The Australian water industry could play an important role in achieving secure, cheap and 100% renewable energy, an ANU study has shown.
The paper – 100% renewable electricity in Australia – found wind and solar photovoltaic (PV) technology could meet 90% of National Electricity Market (NEM) demand.
The remaining 10% could be delivered almost entirely via pumped hydro energy storage (PHES), plus a small amount of biomass.
“PHES as a primary energy storage mechanism is generally overlooked,” the report stated.
That’s despite the fact that “PHES constitutes 97% of electricity storage worldwide (155 GW) because it is much cheaper and has much greater technological maturity than alternative sources, including batteries”.
To demonstrate the capacity of Australia to achieve the almost 10% PHES component, the study mapped hundreds of potential sites for short-term off-river pumped hydro energy storage (STORES).
“STORES sites are pairs of reservoirs, typically 10 hectares each, which are separated by an altitude difference of between 300 and 900m, in hilly terrain, and joined by a pipe with a pump and turbine,” the report explained.
“Water is circulated between the upper and lower reservoirs in a closed loop to store and generate power.
“PHES offers ancillary services including high-inertia, fast-ramping and synchronous capacity for frequency and voltage support.”
Lead researcher, ANU Research School of Engineering’s Professor Andrew Blakers, said the paper also proved Australia could afford to eliminate the need for coal and gas-fired power.
“With Australia wrestling with how to secure its energy supply, we’ve found we can make the switch to affordable and reliable clean power,” he said.
Modelling showed a 100% renewable system would cost $93/MWh at 2016 prices, and that would drop to $75/MWh at 2020s prices.
“Wind and PV, supported by HV interconnectors and PHES, will be decisively cheaper in the 2020s than new coal and gas,” the report stated.
The study included existing biomass generation from agricultural waste (3 TWh/year), but excluded additional deployment of biomass, finding that “utilisation competes with food, timber and ecosystem values for the provision of land, water, fertilisers and pesticides”.
Renewable energy currently accounts for around 15% of Australia’s electricity generation while two thirds comes from coal-fired power stations.