Abengoa/Acciona Power Plant Hydrogen Mitigation Project: Cooperative Research and Development Final Report, CRADA Number CRD-15-583

Gregory Glatzmaier

Research output: NRELTechnical Report


Several Gigawatts (GW) of solar concentrating parabolic trough generating capacity have been installed in the U.S. and internationally in the past five years. Many of these power plants include thermal energy storage, which allows the plants to generate electricity during off-sun hours. The U.S. now has about 1 GW of solar-to-electric generating capacity using concentrating parabolic trough technology. Parabolic trough power plants have a long-standing performance issue relating to the build-up of trace quantities of hydrogen gas in the receiver tubes. Hydrogen is a byproduct of the very slow breakdown of the heat transfer fluid. Accumulation of hydrogen in the receivers causes a loss in the thermal efficiency of the receivers and an overall decrease in the power plant annual electricity output. Since a typical plant contains 50,000 receivers, addressing this issue by individual receiver is not practical. The National Renewable Energy Laboratory (NREL) conceived and developed a method to remove or purge hydrogen from the power plant receivers by removing hydrogen from a single location within the plant. Hydrogen gas is purged from the heat transfer fluid that resides in the power plant expansion tanks. Modeling shows that quantitative removal of hydrogen from the expansion tanks will reverse build-up of hydrogen in the receiver tubes and restore the power plant to its full performance and annual energy output. This method is documented in U.S. Patent 8,568,582, which issued in October 2013. Two companies, Abengoa Solar and Acciona Solar Power, Inc. contacted NREL to discuss solutions to the eventual build-up of hydrogen in their commercial parabolic trough power plants. NREL proposed to implement its method at Acciona's Nevada Solar One (NSO) parabolic trough power plant in Boulder City, Nevada. The first year will consist of laboratory testing at the NREL Energy Systems Integration Facility (ESIF) along with process specification, design, and costing. The second year will be the full-scale implementation of the hydrogen mitigation process at the NSO power plant in Nevada.
Original languageAmerican English
Number of pages59
StatePublished - 2019

NREL Publication Number

  • NREL/TP-5500-74618


  • Acconia
  • concentrating parabolic
  • ESIF
  • gigawatt
  • GW
  • Nevada
  • NSO
  • off-sun
  • solar
  • thermal


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