Researchers at University of California, Irvine, (UCI) reported advances that allow increased reliance on intermittent renewable sources of electric power at the UCI International Colloquium on Environmentally Preferred Advanced Generation late last month.
Funded by Sempra Energy's Southern California Gas Co. (SoCalGas), UCI researchers announced preliminary findings demonstrating that the Southern California college campus about 40 miles south of Los Angeles could increase its portion of renewable energy from 3.5% to 35% by implementing a power-to-gas strategy that recovers normally wasted excess renewably-produced electricity.
In this case, the power-to-gas technology takes excess renewable electricity and converts it to hydrogen that can be blended with natural gas and used in a variety of end uses from residential to large industrial, including power generation.
"A 5% blend of hydrogen with natural gas in the SoCalGas system would provide storage capacity equivalent to $130 billion worth of battery systems if purchased at the U.S. Department of Energy (DOE)-calculated future cost of $200/kWh," said a gas utility spokesperson, who added that renewable hydrogen can also be used in hydrogen fuel cell vehicles or converted to methane to use in a natural gas pipeline and storage system.
Both the UCI researchers and other scientists noted that the conversion of renewable-based electricity to hydrogen has significant advantages over lithium ion batteries, which store energy for shorter time periods, requiring large-scale building of battery systems and infrastructure.
These latest findings came out of the SoCalGas-backed UCI research that has clearly shown the effectiveness of power-to-gas technology as a mean of increasing the use of renewable energy, and "it should be an important component in meeting California's clean energy and greenhouse gas reduction goals," said Jeff Reed, SoCalGas director of business strategy and advanced technology.
UCI's Jack Brouwer, associate director of the Advanced Power & Energy Program and an associate engineering professor, emphasizes power-to-gas technology's ability to allow for continuous renewable generation even when demand is low. "The excess electricity can be used to make hydrogen that can be integrated into existing natural gas pipeline infrastructure and stored for later use," said Brouwer, who teaches in the mechanical/aerospace and civil/environmental engineering sequences.
Citing the more than 100,000 miles of pipeline in the SoCalGas system, Brouwer said the UCI research supports the leveraging of the installed gas infrastructure for storage as a way to "significantly increase" the amounts of renewable energy deployed in California.
The UCI researchers' findings come from a pilot project that started with SoCalGas backing and participation of Proton Onsite, manufacturer of an electrolyzer that produces hydrogen from electricity and water. The researchers now are convinced that this has promise for both statewide and regional power grids.
Power-to-gas systems are currently operating in Germany and Canada, according to the researchers. This study used data from the UCI campus microgrid that includes 4 MW worth of solar panels for peak power needs.
"Simulations showed that by storing excess solar power on sunny days and using an electrolyzer to produce renewable hydrogen, the microgrid could support an additional 30 MW of solar panels," said a SoCalGas spokesperson, adding that this boosted the campuswide proportion of solar to 35%.