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Data as of 2026-09-20
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Built 2026-09-21 (21 September 2026)

Spain Demand Forecast Accuracy: Error, Bias and Worst Miss, 23 August to 20 September 2026

The day-ahead demand forecast for Spain was off by 1.2% on average (mean absolute percentage error) over 685 hours from 23 August to 20 September 2026, and 100% of hours landed within 5% of the reading. Its bias was +0.2%: it ran close to balanced on average. The largest miss was 1,446 MW (4.8%) too high at 9 Sept 2026, 22:00 CEST (UTC+02:00). Dates and times are local (Europe/Madrid).

Key Facts

  • The day-ahead demand forecast for Spain was off by 1.2% on average (mean absolute percentage error) over 685 hours from 23 August to 20 September 2026, and 100% of hours landed within 5% of the reading. Its bias was +0.2%: it ran close to balanced on average. The largest miss was 1,446 MW (4.8%) too high at 9 Sept 2026, 22:00 CEST (UTC+02:00).
  • Across 47 European bidding zones ranked by average error over their own latest 30 day windows, Spain came 2 (1 is the smallest error).
  • On average the forecast differed from reported demand by 339 MW, against average demand of 28,507 MW.
  • The forecast was above reported demand in 54% of compared hours.

Forecast Error at a Glance

685 hours from 23 August to 20 September 2026
Average error1.2%
Bias+0.2%
Hours within 5%100%
Worst miss1,446 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (+42 MW per hour on average): the forecast ran close to balanced on average. The worst miss was 1,446 MW (4.8%) too high at 9 Sept 2026, 22:00 CEST (UTC+02:00): forecast 31,686 MW, reported 30,240 MW.

Source: ENTSO-E Transparency Platform (transparency.entsoe.eu), CC BY 4.0. Aggregated and converted by World Power Monitor; ENTSO-E does not endorse this site. (ENTSO-E Terms of Use plus CC BY 4.0 for listed data items) Data as of 2026-09-20. Accuracy is computed by World Power Monitor from the operator's hourly forecast and reported demand.

