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NREL - National Renewable Energy Laboratory
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Power Block R&D

Power block research at NREL focuses on assessing the potential of advanced power cycles to integrate with concentrating solar power (CSP) systems. This research increases the efficiency and reduces the levelized cost of energy for CSP systems.

Today's CSP systems use conventional thermodynamic power cycles that are employed throughout the power generation industry, including Rankine and Stirling cycles. The CSP systems, which may use a variety of heat-transfer and working fluids, typically have thermal-to-electric conversion efficiencies ranging from 35% to 45%.

Opportunities and Potential Impact

Advancing CSP systems to the target cost of $0.06 per kilowatt-hour, set by the U.S. Department of Energy (DOE) SunShot Initiative, requires significant reduction in balance-of-system costs associated with all aspects of installed solar energy systems.

Researching novel power cycles offers the potential for more aggressive cost reduction versus waiting for evolutionary process improvements. In addition, because CSP facilities are typically located in desert areas where water is scarce, new high-efficiency cycles that use dry cooling are needed.

Current Research Projects and Our Innovation

NREL's power block research focuses on several key areas:

  • Supercritical carbon dioxide (s-CO2) power-cycle modeling for CSP applications—Developing an advanced power system that uses the Brayton cycle and s-CO2 for producing high temperatures, leading to higher system efficiencies, lower-cost power blocks, and smaller-volume thermal energy storage.
  • Particle receiver integrated with a fluidized bed—Building a prototype receiver that integrates with high-efficiency power cycles by using moving particles to transfer and store thermal energy at higher temperatures than molten-salt storage.

Competitively Funded Project

NREL has won a competitive DOE award to fund the following project:

Through innovative research and unique experience, facilities, and capabilities, NREL is working to accomplish the goal of the U.S. Department of Energy's SunShot Initiative to make installed large-scale solar energy systems cost-competitive with other energy sources by 2020.