As pv magazine Australia has reported , the expansion of the Hornsdale battery is intended to provide grid-scale inertia services and fast-frequency response on Australia’s National Electricity Network.

The battery has already brought down grid stabilization costs by roughly $40 million in its first year of operation, according to consultantcy Aurecon.

At the same time, Hornsdale generated roughly $50 million in revenues in less than two years through the provision of both Contingency and Regulation Frequency Control Ancillary Services and through arbitrage trading. Even during severe grid anomalies, such as those impacting an interstate interconnector after a lightning strike, the big battery has successfully kept the lights on in South Australia’s renewable-heavy grid.

Hornsdale will be tasked with supplying fast-frequency response and system inertia – termed “synthetic inertia” when delivered by battery storage. Historically, large fossil-fuel or hydro-electric units, or synchronous generators, have provided system inertia by virtue of their spinning turbines.

Ian Learmouth, the CEO of Clean Energy Finance Corporation, a governmental green bank that has provided debt financing for the project, said that the provision of synthetic inertia is “critical” if renewable penetration levels are to continue to grow.