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

The day-ahead demand forecast for EPE was off by 3.3% on average (mean absolute percentage error) over 719 hours from 28 September to 28 October 2026, and 77% of hours landed within 5% of the reading. Its bias was -1.2%: it ran low on average, an under forecast. The largest miss was 275 MW (21.4%) too high at 28 Sept 2026, 15:00 MDT (UTC-06:00). Dates and times are local (America/Denver).

Key Facts

The day-ahead demand forecast for EPE was off by 3.3% on average (mean absolute percentage error) over 719 hours from 28 September to 28 October 2026, and 77% of hours landed within 5% of the reading. Its bias was -1.2%: it ran low on average, an under forecast. The largest miss was 275 MW (21.4%) too high at 28 Sept 2026, 15:00 MDT (UTC-06:00).
Across 53 US grids ranked by average error over their own latest 30 day windows, EPE came 23 (1 is the smallest error).
On average the forecast differed from reported demand by 34 MW, against average demand of 991 MW.
The forecast was above reported demand in 37% of compared hours.

Forecast Error at a Glance

719 hours from 28 September to 28 October 2026

Average error3.3%

Bias-1.2%

Hours within 5%77%

Worst miss275 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (-12 MW per hour on average): the forecast ran low on average, an under forecast. The worst miss was 275 MW (21.4%) too high at 28 Sept 2026, 15:00 MDT (UTC-06:00): forecast 1,563 MW, reported 1,288 MW.

Source: U.S. Energy Information Administration (EIA). (US Government work, public domain) 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, 05:00 MDT (UTC-06:00)

Hourly reported demand and the day-ahead forecast for EPE over the last 7 days of the window, to 28 Oct 2026, 05:00 MDT (UTC-06:00). Gaps are hours with a missing, zero or implausible report.

Data to 2026-10-28

Show the data table (168 rows)

