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

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

The day-ahead demand forecast for Slovenia was off by 5.7% on average (mean absolute percentage error) over 686 hours from 23 August to 20 September 2026, and 67% of hours landed within 5% of the reading. Its bias was +0.1%: it ran close to balanced on average. The largest miss was 812 MW (162.3%) too high at 20 Sept 2026, 12:00 CEST (UTC+02:00). Dates and times are local (Europe/Ljubljana).

Key Facts

  • The day-ahead demand forecast for Slovenia was off by 5.7% on average (mean absolute percentage error) over 686 hours from 23 August to 20 September 2026, and 67% of hours landed within 5% of the reading. Its bias was +0.1%: it ran close to balanced on average. The largest miss was 812 MW (162.3%) too high at 20 Sept 2026, 12:00 CEST (UTC+02:00).
  • Across 47 European bidding zones ranked by average error over their own latest 30 day windows, Slovenia came 33 (1 is the smallest error).
  • On average the forecast differed from reported demand by 69 MW, against average demand of 1,439 MW.
  • The forecast was above reported demand in 33% of compared hours.

Forecast Error at a Glance

686 hours from 23 August to 20 September 2026
Average error5.7%
Bias+0.1%
Hours within 5%67%
Worst miss812 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (-17 MW per hour on average): the forecast ran close to balanced on average. The worst miss was 812 MW (162.3%) too high at 20 Sept 2026, 12:00 CEST (UTC+02:00): forecast 1,313 MW, reported 500 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)
Slovenia day-ahead demand forecast and reported demand by hour Hourly reported demand and the day-ahead forecast for Slovenia 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. 0 500 1,000 1,500 2,000 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 Slovenia 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
Slovenia day-ahead demand forecast and reported demand by hour
Local hourReported demandDay-ahead forecast
13 Sept, 14:001,319 MW1,231 MW
13 Sept, 15:001,246 MW1,214 MW
13 Sept, 16:001,204 MW1,213 MW
13 Sept, 17:001,204 MW1,220 MW
13 Sept, 18:001,237 MW1,275 MW
13 Sept, 19:001,292 MW1,306 MW
13 Sept, 20:001,336 MW1,313 MW
13 Sept, 21:001,276 MW1,294 MW
13 Sept, 22:001,177 MW1,236 MW
13 Sept, 23:001,101 MW1,125 MW
14 Sept, 00:001,063 MW1,083 MW
14 Sept, 01:001,028 MW1,046 MW
14 Sept, 02:001,035 MW1,027 MW
14 Sept, 03:001,028 MW1,025 MW
14 Sept, 04:001,047 MW1,043 MW
14 Sept, 05:001,128 MW1,152 MW
14 Sept, 06:001,397 MW1,416 MW
14 Sept, 07:001,517 MW1,582 MW
14 Sept, 08:001,620 MW1,646 MW
14 Sept, 09:001,658 MW1,658 MW
14 Sept, 10:001,670 MW1,666 MW
14 Sept, 11:001,702 MW1,687 MW
14 Sept, 12:001,710 MW1,692 MW
14 Sept, 13:001,732 MW1,670 MW
14 Sept, 14:001,702 MW1,619 MW
14 Sept, 15:001,664 MW1,580 MW
14 Sept, 16:001,580 MW1,572 MW
14 Sept, 17:001,519 MW1,573 MW
14 Sept, 18:001,502 MW1,588 MW
14 Sept, 19:001,489 MW1,594 MW
14 Sept, 20:001,514 MW1,584 MW
14 Sept, 21:001,451 MW1,513 MW
14 Sept, 22:001,358 MW1,404 MW
14 Sept, 23:001,271 MW1,290 MW
15 Sept, 00:001,184 MW1,212 MW
15 Sept, 01:001,141 MW1,168 MW
15 Sept, 02:001,143 MW1,143 MW
15 Sept, 03:001,128 MW1,141 MW
15 Sept, 04:001,150 MW1,159 MW
15 Sept, 05:001,228 MW1,250 MW
15 Sept, 06:001,441 MW1,489 MW
15 Sept, 07:001,561 MW1,662 MW
15 Sept, 08:001,673 MW1,704 MW
15 Sept, 09:001,724 MW1,694 MW
15 Sept, 10:001,745 MW1,703 MW
15 Sept, 11:001,836 MW1,727 MW
15 Sept, 12:001,842 MW1,730 MW
15 Sept, 13:001,778 MW1,704 MW
15 Sept, 14:001,731 MW1,649 MW
15 Sept, 15:001,667 MW1,606 MW
15 Sept, 16:001,627 MW1,597 MW
15 Sept, 17:001,557 MW1,597 MW
