World's biggest battery to grow 50 percent bigger next year.

The biggest battery in the world is set to soon grow even bigger.

The Hornsdale Power Reserve in South Australia, built by Tesla and managed by renewable energy company Neoen, will be expanded by an extra 50 percent early next year.

The Hornsdale facility was built in 2017 to help alleviate the energy woes of the state of South Australia, which had seen rolling blackouts the previous summer. Tesla was awarded the contract, and Elon Musk vowed to build it within 100 days or it was free. True to his word, it was completed in November that year.

With a capacity of 129 MWh and an output of up to 100 MW, Hornsdale became the world’s largest lithium-ion storage battery, a title that it still holds two years later. And now, it looks set to strengthen its lead with a new expansion.

Tesla, Neoen and the South Australian government are looking to boost the battery by an extra 50 percent, adding 64.5 MWh of capacity and 50 MW of output. The upgrade will also add Tesla’s Virtual Machine Mode, which will allow the system to help maintain the power grid’s inertia, which provides stability in the face of fluctuating supply and demand.

The South Australian power grid requires 6,000 Megawatt-seconds (MWs) of inertia, and Neoen says that the upgraded Hornsdale facility could deliver up to half of that.

The upgrade is planned to be completed by mid-year 2020.

Sources: South Australia government, Neoen (PDF), New Atlas.