Local hour	Reported demand	Day-ahead forecast
21 Oct, 06:00	903 MW	870 MW
21 Oct, 07:00	902 MW	888 MW
21 Oct, 08:00	917 MW	901 MW
21 Oct, 09:00	927 MW	920 MW
21 Oct, 10:00	949 MW	967 MW
21 Oct, 11:00	1,025 MW	1,037 MW
21 Oct, 12:00	1,105 MW	1,127 MW
21 Oct, 13:00	1,209 MW	1,235 MW
21 Oct, 14:00	1,306 MW	1,344 MW
21 Oct, 15:00	1,375 MW	1,432 MW
21 Oct, 16:00	1,460 MW	1,483 MW
21 Oct, 17:00	1,443 MW	1,462 MW
21 Oct, 18:00	1,378 MW	1,403 MW
21 Oct, 19:00	1,326 MW	1,343 MW
21 Oct, 20:00	1,270 MW	1,263 MW
21 Oct, 21:00	1,203 MW	1,179 MW
21 Oct, 22:00	1,104 MW	1,077 MW
21 Oct, 23:00	1,007 MW	978 MW
22 Oct, 00:00	937 MW	898 MW
22 Oct, 01:00	879 MW	876 MW
22 Oct, 02:00	846 MW	833 MW
22 Oct, 03:00	845 MW	812 MW
22 Oct, 04:00	856 MW	809 MW
22 Oct, 05:00	888 MW	834 MW
22 Oct, 06:00	962 MW	891 MW
22 Oct, 07:00	986 MW	905 MW
22 Oct, 08:00	988 MW	918 MW
22 Oct, 09:00	1,025 MW	946 MW
22 Oct, 10:00	1,198 MW	987 MW
22 Oct, 11:00	1,117 MW	1,052 MW
22 Oct, 12:00	1,203 MW	1,126 MW
22 Oct, 13:00	1,299 MW	1,222 MW
22 Oct, 14:00	1,333 MW	1,301 MW
22 Oct, 15:00	1,369 MW	1,364 MW
22 Oct, 16:00	1,407 MW	1,393 MW
22 Oct, 17:00	1,351 MW	1,348 MW
22 Oct, 18:00	1,337 MW	1,295 MW
22 Oct, 19:00	1,316 MW	1,256 MW
22 Oct, 20:00	1,252 MW	1,194 MW
22 Oct, 21:00	1,176 MW	1,130 MW
22 Oct, 22:00	1,094 MW	1,040 MW
22 Oct, 23:00	988 MW	953 MW
23 Oct, 00:00	927 MW	883 MW
23 Oct, 01:00	870 MW	855 MW
23 Oct, 02:00	830 MW	835 MW
23 Oct, 03:00	817 MW	815 MW
23 Oct, 04:00	817 MW	814 MW
23 Oct, 05:00	844 MW	839 MW
23 Oct, 06:00	904 MW	896 MW
23 Oct, 07:00	919 MW	911 MW
23 Oct, 08:00	926 MW	917 MW
23 Oct, 09:00	949 MW	932 MW
23 Oct, 10:00	983 MW	971 MW
23 Oct, 11:00	1,050 MW	1,028 MW
23 Oct, 12:00	1,129 MW	1,095 MW
23 Oct, 13:00	1,247 MW	1,192 MW
23 Oct, 14:00	1,344 MW	1,268 MW
23 Oct, 15:00	1,419 MW	1,335 MW
23 Oct, 16:00	1,388 MW	1,368 MW
23 Oct, 17:00	1,343 MW	1,322 MW
23 Oct, 18:00	1,184 MW	1,266 MW
23 Oct, 19:00	1,106 MW	1,212 MW
23 Oct, 20:00	1,075 MW	1,140 MW
23 Oct, 21:00	1,045 MW	1,074 MW
23 Oct, 22:00	970 MW	1,002 MW
23 Oct, 23:00	886 MW	928 MW
24 Oct, 00:00	850 MW	866 MW
24 Oct, 01:00	792 MW	807 MW
24 Oct, 02:00	768 MW	769 MW
24 Oct, 03:00	741 MW	747 MW
24 Oct, 04:00	735 MW	737 MW
24 Oct, 05:00	759 MW	739 MW
24 Oct, 06:00	779 MW	757 MW
24 Oct, 07:00	797 MW	757 MW
24 Oct, 08:00	830 MW	769 MW
24 Oct, 09:00	826 MW	787 MW
24 Oct, 10:00	864 MW	819 MW
24 Oct, 11:00	919 MW	866 MW
24 Oct, 12:00	994 MW	927 MW
24 Oct, 13:00	1,069 MW	1,009 MW
24 Oct, 14:00	1,183 MW	1,087 MW
24 Oct, 15:00	1,215 MW	1,150 MW
24 Oct, 16:00	1,214 MW	1,160 MW
24 Oct, 17:00	1,125 MW	1,106 MW
24 Oct, 18:00	1,075 MW	1,056 MW
24 Oct, 19:00	1,041 MW	1,020 MW
24 Oct, 20:00	1,158 MW	974 MW
24 Oct, 21:00	1,154 MW	929 MW
24 Oct, 22:00	889 MW	878 MW
24 Oct, 23:00	874 MW	824 MW
25 Oct, 00:00	862 MW	781 MW
25 Oct, 01:00	750 MW	747 MW
25 Oct, 02:00	715 MW	721 MW
25 Oct, 03:00	697 MW	700 MW
25 Oct, 04:00	683 MW	688 MW
25 Oct, 05:00	688 MW	685 MW
25 Oct, 06:00	705 MW	696 MW
25 Oct, 07:00	704 MW	691 MW
25 Oct, 08:00	719 MW	697 MW
25 Oct, 09:00	720 MW	713 MW
25 Oct, 10:00	760 MW	742 MW
25 Oct, 11:00	809 MW	792 MW
