When is electricity cheap?
Wholesale electricity prices in Australia's National Electricity Market, by hour of day, year and region.
Monthly prices in the midday and evening windows, and the gap between them (the spread, which is the evening price minus the midday price). The spread is a rough indicator of the value of moving energy from midday to the evening, which is what batteries do. Numbered dotted lines mark major events in Australia (grey) and in global energy markets (purple), listed below the chart.
Each line is one year. The shaded bands mark the midday window (10:00 to 15:00) and the evening window (17:00 to 21:00). Compare how the midday dip and the evening peak change from year to year. The daily pattern in winter is quite different from spring, so the Season menu lets you compare like with like.
This table always shows all three measures side by side, so you can compare them. The highlighted column matches the Measure menu. The simple average counts every 5 minute interval equally. The demand weighted average gives more weight to times when more electricity is used, so it is closer to what buyers pay on average. It is usually higher, because expensive periods tend to be busy ones.
The share of 5 minute intervals with a negative price. A negative price means some generators would rather pay than switch off. It tends to happen when solar and wind output is high and demand is low.
Each column is a month and each row an hour of the day. Blue is cheap and red is expensive. The colour scale is capped at the 95th percentile so a few extreme months don't wash out the pattern.
Every 5 minute price in the year, sorted from highest to lowest. The further right the line dips below zero, the more often prices were negative. The chart is cut at $600/MWh, and real spikes go much higher.
Data and definitions
- Source: AEMO dispatch prices (MMSDM
DISPATCHPRICE), excluding intervention pricing runs. - Times are NEM time (AEST, with no daylight saving). Each 5 minute interval is counted in the hour it starts.
- Yearly charts use full calendar years only. The monthly charts use every month available.
- Seasons follow the Southern Hemisphere. Summer is December to February, autumn is March to May, winter is June to August and spring is September to November. Within each calendar year, summer means January, February and December of that year.
- Simple average is the plain average of the 5 minute prices. Demand weighted average weights each price by grid demand at that time (AEMO
TOTALDEMAND, which excludes electricity people use from their own rooftop solar). Median is the middle value, which is not pulled up by price spikes. - Prices are nominal and not adjusted for inflation.