Tesla big battery replaces Hawaii’s last coal plant

A 185MW/565MWh Tesla Megapack battery has been brought online in Hawaii, effectively replacing the state’s last coal power plant which closed in the back half of 2022.

The Kapolei Energy Storage facility on the Hawaiian island of Oahu was brought online late last week. Billed as the “world’s most advanced battery energy storage system”, the battery is a key step in continuing Hawaii’s transition from coal and oil to solar and wind.

Located no 8 acres of land on the southwest side of Oahu, the Kapolei Energy Storage consists of 158 Tesla Megapack 2 XL lithium iron phosphate batteries.

The battery plant provides capacity of 135MW and 540MWh of electricity, with an additional 50MW/25MWh of additional “fast frequency response”.

In addition to providing fast frequency response services, the battery also provides synthetic inertia, allowing it to replicate the power-smoothing function of a spinning turbine, as well as black-start capabilities, meaning that it can help support grid recovery in the event of a blackout.

“This is a landmark milestone in the transition to clean energy,” said Brandon Keefe, executive chairman of Plus Power, the developer and operator of the Kapolei Energy Storage project.

“It’s the first time a battery has been used by a major utility to balance the grid: providing fast frequency response, synthetic inertia, and black start. This project is a postcard from the future — batteries will soon be providing these services, at scale, on the mainland.”

The Kapolei Energy Storage facility is part of a larger portfolio of renewable energy resources operating on the island of Oahu’s isolated energy grid.

However, the abundance of customer-sited solar power had meant that Hawaiian Electric had been forced to regularly curtail large volumes of existing utility-scale solar and wind to keep the electricity system in balance.

The Kapolei Energy Storage will help to avoid these curtailments, with modelling done by Hawaiian Electric finding that, in its first five years of operation, the Kapolei Energy Storage facility will help to reduce renewable energy curtailment by 69% and integrate 10% more new utility-scale renewables than had previously been allowed.

Interconnected near three of Hawaiian Electric’s critical power generation facilities, “This is the first time a standalone battery site has provided grid-forming services at this scale,” exclaimed Mike Snyder, senior director at Tesla Megapack.

“This is a critical application for high renewable penetration grids supplied by 185 MW of Megapack inverters.”