Renewable energy generation hit a new record on Friday, briefly contributing more than two-thirds of the power in Australia’s main grid.
According to the Australian Energy Market Operator (Aemo), the milestone was set at 12.30pm, with a contribution of 68.7%, or 18,882MW, from renewable sources.
The figure is 4.6 percentage points higher than the previous record, which was set on 18 September.
Of total power in the grid on Friday, 34% came from distributed solar, which outstripped black coal’s contribution of 22%.
Renewable penetration rates are measured in 30-minute intervals, and illustrate contributions to the grid within a short period of time.
“It’s very different to 100% renewables 24/7,” said Alison Reeve, climate change and energy deputy program director at the Grattan Institute. “Nevertheless, it does show how much the grid is changing.”
“Five years ago the maximum that we’d managed to get to was 30%, and five years before that, I don’t know that anyone was even measuring [renewables], it was so small.”
One challenge of the energy transition was managing fluctuating contributions from renewable sources, Reeve said. “Once the solar has dropped out [at night], the percentage that you need to ramp up your non-renewables up to is a lot higher,” she said.
“One of the things that is gradually driving particularly coal-fired power plants out of the market at the moment is that they can’t ramp up and down that quickly … they’re not good at switching on and off over a couple of hour periods.”
Gas and hydro generators are more responsive at short timescales. Because of high gas prices currently, “when those gas generators come on they set quite a high price in the electricity market,” Reeve said.
Hydro generators have recently been limited in their operation because of the wet weather on the east coast of Australia, she added. “They can’t send too much water down the river because they don’t want to make any flooding worse,” she said.
Another challenge was replacing the “system’s stability” that coal and gas provide to the electricity grid – the ability to drop and raise generation slightly in order to “keep the voltage in the grid balanced”, Reeve said, which will require more long-duration storage infrastructure such as batteries.
“Until we figure out a way to get that balancing role done by other things like pumped hydro and batteries, and we have enough of those in the system, there will be a natural upper limit on how much renewables penetration we have, particularly once you move beyond the instantaneous … and start to talk about what we can sustain over four or eight hours.”
Reeve described these as “solvable problems”, but which required ironing out of details including costs, storage location and how the services would be valued.
A July report by the International Renewable Energy Agency (Irena) found Australia was now among the world leaders in cheap solar energy.
Behind China and India, in 2021 Australia had the third-lowest utility-scale solar cost in the world, of $0.042 USD/kWh (AU$0.065). This represented a 21% year-on-year drop in price.
According to Irena data, the average cost of electricity from utility-scale solar has dropped by 90% in Australia since 2010.
