South Australia and Victoria Experience Extended Negative Electricity Prices

Negative Wholesale Electricity Prices Observed in South Australia and Victoria

From late April 8 through to the evening of April 12, South Australia and Victoria experienced negative average wholesale electricity prices, as reported by Open Electricity data.

In South Australia, wholesale electricity prices fell below $0.00 per megawatt-hour (MWh) just after midnight on April 8, remaining predominantly negative until 6pm on April 12. This trend was largely driven by wind energy and rooftop solar, which at times exceeded 130 per cent and around 50 per cent of the state’s demand, respectively.

Factors Behind the Negative Prices

Additionally, imports contributed significantly to the demand on April 11, accounting for over 40 per cent with a total of 586MW. South Australia’s reliance on fossil fuels is limited, with gas making only a minor contribution, amounting to less than 6 per cent of demand from both steam and combined cycle gas turbine (CCGT) sources throughout most of the observed period.

Victoria’s Unique Energy Contributions

In contrast, while Victoria also saw average negative prices during the same timeframe, the dynamics were different. On April 9, early in the morning, brown coal generation accounted for more than 70 per cent of the state’s electricity demand. Wind energy was also significant at that time, contributing 53.2 per cent, which led to the curtailment of 19.6 per cent of wind energy generated.

Brown coal continues to be a foundational element of Victoria’s electricity supply, although its demand share dipped to a low of 35.7 per cent at 1pm on April 11, coinciding with increased output from rooftop and utility-scale solar projects.

Comparative Average Prices

During the analysed period from April 8 to April 12, the average wholesale electricity price in South Australia and Victoria was -$6.30 per MWh. In stark contrast, New South Wales and Queensland recorded average prices of $62.59 and $64.66 respectively, largely due to their inability to tap into significant wind energy resources during the night.