‘ Snowy 2.0’ is a plan to turn one section of the hydro scheme into a giant virtual battery capable of powering 500,000 homes for a week on a single charge. Every day the cost of power rises and falls according to supply and demand. At times of high demand, the new 2,000 megawatt plant would generate electricity just like any other hydroelectric facility, powered by the flow of water from a higher reservoir to a lower one. But when there is surplus energy in the grid, engineers will flick the turbines into reverse, using cheap electricity to pump water from a lower reservoir back up to a higher one, ready to be used again as soon as energy demand picks up. Modern pumped hydro schemes typically recover about 80% of the original hydro power.