Tesla, PG&E break ground for a massive Li-ion battery energy storage system

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

Once operational, the project at Moss Landing substation system, in Monterey County, will be one of the largest utility-owned, lithium-ion battery energy storage systems in the world.

“Battery energy storage plays an integral role in enhancing overall electric grid efficiency and reliability, integrating renewable resources while reducing reliance on fossil fuel generation. It can serve as an alternative to more expensive, traditional wires solutions, resulting in lower overall costs for our customers,” said Fong Wan, senior vice president, Energy Policy and Procurement, PG&E.

“The scale, purpose, and flexibility of the Moss Landing Megapack system make it a landmark in the development and deployment of utility-scale batteries.”

According to the company, the BESS will include the installation of 256 Tesla Megapack battery units on 33 concrete slabs. Each unit houses batteries and power conversion equipment in a single cabinet. Transformers and switchgear will also be installed along with the Megapacks to connect energy stored in the batteries with the 115 kW velectric 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. The agreement between the two companies contains an upsize option that can increase the capacity of the system up to six hours or 1.1 GWh total. 

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

PG&E forecasts the BESS will save upwards of $100 million over the 20-year life of the project.