We need a bigger battery

Above: Tesla Powerpacks at Hornsdale Power Reserve (source: Tesla)

Not content with already having the world’s largest operating lithium-ion battery energy storage facility – South Australia’s 100 MW/129 MWh ‘Big Battery’ – Neoen (French renewables developer) is in the process of expanding it, by 50%. And, as of end June, testing was underway on the 50 MW/64.5 MWh expansion at Hornsdale Power Reserve (located at Neoen’s 309 MW Hornsdale wind farm in South Australia).

Part of the rationale for the Hornsdale storage expansion is that it will provide an “Australian-first large-scale demonstration of the potential for battery storage to provide the stabilising inertia services that are critical to the future integration of renewable energy”, says Neoen, which is implementing the project in conjunction with the South Australian government, the Australian Renewable Energy Agency and the Clean Energy Finance Corporation. The expanded facility will also ensure that “South Australia can continue to harvest its world class wind and solar resources and achieve its target of being net 100% renewable by 2030” as well as seeing “the state transition to become a net-exporter of cheap and clean energy to the NEM (National Electricity Market) and further drive down electricity prices for all consumers.”

Like the existing battery storage system at Hornsdale, the expansion will also consist of Tesla Powerpacks. The original facility, famously supplied by Tesla following a commitment by Elon Musk that it would be free if not delivered within 100 days, has been operating since December 2017.

The expanded, 150 MW, Hornsdale Power Reserve will be upgraded with Tesla’s Virtual Machine Mode, which “allows the advanced power inverters to emulate the existing inertia services being supplied by an ageing fleet of fossil fuel power plants”, says Neoen, with Hornsdale able to provide “half of the total [inertia] needs of South Australia.” The Australian Energy Market Operator (AEMO) has identified that the South Australian grid requires some 6000 MWs to maintain a secure operating level of inertia, while it is anticipated that the expanded Hornsdale Power Reserve could provide up to 3000 MWs of inertia.

The expanded facility will “trial responding to supply fluctuations by automatically and rapidly charging and discharging” and “by imitating the behaviour of the existing fossil fuel-based services, the Hornsdale Power Reserve can arrest any grid frequency deviations”, says Neoen, but employing only renewables.

Meanwhile, even bigger battery installations are under consideration for deployment in Australia. Fluence (Siemens/AES energy storage joint venture) has for example proposed installation of a pair of 250 MW/125 MWh battery storage systems at existing substations, one at South Morang, Victoria, the other at Wagga Wagga, NSW.

These operating in tandem, one charging the other discharging, would act as a “virtual transmission line” to address limitations of the existing New South Wales – Victoria interconnector (VNI).

The proposed battery systems could be on- line before December 2021, some seven years sooner than a conventional transmission line option, Fluence believes.

It says it determined that one battery storage system in each of the red highlighted zones in the map (below) would be required.

Wagga Wagga is a critical substation in TransGrid’s transmission network providing a potential pathway for power transfer from NSW to Victoria, as well as from NSWales to South Australia in the near future pending the successful development and installation of a new NSW-SA interconnector. The importance of this location in enabling large-scale power transfers with neighbouring states is highlighted, argues Fluence, by the fact that two key projects identified in the 2018 TransGrid Transmission Annual Planning Report (namely the Darlington Point to Wagga Wagga, Wagga Wagga to Ballarat, and Melbourne capacity upgrades) have a connection with the Wagga Wagga substation.

Fluence notes that the 2019 Victoria Annual Planning Report identified the need to increase capacity between Dederang and South Morang. The proposed battery installations “can provide a solution quicker than the proposed Dederang to South Morang upgrade and eventually can supplement the upgrade to provide long-term benefits”, Fluence argues.

As well as enhancing both import and export capability between New South Wales and Victoria, Fluence argues that the “additional support on either end of the transmission interconnector will enable more efficient use of the existing lines, alleviating current and future limitations.”

The Fluence virtual transmission line proposal was made in response to a call from AEMO and TransGrid for “non-network options” for the upgrade of VNI West.

Existing Fluence battery installations in Australia include Victoria’s first utility-scale facility, the 30 MW/30 MWh battery system at AusNet Services’ Ballarat terminal station.