Statistics
Page built 2026-10-28
Data as of 2026-10-28
Search
Built 2026-10-28 (28 October 2026)

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

The day-ahead demand forecast for PSEI was off by 49.5% on average (mean absolute percentage error) over 719 hours from 28 September to 28 October 2026, and 0% of hours landed within 5% of the reading. Its bias was -49.5%: it ran low on average, an under forecast. The largest miss was 2,246 MW (71.2%) too low at 23 Oct 2026, 09:00 PDT (UTC-07:00). Dates and times are local (America/Los_Angeles).

Key Facts

  • The day-ahead demand forecast for PSEI was off by 49.5% on average (mean absolute percentage error) over 719 hours from 28 September to 28 October 2026, and 0% of hours landed within 5% of the reading. Its bias was -49.5%: it ran low on average, an under forecast. The largest miss was 2,246 MW (71.2%) too low at 23 Oct 2026, 09:00 PDT (UTC-07:00).
  • Across 53 US grids ranked by average error over their own latest 30 day windows, PSEI came 52 (1 is the smallest error).
  • On average the forecast differed from reported demand by 1,287 MW, against average demand of 2,588 MW.
  • The forecast was above reported demand in 0% of compared hours.

Forecast Error at a Glance

719 hours from 28 September to 28 October 2026
Average error49.5%
Bias-49.5%
Hours within 5%0%
Worst miss2,246 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (-1,287 MW per hour on average): the forecast ran low on average, an under forecast. The worst miss was 2,246 MW (71.2%) too low at 23 Oct 2026, 09:00 PDT (UTC-07:00): forecast 909 MW, reported 3,155 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, 04:00 PDT (UTC-07:00)
PSEI day-ahead demand forecast and reported demand by hour Hourly reported demand and the day-ahead forecast for PSEI over the last 7 days of the window, to 28 Oct 2026, 04:00 PDT (UTC-07:00). Gaps are hours with a missing, zero or implausible report. 0 1,000 2,000 3,000 4,000 21 Oct, 05:0022 Oct, 05:0023 Oct, 05:0024 Oct, 05:0025 Oct, 05:0026 Oct, 05:0027 Oct, 05:00
Hourly reported demand and the day-ahead forecast for PSEI over the last 7 days of the window, to 28 Oct 2026, 04:00 PDT (UTC-07:00). 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, 05:002,628 MW1,336 MW
21 Oct, 06:002,999 MW1,528 MW
21 Oct, 07:003,251 MW1,596 MW
21 Oct, 08:003,276 MW1,736 MW
21 Oct, 09:003,181 MW1,834 MW
21 Oct, 10:003,030 MW1,963 MW
21 Oct, 11:002,898 MW1,862 MW
21 Oct, 12:002,802 MW1,636 MW
21 Oct, 13:002,736 MW1,606 MW
21 Oct, 14:002,697 MW1,683 MW
21 Oct, 15:002,715 MW1,680 MW
