sunlight, creating temperatures high enough to drive traditional steam turbines or engines that in turn create electricity. The most cost-effective CSP plants are hundreds of megawatts (MW) in size, making them attractive as wholesale energy suppliers to utilities.

In the last four years, new plants have come online in Arizona, Nevada, and California. The plants’ locations reflect the important conditions required for this type of project. CSP plants need:

  • Financing – The primary barrier to utility-scale solar power is project financing. The 2008 economic crisis severely restricted the private sector capital that is typically used to finance renewable energy projects. Commercial banks today simply do not have enough appetite for long-term, low interest debt to finance construction of every project in the queue.

  • Areas of high direct normal solar radiation – In order to concentrate the sun’s energy, it must not be too diffuse. This feature is captured by measuring the direct normal intensity (DNI) of the sun’s energy. Production potential in the U.S. Southwest stands apart from the rest of the U.S.

  • Contiguous parcels of land with limited cloud cover – A CSP plant operates most efficiently, and thus most cost-effectively, when built in sizes of 100 MW and higher. While land needs will vary by technology, a typical CSP plant requires 5 to 10 acres of land per MW of capacity. The larger acreage accommodates thermal energy storage.

  • Access to water resources – Like other thermal power plants, such as natural gas, coal and nuclear, some systems require access to water for cooling. All require small amounts of water to wash collection and mirror surfaces. CSP plants can utilize wet, dry, and hybrid cooling techniques to maximize efficiency in electricity generation and water conservation.

  • Available and proximate transmission access – CSP plants must be sited on land suitable for power generation with adequate access to an increasingly stressed and outdated transmission grid. Access to high-voltage transmission lines is key for the development of utility-scale solar power projects to move electricity from the solar plant to end users. Much of the existing transmission infrastructure in the Southwest is at full capacity and new transmission is urgently needed.