Belgium · electricity price and wind power

Flanders day-ahead wind power forecast

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Record updated 27 Oct 2026 Scored against Elia

Tomorrow · Wed 28 Oct, 11:00 Brussels

120MW

7.0% of 1,732 MW installed

Elia, same hour: 162 MW
Metered: not yet
80% interval: 44 to 200 MW

Most recent scored day, Tue 27 Oct

Metered 850 MW. OpenWindCast 888 MW, off by 2.2% of capacity; Elia 758 MW, off by 5.3%. OpenWindCast closer

Scoreboard against Elia

Live since 22 Jun 2026 · 128 scored days · 22 Jun to 27 Oct

11% lower error than Elia's own day-ahead forecast

OpenWindCast

3.24%

of capacity

Elia

3.64%

of capacity

Closer on

65%

of days

Error is the average miss at the 11:00 target, as a share of installed capacity (nMAE). Back-test before go-live, shown apart: 271 days, 32% lower error than Elia. Only live days count above.

Forecast against the operator and the metered output

One point per day at 11:00, in MW. The shaded area is what the fleet actually produced; before the Live marker the forecast line is the back-test.

Accuracy by type of day

Live record, split by how windy the day turned out. Average error in % of capacity; further left is better.

OpenWindCast Elia

Type of day	Days	OpenWindCast	Elia	Closer on
Low-wind days below 15% of capacity	89	2.11%	2.59%	69%
Moderate days 15% to 35% of capacity	22	4.60%	4.71%	55%
High-wind days above 35% of capacity	17	7.42%	7.78%	59%

The daily record

One row per day at 11:00, in MW. Misses are in % of capacity. Losing days stay in the record.

JSON

Day (11:00)	OpenWindCast	Elia	Metered	Our miss	Elia miss	Closer
Wed 28 Oct	120	162	not yet	–	–	pending
Tue 27 Oct	888	758	850	2.2%	5.3%	OpenWindCast
Mon 26 Oct	404	405	373	1.8%	1.9%	OpenWindCast
Sun 25 Oct	1,137	974	902	13.5%	4.2%	Elia
Sat 24 Oct	634	654	552	4.7%	5.9%	OpenWindCast
Fri 23 Oct	1,153	971	1,128	1.4%	9.1%	OpenWindCast
Thu 22 Oct	1,123	928	1,033	5.2%	6.1%	OpenWindCast
Wed 21 Oct	747	500	768	1.3%	15.5%	OpenWindCast
Tue 20 Oct	465	419	378	5.1%	2.4%	Elia
Mon 19 Oct	81	139	68	0.8%	4.1%	OpenWindCast
Sun 18 Oct	55	115	67	0.6%	2.8%	OpenWindCast
Sat 17 Oct	219	256	200	1.1%	3.2%	OpenWindCast
Fri 16 Oct	185	171	77	6.2%	5.5%	Elia
Thu 15 Oct	212	206	146	3.8%	3.5%	Elia

Elia's forecast is captured at issue and held fixed. Operators refine their forecasts nearer to delivery, so a value published later may differ. The most recent day or two settle once measured generation is published.

Forecasting wind in Flanders

Flanders is the northern region of Belgium and one of the most turbine-dense onshore areas in Europe. The forecast covers Flemish onshore wind and is scored against Elia's published day-ahead forecast.

Flanders fits a great many turbines into flat, low-lying and heavily developed ground, along the coastal polders, around the port areas and beside the motorway corridors. The terrain itself is about as simple as European wind gets, so the local wind field is comparatively straightforward. What is not straightforward is density. Turbines packed closely together sit in each other's wakes, and an intensively built landscape is aerodynamically rough, so the relationship between the free-stream wind and the power actually delivered is not the clean curve a single isolated turbine would follow.

The benchmark

The benchmark is Elia's own day-ahead forecast for Flemish onshore wind, taken from Elia Open Data. Belgium is the one place where Elia publishes early enough that the benchmark can be captured at the same time the forecast is issued rather than later in the day.

What is published for Flanders

One value per day: onshore wind output at 11:00 local time tomorrow, as a load factor and in megawatts. Once Elia's own forecast for that day is published it is captured and held fixed, and once the metered output is settled both forecasts are scored against it. Every day is added to the record above and nothing is removed or rewritten later. How this is measured.

Questions about wind in Flanders

Why are Flanders and Wallonia separated?

Because they are different fleets in different landscapes. Flanders is dense, flat and coastal-influenced, and Wallonia is higher and more dispersed. Elia publishes them separately, so they can be scored separately. The electricity price is not split that way, because Belgium is a single bidding zone.

Does this include Belgian offshore wind?

No. Belgium's offshore fleet in the North Sea is a separate system and is not part of the Flanders onshore forecast. It does feed the Belgian market, so it is part of the picture the price forecast covers.

Official links for Flanders

Grid operators, their published data, the power exchange and the European transparency platform.

Other bidding zones

Compare every operator: how accurate are European TSO wind power forecasts? · How the scoring works