Forecast and Reported Demand, Last 7 Days

Local time, to 20 Sept 2026, 13:00 CEST (UTC+02:00)
Spain day-ahead demand forecast and reported demand by hour Hourly reported demand and the day-ahead forecast for Spain over the last 7 days of the window, to 20 Sept 2026, 13:00 CEST (UTC+02:00). Gaps are hours with a missing, zero or implausible report. 0 10,000 20,000 30,000 40,000 13 Sept, 14:0014 Sept, 14:0015 Sept, 14:0016 Sept, 14:0017 Sept, 14:0018 Sept, 14:0019 Sept, 14:00
Hourly reported demand and the day-ahead forecast for Spain over the last 7 days of the window, to 20 Sept 2026, 13:00 CEST (UTC+02:00). Gaps are hours with a missing, zero or implausible report.
Data to 2026-09-20
Spain day-ahead demand forecast and reported demand by hour
Local hourReported demandDay-ahead forecast
13 Sept, 14:0024,999 MW24,671 MW
13 Sept, 15:0024,421 MW24,177 MW
13 Sept, 16:0024,436 MW24,226 MW
13 Sept, 17:0025,785 MW24,981 MW
13 Sept, 18:0027,400 MW26,453 MW
13 Sept, 19:0028,123 MW27,611 MW
13 Sept, 20:0029,207 MW29,175 MW
13 Sept, 21:0029,758 MW29,814 MW
13 Sept, 22:0028,186 MW28,192 MW
13 Sept, 23:0026,107 MW26,170 MW
14 Sept, 00:0024,413 MW24,718 MW
14 Sept, 01:0023,377 MW23,542 MW
14 Sept, 02:0022,670 MW22,680 MW
14 Sept, 03:0022,314 MW22,299 MW
14 Sept, 04:0022,193 MW22,163 MW
14 Sept, 05:0022,795 MW22,695 MW
14 Sept, 06:0025,727 MW25,440 MW
14 Sept, 07:0029,019 MW28,773 MW
14 Sept, 08:0030,607 MW30,253 MW
14 Sept, 09:0031,184 MW30,816 MW
14 Sept, 10:0031,209 MW30,950 MW
14 Sept, 11:0031,120 MW30,849 MW
14 Sept, 12:0031,372 MW31,090 MW
14 Sept, 13:0031,956 MW31,642 MW
14 Sept, 14:0032,014 MW31,715 MW
14 Sept, 15:0031,819 MW31,440 MW
14 Sept, 16:0032,077 MW31,793 MW
14 Sept, 17:0033,162 MW32,885 MW
14 Sept, 18:0033,903 MW33,739 MW
14 Sept, 19:0034,442 MW34,087 MW
14 Sept, 20:0035,054 MW34,805 MW
14 Sept, 21:0034,645 MW34,540 MW
14 Sept, 22:0031,511 MW31,350 MW
14 Sept, 23:0028,844 MW28,672 MW
15 Sept, 00:0027,231 MW27,157 MW
15 Sept, 01:0025,851 MW25,928 MW
15 Sept, 02:0024,845 MW24,934 MW
15 Sept, 03:0024,409 MW24,421 MW
15 Sept, 04:0024,210 MW24,170 MW
15 Sept, 05:0024,567 MW24,461 MW
15 Sept, 06:0026,832 MW26,775 MW
15 Sept, 07:0030,046 MW29,872 MW
15 Sept, 08:0031,203 MW31,160 MW
15 Sept, 09:0031,824 MW31,826 MW
15 Sept, 10:0031,886 MW31,969 MW
15 Sept, 11:0031,835 MW31,884 MW
15 Sept, 12:0031,975 MW32,248 MW
15 Sept, 13:0032,417 MW32,905 MW
15 Sept, 14:0032,489 MW33,012 MW
15 Sept, 15:0032,290 MW32,628 MW
15 Sept, 16:0032,703 MW32,965 MW
15 Sept, 17:0033,577 MW34,011 MW
15 Sept, 18:0034,320 MW34,716 MW
15 Sept, 19:0034,565 MW35,129 MW
15 Sept, 20:0035,291 MW35,754 MW
15 Sept, 21:0034,418 MW34,865 MW
15 Sept, 22:0031,111 MW31,988 MW
15 Sept, 23:0028,471 MW29,323 MW
16 Sept, 00:0026,578 MW27,056 MW
16 Sept, 01:0025,154 MW25,712 MW
16 Sept, 02:0024,067 MW24,822 MW
16 Sept, 03:0023,705 MW24,341 MW
16 Sept, 04:0023,502 MW24,102 MW
16 Sept, 05:0023,938 MW24,459 MW
16 Sept, 06:0026,295 MW26,754 MW
16 Sept, 07:0029,559 MW29,663 MW
16 Sept, 08:0030,740 MW30,804 MW
16 Sept, 09:0031,202 MW31,408 MW
16 Sept, 10:0031,215 MW31,563 MW
16 Sept, 11:0031,288 MW31,343 MW
16 Sept, 12:0031,170 MW31,512 MW
16 Sept, 13:0031,465 MW31,874 MW
16 Sept, 14:0031,121 MW31,585 MW
16 Sept, 15:0031,082 MW31,035 MW
16 Sept, 16:0031,348 MW31,154 MW
16 Sept, 17:0031,759 MW31,953 MW
16 Sept, 18:0032,144 MW32,313 MW
16 Sept, 19:0032,726 MW32,651 MW
16 Sept, 20:0033,535 MW33,494 MW
16 Sept, 21:0032,603 MW32,906 MW
16 Sept, 22:0029,429 MW29,906 MW
16 Sept, 23:0026,923 MW27,526 MW
17 Sept, 00:0025,360 MW25,662 MW