21 Oct, 16:002,777 MW1,711 MW
21 Oct, 17:002,875 MW1,742 MW
21 Oct, 18:003,004 MW1,782 MW
21 Oct, 19:003,012 MW1,867 MW
21 Oct, 20:002,946 MW1,846 MW
21 Oct, 21:002,794 MW1,780 MW
21 Oct, 22:002,586 MW1,708 MW
21 Oct, 23:002,412 MW1,435 MW
22 Oct, 00:002,283 MW1,152 MW
22 Oct, 01:002,204 MW1,161 MW
22 Oct, 02:002,175 MW1,123 MW
22 Oct, 03:002,202 MW1,108 MW
22 Oct, 04:002,315 MW1,098 MW
22 Oct, 05:002,565 MW1,242 MW
22 Oct, 06:002,932 MW1,537 MW
22 Oct, 07:003,155 MW1,518 MW
22 Oct, 08:003,183 MW1,509 MW
22 Oct, 09:003,116 MW1,440 MW
22 Oct, 10:003,008 MW1,517 MW
22 Oct, 11:002,915 MW1,570 MW
22 Oct, 12:002,847 MW1,395 MW
22 Oct, 13:002,780 MW1,388 MW
22 Oct, 14:002,751 MW1,528 MW
22 Oct, 15:002,793 MW1,574 MW
22 Oct, 16:002,855 MW1,697 MW
22 Oct, 17:002,963 MW1,839 MW
22 Oct, 18:003,056 MW1,737 MW
22 Oct, 19:003,065 MW1,579 MW
22 Oct, 20:002,991 MW1,527 MW
22 Oct, 21:002,838 MW1,530 MW
22 Oct, 22:002,633 MW1,301 MW
22 Oct, 23:002,463 MW894 MW
23 Oct, 00:002,344 MW662 MW
23 Oct, 01:002,259 MW729 MW
23 Oct, 02:002,219 MW726 MW
23 Oct, 03:002,223 MW617 MW
23 Oct, 04:002,327 MW671 MW
23 Oct, 05:002,551 MW605 MW
23 Oct, 06:002,888 MW783 MW
23 Oct, 07:003,130 MW976 MW
23 Oct, 08:003,181 MW968 MW
23 Oct, 09:003,155 MW909 MW
23 Oct, 10:003,085 MW942 MW
23 Oct, 11:002,971 MW1,143 MW
23 Oct, 12:002,869 MW1,033 MW
23 Oct, 13:002,786 MW996 MW
23 Oct, 14:002,728 MW1,100 MW
23 Oct, 15:002,721 MW896 MW
23 Oct, 16:002,788 MW1,020 MW
23 Oct, 17:002,895 MW1,113 MW
23 Oct, 18:003,008 MW1,232 MW
23 Oct, 19:003,033 MW1,166 MW
23 Oct, 20:002,994 MW1,139 MW
23 Oct, 21:002,913 MW1,114 MW
23 Oct, 22:002,771 MW1,113 MW
23 Oct, 23:002,632 MW1,006 MW
24 Oct, 00:002,527 MW995 MW
24 Oct, 01:002,443 MW948 MW
24 Oct, 02:002,400 MW1,103 MW
24 Oct, 03:002,398 MW932 MW
24 Oct, 04:002,450 MW1,061 MW
24 Oct, 05:002,571 MW1,231 MW
24 Oct, 06:002,765 MW1,119 MW
24 Oct, 07:002,960 MW1,238 MW
24 Oct, 08:003,094 MW1,305 MW
24 Oct, 09:003,131 MW1,303 MW
24 Oct, 10:003,089 MW1,384 MW
24 Oct, 11:003,071 MW1,245 MW
24 Oct, 12:003,013 MW1,131 MW
24 Oct, 13:002,909 MW1,249 MW
24 Oct, 14:002,851 MW1,274 MW
24 Oct, 15:002,845 MW1,048 MW
24 Oct, 16:002,879 MW1,087 MW
24 Oct, 17:002,963 MW1,209 MW
24 Oct, 18:003,054 MW1,277 MW
24 Oct, 19:003,021 MW1,315 MW
24 Oct, 20:002,949 MW1,362 MW
24 Oct, 21:002,849 MW1,528 MW
24 Oct, 22:002,686 MW1,426 MW
24 Oct, 23:002,530 MW1,226 MW
25 Oct, 00:002,399 MW1,219 MW
25 Oct, 01:002,291 MW1,218 MW
25 Oct, 02:002,217 MW1,193 MW
25 Oct, 03:002,198 MW1,087 MW
25 Oct, 04:002,226 MW1,098 MW
25 Oct, 05:002,315 MW1,018 MW
25 Oct, 06:002,454 MW1,068 MW
25 Oct, 07:002,632 MW1,121 MW
