The best hour by hour stack paid one megawatt €366,386 in West Denmark and €396,378 in East Denmark in the twelve months to September 2026, in markets far smaller than the fleet being built

The ceiling in West Denmark, month by month

In each hour the megawatt is sold into FCR, which covers both directions, or once upward and once downward into the best of the other markets, whichever pays more, and only into a market in which Energinet bought something that hour. The bar is the month’s sum. Over the twelve months to September 2026 it came to €366,386.

In East Denmark the fast frequency reserve paid €163,155 for one megawatt in September 2026, when Energinet bought about 4.8 MW of it an hour

FFR is bought hour by hour in DK2 when the system’s inertia is low, and its price ran as high as €987 per megawatt per hour in September 2026. Over the twelve months it paid one megawatt €199,530, the most of any product in either zone, while Energinet bought on average 0.9 MW an hour. So the DK2 ceiling is shown twice: €577,780 with FFR, which a handful of megawatts could earn, and €396,378 without it, which is nearer what the fleet could.

The bars leave FFR out. With it, each month’s figure is in the table below.

Each market on its own, West Denmark

One megawatt sold only into that market, every month, on one scale so the markets can be read against each other; a bar above the scale is cut at the top, the tallest carries its figure, and every month’s figure is in the tables below. The single figures must not be added: a megawatt cannot be in two markets at once, except one up and one down, which the pairs in the table count.

DK1’s FCR is counted at the Danish settlement price, in hours in which Energinet bought FCR from Danish units; over the same twelve months the cross-border price Energinet paid for the share it bought abroad came to €159,003 for one megawatt, against €148,488 at the Danish price. DK1’s aFRR capacity market opened on 2 October 2024.

Each market on its own, East Denmark

How much Energinet buys: the fast products are a few dozen megawatts

The average volume bought each hour over the twelve months, beside what one megawatt was paid in it. A product that pays well but buys little can be filled by a handful of batteries; this is the measure of how crowded each market can get.

For DK2’s FCR products, the volume is the DK2 share of what Energinet and Svenska kraftnät bought together; an hour counts as bought when the joint market bought anything. For DK1’s FCR, the Danish units’ share. The Nordic aFRR and mFRR markets can move capacity between zones, so a zone’s volume can differ from its own need.

The last twelve months, as a table

Euros for one megawatt, by Danish month, before any cost. Every month, zone and market as a CSV · the volumes as a CSV.

West Denmark, DK1

East Denmark, DK2

The imbalance price: a median of €127 in West Denmark in September 2026, below nought in 11% of quarter hours

A battery that delivers more or less than its schedule is settled at the imbalance price, so this is the price of being wrong, and of being right when the system is short. Energinet’s quarter-hour file of the price starts on 4 March 2025. In West Denmark it was highest in September 2026, a mean of €137 with 23% of quarter hours above €200. The band is the middle four fifths of each month’s quarter hours, the line the median and the dot the mean.

