PG&E, Tesla starts the construction of 182.5 MW/730 MWh energy storage project in Monterey

Pacific Gas and Electric Company (PG&E) and Tesla Inc. have started the construction of a 182.5-megawatt (MW) lithium-ion battery energy storage system (BESS) at PG&E's electric substation in Moss Landing in Monterey County.

The system will be designed, constructed, and maintained by PG&E and Tesla, and will be owned and operated by PG&E. Construction is expected to continue into early next year. PG&E aims to have the system energized in early 2021 and fully operational in the second quarter of 2021.

Up to 50 PG&E employees and contractors will construct the system, and all COVID-19 safety protocols including a daily health check, physical distancing, and wearing face coverings will be followed.

The BESS was approved by the California Public Utilities Commission in November 2018 and by the Monterey County Planning commission in February 2020.

The project features 256 Tesla Megapack battery units on 33 concrete slabs. Each unit houses batteries and power conversion equipment in a single cabinet. Transformers and switch-gears will also be installed along with the Megapacks to connect energy stored in the batteries with the 115 kV electric transmission system.

The BESS will have the capacity to store and dispatch up to 730 MWh of energy to the electrical grid at a maximum rate of 182.5 MW for up to four hours during periods of high demand. PG&E's agreement with Tesla contains an upsize option that can increase the capacity of the system up to six hours or 1.1-Gigawatt hour (GWh) total.