Session: 06-01 Thermochemical Redox Cycles: Demonstration and Operation

Paper Number: 115127

115127 - Paths of Solar Energy to Renewable Fuels 

While solar energy technology research has been primarily focused on power generation, electricity production accounts for only about one third of total primary energy consumption. Solar energy can also be converted to fuels, which continue to dominate U.S. energy consumption. Solar-to-fuel conversion will play an increasingly important role in creating storable, transportable alternatives to high energy density fossil fuels.

Concentrating solar thermal (CST) systems can collect thermal energy from the sun, and provide an energy source to chemical processes for fuel production. Fuel production via solar thermal chemical processes integrated with CST uses the full spectrum of sunlight compared to the limited spectrum utilized by photovoltaic power conversion and stores solar energy directly and efficiently. Solar thermochemical processes have been broadly studied in metal-oxide reduction, solar thermochemical hydrogen production, hydrocarbon fuel synthesis, and thermochemical energy storage. NREL is advancing concentrated thermal power-to-fuels research through several approaches, e.g., solar to hydrogen, solar to hydrocarbon fuels or chemicals, photo-electrochemical cells for hydrogen production.

Numerous thermochemical processes (e.g., water splitting for hydrogen production, carbon dioxide reduction, methane reforming, etc.) or thermal electrochemical methods (e.g., integration with solid oxide electrolysis cell) can produce fuels or precursors. Hydrogen is a promising energy carrier that can be obtained from various feedstocks using renewable electrical and thermal energy sources and is the first step in many renewable fuel production pathways. Methods of producing renewable hydrogen have been investigated including thermochemical, electrochemical, and photoelectrochemical processes and some, such as low-temperature electrochemical water splitting, are commercially viable and the production cost is dropping steadily with advances in water splitting technologies and availability of low-cost electricity.

This presentation will discuss various efforts at NREL to couple solar energy with production of renewable hydrogen and other fuels, including coupling CST with high-temperature electrolysis using solid oxide electrolysis cells, solar receiver development for high-temperature thermal and thermochemical processes, and exploring, system-related variables and prospects associated with scaling up solar thermochemical processes.

Presenting Author: Zhiwen Ma NREL

Presenting Author Biography: Zhiwen Ma is a senior engineer in the Thermal Sciences R&D Group at National Renewable Energy Laboratory (NREL). He received his Ph.D. in Mechanical Engineering from Georgia Institute of Technology. Zhiwen is leading the research projects on long duration energy storage using particle-based thermal energy storage, thermal and electrochemical modeling for hydrogen production, and solar fuel processes. He has expertise in computational modeling and experimental testing, renewable solution and system development, component performance and cost analysis. He has published over 60 peer-reviewed papers and was awarded 12 patents.