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Built 2026-10-28 (28 October 2026)

Portugal Demand Forecast Accuracy: Error, Bias and Worst Miss, 30 September to 28 October 2026

The day-ahead demand forecast for Portugal was off by 2.0% on average (mean absolute percentage error) over 685 hours from 30 September to 28 October 2026, and 94% of hours landed within 5% of the reading. Its bias was -0.1%: it ran close to balanced on average. The largest miss was 702 MW (9.4%) too low at 28 Oct 2026, 09:00 WET (UTC+00:00). Dates and times are local (Europe/Lisbon).

Key Facts

  • The day-ahead demand forecast for Portugal was off by 2.0% on average (mean absolute percentage error) over 685 hours from 30 September to 28 October 2026, and 94% of hours landed within 5% of the reading. Its bias was -0.1%: it ran close to balanced on average. The largest miss was 702 MW (9.4%) too low at 28 Oct 2026, 09:00 WET (UTC+00:00).
  • Across 47 European bidding zones ranked by average error over their own latest 30 day windows, Portugal came 7 (1 is the smallest error).
  • On average the forecast differed from reported demand by 110 MW, against average demand of 5,843 MW.
  • The forecast was above reported demand in 49% of compared hours.

Forecast Error at a Glance

685 hours from 30 September to 28 October 2026
Average error2.0%
Bias-0.1%
Hours within 5%94%
Worst miss702 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (-11 MW per hour on average): the forecast ran close to balanced on average. The worst miss was 702 MW (9.4%) too low at 28 Oct 2026, 09:00 WET (UTC+00:00): forecast 6,801 MW, reported 7,503 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 2026-10-28. 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 28 Oct 2026, 12:00 WET (UTC+00:00)
Portugal day-ahead demand forecast and reported demand by hour Hourly reported demand and the day-ahead forecast for Portugal over the last 7 days of the window, to 28 Oct 2026, 12:00 WET (UTC+00:00). Gaps are hours with a missing, zero or implausible report. 0 2,000 4,000 6,000 8,000 21 Oct, 14:0022 Oct, 14:0023 Oct, 14:0024 Oct, 14:0025 Oct, 13:0026 Oct, 13:0027 Oct, 13:00
Hourly reported demand and the day-ahead forecast for Portugal over the last 7 days of the window, to 28 Oct 2026, 12:00 WET (UTC+00:00). Gaps are hours with a missing, zero or implausible report.
Data to 2026-10-28
Show the data table (168 rows)
Local hourReported demandDay-ahead forecast
21 Oct, 14:006,144 MW6,161 MW
21 Oct, 15:006,216 MW6,203 MW
21 Oct, 16:006,420 MW6,369 MW
21 Oct, 17:006,575 MW6,532 MW
21 Oct, 18:006,941 MW6,908 MW
21 Oct, 19:007,631 MW7,623 MW
21 Oct, 20:007,471 MW7,455 MW
21 Oct, 21:006,989 MW6,941 MW
21 Oct, 22:006,436 MW6,375 MW
21 Oct, 23:005,836 MW5,857 MW
22 Oct, 00:005,473 MW5,303 MW
