The Australian Energy Market Operator (AEMO) issued a notice at 2pm for the urgent injection of energy from battery energy storage systems (BESS), which lasted until 7pm.
Among the resources kicking in to answer that call with 96MWh of stored energy was Waratah Super Battery. This 850MW/1,680MWh grid-forming standalone BESS asset was a flagship component of the NSW state government’s energy transition strategy when announced in 2022.
As regular readers of Energy-Storage.news will know, the government awarded Waratah Super Battery fast track status and state funding support in its 2022-2023 budget.
Treasurer and Minister for Energy Matt Kean described the project as a ‘giant shock absorber for the grid.’ It will enable the expansion of transmission capacity and the usable grid capacity for renewables, as well as protect the grid from unexpected incidents.
It would perform this function through a System Integrity Protection Scheme (SIPS) contract, allowing grid operator Transgrid to monitor the grid for disruptions and call the battery into action when needed, such as when lightning strikes or extreme weather constrained the ability to deliver power.
Other BESS assets, such as the Hornsdale Power Reserve in South Australia and the Victorian Big Battery in Victoria also have SIPS contracts in place but, at 700MW/1,400MWh, Waratah’s was the biggest.
In fact, when it played its role in preventing blackouts last year, only a segment of the whole asset was already in commercial operation, having begun energisation in September, but it was still significantly able, along with other assets on the network, to step in and prevent blackouts in Sydney.
Fast-reacting applications and complex grid codes
Developer Akaysha Energy, acquired by global investment powerhouse Blackrock in 2022, won the contract to deliver Waratah later that year through state-owned corporation EnergyCo NSW.
Akaysha, in turn, appointed US-headquartered Powin Energy as the project’s BESS provider. In addition to its system integration know-how, what Powin brought to the table was its partnership with Spanish power conversion system (PCS) and power plant controller (PPC) specialist Eks Energy (EKS).
Powin picked EKS as a technology partner due to its experience working on complex grid codes and equipment configurations for solar PV and storage, which EKS had built up over years of microgrid projects worldwide.
Interestingly, Powin became majority owner of EKS before selling most of its ownership stake to Hitachi Energy in late 2023, just over a year later, signifying the central importance of PCS technology to the overall value proposition of energy storage as a grid asset.
Nowhere is that more exemplified than in the role Waratah Super Battery plays on the NSW grid, says EKS CEO Alberto Prieto when discussing the near-blackout event of November 2024.
“The role of the power conversion system in this case, as in many other cases, really is fundamental because, at the end of the day, it’s the brain of the batteries and the brain of the equipment,” Prieto tells ESN Premium.
The PCS and the power plant controller, or energy management system (EMS), are what enable fast switching into different modes and allow the Waratah Super Battery to swing into action in fractions of a second on receiving the signal from Transgrid.
Powin, Hitachi Energy, and ultimately Akaysha Energy selected EKS as the provider for Waratah because it had the technology, including both PCS hardware and PPC software, to do that.
“One of the reasons we chose them was that the physical hardware itself was a very, very good design, and the real one that got us over the line was the fact that the temperature derate of this inverter is really good, way better than a lot of other PCSs on the market,” Akaysha Energy CEO Nick Carter tells ESN Premium.
At the same time, connecting projects to the grid in Australia means overcoming one of the most stringent grid code compliance regimes in the world, the Generator Performance Standard (GPS).
Even though EKS had never done a grid-connected battery project in Australia before, which required close partnership and handholding (more on that later), Akaysha CEO Carter says it was clear the power conversion architecture specialist had the suite of solutions to get Waratah over the line.
“EKS has its own power plant controller and software that integrates with the inverter controls. According to its business model, EKS integrates its PCS with other DC suppliers a lot,” Carter says.
“That’s their bread and butter, and the fact that they use their own power plant controller and have control over it gave us an immense amount of comfort with the GPS [process].”
Carter notes that there are many metaphorical “dead bodies in the Australian market with respect to the GPS,” where companies trying to integrate and combine PCS and PPC equipment from different providers have failed to get their certification.
