After careful evaluation of several battery systems and working closely with reputed battery system and inverter companies to analyze different technologies, GWP agreed to Skylar’s recommendation to use a 2-MW battery energy storage system (BESS) as a pilot system. This pilot unit was used to evaluate the ACE application. A vacant lot adjacent to the newly built Grandview substation in northwest Glendale, California, U.S., was chosen for the location of the BESS. In March 2016, GWP executed a turnkey equipment supply agreement, whereby Skylar agreed to engineer, procure, construct and commission the BESS.

The main components of the BESS are as follows:

• 2-MW BESS, supplied by Saft

• 2-MVA PCS, supplied by ABB

• 2-MVA, 69-kV, 373-V power transformer, supplied by Virginia Transformer

• 69-kV gas-insulated substation breaker, supplied by GE

• A new 69-kV transmission line connecting the BESS to the Kellogg switching station, completed by GWP.

Lithium-ion Battery