17 Sept, 01:0024,272 MW24,439 MW
17 Sept, 02:0023,628 MW23,533 MW
17 Sept, 03:0023,192 MW23,149 MW
17 Sept, 04:0023,151 MW22,991 MW
17 Sept, 05:0023,540 MW23,408 MW
17 Sept, 06:0025,899 MW25,709 MW
17 Sept, 07:0029,187 MW28,848 MW
17 Sept, 08:0030,301 MW29,967 MW
17 Sept, 09:0030,740 MW30,515 MW
17 Sept, 10:0030,549 MW30,458 MW
17 Sept, 11:0030,066 MW30,150 MW
17 Sept, 12:0030,021 MW30,088 MW
17 Sept, 13:0030,318 MW30,347 MW
17 Sept, 14:0029,713 MW29,981 MW
17 Sept, 15:0029,114 MW29,480 MW
17 Sept, 16:0029,460 MW29,596 MW
17 Sept, 17:0030,500 MW30,218 MW
17 Sept, 18:0031,034 MW31,147 MW
17 Sept, 19:0031,465 MW31,574 MW
17 Sept, 20:0032,827 MW32,805 MW
17 Sept, 21:0032,336 MW32,195 MW
17 Sept, 22:0029,329 MW29,255 MW
17 Sept, 23:0027,159 MW26,921 MW
18 Sept, 00:0025,619 MW25,366 MW
18 Sept, 01:0024,237 MW24,271 MW
18 Sept, 02:0023,374 MW23,427 MW
18 Sept, 03:0022,893 MW23,038 MW
18 Sept, 04:0022,662 MW22,881 MW
18 Sept, 05:0023,147 MW23,245 MW
18 Sept, 06:0025,604 MW25,534 MW
18 Sept, 07:0028,926 MW28,674 MW
18 Sept, 08:0030,157 MW29,823 MW
18 Sept, 09:0030,384 MW30,198 MW
18 Sept, 10:0030,106 MW30,001 MW
18 Sept, 11:0029,736 MW29,544 MW
18 Sept, 12:0029,750 MW29,452 MW
18 Sept, 13:0029,969 MW29,696 MW
18 Sept, 14:0029,657 MW29,453 MW
18 Sept, 15:0029,062 MW28,767 MW
18 Sept, 16:0029,186 MW28,905 MW
18 Sept, 17:0030,030 MW29,685 MW
18 Sept, 18:0030,730 MW30,449 MW
18 Sept, 19:0030,821 MW30,968 MW
18 Sept, 20:0031,635 MW31,934 MW
18 Sept, 21:0031,113 MW31,291 MW
18 Sept, 22:0028,645 MW28,372 MW
18 Sept, 23:0026,558 MW26,272 MW
19 Sept, 00:0025,156 MW25,052 MW
19 Sept, 01:0023,821 MW23,913 MW
19 Sept, 02:0022,786 MW22,867 MW
19 Sept, 03:0022,218 MW22,265 MW
19 Sept, 04:0021,900 MW21,932 MW
19 Sept, 05:0021,681 MW21,757 MW
19 Sept, 06:0022,324 MW22,427 MW
19 Sept, 07:0023,332 MW23,463 MW
19 Sept, 08:0024,272 MW24,263 MW
19 Sept, 09:0025,465 MW25,393 MW
19 Sept, 10:00n/a25,963 MW
19 Sept, 11:0025,696 MW25,746 MW
19 Sept, 12:0025,326 MW25,572 MW
19 Sept, 13:0025,505 MW25,839 MW
19 Sept, 14:0025,247 MW25,616 MW
19 Sept, 15:0024,470 MW24,964 MW
19 Sept, 16:0024,330 MW24,839 MW
19 Sept, 17:0025,432 MW25,664 MW
19 Sept, 18:0026,524 MW26,795 MW
19 Sept, 19:0027,296 MW27,644 MW
19 Sept, 20:0028,504 MW28,739 MW
19 Sept, 21:0028,578 MW28,926 MW
19 Sept, 22:0026,631 MW26,736 MW
19 Sept, 23:0024,834 MW25,025 MW
20 Sept, 00:0023,216 MW23,470 MW
20 Sept, 01:0021,942 MW22,263 MW
20 Sept, 02:0021,107 MW21,276 MW
20 Sept, 03:0020,605 MW20,686 MW
20 Sept, 04:0020,296 MW20,369 MW
20 Sept, 05:0020,113 MW20,254 MW
20 Sept, 06:0020,570 MW20,751 MW
20 Sept, 07:0021,266 MW21,285 MW
20 Sept, 08:0021,642 MW21,661 MW
20 Sept, 09:0022,573 MW22,664 MW
20 Sept, 10:0022,927 MW23,319 MW
20 Sept, 11:0023,054 MW23,236 MW
20 Sept, 12:0023,039 MW23,247 MW
20 Sept, 13:0023,517 MW23,863 MW

Assumptions

  • Only hours with both a forecast and a positive demand reading count (685 of 686 hours in the window). Missing and zero values, and readings under 30% or over 3 times the grid's own median for the window, are treated as reporting faults and left out.
  • Error is (forecast minus reported demand) divided by reported demand; average error uses absolute values so high and low misses do not cancel. Bias keeps the sign and does cancel.
  • Reported demand is preliminary and may be revised. A 30 day window is a short sample and one heat wave or holiday can move these figures.
  • European figures are for the ENTSO-E bidding zone named on this page. US and European grids are ranked separately.