N-1 redundancy built into Waratah project design
Also central to being able to deliver the SIPS contract is the design of the project, says Akaysha Energy CEO Nick Carter.
“One of the core reasons that we won that tender was our technical solution. What that means is that the fundamental design of the system itself was done in such a way that it could guarantee that System Integrity Protection Scheme (SIPS) service,” Carter tells us.
“The whole site, including not just the battery array, and the medium voltage side and all of the balance of plant, but the high voltage system, the high voltage substation, the transmission line, everything up to the point of connection, is designed in a way that any single component on that site can fail and we can still deliver the SIPS service,” Carter says.
The CEO claims that none of its competitors in the AEMO tender “had even thought about designing the system in that way,” where even the failure of a 350MVA transformer could be compensated for by very quickly switching the high voltage bus to allow the SIPS service to be delivered through the remaining two transformers.
“Any part of the other balance of plant can fail, and we can still deliver the 700MW service. We have a double-circuit transmission line; we didn’t need to, we could have just had one circuit, but we put a double-circuit transmission line back to the substation so that if one line fails, we still can deliver the service through a single line and so on and so forth throughout the entire site.”
Preparing the shock absorber
That said, even once the tender was won and the Super Battery was designed, there was a lot of complex work to be done. With more than 280 PCS units on site in total the project required Akaysha, Powin and EKS/Hitachi Energy to work closely together even before installation and commissioning began to understand the system’s integration and operation.
“The typical progress you may find in a more conventional, smaller system is that people underestimate how the communication between the battery management system (BMS) should go with the power converter,” Alberto Prieto says.
A test bench was set up, replicating one module of the Waratah Super Battery, to figure out the best integration between PCS and batteries, while EKS’s team trained Powin’s on the PPC.
Alberto Prieto says understanding both is fundamental: the PCS enables the BESS’s grid-forming capabilities, while the PPC handles its overall operation, including switching into SIPS mode.
Nick Carter says that although the exact details are confidential, meeting the SIPS requirements meant that “bespoke changes” had to be made to the PPC software and the Akaysha CEO says he highly doubts that “any other supplier in the world would have been willing to do that.”
“If we had to ask Tesla to change their power plant controller to suit a SIPS scheme, [for example], the answer probably would have been no.”
Combination of SIPS with merchant revenues
While Waratah Super Battery has a 700MW SIPS in place, the actual sizing of the BESS is 850MW/1,680MWh.
“We think that’s the most powerful battery in the world. We can’t find another one that’s bigger by megawatts,” Carter says.
“There are some that are bigger by megawatt-hours, but our calculations are that it’s still, I think, the second or third largest on a megawatt-hour basis [too].”
Part of the reason for that oversizing is because of the built-in N-1 redundancy referred to earlier, meaning any part of the system can fail and the BESS can still perform its ‘giant shock absorber’ role.
“The other part of it is that that overbuild of 150MW is participating in the merchant market,” the Akaysha CEO says, with the Waratah Super Battery playing into the National Electricity Market (NEM) for applications including Frequency Control Ancillary Services (FCAS).
“The concept that a lot of people struggled to get their heads around is that it’s not a physically quarantined 700MW and 150MW. The whole array is one contiguous array, but, virtually, pieces are portioned off to preserve 700MW for the SIPS service and still be able to participate in the market with the remaining 150MW.”
While it also means Akaysha can take portions of the asset offline if required for scheduled maintenance without risking the hefty penalties of not complying with its SIPS contract, that siphoning off of battery capacity for merchant applications underpins the developer’s business case for Waratah Super Battery.
And not only at Waratah: Carter notes that two of Akaysha’s other projects in Australia, the 150MW/300MWh Ulinda Park BESS in Queensland and the 415MW/1,660MWh Orana BESS also in NSW, will also stack contracted revenue streams with merchant ones. While neither of those are contracted for SIPS and are instead are contracted for their capacity, the principle of overbuild is the same.