Negative Electricity Prices Around the World: Where and Why

Negative wholesale electricity prices occur wherever a market lets bids fall below zero and, for a while, more power is offered at any price than the grid can use. They are most frequent in South Australia and other Australian regions at midday, appear in Denmark and the rest of Europe on windy, sunny or quiet days, show up in Great Britain overnight, and occur in U.S. markets with a lot of wind or solar.

The reasons are much the same everywhere: some plants are costly to switch off, some subsidies are paid for every megawatt-hour produced, wind and solar can outrun demand, and full transmission lines trap surplus power in one area. This guide looks at each market in turn and then at what we have recorded ourselves. For the mechanism in more depth, read why prices go negative.

Why prices fall below zero

A wholesale price is where supply offers meet demand bids. If enough generators are willing to keep running even when they must pay to do so, the clearing price drops through zero. Four conditions usually combine:

1. Inflexible generation. Coal, nuclear and some gas or combined heat and power plants are slow or expensive to stop and restart. EIA put it simply when it described negative prices in California: they “usually result when generators with high shut-down or restart costs must compete with other generators”.
2. Support paid per megawatt-hour. A wind or solar farm that earns a certificate, premium or tax credit for each MWh can profit at a slightly negative market price. In the United States, the IRS describes the clean electricity production credit for facilities placed in service after 2024 as a credit per kilowatt-hour of electricity produced and sold.
3. Renewable surplus at low demand. Every solar panel in a region produces at the same time, and windy nights coincide with low demand.
4. Transmission limits. When interconnectors are full, surplus cannot leave the area, and the local price falls while the neighbour’s stays positive.

Markets also set a price floor, the lowest price an offer may carry. The floor limits how negative a price can go, not how often it goes negative.

Australia’s National Electricity Market

The NEM has the highest frequency of negative prices among the markets we cover. AEMO’s Quarterly Energy Dynamics report for January to March 2026 says that 14.9% of all dispatch intervals across the NEM had negative or zero prices. South Australia recorded the highest share of negative prices, 31.3% of intervals, followed by Victoria at 26.2%, Queensland at 10.4%, New South Wales at 6.7% and Tasmania at 0.2%.

Timing is the clearest signal. Between 09:00 and 17:00 that quarter, negative prices occurred in 67% of dispatch intervals in South Australia and 53% in Victoria. AEMO attributes the daytime pattern to “lower operational demand driven by strong distributed PV output, high large-scale variable renewable generation (VRE) generation, and coal-fired generators operating at minimum stable output levels”.

The same report shows how subsidies shape the depth of negative prices. Large-scale generation certificates averaged A$5 in Q1 2026, against A$29 a year earlier, and the share of negative prices between −A$10/MWh and zero rose from 12% to 68%. AEMO links this to the fall in certificate prices: with less certificate income at stake, the average price during negative intervals rose from −A$35.4/MWh to −A$17.7/MWh.

The NEM’s market price floor is −A$1,000/MWh; the AEMC Reliability Panel’s report lists it at that level for each financial year from July 2023 to June 2026. Prices that reach the floor are rare: the panel counted three floor events in 2023–24, all in South Australia, down from 25 the year before.

Denmark and the European day-ahead market

Denmark’s two price zones, DK1 and DK2, are priced in Europe’s Single Day-Ahead Coupling, which has cleared in 15-minute steps since delivery day 1 October 2025. Under the methodology approved by ACER, the EU energy regulators’ agency, in January 2023, the reference harmonised minimum clearing price for the day-ahead market is −500 EUR/MWh, and it is lowered in steps of 100 EUR/MWh if prices repeatedly come close to it. ACER’s Decision 02/2026 of 4 February 2026 amended the rules on when such an adjustment is triggered.

Danish negative prices usually come from wind. When turbines run hard on a night or weekend with low demand, and neighbouring zones are also well supplied, the price can fall to zero or below. Because DK1 and DK2 have separate links to Norway, Sweden, Germany and, for DK1, the Netherlands and Great Britain, the two zones can clear at very different prices in the same quarter-hour.

Great Britain

Our GB page shows two half-hourly series from Elexon: the market index price and the imbalance (system) price. Negative values tend to come on windy nights and weekends.

Subsidy design matters here too. Under the original Contracts for Difference terms, according to the government’s 2020 impact assessment, generators did not receive difference payments when the day-ahead hourly price was negative for six consecutive hours or more. In its response of 24 November 2020 the government confirmed an “extension of the negative pricing rule for future CfD contracts so that CfD generators are not paid when ‘day ahead’ electricity market prices are negative”. Plants on older contracts or other schemes can still have a reason to generate at negative prices.

United States

U.S. wholesale markets also produce negative prices, mostly where wind or solar is large relative to demand. SPP reports that wind produced 36.7% of its energy in 2025, and windy nights there can push prices below zero. In California, EIA reported in 2017 that during March system average hourly prices between 08:00 and 14:00 were “frequently at or below $0 per megawatthour”. Negative prices are also often local: one congested node can go negative while the wider market stays positive. We do not publish U.S. prices; the operators publish them on their own sites.

What we recorded in the days we have tracked so far

Our data starts on 23 October 2026, so the figures below cover only a few days. They come from AEMO, Energinet and Elexon, and they show what happened, not what is typical. Our negative prices page keeps the running totals.

In South Australia, AEMO’s five-minute prices were negative in 94 of the 437 intervals we hold between 17:55 UTC on 23 October and 11:20 UTC on 25 October 2026, a total of 7 hours 50 minutes. The longer runs (local time is ACDT, UTC+10:30) were:

Date (local)	Negative run	Length	Lowest price
Sat 24 Oct 2026	09:30–11:45 ACDT	2 h 15 min (27 intervals)	−A$29.78/MWh
Sat 24 Oct 2026	13:40–15:40 ACDT	2 h 00 min (24 intervals)	−A$24.73/MWh
Sun 25 Oct 2026	08:10–08:40 ACDT	30 min (6 intervals)	−A$9.13/MWh
Sun 25 Oct 2026	15:00–17:20 ACDT	2 h 20 min (28 intervals)	−A$8.00/MWh

Another nine intervals fell in short runs of 5 to 15 minutes. The first run may have begun earlier, because 32 intervals before it are missing from our data. No other NEM region had a negative five-minute price in the same window; Victoria’s lowest was A$0.01/MWh.

In Denmark, DK1’s day-ahead price was negative for five quarter-hours on Sunday 25 October 2026, from 03:45 to 05:00 CET, at −0.07 DKK/MWh, barely below zero. DK2 had no negative price between 23 October and the end of 25 October.

In Great Britain, the market index price was negative for seven half-hours, all on Sunday 25 October 2026: from 02:00 to 05:00 GMT (lowest −£6.24/MWh) and from 06:00 to 06:30 GMT. The imbalance price was negative for seven half-hours that day as well, reaching −£16.27/MWh. That Sunday was the October clock-change day, which Elexon’s rules give 50 settlement periods instead of 48.

What negative prices mean for consumers

A negative wholesale price is a genuine market result and a signal that more storage, flexible demand or transmission would be valuable. It rarely reaches a household directly: only contracts that pass the wholesale price through, such as some dynamic tariffs, can turn a negative interval into a credit. Our figures are provisional and are not advice.