Published by Watt Utilities | Energy Market Analysis | September 2026
Renewables supplied 80.4 percent of mainland generation at 12:30pm on Saturday 19 September, the highest share in AEMO’s records. Spot prices fell in all four mainland states, with South Australia down 47.3 percent and Victoria down 39.0 percent. Forward contract prices moved the other way and rose in every state. This edition explains why cheap spring power and rising contract prices arrived in the same month.
This report covers the mainland National Electricity Market (NEM), the wholesale market run by the Australian Energy Market Operator (AEMO) across Queensland, New South Wales, Victoria and South Australia. Spot prices are what generators are paid in that market. They differ from the rate on your bill, but sustained moves feed into the retail contract prices set at renewal. We publish a new edition in the first week of each month, once AEMO data for the month just finished is available.
AT A GLANCE: SEPTEMBER 2026
- Spot prices fell in every mainland state. South Australia dropped 47.3 percent to $37.71 per MWh and Victoria fell 39.0 percent to $36.83. New South Wales eased 13.7 percent to $65.32 and Queensland slipped 5.5 percent to $57.10.
- South Australia had its cheapest September in three years, averaging $19.89 per MWh less than in September 2025. Victoria was down $18.44 on a year ago.
- Forward contracts rose while spot prices fell. In the latest ASX market wrap, calendar 2027 base swaps closed at $104.50 in NSW, $85.74 in QLD, $84.72 in SA and $74.61 in VIC, the cheapest mainland state to contract.
- Coal supplied 49.7 percent of mainland generation over the past 90 days, with renewables and storage at 47.3 percent. Coal still carries the grid before sunrise and through the evening peak, which is when prices spike.
- September set records at both ends of the renewable range. The full report shows what that range means for timing your renewal.
NEM Average Spot Price: August vs September 2026
NEM Average Spot Price: August 2026 vs September 2026 ($/MWh)
Source: AEMO (via WEB_AVERAGE_PRICE_DAY monthly exports).
| State | Aug-26 ($/MWh) | Sep-26 ($/MWh) |
|---|
| NSW | 75.71 | 65.32 |
| QLD | 60.42 | 57.10 |
| SA | 71.62 | 37.71 |
| VIC | 60.40 | 36.83 |
The southern states swung below zero on sunny, windy Sundays. South Australia averaged minus $25.67 per MWh on Sunday 20 September, and Victoria recorded five negative days in the month. New South Wales stayed the dearest mainland state at $65.32 per MWh, and Queensland had the smallest fall. Prices in every state then peaked in the same week, between 21 and 25 September.
What’s in the full report
- State by state breakdown for QLD, NSW, VIC and SA, with daily price charts and the drivers behind each move.
- Contracting Outlook: the latest ASX forward prices for calendar 2027 and 2028 read into plain-language guidance on whether to lock in, wait, or hedge in parts.
- Renewable Records: September’s new all-time renewable high and the highest monthly low on record, and what the range means for price risk.
- The 90-day fuel mix and what the near-even coal and renewables split means for your exposure.
- Watt’s News, including our new Caravanning Queensland group energy tender, plus verified Industry News for the month.
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