22 Oct, 01:005,170 MW5,032 MW
22 Oct, 02:004,951 MW4,827 MW
22 Oct, 03:004,841 MW4,706 MW
22 Oct, 04:004,788 MW4,652 MW
22 Oct, 05:004,935 MW4,770 MW
22 Oct, 06:005,455 MW5,186 MW
22 Oct, 07:006,212 MW5,935 MW
22 Oct, 08:006,870 MW6,625 MW
22 Oct, 09:006,970 MW6,758 MW
22 Oct, 10:006,656 MW6,505 MW
22 Oct, 11:006,470 MW6,357 MW
22 Oct, 12:006,189 MW6,144 MW
22 Oct, 13:006,082 MW6,040 MW
22 Oct, 14:006,244 MW6,221 MW
22 Oct, 15:006,396 MW6,351 MW
22 Oct, 16:006,671 MW6,535 MW
22 Oct, 17:006,778 MW6,693 MW
22 Oct, 18:007,130 MW7,041 MW
22 Oct, 19:007,828 MW7,734 MW
22 Oct, 20:007,643 MW7,542 MW
22 Oct, 21:007,172 MW7,067 MW
22 Oct, 22:006,602 MW6,519 MW
22 Oct, 23:006,042 MW5,909 MW
23 Oct, 00:005,687 MW5,459 MW
23 Oct, 01:005,372 MW5,173 MW
23 Oct, 02:005,169 MW4,956 MW
23 Oct, 03:005,053 MW4,815 MW
23 Oct, 04:004,968 MW4,764 MW
23 Oct, 05:005,037 MW4,875 MW
23 Oct, 06:005,472 MW5,271 MW
23 Oct, 07:006,233 MW6,001 MW
23 Oct, 08:007,005 MW6,706 MW
23 Oct, 09:007,074 MW6,879 MW
23 Oct, 10:006,757 MW6,686 MW
23 Oct, 11:006,612 MW6,533 MW
23 Oct, 12:006,322 MW6,292 MW
23 Oct, 13:006,108 MW6,130 MW
23 Oct, 14:006,258 MW6,253 MW
23 Oct, 15:006,289 MW6,277 MW
23 Oct, 16:006,490 MW6,431 MW
23 Oct, 17:006,618 MW6,592 MW
23 Oct, 18:006,995 MW6,937 MW
23 Oct, 19:007,602 MW7,583 MW
23 Oct, 20:007,427 MW7,391 MW
23 Oct, 21:006,994 MW6,889 MW
23 Oct, 22:006,490 MW6,375 MW
23 Oct, 23:005,906 MW5,808 MW
24 Oct, 00:005,456 MW5,352 MW
24 Oct, 01:005,097 MW5,053 MW
24 Oct, 02:004,827 MW4,854 MW
24 Oct, 03:004,699 MW4,710 MW
24 Oct, 04:004,665 MW4,606 MW
24 Oct, 05:004,718 MW4,616 MW
24 Oct, 06:004,864 MW4,785 MW
24 Oct, 07:005,144 MW5,023 MW
24 Oct, 08:005,505 MW5,383 MW
24 Oct, 09:005,700 MW5,576 MW
24 Oct, 10:005,601 MW5,552 MW
24 Oct, 11:005,522 MW5,467 MW
24 Oct, 12:005,502 MW5,439 MW
24 Oct, 13:005,267 MW5,234 MW
24 Oct, 14:005,119 MW5,145 MW
24 Oct, 15:005,114 MW5,150 MW
24 Oct, 16:005,272 MW5,316 MW
24 Oct, 17:005,605 MW5,622 MW
24 Oct, 18:006,099 MW6,015 MW
24 Oct, 19:006,766 MW6,758 MW
24 Oct, 20:006,619 MW6,637 MW
24 Oct, 21:006,196 MW6,203 MW
24 Oct, 22:005,806 MW5,801 MW
24 Oct, 23:005,462 MW5,387 MW
25 Oct, 00:005,095 MW5,005 MW
25 Oct, 01:004,813 MW4,722 MW
25 Oct, 01:004,598 MW4,687 MW
25 Oct, 02:004,482 MW4,494 MW
25 Oct, 03:004,390 MW4,375 MW
25 Oct, 04:004,361 MW4,336 MW
25 Oct, 05:004,359 MW4,360 MW
25 Oct, 06:004,465 MW4,444 MW
25 Oct, 07:004,602 MW4,602 MW
25 Oct, 08:004,974 MW4,879 MW
25 Oct, 09:005,200 MW5,200 MW
25 Oct, 10:005,340 MW5,386 MW
25 Oct, 11:005,470 MW5,578 MW
25 Oct, 12:005,485 MW5,656 MW
25 Oct, 13:005,197 MW5,423 MW
25 Oct, 14:005,066 MW5,247 MW
25 Oct, 15:005,156 MW5,214 MW
25 Oct, 16:005,394 MW5,350 MW
25 Oct, 17:005,816 MW5,728 MW
25 Oct, 18:006,475 MW6,425 MW
25 Oct, 19:006,689 MW6,611 MW
25 Oct, 20:006,438 MW6,512 MW
25 Oct, 21:005,995 MW6,139 MW
