Continental-scale assessment of micro-pumped hydro energy storage using agricultural reservoirs

Abstract

The transition to low-carbon power systems necessitates cost-effective energy storage solutions. This study provides the first continental-scale assessment of micro-pumped hydro energy storage and proposes using agricultural reservoirs (farm dams) to significantly reduce construction costs. The continent of Australia is used as a representative case study for other arid and temperate regions internationally. From a new survey of its 1.7 million farm dams, we identified 30,295 promising pumped hydro sites in dam-to-dam and dam-to-river reservoir configurations. The average site had nearby reservoirs (132 m) with a high head height (32 m) and substantial discharge capacity (52 kWh). We then benchmarked a representative micro-pumped hydro site to a commercially available lithium-ion battery for a solar-powered irrigation system. Despite a low discharge efficiency (68%), pumped hydro storage was 30% less expensive (0.215 USD/kWh) for larger single-cycle loads (∼41 kWh/day) due to its high storage capacity. By capitalising on existing farm dams, micro-pumped hydro energy storage may support the uptake of reliable, low-carbon power systems in agricultural communities.