On Friday, Tesla switched on the massive 100MW, 129MWh battery installation it built in South Australia, just as the state is about to head into the grid-taxing summer season. The installation was completed last week, ending a bet between Tesla CEO Elon Musk and Australian billionaire Mike Cannon-Brookes. The bet was made in March, when Musk tweeted to an incredulous Cannon-Brookes that Tesla could build and install a massive lithium-ion battery installation in "100 days or it is free."
Last year in South Australia was a bad one for blackouts caused by weather and grid failure. Some blamed the intermittency of renewables for the issues—wind has become a big player in the region's energy mix. Storage is a way to smooth out that intermittency. Tesla's installation is situated next to the new Hornsdale Wind Farm, a swath of land that can provide up to 100MW of power at full capacity.
Although the bet was made in March, it wasn't a given that South Australia would allow Tesla to build its battery installation. The electric vehicle and battery company went through a competitive bidding process to have access to an A$150 million ($115 million) renewable energy fund for a 100MW storage contract. Tesla meant to be competitive, though. In March, Musk tweeted to Cannon-Brookes that an installation would cost “$250/kWh at the pack level for 100MWh+ systems,” bringing a 129MWh system to about $32.35 million before taxes and labor. Still, South Australia has not revealed what it's paying to Tesla in total.