South Australia and Victoria both experienced negative average wholesale electricity prices from late on April 8 into the evening on April 12, according to Open Electricity data.
As soon as South Australia’s wholesale electricity prices dipped below $0.00/megawatt-hours (MWh) around midnight on April 8, they remained mostly in the negative until 6pm on April 12.
The combined power of wind energy and rooftop solar drove the lion’s share of this, with periods where wind and rooftop solar contributed to over 130 per cent and around 50 per cent of South Australian demand, respectively.
Imports also played a role, contributing to more than 40 per cent of demand periodically on April 11, comprising 586MW.
In keeping with South Australia’s limited fossil-fuel footprint, gas was a marginal contributor to demand, contributing less than 6 per cent (across steam and combined cycle gas turbine [CCGT] sources) for most of the period.
In Victoria it was a same-but-different story, with average negative prices across the same timeframe, but the contributors were different.
There was a period in the early morning on April 9 where brown coal generation contributed to more than 70 per cent of electricity demand in Victoria, with wind energy also contributing 53.2 per cent of demand at that time, leading to 19.6 per cent of wind energy being curtailed.
Brown coal generation continues to be an anchor for Victorian electricity, with its demand contribution dipping to a low of 35.7 per cent at 1pm on April 11 when rooftop and utility-scale solar were active players.
The average wholesale electricity price across South Australia and Victoria during the analysed period from April 8–12 was -$6.30/MWh. At the same time, NSW averaged $62.59 and Queensland averaged $64.66, with these states unable to call on enough wind energy resources during night-time periods.
Learn more about Open Electricity data here.
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