West Denmark, DK1

East Denmark, DK2

The imbalance price as a table

Month	Zone	Mean	10th percentile	Median	90th percentile	Below nought	Above €200
October 2026 (part)	DK2	€152	€14	€148	€268	3%	27%
October 2026 (part)	DK1	€156	€20	€148	€293	3%	28%
September 2026	DK2	€140	−€1	€129	€263	11%	21%
September 2026	DK1	€137	−€0.31	€127	€294	11%	23%
August 2026	DK2	€139	€1.59	€130	€253	8%	16%
August 2026	DK1	€127	€0.22	€120	€254	9%	16%
July 2026	DK2	€101	−€12	€82	€215	21%	12%
July 2026	DK1	€103	−€10	€88	€268	20%	15%
June 2026	DK2	€104	−€6	€87	€216	15%	12%
June 2026	DK1	€111	−€5.42	€71	€251	14%	16%
May 2026	DK2	€116	−€2.42	€95	€198	13%	9%
May 2026	DK1	€105	−€1.44	€96	€201	12%	11%
April 2026	DK2	€78	−€8.64	€58	€168	20%	7%
April 2026	DK1	€75	−€7.25	€67	€175	16%	7%
March 2026	DK2	€102	€0	€89	€215	9%	12%
March 2026	DK1	€99	€2	€90	€196	8%	9%
February 2026	DK2	€113	€14	€86	€249	6%	12%
February 2026	DK1	€91	€26	€84	€134	1%	2%
January 2026	DK2	€112	€16	€89	€204	5%	11%
January 2026	DK1	€104	€31	€83	€172	3%	7%
December 2025	DK2	€72	−€8.32	€58	€160	17%	7%
December 2025	DK1	€86	€16	€67	€161	2%	7%
November 2025	DK2	€97	−€6.73	€69	€257	16%	13%
November 2025	DK1	€90	€13	€67	€173	3%	7%
October 2025	DK2	€93	−€12	€57	€268	19%	15%
October 2025	DK1	€89	€0.67	€54	€212	8%	11%
September 2025	DK2	€65	−€32	€28	€201	30%	10%
September 2025	DK1	€71	−€13	€24	€142	24%	8%
August 2025	DK2	€80	−€8	€45	€139	20%	7%
August 2025	DK1	€72	−€10	€38	€138	19%	7%
July 2025	DK2	€79	−€8	€25	€136	19%	7%
July 2025	DK1	€86	−€8	€40	€241	14%	11%
June 2025	DK2	€58	−€19	€7.08	€179	36%	9%
June 2025	DK1	€68	−€24	€4.29	€193	39%	10%
May 2025	DK2	€64	−€57	€0.64	€255	48%	12%
May 2025	DK1	€69	−€15	€18	€162	33%	9%
April 2025	DK2	€73	−€41	€9.83	€271	41%	13%
April 2025	DK1	€81	−€13	€43	€251	18%	13%
March 2025	DK2	€90	−€33	€16	€268	37%	14%
March 2025	DK1	€99	−€14	€38	€250	20%	14%

Energinet, ImbalancePrice, every quarter hour, euros per megawatt hour, by Danish month; March 2025 starts on the 4th. As a CSV.

The day-ahead price is read every day and held back until Energinet confirms its terms

Energinet republishes the day-ahead price for both zones on Energi Data Service under the same open licence, and the site reads and keeps it every day. It is not shown here until Energinet confirms in writing that its republication carries no reservation from Nord Pool, the exchange that produces it and that declined the site permission to show its prices. Denmark’s two hour spread is already on the Europe page, from the German regulator’s open data.

How each figure is made

Each hourly row of an Energinet reserve file has a price in euros per megawatt per hour and the volume bought; the money for one megawatt in that hour is the price, put in the month in which the hour starts, in Danish time. An hour counts only if Energinet bought some volume in that market in that hour: if it bought nothing, no battery was paid, whatever price is shown, and an hour with no row earns nothing. DK2’s FCR products use Energinet’s “Total” row, the volume-weighted price of the two daily auctions. The pair figures add the up side and the down side, because a battery can hold one megawatt up and one down in the same hour. The ceiling takes, for every hour, the better of the symmetric product (FCR in DK1, FCR-N in DK2) or the best upward product plus the best downward one. A second calculation written separately in pandas checks every single-market figure before it is published; the two agree to the cent on all 426 of them. At the October clock change of 2024 and 2025 Energinet’s FCR file in DK2 dates the first of the two 02:00 hours an hour late; the calculation corrects it by the minute Energinet writes on the second.

What is left out

Energy trading on the day-ahead and intraday markets, which batteries of two hours and more depend on. The energy paid when Energinet activates a reserve, which it publishes for the whole market and not per provider. Energinet’s monthly mFRR auction in DK2, which is not on Energi Data Service. Availability, degradation, the optimiser’s share, grid tariffs and imbalance costs, none of which is taken off. So these are the most a megawatt could have been paid, and a real battery earns less.

Source: Energinet (www.energidataservice.dk), CC BY 4.0: FcrDK1, FcrNdDK2, FFRDK2, AfrrReservesNordic, mFRRCapacityMarket, MfrrCapacityMarketExtra and ImbalancePrice, read 25 October 2026. The figures are calculated by Vitreous from Energinet’s prices and volumes; Energinet has not checked them. The calculation is dk/tools/revenue.py and its check dk/tools/test_revenue.py in the repository.