Genex heads underground on 250 MW/2 GWh pumped hydro project


Sydney-based developer Genex has confirmed that tunnelling works have commenced at its $777 million Kidston Pumped Hydro Storage Project being developed at the site of two abandoned gold mine pits near Kidston, about 270 kilometres north-west of Townsville in northern Queensland.

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

Planned for commissioning in 2024, the pumped hydro energy storage plant 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 metres down two vertical inlet shafts through reversible turbine-generators – to be located approximately 250 metres below ground level – into the lower reservoir to generate electricity.

Genex announced on Friday it had already undertaken extensive works in the past two months to establish the 1.5-kilometre-long underground main access tunnel which 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.

Water will be transferred underground from the larger, upper to the lower reservoir.

Image: Genex

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

“Following an intense period of site establishment and preparation works, I am delighted that the EPC contractor JV of McConnell Dowell and John Holland has formally commenced the underground excavation works for the Kidston Pumped Storage Hydro Project,” he said.

“This represents a significant milestone in the project construction timeline, which was achieved ahead of schedule. 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.”

Work on the main access tunnel is expected to continue on a 24/7 basis with the shaft progressing at an average rate of 8 metres per day over the next six months.

In addition to the underground works, Genex said work on a 22 kV distribution line which will connect the site to Ergon Energy’s Kidston substation is almost complete with the transformer already installed.

Work is also progressing on the prototype testing of electrical towers for a new 186km 275 kV 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 275 kV transmission line, allowing the facility to connect with the National Electricity Market (NEM).

The main access tunnel will lead to a ‘powerhouse cavern’ 250m underground.

Image: Genex

The Kidston Pumped Hydro Storage Project will have 250 MW generating capacity and energy storage capacity of 2 GWh. 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 provider EnergyAustralia will operate the pumped hydro storage asset for up to 30 years after inking a binding energy storage services agreement (ESSA).

Under the 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, 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; and should EnergyAustralia take 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.

Members of the construction team assess the tunnel works.

Image: Genex

Genex said the construction program remains on schedule for first generation in Q4 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.

When complete 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.

There are however several pumped hydro projects in the pipeline in Australia, including the 400 MW Big T project being developed by Melbourne-based BE Power in southeast Queensland.

The Queensland government has also called for tenders for the proposed 1 GW Borumba Dam pumped hydro energy storage project being developed near Gympie in the state’s south-east.

Further south, the NSW and federal governments are pushing ahead with the $4.6 billion Snowy 2.0 pumped hydro storage project. The pumped-hydro expansion of the existing Snowy Scheme will provide 2 GW of on-demand generation and 350,000 MWh of large-scale energy storage.

EnergyAustralia is 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.

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