Tesla Megapacks replace Hawaii’s last coal plant

The Kapolei Energy Storage facility on Oʻahu, built with Tesla Megapacks, provides about 185 MW / 565 MWh of grid-scale storage. It was central to Hawaii retiring its last coal-fired power plant, storing solar energy during the day and discharging it in the evening to keep the grid stable without fossil fuel.

It is a concrete example of Tesla Energy doing what critics said batteries couldn’t — replace baseload fossil generation at utility scale. Tesla deployed a record 31.4 GWh of energy storage in 2024, of which projects like Kapolei are the visible payoff.

Hawaii is a revealing test case: an isolated island grid that historically burned imported oil and coal, it carries some of the highest electricity prices in the US, so storage that shifts cheap midday solar into the evening peak delivers immediate savings and resilience. Crucially, the islands chose to replace a retiring coal plant with batteries rather than a new gas plant — exactly the substitution skeptics said grid-scale storage was not yet ready to make. Tesla’s standardised, factory-built Megapack is what turned that one-off engineering feat into something repeatable on grids worldwide.