A worked-out open-pit gold mine normally ends the same way everywhere. The operator pulls the plant, fences the highwall, posts a rehabilitation bond, and the hole slowly fills with groundwater nobody is allowed to swim in.<\/p>\n
Kidston, in far north Queensland, got a different ending. The mine stopped processing ore in 2001 and left two enormous pits sitting next to each other, one noticeably higher than the other, about 174 miles northwest of Townsville beside a ghost town and a working airstrip.<\/p>\n
Genex Power<\/a> looked at the vertical gap between those two holes and decided it was a battery. At its deepest, the drop from the upper pit into the lower one is 715 feet. Send water down that distance through a pair of turbines and you get 250 megawatts for eight hours straight.<\/p>\n That project, K2-Hydro, is Australia’s first new pumped hydro plant in more than 40 years and, according to the federal agency that lent it the money, the first one anywhere built inside an abandoned gold mine. It was supposed to be dispatching power into the grid this October. It is now not due to finish until July 2027.<\/p>\n There is no dam across a river here, and no river worth damming. Kidston is a closed loop, which means the same water goes up and down forever and the plant does not care whether it rains.<\/p>\n The upper reservoir is Wises Pit, 128 acres of surface water. The lower one is Eldridge Pit, 133 acres. Genex puts the maximum gross head at 218 meters, or 715 feet, dropping to 181 meters (594 feet) once the top pool is low and the bottom one is full.<\/p>\n That range is the awkward part, and it comes from the shape of the mine rather than from anything an engineer chose. The pits were dug to chase ore, not to hold water, so they behave very differently as reservoirs.<\/p>\n Andritz Hydro<\/a>, which supplied the turbines, says the water level in the upper pit moves only about 10 feet across a full cycle. The lower pit swings roughly 131 feet. The machine has to stay efficient across all of it.<\/p>\n Filling the top one was its own job. Crews sealed Wises Pit with a 3.7-mile embankment and an HDPE liner, then ran six high-capacity pumps to move more than 25 billion liters, about 6.6 billion gallons, out of Eldridge and up into Wises to charge the system for the first time.<\/p>\n The holes were free. Nothing beneath them was.<\/p>\n The powerhouse sits 250 meters down, roughly 820 feet, reached by a 1.1-mile decline tunnel. Above it are twin intake shafts 771 feet deep. Below it, twin tailrace tunnels run 1,083 feet back out toward the lower pit. A separate 820-foot shaft carries the cable to the surface.<\/p>\n In 2022 the tunneling crew hit fractured rock carrying groundwater and work on the main tunnel stopped. The fix was to go around it, which added 1,430 feet to the route.<\/p>\n That is the pattern with this project. The principle behind pumped storage has been settled for over a century, and ARENA<\/a> describes the cycle in the same terms it would use for any conventional scheme. The hard part at Kidston was hard rock, water where nobody wanted it, and a job site 174 miles from the nearest city.<\/p>\n Remote industrial sites in Australia have been quietly turning into energy experiments for a while now. A working gold mine in Western Australia recently ran 155 straight hours with every engine switched off<\/a>, and Fortescue is building the largest off-grid renewable network in heavy industry<\/a> in the Pilbara. Kidston is the version where the mine is already dead.<\/p>\n Two reversible Francis pump-turbines do all the work, 125 megawatts each, paired with 149 MVA motor-generators spinning at 375 rpm. The runners are 11.3 feet across.<\/p>\n Reversible means one machine covers both jobs. Spin it one way and it generates. Spin it the other and it becomes a pump, pushing water back uphill when power is cheap or free. Genex quotes a start-up time under 30 seconds, which is the number that matters when a coal unit trips off the grid without warning.<\/p>\n Andritz also holds an operations and maintenance contract running more than a decade, and says the plant will be managed remotely from its control center in Schio, in northern Italy. A water battery in the Queensland outback, minded from a town near Vicenza.<\/p>\n EnergyAustralia signed a 30-year storage services agreement that hands it full dispatch rights once the plant is handed over. Genex owns the asset. Somebody else decides when it runs.