25 Oct, 22:005,606 MW5,721 MW
25 Oct, 23:005,168 MW5,264 MW
26 Oct, 00:004,891 MW4,938 MW
26 Oct, 01:004,676 MW4,695 MW
26 Oct, 02:004,519 MW4,532 MW
26 Oct, 03:004,370 MW4,459 MW
26 Oct, 04:004,363 MW4,479 MW
26 Oct, 05:004,509 MW4,623 MW
26 Oct, 06:005,028 MW5,285 MW
26 Oct, 07:005,795 MW5,961 MW
26 Oct, 08:006,518 MW6,525 MW
26 Oct, 09:006,610 MW6,625 MW
26 Oct, 10:006,425 MW6,457 MW
26 Oct, 11:006,401 MW6,360 MW
26 Oct, 12:006,280 MW6,197 MW
26 Oct, 13:006,250 MW6,125 MW
26 Oct, 14:006,498 MW6,366 MW
26 Oct, 15:006,612 MW6,539 MW
26 Oct, 16:006,748 MW6,729 MW
26 Oct, 17:006,977 MW6,978 MW
26 Oct, 18:007,472 MW7,499 MW
26 Oct, 19:007,611 MW7,646 MW
26 Oct, 20:007,364 MW7,449 MW
26 Oct, 21:006,916 MW6,932 MW
26 Oct, 22:006,320 MW6,351 MW
26 Oct, 23:005,720 MW5,772 MW
27 Oct, 00:005,290 MW5,365 MW
27 Oct, 01:005,007 MW5,111 MW
27 Oct, 02:004,818 MW4,946 MW
27 Oct, 03:004,725 MW4,870 MW
27 Oct, 04:004,753 MW4,870 MW
27 Oct, 05:004,892 MW4,968 MW
27 Oct, 06:005,370 MW5,503 MW
27 Oct, 07:006,082 MW6,155 MW
27 Oct, 08:006,762 MW6,791 MW
27 Oct, 09:006,896 MW6,933 MW
27 Oct, 10:006,810 MW6,827 MW
27 Oct, 11:006,982 MW6,837 MW
27 Oct, 12:006,823 MW6,710 MW
27 Oct, 13:006,832 MW6,666 MW
27 Oct, 14:007,060 MW6,850 MW
27 Oct, 15:007,142 MW6,892 MW
27 Oct, 16:007,164 MW6,991 MW
27 Oct, 17:007,309 MW7,167 MW
27 Oct, 18:007,752 MW7,635 MW
27 Oct, 19:007,930 MW7,759 MW
27 Oct, 20:007,643 MW7,540 MW
27 Oct, 21:007,122 MW7,015 MW
27 Oct, 22:006,507 MW6,435 MW
27 Oct, 23:005,918 MW5,847 MW
28 Oct, 00:005,495 MW5,307 MW
28 Oct, 01:005,214 MW5,037 MW
28 Oct, 02:005,065 MW4,864 MW
28 Oct, 03:004,950 MW4,786 MW
28 Oct, 04:004,866 MW4,763 MW
28 Oct, 05:004,979 MW4,861 MW
28 Oct, 06:005,476 MW5,408 MW
28 Oct, 07:006,425 MW6,051 MW
28 Oct, 08:007,311 MW6,695 MW
28 Oct, 09:007,503 MW6,801 MW
28 Oct, 10:007,139 MW6,596 MW
28 Oct, 11:006,899 MW6,499 MW
28 Oct, 12:006,703 MW6,294 MW

Assumptions

  • Only hours with both a forecast and a positive demand reading count (685 of 685 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.
Cite this page
APA 7

World Power Monitor. (2026). Portugal Demand Forecast Accuracy: Error, Bias and Worst Miss. https://worldpowermonitor.com/forecast-accuracy/pt/

Plain text

World Power Monitor. Portugal Demand Forecast Accuracy: Error, Bias and Worst Miss. Data as of 2026-10-28. Data from ENTSO-E Transparency Platform. https://worldpowermonitor.com/forecast-accuracy/pt/

BibTeX 
@misc{wpm_forecast_accuracy_pt_2026,
  title = {{Portugal Demand Forecast Accuracy: Error, Bias and Worst Miss}},
  author = {{World Power Monitor}},
  year = {2026},
  note = {Data as of 2026-10-28. Data from ENTSO-E Transparency Platform.},
  url = {https://worldpowermonitor.com/forecast-accuracy/pt/}
}

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