The multi-gigawatt proving ground: Wärtsilä on Australia’s energy storage market

The Eraring BESS site, owned by Australian utility Origin Energy, recently saw its stage three expansion green-lit.

This makes it Australia’s largest approved BESS with around 2,800MWh energy storage capacity, the same size as the existing black coal-fired power plant connected to the site’s National Electricity Market (NEM). When completed in 2027, it will have a power output of 700MW.

Stage one of the Eraring BESS is currently under construction and is anticipated to come online in the final quarter of 2025. Stage one has a capacity of 460MW and a dispatch duration of 2-hours. Construction of the second stage of the battery is scheduled to begin early in 2025 and come online in the first quarter of 2027, adding a further 240MW with a dispatch duration of 4-hours.

Both stages one and two of the BESS project are being delivered by Finnish marine and energy technology group Wärtsilä. A supplier for the third stage has not been disclosed at this moment.

To find out more about the project and the complications in developing a BESS on this scale, Energy-Storage.news spoke with Tang.

Australia’s need for energy storage to prevent blackouts

Tang explains that the Eraring project will harness Wärtsilä’s digital energy management and controls platform, GEMs. This technology has been used in other Australian BESS projects, such as Amp Energy’s 150MW/300MWh 2-hour duration Bungama BESS in South Australia.

“One of the neat things is that it [the BESS] will operate in virtual, synchronous machine mode, which means that it will be able to essentially set the voltage and enable short circuit current capabilities, such as reactive current group control and synthetic inertia, to support grid stability and security. We’re quite proud of this project, and we’ve been working with Origin Energy for many years,” Tang adds.

Grid stability across the NEM has become a key focus for Australia as it begins to decarbonise and undergo its energy transition. With widescale deployment of variable renewable energy generation and the withdrawal of coal-fired power, energy storage will be needed to ensure lights stay on.

A good example of this can be seen with the recent heatwave in New South Wales, which saw the Australian Energy Market Operator (AEMO) call upon the newly energised 1,680MWh Waratah Super Battery to maintain 96MWh of energy storage to prevent blackouts in the state.

One major concern regarding the withdrawal of coal-fired power plants is the loss of inertia in the electrical grid, which is crucial for maintaining a stable frequency. As traditional generators are shut down, their rotational inertia, which helps stabilise frequency, is also lost. This results in an overall decrease in system inertia. This challenge is significant when it comes to increasing the use of renewable energy generation technologies on the grid whilst maintaining stability.

Tang touches on this topic, expressing that it has become one of the key developments in the minds of Australian regulators.

“When you move towards a solar-plus-storage environment, you lose that inertia. There’s been a lot of talk in Australia throughout about how we absorb that. Some have considered synchronous condensers to be a buffer to absorb the excess energy but these are very expensive and would be a single purpose,” Tang says.

Another potential technology that has been discussed globally is virtual inertia. A growing number of battery storage projects in Australia are using advanced inverter technology to deliver a synthetic version of the synchronous inertia provided by the large rotating mass of thermal power plants.

These respond to grid signals, adjusting the supply and demand of power by charging and discharging electrons rather than mechanically adjusting the voltage.

“There has been talk about virtual inertia in the marketplace. There was a lot of debate about whether or not it would work and whether or not you could actually get Insulated Gate Bipolar Transistors (IGBTs) to perform the equivalent function of inertia,” Tang explains.

IGBTs are a component of grid-forming advanced inverter power conversion system (PCS) equipment that enables inverter-based energy systems to deliver services like inertia that have typically come from the rotating mass of thermal power generators.

IGBTs are semiconductor devices that combine the voltage control of Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) with the current capabilities of Bipolar Junction Transistors (BJTs). This allows them to handle high voltages and currents while enabling precise control. IGBTs are mainly used in electric power conversion systems to manage electrical energy flow.

Within Australia the advantages of advanced inverters have been recognised by, for example, the Australian Renewable Energy Agency (ARENA) funding their addition to large-scale BESS projects including new-build projects and retrofits at notable projects like Hornsdale Power Reserve in South Australia.

“We have used IGBTs in multiple projects in the UK, the US and other areas. Eraring will be one of the early projects in the NEM that will provide this synthetic inertia,” Tang says.

Showcasing the feasibility of multi-gigawatt BESS to the world

Tang hopes the Eraring BESS can help showcase to the world the feasibility of deploying multi-gigawatt-scale energy storage systems.

“You have some desert projects in the US that occasionally hit the 1GWh range. But with Australia, between this project and some of the other announced projects that are going on, 1GWh almost seems like the average size,” Tang explains.

“The Eraring project, at over 2GWh is massive globally. It’s about proving that these things can be done at scale. I think that’s important.”

As with many developers worldwide, Tang explains that Australia has become a key focus market for Wärtsilä, with the company having dedicated “significant resources” to the country.

“Australia has been one of our target markets for our energy storage business. We have essentially seven target markets, the US, certain markets in Europe, like the United Kingdom, Belgium, Netherlands, Italy, and the APEC region,” Tang explains.

“Australia, Taiwan and the Philippines are big focuses for us, but Australia is just about our single largest market. We have dedicated significant resources to the market. I think you’ll be seeing more good things coming from us, out of the Australian market, on the BESS side.”