Compressed air used in energy storage project

The Australian Renewable Energy Agency has announced $6 million in funding to Hydrostor Australia for Australia’s first energy storage project using compressed air.

Hydrostor will construct the 5 MW / 10 MWh fuel-free Advanced Compressed Air Energy Storage (A-CAES) facility, which will re-purpose the Angas Zinc Mine  in Strathalbyn, 60km southeast of Adelaide.

The $30 million commercial demonstration project will use the existing mine to develop a below-ground air-storage cavern that uses an innovative design to achieve emissions free energy storage. The facility will provide synchronous inertia, load shifting, frequency regulation and support for grid security and reliability.

Utilising the existing mine will help to increase renewable energy supply to the South Australian and national energy grid while also converting a brownfield site into a clean energy hub.

Hydrostor’s project also received $3 million in funding from the South Australian government through its Renewable Technology Fund.

The technology works by using electricity from the grid to produce compressed air, which is stored in a purpose-built underground cavern kept at constant pressure using hydrostatic head from a water column.

During charging, heat from the compressed air is collected and stored before the cooled air displaces water out of the cavern up to a water reservoir on the surface. To discharge, water flows back into the cavern forcing air to the surface under pressure where it is heated with the stored thermal energy and drives a turbine to generate electricity.

As a fuel-free storage technology, A-CAES has similar applications to pumped hydro. Most notably, it can provide the dispatchability required to ensure reliability of the power system as more solar and wind power is installed.