Plugging Batteries: Southern California Edison’s Colin Cushnie at a Rosemead substation of the utility. The company is working on a 20-megawatt storage facility in Mira Loma.

Plugging Batteries: Southern California Edison’s Colin Cushnie at a Rosemead substation of the utility. The company is working on a 20-megawatt storage facility in Mira Loma. Photo by Ringo Chiu.

Ever since Benjamin Franklin’s attempt to harness lightning, inventors have tried to find clever ways to store electricity. Last month, Southern California Edison announced plans to encourage just that as part of an ongoing state effort to increase renewable energy capacity over the next decade.

The Rosemead utility has contracted Tesla Motors Inc. to build a 20-megawatt battery storage facility in Mira Loma, which would be able to deliver maximum power for four hours, before the end of the year. The batteries will help replace natural gas storage capacity lost as a result of the Aliso Canyon storage facility leak, said Colin Cushnie, vice president of energy procurement and management in SoCal Edison’s power supply unit.

“Edison will be able to operate the devices to discharge electricity during peak demand or when there is insufficient natural gas to supply our power plants,” he said.

But batteries aren’t the only type of energy storage system being developed by local companies. SolarReserve of Santa Monica has pioneered solar plants that use an array of mirrors to focus light from the sun into a central tower filled with heat-conducting molten salt, which is used to generate electricity through steam.

Then there’s Eagle Crest Energy, which plans to pump water uphill at an abandoned surface mine in the Mojave Desert when electrical rates are low, then flow the water downhill through hydroelectric turbines to a lower reservoir when rates are high, taking advantage of a price differential.

The growth in the electricity storage market is partly related to twin mandates by the California Public Utilities Commission that investor-owned utilities in the state increase their energy storage capacity to 1,325 megawatts by the end of 2024, enough to power nearly 1 million homes, and that 50 percent of California’s energy come from renewables by 2030.

However, the economics of energy storage still need to be worked out, said Haresh Kamath, senior program manager at the Electric Power Research Institute in Palo Alto, noting the abundance of cheap natural gas capacity available in the United States.

“There are a lot easier and lower-cost ways of getting the capacity that the state needs,” Kamath said.

Storage is in many ways the Holy Grail of the clean energy sector. Solar plants generate electricity only when the sun is out; wind farms produce even when demand is at its lowest. The growth of the storage sector makes it easier for those generation sources to pencil out.

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