Queensland coal giant adds pumped hydro to growing energy storage mix

Queensland government-owned generation company Stanwell Corporation is adding pumped hydro to its rapidly growing energy storage portfolio, with the purchase of a share in the so-called “Big-T” project proposed for 45km northeast of Toowoomba.

The Cressbrook pumped hydro energy storage (PHES) project, which has so far been co-developed by BE Power and GE Renewable energy, will generate 400 megawatts (MW) of continuous electricity for 10 hours per day, with plans to add a big battery with a capacity of 200 megawatt hours (MWh).

Stanwell said late last week that it will buy BE Power’s stake in the project and – in partnership with an unspecified “established global pumped hydro operator” – progress the project to a final investment decision.

Stanwell says additional investment partners will be sought to help fund the project’s construction.

The acquisition forms part of Stanwell’s scramble to replace its coal-heavy generation portfolio with firmed solar and wind at a pace in keeping with the state’s renewable energy targets of 50 per cent by 2030, 70 per cent by 2032 and 80 per cent by 2035.

Energy storage will be a big part of this effort and, to this end, Stanwell also last week announced a deal to buy up all of the storage capacity from the final stage of the massive Supernode battery being built near Brisbane by Quinbrook Infrastructure Partners.

Once again, as part of the deal, Stanwell’s Asset Maintenance Company will be given preference to service and maintain the facility over its projected 50-year operational life.

“The development of medium duration energy storage, like pumped hydro, is crucial to enable the continued build out of renewable energy generation,” said Stanwell CEO Michael O’Rourke, on Friday.

O’Rourke says Cressbrook PHES – expected to commence operations in mid-2033 – will meet around 25 per cent of Stanwell’s future energy storage requirements and support the ongoing development of Stanwell’s Tarong Clean Energy Hub, which has begun construction with a 300MW/600MWh big battery.

The PHES project will use Lake Cressbrook as the lower reservoir with a new upper reservoir to be built on land 2.1km northeast of the lake. During periods of high electricity demand or to firm the grid, up to 6.4GL of water would be released from the upper reservoir downstream into Lake Cressbrook, driving two 200 MW turbines for a period of up to 10 hours.