AGL and Idemitsu Australia have received $9.45 million in state government funding to progress work on a feasibility for study for the proposed Muswellbrook pumped hydro project at Bells Mountain.
The 250 megawatt Muswellbrook project would provide eight hours of energy storage.
The new funding, provided under the the NSW government's Pumped Hydro Recoverable Grants Program, will enable the project to advance development studies to a stage that means the project is ready for investment.
Pumped hydro works by circulating water from the lower reservoir into an upper storage site, with the proposed Muswellbrook Pumped Hydro project exploring an innovative model whereby an existing mine void from Idemitsu's Muswellbrook Coal mine acts as the lower reservoir.
Upon demand, water is released from the upper storage site and uses gravity to turn turbines and generate electricity.
The grant funding will be used to complete a targeted geotechnical due diligence program, detailed design of the project, connection studies and contractor engagement.
The joint venture will also undertake comprehensive Traditional Owner and community consultation to prepare the project for an investment decision.
A preliminary engineering study began in 2019 to determine whether the project is technically feasible, provide cost estimates for both construction and operation, and assess the required planning and approval processes.
AGL Chief Operating Officer, Markus Brokhof, welcomed the support of the NSW government and said he was pleased to see the project progressing to the next stage.
"Today we're announcing another step forward in planning for what could be a significant energy asset for the people of Australia and the Upper Hunter community," he said.
"As we transition to more renewable energy sources, pumped hydro provides a reliable on-demand generation source and acceleration of our development studies will help us understand how the Project could be delivered.
"AGL has 2.9GW of wind, battery, pumped hydro and other low carbon and firming projects in active planning and development, and we will continue to look to invest is projects like Muswellbrook Pumped Hydro."