Finland has grown to around 9.4 GW of wind capacity across roughly 2,000 turbines in under a decade, almost all of it onshore. OpenWindCast publishes an independent day-ahead forecast of Finnish wind output and scores it daily against Fingrid's own published 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.
The Finnish fleet runs up the Gulf of Bothnia coast and inland across Ostrobothnia and into Lapland, over flat, forested and cold country. Two things make it distinctive. The turbines are recent, tall and high-rated, so the fleet spends a large share of its time on the steep part of the power curve, where a modest error in wind speed translates into a large error in megawatts. And in winter, blade icing can take capacity out of service while the wind is still blowing, which is a well-known limitation for any forecast built on wind conditions alone.
The benchmark is Fingrid's own day-ahead wind forecast, taken from Fingrid's open data service rather than through ENTSO-E, along with the metered generation and the installed capacity used to score it. Fingrid publishes early enough that the comparison is available the same day.
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 Fingrid'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.
Because blade icing removes capacity while the wind is still blowing. It is one of the reasons the full daily record is published rather than a headline average, so the harder days stay visible.
Finland's offshore capacity is small next to its onshore fleet and is not separated out. The forecast tracks the fleet Fingrid's own forecast covers.
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.