Australian energy company AGL is close to signing a A$400 million deal with Idemitsu of Japan to convert a coal mine into a pumped storage hydro power plant.

Local media in the Australian state of New South Wales says that the proposed project would replace the capacity of AGL’s Liddell coal-fired power station, which is due to close in 2022.

The project would see Idemitsu’s open cast Muswellbrook coal mine, which is due to close in the next three years, converted into a pumped storage hydropower plant. AGL and Idemitsu will carry out a feasibility study into the viability of the proposal, the Muswellbrook Chronicle reported.

AGL has been criticised for its decision to close the 2000 MW Liddell power plant. Earlier in May the firm received a A$250 million unsolicited offer for the power plant from Chow Tai Fook Enterprises and Alinta Energy Pty Limited.

AGL says it has rejected the offer and says it will continue with its plan to repurpose Liddell.