25 Oct, 08:002,787 MW1,152 MW
25 Oct, 09:002,918 MW1,252 MW
25 Oct, 10:002,972 MW1,290 MW
25 Oct, 11:002,990 MW1,398 MW
25 Oct, 12:002,968 MW1,377 MW
25 Oct, 13:002,930 MW1,350 MW
25 Oct, 14:002,876 MW1,273 MW
25 Oct, 15:002,863 MW1,288 MW
25 Oct, 16:002,900 MW1,407 MW
25 Oct, 17:002,998 MW1,543 MW
25 Oct, 18:003,097 MW1,612 MW
25 Oct, 19:003,085 MW1,636 MW
25 Oct, 20:003,011 MW1,493 MW
25 Oct, 21:002,864 MW1,535 MW
25 Oct, 22:002,646 MW1,299 MW
25 Oct, 23:002,449 MW1,229 MW
26 Oct, 00:002,316 MW1,200 MW
26 Oct, 01:002,230 MW1,212 MW
26 Oct, 02:002,185 MW1,208 MW
26 Oct, 03:002,181 MW1,207 MW
26 Oct, 04:002,291 MW1,237 MW
26 Oct, 05:002,527 MW1,240 MW
26 Oct, 06:002,856 MW1,622 MW
26 Oct, 07:003,083 MW1,698 MW
26 Oct, 08:003,133 MW1,592 MW
26 Oct, 09:003,134 MW1,647 MW
26 Oct, 10:003,082 MW1,752 MW
26 Oct, 11:003,030 MW1,686 MW
26 Oct, 12:002,953 MW1,395 MW
26 Oct, 13:002,877 MW1,395 MW
26 Oct, 14:002,841 MW1,402 MW
26 Oct, 15:002,847 MW1,430 MW
26 Oct, 16:002,918 MW1,430 MW
26 Oct, 17:003,064 MW1,552 MW
26 Oct, 18:003,169 MW1,604 MW
26 Oct, 19:003,126 MW1,509 MW
26 Oct, 20:003,026 MW1,526 MW
26 Oct, 21:002,843 MW1,447 MW
26 Oct, 22:002,617 MW1,436 MW
26 Oct, 23:002,416 MW1,230 MW
27 Oct, 00:002,281 MW1,308 MW
27 Oct, 01:002,179 MW1,308 MW
27 Oct, 02:002,117 MW1,337 MW
27 Oct, 03:002,122 MW1,391 MW
27 Oct, 04:002,204 MW1,306 MW
27 Oct, 05:002,429 MW1,398 MW
27 Oct, 06:002,765 MW1,680 MW
27 Oct, 07:002,983 MW1,765 MW
27 Oct, 08:003,040 MW1,824 MW
27 Oct, 09:003,034 MW1,640 MW
27 Oct, 10:003,022 MW1,524 MW
27 Oct, 11:003,006 MW1,515 MW
27 Oct, 12:002,987 MW1,530 MW
27 Oct, 13:002,918 MW1,538 MW
27 Oct, 14:002,868 MW1,538 MW
27 Oct, 15:002,891 MW1,535 MW
27 Oct, 16:002,973 MW1,533 MW
27 Oct, 17:003,106 MW1,702 MW
27 Oct, 18:003,242 MW1,839 MW
27 Oct, 19:003,219 MW1,830 MW
27 Oct, 20:003,142 MW1,569 MW
27 Oct, 21:002,970 MW1,634 MW
27 Oct, 22:002,740 MW1,570 MW
27 Oct, 23:002,534 MW1,491 MW
28 Oct, 00:002,401 MW1,553 MW
28 Oct, 01:002,295 MW1,491 MW
28 Oct, 02:002,243 MW1,527 MW
28 Oct, 03:002,249 MW1,419 MW
28 Oct, 04:002,347 MW1,471 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). PSEI Demand Forecast Accuracy: Error, Bias and Worst Miss. https://worldpowermonitor.com/forecast-accuracy/psei/

Plain text

World Power Monitor. PSEI 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/psei/

BibTeX 
@misc{wpm_forecast_accuracy_psei_2026,
  title = {{PSEI 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/psei/}
}

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

The Copy buttons add today's date as the access date.