Wallonia is the southern region of Belgium, with roughly 650 turbines and about 1.6 GW of monitored onshore capacity, spread mainly across the provinces of Hainaut, Namur and Liège. OpenWindCast publishes an independent day-ahead forecast of Walloon onshore wind and scores it daily against Elia's own forecast.
Averages across all zones. Every number on this page is recomputed daily from the public record below.
Great Britain has one of the largest onshore wind fleets in Europe, with most capacity in Scotland. The forecast covers GB onshore wind and is scored against NESO's own forecast, published through Elexon.
Every forecast ships with an 80% interval. This shows how often the actual output landed inside it, and how wide it was.
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 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.
One value per day: onshore wind output at 11:00 local time tomorrow, expressed as a load factor and published before 12:00 local, ahead of the day-ahead auction rather than after it. 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 below and nothing is removed or rewritten later, so the full history is there to be checked rather than summarised. How this is measured.
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.
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.
Compare every zone: how accurate are European TSO wind forecasts?
Mean absolute error as a percentage of installed capacity. Lower is better.
The share of days the forecast lands closer to the metered output than the operator's own forecast.
The range the actual output should land in 80% of the time, recalibrated daily.
NESO's published day-ahead 11:00 forecast, a fixed yardstick that is never used as an input.
A forecast of wind generation for the next delivery day, issued before the day-ahead electricity auction closes at 12:00 CET. Market participants use it to decide how much wind energy to bid into the auction.
One value per zone per day: the onshore wind output at 11:00 local time on the next day, expressed as a load factor and converted to megawatts with the installed capacity the grid operator publishes. Every forecast is published in the morning, before 12:00 local time.
Each day, the absolute error of the OpenWindCast forecast and of the grid operator's own day-ahead forecast are compared on the same 11:00 target. The site reports the mean absolute error as a share of installed capacity (nMAE), the win rate, and, where official prices are available, the imbalance cost of bidding each forecast.
Benchmark forecasts, metered generation and installed capacity come from the grid operators: Energinet, Elia, Fingrid, Red Eléctrica, the four German TSOs, PSE, REN, NESO via Elexon, and EirGrid with SONI, mostly through the ENTSO-E Transparency Platform. Weather inputs come from Open-Meteo.
Yes. The dashboard and the daily verification record are public, and each zone's history can be downloaded as CSV from the forecast section. For anything else, email m.sahaf@live.com.