| Planning & projects
Innovative storage New research suggests Australia’s agricultural water
reservoirs could be an innovative energy storage solution for variable renewables. According to recent studies by the University of New South Wales, tens of thousands of small-scale hydro energy storage sites could be built from Australia’s farm dams, supporting the uptake of reliable, low-carbon power systems in rural communities. Agricultural reservoirs, such as those used for solar- power irrigation, could be connected to form micro- pumped hydro energy storage systems. The research, published in Applied Energy, is described as being the world’s first study to assess such potential of these small-scale systems. “The transition to low-carbon power systems like wind and solar photovoltaics needs cost-effective energy storage solutions at all scales,” said Dr Nicholas Gilmore, lead author of the study and lecturer at the School of Mechanical and Manufacturing Engineering at the University of New South Wales Engineering. “We thought if you’re geographically fortunate to have two significant water volumes separated with sufficient elevation, you might have the potential to have your own hydro energy storage system.” Along with researchers from Deakin University and the University of Technology Sydney, the team used satellite imagery to create unique agricultural reservoir pairings across Australia from a 2021 dataset of farm dams. They then used graph theory algorithms – a branch of mathematics that models how nodes can be organised and interconnected – to filter commercially promising sites based on minimum capacity and slope. “If you have a lot of dams in close proximity, it’s not
viable to link them up in every combination,” said Dr Thomas Britz, co-author of the study and senior lecturer at UNSW Science’s School of Mathematics and Statistics. “So, we use these graph theory algorithms to connect the best dam configurations with a reasonable energy capacity.” From nearly 1.7 million farm dams, the researchers identified over 30,000 promising sites across Australia for micro-pumped hydro energy storage. The average site could provide up to 2kW of power and 30kWh of usable energy – enough to back up a South Australian home for 40 hours.
“We identified tens of thousands of these potential
sites where micro-pumped hydro energy storage systems could be installed without undertaking costly reservoir construction,” Gilmore said. “That’s thousands of households that could potentially increase their solar usage, saving money on their energy bills, and reducing their carbon footprint.” The research team also benchmarked a micro- pumped hydro site to a commercially available lithium- ion battery in solar-powered irrigation systems. Despite a low discharge efficiency, they found the pumped hydro storage was 30 per cent cheaper for a large single cycle load due to its high storage capacity. “While the initial outlay for a micro-pumped hydro
energy storage system is higher than a battery, the advantages are larger storage capacity and potential durability for decades,” Gilmore explained. “But that cost is significantly reduced anyway by capitalising on existing reservoirs, which also has the added benefit of less environmental impact.” Building micro-pumped hydro energy power systems
from existing farm dams could also assist rural areas susceptible to power outages that need a secure and reliable backup power source. Battery backup power is generally limited to less than half a day, while generators, though powerful, are dependent on affordable fuel supply and produce harmful emissions.
Above: The US Bureau of Reclamation’s Glen Canyon Dam is the second highest concrete arch dam in the US
Below: A farm dam in rural Victoria, Australia. New research by the University of New South Wales estimates that tens of thousands of small-scale hydro energy storage sites could be built from Australia’s farm dams
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