Over the past three days, solar and wind output has exceeded South Australia’s electricity needs by 5.9%, data from the system operator shows.
The surplus has been exported to the state of Victoria and used to charge up South Australia’s big batteries, which inject that power back into the grid when it’s needed.
Wind has held the largest share of the mix, followed by solar panels on the roofs of homes and businesses, and then solar farms. The state has no hydropower or biomass plants.
As a result of the excess renewable energy generation, spot power prices have averaged negative A$26.15 per megawatt hour (MWh) over the past three days. That may be a good thing for consumers, but negative pricing poses a challenge for renewable energy developers.
Excess renewables output is nothing new for South Australia. This time last year, the state recorded a 10-day streak of excess solar and wind generation.
Yes, but: Even though solar and wind have comfortably met power demand, South Australia has continued to operate its gas turbines to maintain the strength of the system.
The minimum share of gas in the mix was 3.5%.
The state, which has no remaining coal-fired power plants, is working to muscle gas out of the mix as well by investing in synchronous condensers, additional big batteries, and a green hydrogen power plant.