From pv magazine 01/2022
As Andrew Horvath, founder and global group chairman of Star Scientific, has said, “it would be an absolute tragedy for Australia if we were to demolish our fossil fuel infrastructure.” More on Horvath’s gob-smackingly logical propositions later, but the fact is that Australia’s fossil fuel plants – coal and gas fired – sit at the heart of existing transmission infrastructure that was built out to serve populations and industry. The industry is perfectly positioned to change its spots and support, rather than compete with, renewable energy.
Australia’s traditional energy-generation companies are charged with keeping the lights on and providing services relevant in a brave renewable world. They have observed the versatility of South Australia’s massive Hornsdale Power Reserve – 150MW/194MWh of Tesla lithium-ion energy storage technology, in banking and rapidly discharging the state’s renewable riches as needed, keeping demand and supply in balance, and maintaining harmonious frequency control.
A portion of Hornsdale’s capacity is reserved for lucrative trading on the National Electricity Market (NEM) – buying when demand and prices are low and selling at the high points. At the same time, the installation has saved South Australian energy consumers millions collectively, including $119 million in 2019 alone by significantly reducing the need to rev up expensive gas peaking plants to meet periods of high demand when renewables are becalmed.
AGL, the owner of coal- and gas-fired power stations up and down Australia’s long, stringy NEM, and which acknowledges it is Australia’s largest emitter of greenhouse gases by a long shot, was also an early adopter in terms of its investments in renewable energy generation. But over the past two years or so, its profits have taken a huge hit due to poor contractual commitment and outages at its fossil-fuelled assets, plus remediation costs. AGL has recently announced a re-energising fleet of battery energy storage projects. The most monumental of these are set to take up dual occupancy of fossil-fuel plant real estate: 500MW at the Liddell coal-fired plant in New South Wales, which is scheduled to close in 2023; 200MW at its Loy Yang coal-fired plant in Victoria; and 250MW at its Torrens Island gas-fired facility in South Australia.
“It’s easy to forget the critical role our thermal assets play in ensuring Australians have reliable and affordable energy,” Markus Brokhof, AGL’s chief operating officer, told pv magazine. Leveraging their connectivity will help, he says, “to secure energy reliability as Australia increases its reliance on renewable technologies.”
Other Australian fossil-fuel infrastructure sites set to distribute batteries include the former Kwinana coal-fired power station in Western Australia; the Western Australian Government has awarded New Horizons Ahead (formerly Engie EPS) a $155 million contract to build a 100MW/200MWh battery energy storage project. And in south-east Queensland, Stanwell Corporation is planting a 150MW battery on the site of existing Tarong Power Station.
Faking wave forms
AGL’s Torrens Island battery in South Australia is at the forefront of grid-stabilising technologies in that it will be connected to the NEM via SMA grid-forming inverters, which rather than synchronising to the grid’s voltage waveform, will set frequencies that provide the grid with “virtual inertia” that mimics the effect of the onsite synchronous gas-fired generation that the battery will eventually replace.
Joshua Birmingham, director of large-scale and project solutions at SMA Australia, said “the grid is structured around the traditional model of large generators, with the transmission network running out from them. So, providing system strength into that transmission network is absolutely critical.”
Birmingham pointed out that existing power stations have grid infrastructure, such as switchyards and transformers, that renewables-based generation and storage can make use of. And not only will batteries perform like-for-like services to fossil-fuelled generators, but they also actually one-up the gas turbines in that they can respond more rapidly to grid demand and system strength requirements than it takes a gas turbine to ramp up and deliver.
Birmingham said grid-forming has long been a capability of SMA inverter technology, but that its deployment in Australia has been held back by integration requirements and the need for proof of concept at scale. He said AGL’s Torrens Island project is groundbreaking, both locally and in the global arena. “This will be the world’s largest grid-forming plant,” he said, noting that the 109 inverters SMA is connecting to the battery will solve problems of grid stability not yet experienced anywhere else in the world.
Separately, Birmingham and Brokhof agree that batteries are not a one-stop solution to replacing the spinning mass, the 2GW heft, of a Liddell or a Loy Yang fossil-fuel plant. Birmingham said the strategy of using existing fossil infrastructure to connect grid-forming battery systems will ultimately be complemented by islanded microgrids at the edges of transmission/distribution networks, running their own stable power systems using grid-forming inverters, but still connected to the grid and capable of giving and receiving reciprocal services.
