Advanced Compressed Air Energy Storage: Enabling Grid Reliability and Flexibility in a Transforming Energy Market

Posted on May 20th, 2019 in News, Uncategorized

The Australian energy market continues to transform as market forces are driving increased uptake of renewable energy and the retirement of dispatchable, synchronous generation (i.e. coal-fired and gas power plants). Within this changing energy mix, long duration grid-scale energy storage will play a critical role in enabling the integration of variable renewable energy resources and maintaining system reliability through the provision of clean and dispatchable capacity to the grid.

Hydrostor, a developer of utility-scale energy storage facilities using their proprietary Advanced Compressed Air Energy Storage (“A-CAES”) technology, is looking to play a key role in this market transformation. The company recently announced Australia’s first compressed air energy storage project, which will demonstrate the benefits of adding its emission-free, flexibly-sited, bulk energy storage to the diverse range of technology helping Australia transition to a lower-cost, cleaner, more reliable electricity grid.

A-CAES technology works by using electricity from the grid to run a compressor, producing heated compressed air. Heat is extracted from the air stream and stored inside a proprietary thermal store preserving the energy for use later in the cycle. Compressed air is then stored in a purpose-built underground cavern, which is kept at a constant pressure using hydrostatic head from a water column. During charging, compressed air displaces water out of the cavern up a water column to a surface reservoir, and during discharge water flows back into the cavern forcing air to the surface under pressure where it is re-heated using the stored heat and then expanded through a turbine to generate electricity on demand. An animation describing A-CAES is available at

The Angas A-CAES Project, Hydrostor’s first of many A-CAES projects within Australia, is nearing construction near Strathalbyn, South Australia. The 5 MW facility will be dispatched into the National Electricity Market (NEM) to provide synchronous inertia, load shifting, frequency regulation, and support grid security and reliability. It will also enable the integration of variable renewable energy resources, such as solar and wind. By siting at the Angas Zinc Mine, currently in care and maintenance, the project will repurpose existing underground mining infrastructure as the A-CAES system’s sub-surface air storage cavern, benefiting both the electricity grid in South Australia and the local community by converting an unused brownfield site into a clean energy project that drives economic development. The project has been awarded a combined total of $9 million of grant funding from the Australian Renewable Energy Agency (ARENA) and the Government of South Australia Renewable Technology Fund.

The successful deployment of Hydrostor’s Angas A-CAES Project will open up opportunities throughout Australia for the build-out of full-scale (50+ MW), long duration (4-24+ hours), long life (50+ years) projects, adding clean energy capacity and boosting reliability of power supplies across the NEM. Hydrostor’s emission-free solution can be flexibly located where required on the grid, is deployable at both greenfield and brownfield sites, and offers a compelling, low-cost alternative to geographically-constrained bulk energy storage technologies such as pumped hydro. The company is currently advancing several full-scale projects in Australia and working to identify additional sites for A-CAES deployment across the country.