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

Sweden South (SE4) Demand Forecast Accuracy and Bias, 23 August to 20 September 2026

The day-ahead demand forecast for Sweden South (SE4) was off by 8.1% on average (mean absolute percentage error) over 686 hours from 23 August to 20 September 2026, and 31% of hours landed within 5% of the reading. Its bias was +7.3%: it ran high on average, an over forecast. The largest miss was 570 MW (30.2%) too high at 7 Sept 2026, 15:00 CEST (UTC+02:00). Dates and times are local (Europe/Stockholm).

Key Facts

  • The day-ahead demand forecast for Sweden South (SE4) was off by 8.1% on average (mean absolute percentage error) over 686 hours from 23 August to 20 September 2026, and 31% of hours landed within 5% of the reading. Its bias was +7.3%: it ran high on average, an over forecast. The largest miss was 570 MW (30.2%) too high at 7 Sept 2026, 15:00 CEST (UTC+02:00).
  • Across 47 European bidding zones ranked by average error over their own latest 30 day windows, Sweden South (SE4) came 38 (1 is the smallest error).
  • On average the forecast differed from reported demand by 159 MW, against average demand of 2,012 MW.
  • The forecast was above reported demand in 90% of compared hours.

Forecast Error at a Glance

686 hours from 23 August to 20 September 2026
Average error8.1%
Bias+7.3%
Hours within 5%31%
Worst miss570 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (+140 MW per hour on average): the forecast ran high on average, an over forecast. The worst miss was 570 MW (30.2%) too high at 7 Sept 2026, 15:00 CEST (UTC+02:00): forecast 2,454 MW, reported 1,884 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)
Sweden South (SE4) day-ahead demand forecast and reported demand by hour Hourly reported demand and the day-ahead forecast for Sweden South (SE4) 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. 0 750 1,500 2,250 3,000 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 Sweden South (SE4) 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
Sweden South (SE4) day-ahead demand forecast and reported demand by hour
Local hourReported demandDay-ahead forecast
13 Sept, 14:001,967 MW2,028 MW
13 Sept, 15:002,028 MW2,019 MW
13 Sept, 16:001,996 MW2,053 MW
13 Sept, 17:002,009 MW2,141 MW
13 Sept, 18:002,120 MW2,193 MW
13 Sept, 19:002,136 MW2,207 MW
13 Sept, 20:002,154 MW2,214 MW
13 Sept, 21:002,026 MW2,137 MW
13 Sept, 22:001,918 MW2,034 MW
13 Sept, 23:001,956 MW1,963 MW
14 Sept, 00:001,751 MW1,857 MW
14 Sept, 01:001,699 MW1,809 MW
14 Sept, 02:001,693 MW1,799 MW
14 Sept, 03:001,792 MW1,791 MW
14 Sept, 04:001,737 MW1,830 MW
14 Sept, 05:001,861 MW1,937 MW
14 Sept, 06:002,113 MW2,210 MW
14 Sept, 07:002,287 MW2,456 MW
14 Sept, 08:002,269 MW2,507 MW
14 Sept, 09:002,336 MW2,476 MW
14 Sept, 10:002,377 MW2,492 MW
14 Sept, 11:002,337 MW2,495 MW
14 Sept, 12:002,301 MW2,492 MW
14 Sept, 13:002,279 MW2,488 MW
14 Sept, 14:002,307 MW2,460 MW
14 Sept, 15:002,311 MW2,448 MW
14 Sept, 16:002,282 MW2,422 MW
14 Sept, 17:002,310 MW2,453 MW
14 Sept, 18:002,299 MW2,460 MW
14 Sept, 19:002,226 MW2,459 MW
14 Sept, 20:002,103 MW2,435 MW
14 Sept, 21:002,087 MW2,322 MW
14 Sept, 22:001,959 MW2,213 MW
14 Sept, 23:001,825 MW2,034 MW
15 Sept, 00:001,747 MW1,962 MW
15 Sept, 01:001,724 MW1,899 MW
15 Sept, 02:001,754 MW1,879 MW
15 Sept, 03:001,708 MW1,875 MW
15 Sept, 04:001,753 MW1,897 MW
15 Sept, 05:001,900 MW1,999 MW
15 Sept, 06:002,070 MW2,268 MW
15 Sept, 07:002,340 MW2,487 MW
15 Sept, 08:002,283 MW2,519 MW
15 Sept, 09:002,286 MW2,479 MW
15 Sept, 10:002,223 MW2,502 MW
15 Sept, 11:002,245 MW2,491 MW
15 Sept, 12:002,346 MW2,465 MW
15 Sept, 13:002,420 MW2,477 MW
15 Sept, 14:002,396 MW2,454 MW
15 Sept, 15:002,360 MW2,442 MW
15 Sept, 16:002,321 MW2,440 MW
