California utility regulators approved a proposal by Pacific Gas & Electric to build four energy storage projects, totaling nearly 570 megawatts (MW) and 2,270 megawatt hours south of San Francisco.

The vote in early November came after regulators in January rejected out-of-market payments for three gas-fired power plants at the Moss Landing site. Instead, regulators asked the utility to procure new energy storage capacity. (Read the decision.)

The utility's search prompted more than two dozen storage proposals with 100 variations. PG&E narrowed the list to four, which it presented to state regulators in late June.

One of the projects, Vistra Energy Moss Landing storage project, would be owned by Dynegy Marketing and Trade, a unit of Vistra Energy Corp. The holding company manages more than 40 gigawatts of generating capacity across 12 states. The project would be a transmission-connected, stand-alone Lithium-ion (li-ion) battery energy storage resource in Monterey County. The facility, which would feature a 300 MW, four-hour-duration battery array, could enter service in December 2020 under a 20-year contract.

A second project, Hummingbird Energy Storage, would be owned by a unit of Esvolta, a new company that is partnering with Oregon-based Powin Energy Corp. and Australia-based Blue Sky Alternative Investments. The Santa Clara County-sited resource would include a 75 MW, four-hour-duration li-ion battery array. It also could enter service in December 2020 and would operate under a 15-year contract.

One so-called behind-the-meter proposal also was accepted by PG&E. It came from Micronoc and would total 10 MW of four-hour-duration storage. In practice, the project would bundle the discharge capacity of li-ion batteries located at multiple customer sites. That’s in step with Micronoc’s business model of developing distributed energy storage projects, most of them so far in South Korea. A 10-year service contract with PG&E could start in October 2019.

PowerPack li-ion batteries from Tesla would form the backbone of a 182.5 MW array with a four-hour discharge duration. The batteries would be located at a PG&E substation in Monterey County. The array could enter service by the end of 2020 and include a 20-year performance guarantee from Tesla.

Other California Storage

The regulatory mandate directing PG&E to seek energy storage proposals was not the first time California regulators acted to boost storage.

In February 2013, regulators told utility Southern California Edison to secure energy storage and other resources to meet an expected shortfall stemming from the closure of the San Onofre nuclear power plant. In that instance, the utility’s energy storage target was 50 MW. It ultimately procured more than 260 MW of storage capacity.

Then, in May 2016, regulators again directed SoCalEd to procure storage to ease electric supply shortages that were feared as a result of a leak at a natural gas storage facility. As a result, more than 100 MW of grid-level energy storage was placed into service.