AEMO became aware of the situation after Queensland's Kogan Creek 750MW coal power station ran into problems and caused network disruptions, leading to AEMO asking Hornsdale to make good on its contingency services promise and deliver frequency control ancillary services (FCAS). Hornsdale is one of the most famous large-scale battery storage systems in the world, built and connected to the grid in just 100 days, following a 2016 Twitter exchange between Tesla CEO Elon Musk and Australian tech billionaire Mike Cannon-Brookes. Developed by French company Neoen using Tesla's grid-scale BESS equipment, reports on the system's technical operation and market participation have been positive besides this latest penalty being applied.