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Wallonia day-ahead wind power forecast

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Record updated 27 Oct 2026 Scored against Elia

Tomorrow · Wed 28 Oct, 11:00 Brussels

62MW

3.7% of 1,672 MW installed

Elia, same hour: 97 MW
Metered: not yet
80% interval: 22 to 136 MW

Most recent scored day, Tue 27 Oct

Metered 709 MW. OpenWindCast 733 MW, off by 1.5% of capacity; Elia 730 MW, off by 1.3%. Elia closer

Scoreboard against Elia

Live since 4 Jul 2026 · 116 scored days · 4 Jul to 27 Oct

0% higher error than Elia's own day-ahead forecast

OpenWindCast

2.83%

of capacity

Elia

2.83%

of capacity

Closer on

50%

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: 283 days, 20% 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	85	1.61%	1.97%	56%
Moderate days 15% to 35% of capacity	17	4.90%	4.14%	35%
High-wind days above 35% of capacity	14	7.75%	6.44%	29%

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	62	97	not yet	–	–	pending
Tue 27 Oct	733	730	709	1.5%	1.3%	Elia
Mon 26 Oct	367	444	382	0.9%	3.7%	OpenWindCast
Sun 25 Oct	963	1,022	893	4.2%	7.7%	OpenWindCast
Sat 24 Oct	515	685	567	3.1%	7.0%	OpenWindCast
Fri 23 Oct	1,091	1,231	1,248	9.4%	1.1%	Elia
Thu 22 Oct	1,075	1,110	1,058	1.0%	3.1%	OpenWindCast
Wed 21 Oct	724	599	874	9.0%	16.4%	OpenWindCast
Tue 20 Oct	234	275	244	0.6%	1.8%	OpenWindCast
Mon 19 Oct	60	65	113	3.2%	2.9%	Elia
Sun 18 Oct	34	77	35	0.1%	2.5%	OpenWindCast
Sat 17 Oct	252	291	302	3.0%	0.7%	Elia
Fri 16 Oct	191	169	170	1.3%	0.0%	Elia
Thu 15 Oct	147	188	137	0.6%	3.1%	OpenWindCast

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 Wallonia

Wallonia is the southern region of Belgium, with most turbines across the provinces of Hainaut, Namur and Liège. The forecast covers Walloon onshore wind and is scored against Elia's published day-ahead forecast.

Walloon wind sits higher and more thinly spread than its Flemish neighbour, on the plateaux of Hainaut and Namur and rising eastward towards the Ardennes. The elevation brings a better wind resource along with a rougher and more varied surface, and the fleet is arranged in small scattered clusters rather than dense corridors. Two regions of one small country, an hour apart, therefore present noticeably different forecasting problems.

The benchmark

The benchmark is Elia's own day-ahead forecast for Walloon onshore wind, from Elia Open Data, covering both the distribution-connected and the Elia-grid-connected fleet. As in Flanders, Elia publishes early enough that the benchmark is captured at the time the forecast is issued.

What is published for Wallonia

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 Wallonia

How does Wallonia differ from Flanders?

Wallonia is higher and more dispersed, on the plateaux of Hainaut and Namur rising towards the Ardennes, while Flanders is flat, dense and closer to the coast. Elia forecasts and publishes the two separately. The electricity price is not split that way, because Belgium is a single bidding zone.

What does 'monitored capacity' mean?

It is the onshore capacity Elia tracks and forecasts for Wallonia, which is the basis the benchmark is built on, so the forecast, the benchmark and the outcome all sit on the same fleet.

Official links for Wallonia

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