Southern California Gas Co. (SoCalGas) has introduced a new innovative solar-powered hydrogen (H2) generation system.
The project is a partnership between SoCalGas, Pacific Northwest National Laboratory (PNNL) and the STARS Corporation. The generation system uses sunlight to convert natural gas and water into H2 and capture the carbon dioxide (CO2) to prevent carbon emissions.
H2 has many applications, including powering vehicles and homes, but unlike methane, it is not typically found on its own in nature so researchers have developed ways to produce it from other compounds.
SoCalGas supports efforts to increase H2 production, particularly for use along ‘California’s Hydrogen Highway’, a series of H2-fuelling stations throughout the state. Currently there are 35 H2 fuelling stations in the state, with another 29 stations in development. Increasing this fuelling infrastructure could help speed the deployment of zero emission H2 fuel cell vehicles which play a significant role in reducing California’s greenhouse gas and smog emissions, according to the California Air Resources Board.
The solar thermochemical advanced reactor system (STARS) produces H2 through a thermochemical process where the sun provides thermal energy to break down natural gas and water into H2 and CO2 in a process called steam methane reforming. Results from extensive testing show STARS can be configured to produce H2 and other chemicals without any carbon emissions reaching the atmosphere. These chemicals ‘trap’ and use the carbon that would otherwise be emitted. The carbon then can be used to make chemicals that become resins and plastic materials, explained SoCalGas.
This technology is undergoing field testing at San Diego State University’s Brawley campus where it runs on solar and renewable electricity. Demonstrations have shown the set-up is extremely efficient, with an energy-to-chemical energy conversion efficiency above 70 percent, making it one of the world’s most efficient solar processes. Currently the system produces about 25 kg of H2 per day if operated around the clock using a combination of solar energy and renewable gas or electricity. This is the equivalent of 25 gallons of gasoline or diesel fuel. Research suggests the system could produce 100 kg of H2 per day with a more advanced design.
The STARS generation system has been in development by PNNL and the U.S. Department of Energy (DOE) for more than 10 years. SoCalGas is working with the DOE to make these systems commercially viable.