Hornsdale Power Reserve (2017)
Tesla built a 100 MW / 129 MWh lithium-ion battery in South Australia, the world's largest at the time. Elon Musk bet he could deliver it in 100 days or it would be free. It responded to grid frequency faster than any thermal plant.
The battery earned tens of millions in its first year from grid services and cut frequency-control costs.
It proved grid-scale batteries could be profitable and was quickly superseded by larger installations.
Same pattern Summerfield faces: South Australia's first big battery was overtaken within years, and 960 MWh projects are now routine — with even larger ones already under construction.