25 Oct, 12:00	860 MW	859 MW
25 Oct, 13:00	925 MW	933 MW
25 Oct, 14:00	1,018 MW	1,008 MW
25 Oct, 15:00	1,078 MW	1,071 MW
25 Oct, 16:00	1,118 MW	1,102 MW
25 Oct, 17:00	1,143 MW	1,068 MW
25 Oct, 18:00	1,123 MW	1,036 MW
25 Oct, 19:00	1,125 MW	1,021 MW
25 Oct, 20:00	1,066 MW	985 MW
25 Oct, 21:00	1,020 MW	937 MW
25 Oct, 22:00	955 MW	868 MW
25 Oct, 23:00	848 MW	795 MW
26 Oct, 00:00	788 MW	741 MW
26 Oct, 01:00	732 MW	745 MW
26 Oct, 02:00	734 MW	729 MW
26 Oct, 03:00	714 MW	718 MW
26 Oct, 04:00	726 MW	723 MW
26 Oct, 05:00	763 MW	752 MW
26 Oct, 06:00	829 MW	812 MW
26 Oct, 07:00	896 MW	829 MW
26 Oct, 08:00	941 MW	832 MW
26 Oct, 09:00	874 MW	826 MW
26 Oct, 10:00	892 MW	846 MW
26 Oct, 11:00	1,027 MW	883 MW
26 Oct, 12:00	966 MW	928 MW
26 Oct, 13:00	1,006 MW	988 MW
26 Oct, 14:00	1,086 MW	1,060 MW
26 Oct, 15:00	1,161 MW	1,120 MW
26 Oct, 16:00	1,228 MW	1,170 MW
26 Oct, 17:00	1,210 MW	1,161 MW
26 Oct, 18:00	1,205 MW	1,130 MW
26 Oct, 19:00	1,172 MW	1,108 MW
26 Oct, 20:00	1,114 MW	1,063 MW
26 Oct, 21:00	1,050 MW	1,000 MW
26 Oct, 22:00	962 MW	914 MW
26 Oct, 23:00	890 MW	833 MW
27 Oct, 00:00	823 MW	769 MW
27 Oct, 01:00	789 MW	792 MW
27 Oct, 02:00	761 MW	749 MW
27 Oct, 03:00	752 MW	734 MW
27 Oct, 04:00	755 MW	739 MW
27 Oct, 05:00	799 MW	769 MW
27 Oct, 06:00	868 MW	832 MW
27 Oct, 07:00	884 MW	849 MW
27 Oct, 08:00	876 MW	844 MW
27 Oct, 09:00	885 MW	840 MW
27 Oct, 10:00	909 MW	855 MW
27 Oct, 11:00	948 MW	884 MW
27 Oct, 12:00	998 MW	925 MW
27 Oct, 13:00	1,085 MW	979 MW
27 Oct, 14:00	1,156 MW	1,050 MW
27 Oct, 15:00	1,216 MW	1,124 MW
27 Oct, 16:00	1,282 MW	1,191 MW
27 Oct, 17:00	1,279 MW	1,189 MW
27 Oct, 18:00	1,237 MW	1,181 MW
27 Oct, 19:00	1,187 MW	1,158 MW
27 Oct, 20:00	1,121 MW	1,098 MW
27 Oct, 21:00	1,058 MW	1,028 MW
27 Oct, 22:00	964 MW	941 MW
27 Oct, 23:00	879 MW	857 MW
28 Oct, 00:00	813 MW	791 MW
28 Oct, 01:00	768 MW	770 MW
28 Oct, 02:00	750 MW	746 MW
28 Oct, 03:00	739 MW	733 MW
28 Oct, 04:00	755 MW	739 MW
28 Oct, 05:00	786 MW	770 MW

Assumptions

Only hours with both a forecast and a positive demand reading count (719 of 720 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.
US figures are for the EIA balancing authority or region named on this page. US and European grids are ranked separately.

Cite this page

APA 7

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

Plain text

World Power Monitor. EPE Demand Forecast Accuracy: Error, Bias and Worst Miss. Data as of 2026-10-28. Data from U.S. Energy Information Administration. https://worldpowermonitor.com/forecast-accuracy/epe/

BibTeX

@misc{wpm_forecast_accuracy_epe_2026,
  title = {{EPE Demand Forecast Accuracy: Error, Bias and Worst Miss}},
  author = {{World Power Monitor}},
  year = {2026},
  note = {Data as of 2026-10-28. Data from U.S. Energy Information Administration.},
  url = {https://worldpowermonitor.com/forecast-accuracy/epe/}
}

Permalink: https://worldpowermonitor.com/forecast-accuracy/epe/

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

Key Facts

Forecast Error at a Glance

Forecast and Reported Demand, Last 7 Days

Assumptions

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