The past month has been littered with news of exceptionally large battery storage developments, yet none in the world can compare to the news that Vistra’s permit to expand an energy storage system under construction at its natural gas-fired Moss Landing generation station to 1,500 MW/6,000 MWh has been approved.

That’s right. Gigawatt-scale battery energy storage is on the table.

The proposed expansion would quadruple the battery system’s size and make it the largest battery storage installation in the world, a couple of times over.

While the permit has been approved, the expansion will happen “should market and economic conditions support it,” according to Vistra President and CEO Curtis Morgan.

For some perspective as to how large this battery is, consider that, according to the U.S. Energy Information Administration, the country’s entire installed battery storage capacity at the end of 2018 came in at 869 MW, while total installed battery storage at the end of 2019 (including behind-the-meter) was approximately 1.7 GW, according to Wood Mackenzie. This one battery, when completed, will be larger in capacity than every other utility-scale battery energy storage system in the country, combined.

The system is coming in stages, only two of which have been formally announced. The first 300-MW phase is planned for completion by the end of 2020, with the second, a 100-MW expansion expected to come a year later in 2021.

Global perspective

This system is not the only gargantuan battery going in at the Moss Landing site. Set to clock in at 182.5 MW and 730 MWh, the Moss Landing battery energy storage system will be comprised of 256 Tesla Megapack battery units on 33 concrete slabs at the substation. The project’s targeted completion and energization is set for early-2021, with the project achieving full commercial operation in Q2 2021.

For further perspective, compare the size of the proposed Vistra battery expansion with the list of the largest battery energy storage installations in the world thus far.

The world’s largest operating battery storage system, the Hornsdale Power Reserve in South Australia, utilizes Tesla batteries and is colloquially known as the Tesla Big Battery, though it will soon be unseated by Tesla’s Moss Landing installation.