Aerial view of Broken Hill, outback Australia

The Australian Renewable Energy Agency (ARENA) has announced funding for two major projects that will repurpose existing energy assets into renewable energy facilities.

The Broken Hill disused mine in New South Wales has been conditionally approved with $45 million in funding to construct a 200MW/1600MWh fuel-free energy storage facility, developed by Hydrostor Inc, utilising their Advanced Compressed Air Energy Storage (A-CAES) technology. 

AGL has also received $422,582 in funding to investigate the viability of retrofitting the Torrens Island Power Station B in South Australia with thermal energy storage technology.

Silver City Energy Storage Project
ARENA’s funding for the Silver City Energy Storage Project, developed by Hydrostor, is conditional upon the project reaching financial close, which is expected to occur in late 2023. Once built, the project will be one of the world’s largest compressed air projects, providing at least eight hours of storage.

The $652 million project will re-purpose a disused mine to facilitate the development of a subsurface air-storage cavity that will be used to store compressed air.

The project operates by compressing air during times of low electricity prices, storing it and releasing it through a turbo-expander to generate electricity during times of high demand and high energy prices.

The project is supported by Transgrid which earlier this year announced Hydrostor’s A-CAES technology as the preferred solution in the Regulatory Investment Test for Transmission (RIT-T) to provide back-up power supply for the city of Broken Hill. The project will reserve at least 250MWh of storage for this back-up power service.

Hydrostor’s A-CAES technology provides an alternative to Pumped Hydro Energy Storage (PHES) for bulk energy storage, having a comparable price point and additional benefits including providing more flexible site selection, shorter development and construction times, and a lower environmental impact.

The flexible site selection allows Hydrostor’s A-CAES technology to target specific problems and capture new value streams, including fringe-of-grid applications such as at Broken Hill, Renewable Energy Zones (REZs), and off-grid applications.

ARENA CEO, Darren Miller, said new technologies for medium duration storage will help to improve the economics of energy storage and give us a range of options for our future energy storage needs.

“Whether it be through pumped hydro, or innovative solutions like compressed air storage, medium and long duration storage is going to be vital to supplying power during the evening and morning peak-demand periods as Australia looks towards achieving 82 per cent renewable energy by 2030,” Mr Miller said. 

“Hydrostor’s innovative solution provides us with another option to add to the mix. As a fuel-free storage technology, compressed air storage technology has similar applications to pumped hydro, such as providing dispatchability required to ensure reliability of the power system as more solar and wind power is installed.

“In Australia’s regional towns at the fringe of the grid such as Broken Hill, new large scale storage technologies can provide back-up power to communities that will improve the reliability of electricity supply. Having more grid scale storage will also support more solar and wind in regional areas.”

Transgrid’s Executive General Manager of Network, Marie Jordan, said they welcomed the Federal Government’s vote of confidence in this project which “demonstrates that clean energy solutions can provide the highest net benefit for consumers”.

“This technology would be an Australian first, providing a reliable back-up supply for 17,000 people who live in Broken Hill and could see the mining city host one of the largest renewable mini-grids in the world,” Ms Jordan said. 

“We will continue to support the nation’s efforts to accelerate the transition to renewable energy by seeking and implementing solutions which support Australia’s clean energy targets.”

In May, Transgrid identified Canadian firm Hydrostor Inc.’s Silver City Energy Storage Project proposal to use compressed air as the preferred long-term solution to support the reliability of electricity supply for the city.

Broken Hill is currently supplied by one transmission line that runs 260km from Buronga, New South Wales, near the Victorian border. Hydrostor’s Silver City Energy Storage Project would support electricity supply for the town and ongoing mining demand when the transmission line is temporarily out of service for activities like repairs and maintenance.  

The Hydrostor solution has the potential to accommodate the increase in mining load planned in the area. The project would be able to store up to 1,600MWh of renewable generation which could be made available to meet peak demand, benefiting existing generator customers and electricity consumers.

Curtis Van Walleghem, Hydrostor’s CEO said, “We are grateful for the financial support provided by ARENA and look forward to continuing to work with stakeholders including Transgrid to advance critical infrastructure that enables reliable and low impact electricity supply to Broken Hill.” 

AGL Thermal Storage at Torrens Island Power Station B Feasibility Study
AGL’s  $1.01 million feasibility study would investigate options to use grid electricity to charge the thermal energy storage and discharge through one of the power station’s existing 200MW steam turbines, which ordinarily runs on gas, when electricity is required on the grid.

The study will test the feasibility of repurposing existing electricity infrastructure at sites like Torrens Island to be powered by renewable-powered electricity and energy storage.

AGL’s feasibility study will be conducted over approximately 12 months, with two shortlisted manufacturers to be looked at for the thermal solution, with a view to establish the technical and commercial feasibility of the chosen preferred solution:

  • German company Kraftblock
    • Utilising synthetic pellets comprising up to 85 per cent recycled material as the heat storage medium to achieve operating temperatures of up to 1300°
  • Australian company: MGA Thermal
    • Utilising proprietary Miscibility Gap Alloy (MGA) technology as the heat storage medium to achieve operating temperatures of up to 760 °C. MGA Blocks are purpose-invented and used in thermal energy storage systems which deliver continuous high temperature heat or electricity that is safe, low cost and high capacity

Findings from the feasibility study are expected to be replicable and scalable with other thermal generators across the National Energy Market (NEM), with technology providers being able to benefit from the information.

ARENA CEO, Darren Miller, said the study will explore the role thermal energy storage can take in allowing higher levels of renewable energy production across the NEM by repurposing existing power stations and energy infrastructure.

“AGL’s study comes at an important time when we need to look at all options for renewable energy storage. As thermal power stations close, there could be an opportunity to retrofit these sites as we head towards net zero emissions,” Mr Miller said.

“Given the potential long lead time and geographic constraints of other storage technologies, alternative pathways such as retrofitting existing power stations with thermal energy storage could be a viable solution to add to the mix and address Australia’s medium duration storage requirements. It also provides an opportunity to extract further value from existing infrastructure such as grid connection and transmission lines.”

AGL COO, Markus Brokhof, said the thermal battery feasibility study demonstrates AGL’s commitment to fast-tracking decarbonisation and investing in innovative technology and energy solutions.

“This is one of the first feasibility studies to look at how a thermal battery could reduce costs and lower emissions for gas-fired power stations,” Mr Brokhof said. 

“Future studies will also look at how to replicate and scale thermal batteries, allowing them to be rolled out as an energy solution for commercial and industrial customers requiring heat.

“It made sense to trial this emerging technology at Torrens Island, where plans to transform the site into an industrial energy hub are already underway with the construction of the 250MW Torrens Island Battery and the adjacent 210MW fast-start Barker Inlet Power station, operational since 2019.”

Image courtesy of Transgrid. 

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