Renewable and negative price records fall in the September quarter

1 min

AEMO’s latest Quarterly Energy Dynamics report shows that renewable energy continued to set new records during the September quarter, reaching 61.4% instantaneous penetration1 and supplying 31.7% of total electricity generated in the National Electricity Market (NEM).

Renewable output was boosted by commissioning and ramp-up of new wind and solar generation over the seasonally windy quarter, higher distributed PV (+341MW on average) combined with higher rainfall driving increased hydro output from Tasmania.

AEMO Chief Markets Officer, Violette Mouchaileh, said that the quarter began with a continuation of volatile market conditions experienced during May and June.

“In July, mainland NEM electricity prices averaged $111/MWh and gas prices were $15.61/GJ. This price volatility was influenced by an outage at the Longford Gas Plant reducing gas supply coinciding with low storage levels in Victoria and higher international gas prices creating strong liquefied natural gas (LNG) export demand.

“However, following Longford’s return to full production and with milder weather these conditions stabilised with September gas prices falling to $8.09/GJ and mainland NEM electricity prices averaging $37/MWh.

“This trend of falling prices through the quarter was in sharp contrast to international energy prices for LNG and coal which continued to rise throughout the quarter reaching record levels,” she said.

The increase in renewable energy supply, combined with a mild August and COVID-19 restrictions reducing demand, led to wholesale electricity prices being negative or zero for 16% of trading intervals, more than double the previous record of 7% in Q4 2020.

In Victoria, average spot prices between 10am and 3:30pm fell from $30/MWh in 2020 to just $0.01/MWh during August and September. This follows South Australia achieving average daytime prices below zero consistently between 10am and 3:30pm (AEST) during the March 2021 quarter, the first time in the NEM’s history.

“The continued growth in distributed PV pushed minimum operational demand levels to record lows. In New South Wales, minimum demand from the grid fell to 4,872MW, the lowest level since Q1 2000, while South Australia’s minimum demand record fell by 21% to 236 MW,” Ms Mouchaileh said.

Similar to the NEM, Western Australia’s Wholesale Electricity Market (WEM) set new renewable energy records, contributing 25% of total demand for the quarter and a 70% instantaneous renewable penetration record on 7 September.

Total Western Australia domestic gas consumption decreased by 4.7PJ from Q3 2020 to 95.3PJ. Total gas supply was 97PJ, which is 4.1PJ less than Q3 2020 and decreased in line with changes in total consumption.

GPG output decreased by 20% in Q3 2021 from Q3 2020 due to higher coal availability (+7%) and increased output from wind (+36%), solar (+89%) and distributed PV (+13%) with an additional 379MW of distributed PV capacity added in the last year.

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1 Determined over a 30 minute interval.

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