Genex Power says it is now ahead of schedule on the construction of a new engineering project to transform a retired gold mine site in Australia into a 250MW/2GWh pumped hydro energy storage facility.

From pv magazine Australia

Sydney-based developer Genex has confirmed that work has commenced at its AUD 777 million ($556.3 million) Kidston Pumped Hydro Storage Project under development at two abandoned gold mine pits near Kidston, about 270 kilometers northwest of Townsville, in northern Queensland, Australia.

The pumped hydro facility is the centerpiece of what will become the Kidston Clean Energy Hub, which includes the existing 50MW Kidston Solar Farm, which Genex has been operating since 2017. Up to 270MW of additional solar and up to 150MW of wind generation have also been proposed.

The pumped hydro energy storage plant, planned for commissioning in 2024, involves the transfer of water between the two disused gold mine pits, which are located at different elevations. Water stored in the upper reservoir will drop about 220 meters down two vertical inlet shafts through reversible turbine-generators – to be located approximately 250 meters below ground level – into the lower reservoir to generate electricity.

Genex said last week that it has already undertaken extensive works in the past two months to establish the 1.5-kilometer-long underground main access tunnel. It will lead to the “powerhouse cavern” which will house the two 125 MW Andritz hydro reversible pump turbines. The company said preparation works for the main access tunnel had been completed and the underground excavation works formally commenced with the first major blast.

Genex CEO James Harding said the start of major engineering works at the site was a significant milestone for the project.

“This represents a significant milestone in the project construction timeline, which was achieved ahead of schedule,” he said. “We look forward to working alongside the EPC JV and keeping the market updated as the program continues to push ahead over the course of this year.”

Genex is almost finished building a 22kV distribution line that will connect the site to Ergon Energy’s Kidston substation, as the transformer is already installed. Work is also progressing on prototype tests of electrical towers for a new 275kV transmission line being constructed by Powerlink Queensland between Kidston and a new switchyard at Mount Fox. This will connect with the existing Ross to Chalumbin 275kV transmission line, allowing the facility to connect with the National Electricity Market (NEM).

The Kidston Pumped Hydro Storage Project will have 250MW generating capacity and energy storage capacity of 2GWh. The company said the storage equates to eight hours of generation at full load, or enough to power 143,000 homes. It will have a start-up time of less than 30 seconds, allowing it to respond quickly to any shortages of electricity supply.

Electricity supplier EnergyAustralia will operate the pumped hydro storage asset for up to 30 years after signing a binding energy storage services agreement (ESSA). EnergyAustralia, which is owned by Hong Kong-based China Light and Power Group (CLP), will have full operational dispatch rights for the hydro plant under the ESSA, in exchange for a fixed annual rental payment that will increase over the term of the agreement.

The 30-year agreement for operation of the asset is divided into 10-year terms, with two options to extend after the first 10-year period. If EnergyAustralia takes the agreement to its full extension, it will have the right to acquire Genex’s holding in the project which has an expected life of at least 80 years. Genex said the construction program remains on schedule for first generation in the fourth quarter of 2024.

The Kidston Pumped Storage Hydro Project is the first pumped hydro power station to be built in Australia since the Wivenhoe Power Station was constructed in Queensland in 1984. Upon completion, it will be one of four operating pumped hydro energy storage projects in Australia, including the Wivenhoe Power Station and the Tumut 3 power station that forms part of the Snowy Hydro scheme and the Shoalhaven Scheme in New South Wales.

However, there are several pumped hydro projects in the pipeline in Australia, including the 400 MW Big T project being developed by Melbourne-based BE Power in southeastern Queensland. EnergyAustralia is also investigating the feasibility of developing a 350 MW pumped hydro energy storage facility near its Mt Piper coal-fired power station at Lithgow while fellow gen-tailer AGL has revealed plans to explore the engineering feasibility of establishing a 250 MW, eight-hour duration pumped-hydro energy storage project at its Bells Mountain coal mine site in the Hunter Valley.