15 Sept, 18:001,520 MW1,608 MW
15 Sept, 19:001,503 MW1,617 MW
15 Sept, 20:001,569 MW1,609 MW
15 Sept, 21:001,533 MW1,541 MW
15 Sept, 22:001,412 MW1,433 MW
15 Sept, 23:001,342 MW1,319 MW
16 Sept, 00:001,253 MW1,235 MW
16 Sept, 01:001,192 MW1,193 MW
16 Sept, 02:001,158 MW1,168 MW
16 Sept, 03:001,166 MW1,167 MW
16 Sept, 04:001,198 MW1,186 MW
16 Sept, 05:001,261 MW1,279 MW
16 Sept, 06:001,490 MW1,524 MW
16 Sept, 07:001,668 MW1,689 MW
16 Sept, 08:001,683 MW1,733 MW
16 Sept, 09:001,749 MW1,714 MW
16 Sept, 10:001,741 MW1,722 MW
16 Sept, 11:001,809 MW1,740 MW
16 Sept, 12:001,817 MW1,744 MW
16 Sept, 13:001,796 MW1,723 MW
16 Sept, 14:001,725 MW1,677 MW
16 Sept, 15:001,671 MW1,632 MW
16 Sept, 16:001,600 MW1,615 MW
16 Sept, 17:001,558 MW1,611 MW
16 Sept, 18:001,519 MW1,621 MW
16 Sept, 19:001,568 MW1,627 MW
16 Sept, 20:001,602 MW1,621 MW
16 Sept, 21:001,504 MW1,553 MW
16 Sept, 22:001,426 MW1,444 MW
16 Sept, 23:001,330 MW1,330 MW
17 Sept, 00:001,241 MW1,245 MW
17 Sept, 01:001,222 MW1,202 MW
17 Sept, 02:001,195 MW1,173 MW
17 Sept, 03:001,169 MW1,167 MW
17 Sept, 04:001,203 MW1,185 MW
17 Sept, 05:001,257 MW1,275 MW
17 Sept, 06:001,493 MW1,511 MW
17 Sept, 07:001,650 MW1,660 MW
17 Sept, 08:001,776 MW1,709 MW
17 Sept, 09:001,823 MW1,717 MW
17 Sept, 10:001,778 MW1,724 MW
17 Sept, 11:001,858 MW1,744 MW
17 Sept, 12:001,914 MW1,748 MW
17 Sept, 13:001,867 MW1,718 MW
17 Sept, 14:001,806 MW1,662 MW
17 Sept, 15:001,740 MW1,624 MW
17 Sept, 16:001,665 MW1,620 MW
17 Sept, 17:001,585 MW1,625 MW
17 Sept, 18:001,551 MW1,648 MW
17 Sept, 19:001,579 MW1,651 MW
17 Sept, 20:001,572 MW1,637 MW
17 Sept, 21:001,506 MW1,560 MW
17 Sept, 22:001,407 MW1,448 MW
17 Sept, 23:001,363 MW1,333 MW
18 Sept, 00:001,257 MW1,240 MW
18 Sept, 01:001,224 MW1,199 MW
18 Sept, 02:001,172 MW1,175 MW
18 Sept, 03:001,208 MW1,170 MW
18 Sept, 04:001,193 MW1,181 MW
18 Sept, 05:001,257 MW1,260 MW
18 Sept, 06:001,454 MW1,495 MW
18 Sept, 07:001,642 MW1,651 MW
18 Sept, 08:001,720 MW1,694 MW
18 Sept, 09:001,782 MW1,696 MW
18 Sept, 10:001,754 MW1,706 MW
18 Sept, 11:001,838 MW1,728 MW
18 Sept, 12:001,871 MW1,732 MW
18 Sept, 13:001,802 MW1,697 MW
18 Sept, 14:001,726 MW1,627 MW
18 Sept, 15:001,623 MW1,581 MW
18 Sept, 16:001,589 MW1,572 MW
18 Sept, 17:001,542 MW1,573 MW
18 Sept, 18:001,510 MW1,583 MW
18 Sept, 19:001,493 MW1,591 MW
18 Sept, 20:001,548 MW1,582 MW
18 Sept, 21:001,470 MW1,515 MW
18 Sept, 22:001,367 MW1,398 MW
18 Sept, 23:001,274 MW1,276 MW
19 Sept, 00:001,136 MW1,165 MW
19 Sept, 01:001,051 MW1,109 MW
19 Sept, 02:001,035 MW1,066 MW
19 Sept, 03:00994 MW1,058 MW
19 Sept, 04:00996 MW1,062 MW
19 Sept, 05:001,004 MW1,085 MW
19 Sept, 06:001,068 MW1,168 MW
19 Sept, 07:001,184 MW1,299 MW
19 Sept, 08:001,181 MW1,393 MW
19 Sept, 09:001,056 MW1,404 MW
19 Sept, 10:00997 MW1,403 MW
19 Sept, 11:00882 MW1,421 MW
19 Sept, 12:00769 MW1,425 MW
19 Sept, 13:00731 MW1,384 MW
19 Sept, 14:00641 MW1,315 MW
19 Sept, 15:00669 MW1,289 MW
19 Sept, 16:00749 MW1,285 MW
19 Sept, 17:00947 MW1,289 MW
19 Sept, 18:001,073 MW1,301 MW
19 Sept, 19:001,182 MW1,314 MW
19 Sept, 20:001,227 MW1,307 MW
19 Sept, 21:001,207 MW1,285 MW
19 Sept, 22:001,140 MW1,224 MW
19 Sept, 23:001,019 MW1,108 MW
20 Sept, 00:00983 MW1,056 MW
20 Sept, 01:001,081 MW1,012 MW
20 Sept, 02:00883 MW969 MW
20 Sept, 03:00899 MW959 MW
20 Sept, 04:00891 MW962 MW
20 Sept, 05:00873 MW972 MW
20 Sept, 06:001,050 MW1,011 MW
20 Sept, 07:00975 MW1,109 MW
20 Sept, 08:00884 MW1,205 MW
20 Sept, 09:00769 MW1,255 MW
20 Sept, 10:00616 MW1,291 MW
20 Sept, 11:00593 MW1,316 MW
20 Sept, 12:00500 MW1,313 MW
20 Sept, 13:00495 MW1,274 MW

Assumptions

  • Only hours with both a forecast and a positive demand reading count (686 of 687 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.