In 2017, Tesla installed what was then the world's largest lithium-ion battery — 100 megawatts — next to the Hornsdale Wind Farm in South Australia, built in just over 100 days, changed how the entire energy industry thinks about grid stability.

 

"One battery in the South Australian outback changed how the entire world thinks about grid storage.

In 2017, Tesla installed what was then the world's largest lithium-ion battery — 100 megawatts — next to the Hornsdale Wind Farm in South Australia, built in just over 100 days under a public wager from Elon Musk. Critics dismissed it as a publicity stunt. Within its first year of operation, the Hornsdale Power Reserve had already saved South Australian consumers tens of millions of dollars by responding to grid frequency disturbances in milliseconds — faster than any conventional gas turbine could react.

The Hornsdale project didn't just demonstrate that batteries could stabilize a grid. It rewrote the economics of grid services entirely. Traditional gas peaker plants had long charged premium rates for the ability to respond quickly during demand spikes. Battery storage undercut that pricing model almost immediately, forcing a fundamental reassessment of how much fast-response capacity was actually worth.

Australia has since expanded aggressively on that proof of concept, with battery storage capacity growing more than tenfold across the National Electricity Market since Hornsdale's commissioning. Grid operators across California, the UK, and Germany have cited the South Australian project directly when building their own large-scale storage business cases.

One battery, built in one hundred days, changed how the entire energy industry thinks about grid stability.

Source: Australian Energy Market Operator (AEMO), Hornsdale Power Reserve Performance Report, 2023

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