Portugal · onshore wind

Portugal day-ahead wind power forecast

Portugal has around 5.4 GW of onshore wind across more than 2,800 turbines, concentrated in the mountainous north and centre of the country. OpenWindCast publishes an independent day-ahead forecast of Portuguese wind output and scores it daily against REN's own forecast.

Record updated 22 Sept 2026 Scored against REN

Tomorrow · Wed 23 Sept, 11:00 Lisbon

89MW

1.6% of 5,401 MW installed

REN, same hour: 120 MW
Metered: not yet
80% interval: 0 to 253 MW

Most recent scored day, Tue 22 Sept

Metered 624 MW. OpenWindCast 225 MW, off by 7.4% of capacity; REN 282 MW, off by 6.3%. REN closer

Scoreboard against REN

Live since 6 Jul 2026 · 77 scored days · 6 Jul to 22 Sept

8% higher error than REN's own day-ahead forecast

OpenWindCast

2.64%

of capacity

REN

2.45%

of capacity

Closer on

47%

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: 322 days, 7% lower error than REN. 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 REN

Type of day	Days	OpenWindCast	REN	Closer on
Low-wind days below 15% of capacity	66	1.96%	1.74%	47%
Moderate days 15% to 35% of capacity	7	5.78%	6.52%	57%

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	REN	Metered	Our miss	REN miss	Closer
Wed 23 Sept	89	120	not yet	–	–	pending
Tue 22 Sept	225	282	624	7.4%	6.3%	REN
Mon 21 Sept	525	616	690	3.1%	1.4%	REN
Sun 20 Sept	1,073	900	655	7.7%	4.5%	REN
Sat 19 Sept	608	809	844	4.4%	0.7%	REN
Fri 18 Sept	1,118	1,116	1,842	13.4%	13.4%	OpenWindCast
Thu 17 Sept	1,085	1,208	2,097	18.7%	16.5%	REN
Wed 16 Sept	2,043	2,544	2,532	9.1%	0.2%	REN
Tue 15 Sept	359	540	382	0.4%	2.9%	OpenWindCast
Mon 14 Sept	53	99	70	0.3%	0.5%	OpenWindCast
Sun 13 Sept	292	380	380	1.6%	0.0%	REN
Sat 12 Sept	352	402	691	6.3%	5.4%	REN
Fri 11 Sept	192	277	468	5.1%	3.5%	REN
Thu 10 Sept	216	219	110	2.0%	2.0%	OpenWindCast

REN's forecast is captured on the day it is published 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 Portugal

Portugal has one of the most established onshore wind fleets in Europe, concentrated in the northern and central highlands. The forecast covers Portuguese onshore wind and is scored against the day-ahead forecast REN publishes through the ENTSO-E Transparency Platform.

Portugal has the most demanding terrain in the portfolio. The fleet sits along the highland ridges of the north and centre, where turbines are placed on the sharpest local features precisely because that is where the wind accelerates. This is where the resolution of general-purpose weather models becomes the binding constraint: a model reports one average wind for a grid cell several kilometres across, while the turbines stand on a crest a few hundred metres wide inside it. The gap between those two is not something any zone-level forecast can fully close, and it applies to REN's forecast and to ours alike.

The benchmark

The benchmark is REN's own day-ahead wind forecast for the Portuguese bidding zone, published through the ENTSO-E Transparency Platform, captured on the day of publication and then frozen. Metered generation and installed capacity come from the same platform.

What is published for Portugal

One value per day: onshore wind output at 11:00 local time tomorrow, as a load factor and in megawatts. Once REN'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 Portugal

Why is complex terrain such a problem for wind forecasting?

Because turbines are sited on exactly the features a weather model smooths away. The model reports the wind over a grid cell several kilometres wide, and the turbine stands on a ridge a few hundred metres wide inside that cell.

Does that mean forecasts here cannot improve?

It means there is a floor set by the resolution of the available weather models, and it applies to every forecaster in the zone equally.

Other bidding zones

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