Broken Hill Energy Storage Project

Clean, Safe, and Reliable Long Duration Energy Storage – Using only Air, Gravity, and Water

As Australia modernizes its grid infrastructure, and moves towards aggressive carbon emission reductions, it is undergoing one of the most rapid energy transitions in the world.  Large-scale and long duration energy storage is critical to support the growing levels of variable renewable energy (VRE) like solar and wind already on the nation’s electricity grid, as well as to manage ongoing retirements of conventional generation.  A-CAES is uniquely suited to meet these needs on the Australian grid given its large-scale synchronous capacity that can be located specifically where the grid needs (and without major new transmission investments required). 

Our Broken Hill A-CAES Project is a cost-effective, emissions-free storage solution that provides unmatched benefits to consumers in a remote region with extensive renewable infrastructure and resources. Located in Broken Hill, New South Wales (NSW), this Project will eliminate the need for major investments in expensive new transmission lines and ongoing reliance on highly polluting diesel generators.  The Project will create enduring jobs that leverage the skills of the local workforce to deliver a clean, resilient future-proof power solution to the town of Broken Hill and the surrounding resources industry.


About the project

Integrate Renewable Energy

Stimulate Economic Growth and New Jobs

Transmission & Fossil Fuel Alternative

Repurpose Mining Infrastructure

The Broken Hill Project is a 200 MW utility-scale Advanced-Compressed Air Energy Storage (A-CAES) facility that is being jointly developed by Hydrostor and Energy Estate. The Project will be located at a local decommissioned mine and is designed to provide up to 8 hours of electricity discharge at a time (i.e. up to 1,600 MWh). The Project is the first large-scale, long-duration energy storage project in Australia to be selected as a preferred solution in the first stage of a regulatory transmission planning process by a major utility. The feasibility-stage development work for the Project is supported with funding from the NSW government’s Emerging Energy Program.  The Project will provide critical back-up generation to ensure reliability of the electricity supply to the Broken Hill community and will solve significant congestion issues being experienced by existing renewable projects in the region. The Broken Hill A-CAES project will allow the region to sustainably unlock the full economic potential of its traditional and renewable natural resources and our goals include working with existing and new resource companies to provide them with a low cost sustainable energy solution.


  • Size: 200 MW / up to 1,600 megawatt hours (MWh) (8 hours duration)
  • Owner: Hydrostor, Energy Estate
  • Location: Broken Hill, New South Wales (NSW), AUS 
  • Application: Renewables Integration, Non-Network Transmission Reliability Solution
  • Economic: Up to 750 full-time equivalent job years during construction, AUS$550 million of expenditure will take place in New South Wales, of which 40% (or AUS$240+ million) will be in the local Broken Hill community (Third Party Report: ACIL Allen)
  • Project Design Life: 50+ years
  • In-Service: 2025



Driving economic growth: Provides diversified skilled mining and construction job opportunities and generates significant regional economic development during both the construction and operation phases of the Project. Delivers greater direct and indirect benefits compared to lithium-ion battery projects, with substantial in-situ construction works and a 50+ year lifetime. Additionally, A-CAES uses standard components and enables skilled workers from the mining and fossil-fuel industry to leverage existing skills while contributing to Australia’s clean energy future.


Achieving environmental objectives: Provides an emission-free power plant that supports Australia’s objective of reducing carbon emissions to 26-28% below 2005 levels by 2030 in addition to Broken Hill’s local goal of achieving 100% renewable energy supply by 2030. Also avoids the burning and trucking in of large amounts of diesel fuel that supplies the current reliability solution for Broken Hill.  

Minimal land and water requirements: A-CAES can provide the equivalent bulk energy storage capabilities as pumped hydro with substantially lower land and water requirements, while repurposing existing mining infrastructure that would otherwise be retired.

Facilitating delivery of renewables: Deliver on-demand electricity when the grid needs it by storing and dispatching renewable energy generated in Western NSW and Western Victoria. The Broken Hill A-CAES facility will unlock the region’s renewable potential by relieving the pressure on the existing overloaded electrical transmission system. This will reduce line losses and curtailment of existing renewable facilities and allow new renewable projects to come online in the region.


Ensuring reliable supply to the Town of Broken Hill: The Project will deliver backup electrical capacity for Broken Hill ensuring the lights stay on and the mining infrastructure continues to operate in the event that the transmission line fails. A-CAES can also improve the reliability of supply to Broken Hill by making maximum use of existing renewables in the region, without the need to import and store large quantities of diesel fuel.

Delivering transmission system value: The Project will also maximize the efficient use of the existing transmission lines with benefits for the consumer and for generators across Western NSW and Victoria. Today, the transmission lines that transport the electricity generated in the Western areas of NSW and Victoria to major demand centres such as Sydney and Melbourne often reach their maximum safe capacity when renewable output is at its peak. This leads to higher line loses and forces local renewable production to be scaled back or shut down entirely, preventing these facilities from realizing their full economic and environmental potential. Traditionally, this problem is solved by the construction of expensive new transmission lines that are unsightly, prone to impacts from severe weather and can take years to gain environmental and stakeholder consent. The Broken Hill A-CAES project will instead solve this problem at much lower cost to the consumer by storing excess renewable electricity when transmission capacity is constrained and then sending that electricity down the same lines later in the day when capacity is available.

Offering low-cost expansion options once operational: Options to cost-effectively expand either storage duration (i.e. MWhs of storage) or capacity (i.e. MWs of capacity) post-construction, allowing for low-cost, easy to deliver, future adjustment of the Project’s configuration as market and grid needs continue to evolve.


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