Hydro may boost share of renewables in electricity grid

Hydro power could provide cost-effective large-scale energy storage that can support high levels of renewable energy in Australia's electricity grid. The Australian National University (ANU) is leading a study to map potential short-term off-river pumped hydro energy storage (STORES) sites, which would enable renewable energy to provide a larger share of generation to the national electricity grid. Lead researcher Professor Andrew Blakers from ANU said the low cost and technical maturity of STORES could allow solar photovoltaic and wind energy to reliably reach penetration levels above 50 per cent and push towards 100 per cent renewables. "Water is constantly flowing between the reservoirs to balance supply and demand, and STORES has the potential to support grid stability through inertial spinning reserve and very fast ramp rates from zero to 100 per cent in minutes," he said. STORES sites are pairs of reservoirs which are separated by an altitude difference of between 300 - 900 metres, in hilly terrain, and joined by a pipe. Water is circulated between the upper and lower reservoirs in a closed loop to store and generate power. "South Australia has one possible STORES site with an altitude difference of up to 600 metres in the hills to the east of Spencer Gulf.