Italy has close to 12.9 GW of onshore wind across more than 7,500 turbines, almost all of it in the south: Puglia, Campania, Basilicata, Calabria, Sicily and Sardinia. OpenWindCast publishes an independent day-ahead forecast of Italian wind output and scores it daily against Terna'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.
Italian wind is southern, mountainous and clustered into a small number of regions. Much of the capacity sits along the southern Apennines and in the interiors of Sicily and Sardinia, terrain that weather models resolve only coarsely. The coastal sites along the Adriatic, Ionian and Tyrrhenian shores add a land and sea breeze component that varies through the day and is not driven by the large-scale weather pattern alone. Because the fleet is concentrated in a handful of regions rather than spread across the country, there is little of the internal error cancellation that larger, more dispersed fleets benefit from.
The benchmark is Terna's own day-ahead wind forecast for the Italian bidding zone, published through the ENTSO-E Transparency Platform, captured on the day of publication and then held fixed. Metered generation and installed capacity come from the same platform.
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 Terna'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.
No. It is the national Italian aggregate that Terna publishes day-ahead. Italy's internal zonal structure is not separated here.
No. OpenWindCast forecasts wind generation only.
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.