AGL to build world’s biggest “grid forming” battery at ageing Torrens Island gas plant

Australian energy giant AGL and the Finland-based technology group Wärtsilä are to build a 250MW big battery at Torrens Island near Adelaide, the first of what is expected to be a massive rollout of large scale battery storage by the company across the country.

The 250MW big battery, sized initially at one hour storage but likely to expand to up to four hours storage (1,000MWh), is being built at the site of its ageing Torrens Island gas plant, where the ageing gas generators are progressively being shut down or mothballed.

AGL expects to begin construction of the battery later this year, and complete it in early 2023. It is destined to be the biggest grid forming battery in the world, with the ability to operate as a “virtual synchronous machine”. The battery is also significant because it will be the first on the main grid to be built at the site of an existing coal or gas generator, although many such installations are planned.

It will be the first of a planned 850MW (with varying hours of storage) to be built by the company, mostly at the sites of its ageing coal and gas generators that also include the soon to be closed Liddell and Loy Yang A.

AGL has also signed contracts to have dispatch control over the output of other battery storage installations, including the nearly complete 100MW/150MWh Wandoan South battery in Queensland, and two big battery projects near Balranald and Lismore to be built by Australian developer Maoneng.

“This grid-scale battery will support South Australia’s energy transition, providing essential capacity when renewable generation is impacted and during periods of high demand, demonstrating once more that AGL is taking a leading role in reshaping the energy future,” AGL chief operating officer Markus Brokhof said in a statement.

The battery will play roles already pioneered by other batteries, such as frequency control and time-shifting the output of renewables.

Brokhof told RenewEconomy in an interview that one hour batteries were the most viable in the grid at the moment, although that would change as more coal and gas generators left the grid and as battery costs continued to fall.

“We had a lot of discussion about this in the company,” he said. “We concluded that a 1-hour battery would be most viable in the short term …. the revenue model shows that you can extract utmost value in a one hour battery.”

“With more baseload out of the market, you will see then a change in the market environment.”

The most significant part of this battery is that after an initial stage operating in “grid following mode”, the Torrens Island battery will also include technology that will enable it to operate in “grid forming” mode, making it the largest of its type in the world.

The use of “grid forming” inverters are considered crucial in the transition from conventional “baseload” and “synchronous” generation to a new system based around inverter based technologies such as wind, solar and battery storage.

The Australian Energy Market Operator is keenly watching the development of grid-forming inverters because of the crucial role they can play in the transition to renewables, which it says in its latest report will need to occur by 2035 if it is to be consistent with 1.5°C scenarios.

AEMO boss Daniel Westerman told RenewEconomy’s Energy Insiders podcast last month that grid inverters were a promising technology, but needed to see it deployed at larger scale before fully embracing the shift.

In a new white paper last week, AEMO said it wanted to fast-track the deployment of grid forming inverters because of the crucial rule it will play in a grid dominated by renewables.

The fact that this is occurring in South Australia is also significant. The state closed its last coal generator in 2016, and has since shifted to a world-leading share of 60 per cent wind and solar in the past year.

This month, it is deploying synchronous condensers that will enable constraints on wind and solar to be gradually and dramatically relaxed, and will mean that gas generation will decline significantly because they will no longer be needed at all times to provide “system strength.”

That decision to deploy syncons was taken two years ago based on the technology choices available. Many senior engineers believe that future choices will be based around inverter technologies, and battery storage, because of their flexibility and their ability to deliver multiple services, will be the way forward.

Inverter manufacturer SMA – which will provide its technology for the Torrens Island installation – has recently scored some big wins in the development of inverter technologies that has underlined their potential.

The first was in solving “oscillation” issues that heavily impacted five solar farms in a weak part of the grid in western Victoria and south-west NSW, and also in addressing system strength issues in north Queensland.

The significance of the Queensland situation was that a solution was found at a fraction of the cost, and time, that it would take to use more conventional approaches, such as the deployment of syncons.

Meanwhile, big batteries such as the Hornsdale Power Reserve – also in South Australia – have been demonstrating their ability to act as “virtual synchronous machines”, particularly in response to the Callide coal explosion that sent shock-waves through the Queensland grid.

The new 50MW/75MWh Wallgrove battery in western Sydney being built by Transgrid will also deploy similar capabilities, as will a new battery being built by Rio Tinto using Hitachi ABB technology at Tom Price in its private network in the Pilbara.

The Dalrymple North battery in South Australia, although small at 30MW/8MWh, has already demonstrated its ability to deliver “grid forming” services as one of its prime functions is to provide power to the local network in case it is cut off from the rest of the grid.

AGL’s Brokhof says the new big batteries will enable the company’s coal and gas hubs to be developed into “low carbon” industrial energy hubs, with the addition of renewables and hydrogen electrolysers also canvassed.

Wärtsilä energy president Sushil Purohit said Australia has a unique opportunity to swiftly decarbonise and transition to full renewable integration.

“Coupled with a combination of our flexibility technologies, this is a ground-breaking partnership to support the balance of renewable variability and bring affordable electricity supply for local customers,” he said in a statement.

The company added: “When installed, the system will support a broad portfolio of generating assets, both thermal and renewable, and help Australia to decarbonise and transition towards 100% renewable energy future.”

“The Wärtsilä system will operate initially in grid-following mode before switching at a later date to grid-forming mode (virtual synchronous generation–VSG), making it the largest energy storage solution capable of operating in this mode.’

“This will enable very fast response times and will future-proof the Torrens Island facility. The complex solution is supported by Wärtsilä’s advanced GEMS Power Plant Controller and energy management software.”

The battery to be built at Torrens Island will use LFP (lithium iron phosphate) technology, which is less prone to thermal runaway, an issue that has emerged since a blaze erupted in two Tesla megapack containers at the huge 300MW/450MWh Victoria big battery in Victoria.

Tesla is also switching to LFP batteries from NMC chemistry (lithium, nickel, manganese, cobalt) but it is not clear which chemistry is used in the megapacks in Victoria. The Torrens Island battery will use cells provided by China’s CATL.

“We would not say (the VBB fire) is a typical issue,” Brokhof said. “It is a concern, but it also shows you can control it …. a big battery is no different to a large industrial site.”

By:  Giles Parkinson

From: https://reneweconomy.com.au/agl-picks-wartsila-to-build-its-first-250mw-big-battery-at-ageing-gas-plant/