THE Hunter region’s most criticised coal mining legacy – the holes in the ground – could be one of its major assets under plans for a pumped hydro energy storage revolution in Australia.
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An Australian National University study has identified hundreds of possible pumped hydro storage sites in the Hunter that could deliver the instant power needed to back solar and wind energy during demand peaks and fluctuations.
The Hunter’s more than 200-year coal history, and development of an extensive electricity transmission network, gives it a “significant advantage” over other areas around Australia where more than 22,000 possible pumped hydro sites have been identified, said one of the ANU study authors, engineer Matthew Stocks.
“You already have a transmission network, there are wonderful wind resources and you have existing holes in the ground which could be used. It’s a significant advantage the Hunter has over other areas,” Mr Stocks said.
“You don’t have to build a lower reservoir because there’s already holes in the ground and it’s ready to go.”
Pumped hydro – where water is pumped through a pipe to an upper reservoir when there is excess electricity, and the energy is later recovered by letting it flow down again through a turbine that coverts it back to electricity – is likely to figure in AGL’s plan for the Federal Government in response to pressure to keep Liddell power station open beyond 2022.
Muswellbrook Shire Council has already committed to exploring the possibility of a pumped hydro project after mayor Martin Rush and council representatives met with Mr Stocks and ANU engineering Professor Andrew Blakers in Canberra two weeks ago.
You already have a transmission network, there are wonderful wind resources and you have existing holes in the ground which could be used. It’s a significant advantage the Hunter has over other areas.
- Australian National University engineer Matthew Stokes
The hundreds of sites identified in the Upper Hunter include 15 in the Rossgole area north-west of Muswellbrook where Prime Minister Malcolm Turnbull has a property. Another prime location links Ravensworth mine pit and Mount Owen nearly two kilometres away.
Mr Rush said the Upper Hunter was “replete with decent sites”.
“Council is undertaking a desktop feasibility study with respect to some of these sites and we hope to have concluded that work in time to inform some of the discussions that AGL is having with the Federal Government,” Mr Rush said.
A map of possible Hunter pumped hydro sites shows a concentration in the Barrington Tops, but also significant clusters near other ridgeline areas in Lake Macquarie, Pokolbin, Cessnock, east of Singleton, west of Aberdeen and near Dungog, Carrowbrook and Scone.
Pumped hydro typically delivers maximum power for between five and 25 hours. It requires pairs of modestly-sized reservoirs at different altitudes, typically with an area of 10 to 100 hectares. A minimum slope of 15 per cent is required.
Mr Stocks said efficiencies of 90 per cent in each direction are possible. During a media inspection of Liddell power station on Tuesday Liddell general manager Kate Coates said coal-fired power stations achieved only 35 per cent efficiency. New generation “high efficiency, low emission” coal-fired power stations only achieved marginally better, at up to 42 per cent efficiency, she said.
Most of the potential pumped hydro sites identified in Australia by the ANU team were off-river, Mr Stocks said. All 22,000 are outside national parks and urban areas.
Pumped hydro is considerably cheaper than other available electricity storage options such as batteries and flywheels. It has has no standby losses while water waits in the reservoir and it can reach full power in less than a minute.
The ANU study showed that NSW has 8500 possible sites, followed by Victoria with 4400.
The work highlights the possibility that many smaller pumped hydro sites could be completed sooner than Mr Turnbull’s Snowy 2.0 project, and be less challenging than drilling in the Snowy Mountains.
Pumped hydro to complement the growth of solar and wind projects could also provide an alternative to the loss of the 1680-megawatt capacity Liddell power station.
Environment and Energy Minister Josh Frydenberg said investing in renewable storage technologies, such as pumped hydro and batteries, would play a key role in securing an affordable and reliable energy network in Australia.
“The Turnbull Government is already supporting a major expansion of the Snowy Hydro scheme and looking at further hydro-electricity and pumped storage opportunities in Tasmania, the Upper Spencer Gulf in South Australia and Kidston in Queensland,” Mr Frydenberg said.
“As the Chief Scientist Dr Alan Finkel noted in his review of the National Electricity Market, pumped hydro storage systems are the most mature electrical energy storage systems available.”