Repurposing fossil sites
AGL’s Brokhof, on the other hand, is thinking more in terms of repurposing fossil-fuel sites as “integrated industrial energy hubs,” transforming “our large-scale thermal sites into sites with a low-carbon footprint and a highly efficient ecosystem.” Part of this approach is that it helps redeploy local workforces that have long operated the fossil fuel plants in AGL’s portfolio, and the coal mines that supply them. Brokhof said the hubs “will provide essential jobs and economic activity to the regions while also supporting Australia’s energy transition and our goal of net-zero emissions by 2050.”
In September, AGL conducted a survey of Upper Hunter residents on the impending closure of Liddell and future opportunities for the site. Its outcomes are still in the works, though a likely mix of grid-scale batteries, a waste-to-energy facility, and a potential connection to the decommissioning Muswellbrook Coal Mine are all possible.
Idemitsu Australia Resources, the new owners of the mine, and AGL are jointly investigating repurposing Muswellbrook’s main void, which is capable of holding six gigalitres (Gl) of water, into a pumped-hydro energy storage opportunity. Again, its proximity to grid infrastructure, to new renewables generation, and to a skilled electricity-managing workforce give weight to the proposed $450 million, long-duration (eight-hour) 250MW renewable energy storage facility.
The project requires a 1.9Gl-reservoir to be excavated 2,000 meters up nearby Bells Mountain. Excess energy from renewable generation will be used to pump the water from the Muswellbrook void up the incline; then when energy in the region is insufficient to meet demand, water will be released to flow through electricity-generating turbines.
Digging-in the data centres
Meanwhile, strategic energy consulting firm Energy Estate sees global data centres taking root in disused Australian coal pits. In underground bunkers, backfilled for insulation, the data processors could operate in a colder, more stable environment than surface temperature, said Simon Currie, principal at Energy Estate. They would create a flexible load if enabled with battery energy storage, to help balance demand and supply near energy nodes such as Liddell.
Currie and his team are also working with AGL, in the context of its plans for Liddell, on a blueprint for a Hunter Valley hydrogen network, dubbed H2N. In one scenario, pipelines for hydrogen produced in the budding Renewable Energy Zones of New South Wales, could follow existing transmission easements to the Liddell site/Energy Hub for use in heavy industry in the region, or for processing and export via the Port of Newcastle.
“Existing transmission becomes an investment attraction,” Currie told pv magazine. “And that completely changes the narrative – one organisation’s trash becomes someone else’s treasure.” On that topic, he noted that Australia’s first two proposed offshore wind developments – the 2.2GW Star of the South project off the Victorian coast, and the 7.5GW Oceanex distributed floating-wind project in the waters off NSW – are planned to take advantage of LaTrobe Valley grid connections around Loy Yang, and defunct coal-fired power stations, and those connected to existing NSW fossil-fuel plants, respectively.
One of the most compelling use cases for existing coal- and gas-fired power stations that have up to a decade of life still in them, is as green-hydrogen-powered stations that will operate on the grid exactly as they do now.
Earlier this year, a report by Green Energy Markets and the Institute for Energy Economics and Financial Analysis showed that up to five of Australia’s 16 remaining fossil-fuelled power stations scheduled to close between 2029 and 2043, could become financially unviable within the next four years, due to the influx of cheaper renewable energy generators.
Andrew Horvath, global group chairman of Star Scientific, said stability of the grid will be seriously at risk if these stations simply shut down before alternative sources of inertia and system strength have been established.
Steam for turbines
Star Scientific has developed a solution that depends on a reliable supply of cheap green hydrogen. Its Hydrogen Energy Release Optimiser (HERO) won the S&P Global Platts Global Energy Award late last year for its technology – a substance that can be distributed across a substrate such as ceramic or particular metals. “When it comes into contact with hydrogen and oxygen it goes from zero to over 700 C in three minutes,” explained Horvath. HERO has been translated into what Horvath calls a “plug-and-play” device that can be retrofitted to power-station turbines to create the steam needed to turn them and generate electricity. “Take the existing boiler offline, put HERO online, and your pollution issues stop, but you maintain those big spinning mass turbines” at the heart of existing infrastructure, providing stability during Australia’s energy transition, said Horvath.
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