<\/p>\n Kidston cleared its first real market milestone on November 18, 2025, when Genex registered it with the Australian Energy Market Operator. Four unit codes went into the system, two for generating and two for pumping. It was the first pumped hydro registration on Australia’s main grid in about 40 years. The last plant before it was Wivenhoe, opened in 1984.<\/p>\n Registration is not operation. Renew Economy<\/a> reported in May that completion had moved to July 2027, a full year past the original October 2026 date, and that the company had been quietly showing the new schedule in presentation slides since at least March.<\/p>\n Genex chief executive Craig Francis told the outlet there were “no technical issues” and put the slip down to the complexity of the civil works. The same publication had reported in November that Francis expected the first unit to be energized the following month.<\/p>\n The rest of the site has moved around too. A planned 258-megawatt wind farm was cut to 120 megawatts in 2025 and paired with a 150-megawatt, 600-megawatt-hour battery. By May, Francis said the wind project was under review because of construction costs and the location, and Renew Economy noted the proposal had come off the company’s website.<\/p>\n None of that touches the pumped hydro plant, which is a separate build with its own money behind it: a total funded construction cost of around A$777 million, roughly $545 million, underwritten by a A$610 million loan from the Northern Australia Infrastructure Facility, a A$47 million grant from ARENA and A$147 million from the Queensland government.<\/p>\n On July 15, the New South Wales government approved a A$1.8 billion pumped hydro and solar project<\/a>, about $1.26 billion, on the Stratford Mining Complex in the Gloucester Valley, roughly 62 miles north of Newcastle, where coal mining stopped in 2024.<\/p>\n The developer is Gloucester Coal Pty Ltd, a subsidiary of Yancoal Australia. The plan is a 300-megawatt pumped hydro station with 12 hours of storage, four hours longer than Kidston, plus a 320-megawatt solar farm to charge it.<\/p>\n Water will move through a tunnel between a new upper reservoir and an existing dam on the site, with the first fill taken from the mine’s own water. The state expects it to cover around 13% of its 2034 long-duration storage target, and local reporting on the approval put the earliest operating date at 2029.<\/p>\n Planning minister Paul Scully described it as the first pumped hydro scheme to win final planning approval in the state in six years. Until now the only two pumped hydro projects actually under construction in Australia have been Kidston and Snowy 2.0, and Renew Economy has noted that Kidston has largely avoided the cost blowouts that hit the much larger Snowy scheme.<\/p>\n The gold at Kidston is long gone. Genex’s own corporate material puts production at 3.5 million ounces between 1985 and 2001, when processing stopped for good.<\/p>\n What the mine left behind was worth building on anyway. Two water-filled voids at different elevations, an accommodation camp, an airstrip, sealed roads, a switchyard and existing rights to water from a dam up the road. That inherited infrastructure is a large part of why a project this size penciled out at all, and it is the same argument Yancoal is now making about a coal pit 1,000 miles to the south.<\/p>\n Dead mines are turning out to be useful in odd ways. A disused Finnish mine is being lined up as an energy store using falling water rather than the steel weights originally planned<\/a>, on the same basic logic: the hole is already there, and digging is the expensive part.<\/p>\n So the interesting figure at Kidston is not the 250 megawatts, and it is not the 715-foot drop. It is whether the second one of these costs less than the first. Stratford should tell us by 2029.<\/p>\n","protected":false},"excerpt":{"rendered":" A worked-out open-pit gold mine normally ends the same way everywhere. The operator pulls the plant, fences the highwall, posts … <\/p>\nThe entire machine is the distance between two holes<\/h2>\n
Everything under the pits had to be dug<\/h2>\n
The turbines will be watched from a town in northern Italy<\/h2>\n
It was supposed to start this October<\/h2>\n
New South Wales just approved the same idea on a coal pit<\/h2>\n
The number to watch is not 250 megawatts<\/h2>\n