The ISP divides storage into three distinct categories based on the functions they perform. Short-duration energy storage, categorised as systems with durations below 4 hours, provides rapid frequency response and short-duration peak management.
Meanwhile, medium-duration storage, covering systems from 4-12 hours, handles the daily intraday cycle of absorbing midday solar surplus and dispatching it during the evening peak.
Together, these two categories make up the 35GW target.
LDES, at 12 hours and above, firms renewables across extended low-wind and low-solar periods and during winter – a role the ISP assigns to pumped hydro and the NEM’s existing hydro fleet.
The ISP’s Optimal Development Path (ODP) calls for almost 120GW of grid-scale wind and solar, nearly 50GW of utility-scale storage and hydro, 17GW of flexible gas and 6,000km of new transmission by 2050. Most of the NEM’s remaining coal fleet would withdraw by 2038, with all to exit by 2049.