15 Sept, 17:002,342 MW2,492 MW
15 Sept, 18:002,342 MW2,492 MW
15 Sept, 19:002,432 MW2,484 MW
15 Sept, 20:002,390 MW2,454 MW
15 Sept, 21:002,168 MW2,322 MW
15 Sept, 22:002,107 MW2,172 MW
15 Sept, 23:001,918 MW2,019 MW
16 Sept, 00:002,002 MW1,931 MW
16 Sept, 01:001,892 MW1,865 MW
16 Sept, 02:001,878 MW1,827 MW
16 Sept, 03:001,840 MW1,815 MW
16 Sept, 04:001,717 MW1,837 MW
16 Sept, 05:001,794 MW1,944 MW
16 Sept, 06:001,944 MW2,192 MW
16 Sept, 07:002,210 MW2,443 MW
16 Sept, 08:002,284 MW2,528 MW
16 Sept, 09:002,272 MW2,504 MW
16 Sept, 10:002,189 MW2,523 MW
16 Sept, 11:002,206 MW2,525 MW
16 Sept, 12:002,200 MW2,506 MW
16 Sept, 13:002,209 MW2,511 MW
16 Sept, 14:002,180 MW2,483 MW
16 Sept, 15:002,233 MW2,470 MW
16 Sept, 16:002,151 MW2,456 MW
16 Sept, 17:002,200 MW2,482 MW
16 Sept, 18:002,326 MW2,486 MW
16 Sept, 19:002,258 MW2,501 MW
16 Sept, 20:002,273 MW2,459 MW
16 Sept, 21:002,067 MW2,357 MW
16 Sept, 22:001,955 MW2,219 MW
16 Sept, 23:001,956 MW2,059 MW
17 Sept, 00:001,726 MW1,982 MW
17 Sept, 01:001,891 MW1,932 MW
17 Sept, 02:001,804 MW1,898 MW
17 Sept, 03:001,790 MW1,893 MW
17 Sept, 04:001,865 MW1,908 MW
17 Sept, 05:001,957 MW2,012 MW
17 Sept, 06:002,123 MW2,273 MW
17 Sept, 07:002,333 MW2,509 MW
17 Sept, 08:002,439 MW2,538 MW
17 Sept, 09:002,437 MW2,523 MW
17 Sept, 10:002,288 MW2,544 MW
17 Sept, 11:002,322 MW2,553 MW
17 Sept, 12:002,289 MW2,507 MW
17 Sept, 13:002,451 MW2,504 MW
17 Sept, 14:002,456 MW2,479 MW
17 Sept, 15:002,568 MW2,477 MW
17 Sept, 16:002,453 MW2,464 MW
17 Sept, 17:002,587 MW2,505 MW
17 Sept, 18:002,469 MW2,514 MW
17 Sept, 19:002,383 MW2,513 MW
17 Sept, 20:002,212 MW2,468 MW
17 Sept, 21:002,181 MW2,370 MW
17 Sept, 22:002,045 MW2,213 MW
17 Sept, 23:001,820 MW2,067 MW
18 Sept, 00:001,778 MW1,981 MW
18 Sept, 01:001,732 MW1,915 MW
18 Sept, 02:001,765 MW1,880 MW
18 Sept, 03:001,741 MW1,866 MW
18 Sept, 04:001,800 MW1,894 MW
18 Sept, 05:001,899 MW2,006 MW
18 Sept, 06:002,098 MW2,260 MW
18 Sept, 07:002,318 MW2,491 MW
18 Sept, 08:002,458 MW2,542 MW
18 Sept, 09:002,426 MW2,521 MW
18 Sept, 10:002,400 MW2,540 MW
18 Sept, 11:002,386 MW2,536 MW
18 Sept, 12:002,274 MW2,498 MW
18 Sept, 13:002,343 MW2,482 MW
18 Sept, 14:002,173 MW2,411 MW
18 Sept, 15:002,295 MW2,386 MW
18 Sept, 16:002,298 MW2,354 MW
18 Sept, 17:002,242 MW2,403 MW
18 Sept, 18:002,180 MW2,412 MW
18 Sept, 19:002,372 MW2,396 MW
18 Sept, 20:002,247 MW2,339 MW
18 Sept, 21:001,992 MW2,228 MW
18 Sept, 22:001,838 MW2,106 MW
18 Sept, 23:001,823 MW2,001 MW
19 Sept, 00:001,629 MW1,910 MW
19 Sept, 01:001,572 MW1,844 MW
19 Sept, 02:001,547 MW1,794 MW
19 Sept, 03:001,549 MW1,769 MW
19 Sept, 04:001,577 MW1,754 MW
19 Sept, 05:001,568 MW1,776 MW
19 Sept, 06:001,596 MW1,808 MW
19 Sept, 07:001,630 MW1,861 MW
19 Sept, 08:001,791 MW1,971 MW
19 Sept, 09:001,867 MW2,064 MW
19 Sept, 10:001,958 MW2,121 MW
19 Sept, 11:002,079 MW2,137 MW
19 Sept, 12:002,114 MW2,144 MW
19 Sept, 13:002,137 MW2,144 MW
19 Sept, 14:002,143 MW2,134 MW
19 Sept, 15:002,108 MW2,113 MW
19 Sept, 16:002,006 MW2,116 MW
19 Sept, 17:001,959 MW2,162 MW
19 Sept, 18:002,019 MW2,176 MW
19 Sept, 19:002,005 MW2,184 MW
19 Sept, 20:001,939 MW2,142 MW
19 Sept, 21:001,796 MW2,050 MW
19 Sept, 22:001,760 MW1,982 MW
19 Sept, 23:001,746 MW1,904 MW
20 Sept, 00:001,661 MW1,809 MW
20 Sept, 01:001,765 MW1,769 MW
20 Sept, 02:001,741 MW1,728 MW
20 Sept, 03:001,716 MW1,713 MW
20 Sept, 04:001,565 MW1,695 MW
20 Sept, 05:001,549 MW1,722 MW
20 Sept, 06:001,748 MW1,741 MW
20 Sept, 07:001,759 MW1,782 MW
20 Sept, 08:001,824 MW1,870 MW
20 Sept, 09:001,821 MW1,966 MW
20 Sept, 10:001,889 MW2,019 MW
20 Sept, 11:001,777 MW2,058 MW
20 Sept, 12:001,841 MW2,092 MW
20 Sept, 13:001,979 MW2,095 MW

Assumptions

  • Only hours with both a forecast and a positive demand reading count (686 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.