South Australia battery to deliver world-first inertia services

The Hornsdale Power Reserve big battery developed by Neoen Australia is expected to become the first big battery in the world to deliver grid-scale inertia services, using Tesla’s Virtual Machine Mode technology.

The 150MW/193.5MWh facility has recently received the go-ahead from the Australian Energy Market Operator (AEMO), allowing it to provide this innovative service to the National Electricity Market (NEM) in South Australia.

System inertia is a form of energy stored in electricity-producing generators comprised of spinning parts, which rotate at the right frequency to balance supply and demand, spinning faster or slower as needed. 

Although system inertia is key to the stability of grids, as it caters for these supply and demand imbalances, in recent years it has become increasingly difficult to maintain with the influx of intermittent wind and solar power and the retirement of coal-fired plants.

Inertia has traditionally been provided by gas or coal-fired generators, but the closure of thermal power plants, in addition to Australia’s fast-growing renewable energy sector, is causing inertia shortfalls in the grid. Currently, South Australia is the state most heavily reliant on wind and solar power, with 64 per cent renewable energy penetration. 

Through the use of system inertia, Hornsdale Power Reserve is expected to provide an estimated 2,000 megawatts of inertia, equivalent to 15 per cent of the predicted shortfall in South Australia's network, which serves more than 1.7 million people and 150,000 businesses.

Neoen chairman Xavier Barbaro said extending the range of services the big battery could offer created "additional layers of value for existing battery storage investments".

The Australian Renewable Energy Agency (ARENA), which helped fund testing of the system over the past two years, said the project was pioneering in demonstrating the full technical capabilities of batteries with advanced inverter technology.

"Improving the economics of energy storage is going to be key in our transition to high shares of renewable electricity," Chief Executive Darren Miller said in a statement.

The South Australian government contributed AU$15m to the project through its Grid Scale Storage Fund, while ARENA contributed AU$8m as part of its Advancing Renewables Program. AEMO has expressed its desire to be able to support instantaneous renewable energy penetration levels in the NEM that it oversees of up to 100 per cent by 2025. 

“The Hornsdale Power Reserve was revolutionary when we commissioned it back in 2017 and continues its pioneering role," said Tom Koutsantonis, South Australian Minister for Energy and Mining. "It is leading the innovation of inverter-based technologies – paving the way for more, much-needed large-scale storage projects both in Australia and beyond.”

The technology has already been tested at scale in a 30MW/8MWh battery energy storage system commissioned in a remote part of the state back in 2018.