Peninsula Clean Energy and San Jose Clean Energy, community choice aggregators that procure power for 1.7 million people in the San Francisco Bay area, plan to seek enough renewable energy for roughly 200,000 homes, the local government-run electricity suppliers announced Aug. 3.
In their joint request for proposals, due Sept. 4, the aggregators, or CCAs, asked for long-term power purchase agreements totaling 1 million MWh annually from new renewable energy sources, either stand-alone or battery-backed facilities. The projects must start delivering power by the end of 2024.
"Community choice energy providers are driving California's clean energy future by investing billions in renewable energy and battery storage," San Jose Mayor Sam Liccardo said in a statement.
While the request is open to all eligible renewable energy resources under the state's renewable portfolio standard, which calls for 60% of California's electricity to come from renewable resources by 2030, solar power plants coupled with lithium-ion battery systems have dominated recent solicitations from aggregators and investor-owned utilities.
"Those types of hybrid resources have really developed a lot over the last couple of years," Siobhan Doherty, director of power resources at Peninsula Clean Energy, said in an Aug. 4 interview. "We have really seen prices come down."
Numerous recent deals for solar-plus-storage resources in the Western U.S. have levelized energy prices in the range of $30/MWh to $40/MWh, in nominal dollars, according to an S&P Global Market Intelligence analysis.
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Peninsula Clean Energy, which buys power for San Mateo County, has signed power purchase agreements for 550 MW of solar, wind and hydroelectric to date. It is considering large-scale battery storage in its latest request for proposals in order to help offset its reliance on natural gas-fired generation during periods of peak demand as the sun sets, according to Doherty. San Jose Clean Energy previously has contracted for 262 MW of solar and 10 MW of battery storage.
In addition to conventional lithium-ion batteries that typically store energy for up to 4 hours, Peninsula Clean Energy and San Jose Clean Energy, along with a host of other CCAs, are exploring alternative energy storage technologies to store electricity for longer periods of time. Peninsula Clean Energy plans to offer its customers 100% renewable energy around the clock by 2025.
Peninsula also plans to test the role of small-scale battery storage in its decarbonization efforts. It is one of three CCAs that recently signed agreements with home solar company Sunrun Inc. to provide 13 MW of battery backup capacity at up to 6,000 solar-powered homes in the next three years. The installations are initially intended to supply power when Pacific Gas and Electric Co., which operates the grid that supplies CCAs with the power they purchase, conducts emergency power shutoffs to prevent wildfires.
The systems will also be aggregated into virtual power plants to offset peak power demand, Doherty said.