Electricity Market Guide: GB, Denmark, Australia, Taiwan, US

The electricity markets on our pages all balance supply and demand continuously, but they differ in who runs them, how often a price is set and what data is published in near real time. Great Britain and the Australian NEM publish frequent wholesale prices, Denmark publishes day-ahead auction prices in 15-minute steps, Taiwan publishes generation only, and the U.S. pages show hourly grid data from the EIA without prices.

This guide gives a practical overview of each market so the numbers on the market pages make sense. It explains structure, not strategy, and none of it is trading advice.

The markets at a glance

Market	Data publisher on our pages	Price interval	Local time vs our storage	What we show
Great Britain	Elexon (BMRS / Insights Solution)	Half-hour settlement periods	Europe/London, stored in UTC	Prices, generation, demand
Denmark (DK1, DK2)	Energinet (Energi Data Service)	15-minute day-ahead	Europe/Copenhagen, stored in UTC	Prices, national generation, derived demand
Australia (NEM)	AEMO (NEMWEB)	Five-minute dispatch	NEM time UTC+10	Prices, regional demand, mix where published
Taiwan	Taipower (data.gov.tw)	No price published	Asia/Taipei, stored in UTC	Generation mix only
United States	U.S. EIA (EIA-930)	No price shown	Hourly, delayed	Demand, net generation, interchange, fuel mix

Great Britain

Great Britain, meaning England, Scotland and Wales, is balanced as a single price zone. Elexon administers settlement and publishes the BMRS data service. The trading day is split into half-hour settlement periods: a normal day has 48 of them, rising to 50 on the long clock-change day in October.

Two prices matter on our Great Britain page. The imbalance price is what market parties pay or receive for being out of balance. Since the P305 modification in November 2015, Britain has used a single imbalance price, so there is one price for both directions. The market index price is a traded-price signal for the same half-hour. The two can differ widely, because one reflects the system operator’s balancing actions and the other reflects trading.

Generation on our page comes from Elexon’s FUELINST dataset, which covers only transmission-connected plant. Rooftop and most small solar, and much of the smaller wind on distribution networks, do not appear, so the renewable share is a share of metered transmission output. Britain is linked to its neighbours by interconnectors, including Viking Link to Denmark, which has a design capacity of 1,400 MW and was put into operation on 29 December 2023. Household bills follow wholesale costs only with a delay, through the Ofgem price cap.

Denmark

Denmark has two bidding zones. DK1 is the west, Jutland and Funen, connected to continental Europe, Norway and Great Britain. DK2 is the east, Zealand, Lolland-Falster and the Copenhagen area, connected to Sweden and, through the Kriegers Flak Combined Grid Solution, to Germany. The Great Belt Power Link joins the two with a capacity of 600 MW, so the zones can and often do show different prices at the same moment.

Danish prices on our pages are day-ahead auction results, published by Energinet through Energi Data Service under a CC BY 4.0 licence. The European day-ahead auction has used a 15-minute market time unit since delivery day 1 October 2025, so each Danish price covers a quarter of an hour, and we show it against the start of its interval. A day-ahead price is fixed the day before delivery. It is not a measurement of the grid at that moment and does not include real-time balancing costs or the network tariffs, fees and taxes that make up a household bill; the Danish-language elpriser pages set those out separately.

Denmark does not publish a near-real-time consumption figure, so the Danish demand on our pages is calculated from production and cross-border exchange and is labelled Derived. The methodology gives the exact formula.

Australia (NEM)

The National Electricity Market covers five regions: Queensland, New South Wales, Victoria, South Australia and Tasmania. AEMO operates it and publishes dispatch data through NEMWEB. Five-minute settlement began on 1 October 2021, so the spot price is set every five minutes in each region. NEM market time is AEST, ten hours ahead of UTC, all year; South Australia’s local standard time is UTC+9.5, and several states move their clocks for daylight saving, so local time and market time often differ.

Prices can move across a very wide range. The market price cap for 2026-27 is A$23,200/MWh, set by the Australian Energy Market Commission, and negative prices are possible, especially on mild, sunny, windy days. Regions are linked by interconnectors whose limits often decide whether their prices move together. Basslink, the cable between Tasmania and Victoria, is rated at about 500 MW; AEMO gives the Heywood interconnector between South Australia and Victoria a nominal design limit of up to 650 MW in either direction, and describes Murraylink as a 220 MW DC cable.

Our Australian cheapest hours pages also show AEMO’s own pre-dispatch prices for hours still to come, always labelled “forecast by AEMO”. They are AEMO’s published forecast, not ours.

Taiwan

Taiwan is an island grid with no interconnectors to other countries, so generation must match local demand at every moment. Taipower, the state utility, publishes output by plant type through data.gov.tw dataset 8931, which updates every 10 minutes, under the Open Government Data License, Taiwan v1.0. The feed contains no wholesale price and no demand figure, so our Taiwan page shows only the generation mix and the renewable share.

Gas and coal supply most of the power, and solar peaks at midday. Taiwan’s Nuclear Safety Commission states that all three nuclear plants have entered their decommissioning stage, so nuclear does not appear as a baseload source.

United States (EIA-930)

The U.S. pages use the EIA’s Hourly and Daily Balancing Authority Operations Report, Form EIA-930, shown through EIA’s Hourly Electric Grid Monitor. It reports hourly demand, net generation, interchange with neighbours and, where available, generation by fuel. The data is preliminary, revised later and arrives an hour or two late, so these pages refresh on a slower cycle and their counters do not tick. We do not show U.S. wholesale prices.

The regions differ a lot. ERCOT, which serves most of Texas, is unusual because the balancing authority, the interconnection and the regional transmission organization are all the same entity, and ERCOT does not have a centralized capacity market. PJM coordinates the grid for 13 states and the District of Columbia and serves more than 67 million people; it does run a capacity auction, and its 2027/2028 Base Residual Auction secured 134,479 MW. SPP serves all or part of 17 states, and wind produced 36.7% of its energy in 2025. ISO New England reports that net flows over external ties met 7% of the region’s energy needs in 2025.

Things that trip people up

Interval start or end

Sources stamp intervals differently. AEMO’s files mark the end of a five-minute interval, while Elexon and Energinet use the start. We store every value against the start of its interval in UTC, so the same moment lines up across markets.

Prices are not bills

Every price on our market pages is a wholesale price per megawatt-hour, before network charges, taxes and retail margins. A low wholesale price does not mean a household bill falls on the same day.

Provisional data

Operators revise data. A figure on our pages can change after it is first published, and we keep a revision history rather than overwriting it silently. If a feed stops, the page says it is paused and shows the last value with its time; we do not fill the gap with a guess.

For definitions of the terms used here, see the glossary. For what makes prices rise and fall, see wind, solar and gas: what moves electricity prices.