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

PACE Demand Forecast Accuracy: Error, Bias and Worst Miss, 21 August to 20 September 2026

The day-ahead demand forecast for PACE was off by 7.8% on average (mean absolute percentage error) over 719 hours from 21 August to 20 September 2026, and 43% of hours landed within 5% of the reading. Its bias was +5.3%: it ran high on average, an over forecast. The largest miss was 2,006 MW (27.9%) too high at 27 Aug 2026, 19:00 MDT (UTC-06:00). Dates and times are local (America/Denver).

Key Facts

  • The day-ahead demand forecast for PACE was off by 7.8% on average (mean absolute percentage error) over 719 hours from 21 August to 20 September 2026, and 43% of hours landed within 5% of the reading. Its bias was +5.3%: it ran high on average, an over forecast. The largest miss was 2,006 MW (27.9%) too high at 27 Aug 2026, 19:00 MDT (UTC-06:00).
  • Across 53 US grids ranked by average error over their own latest 30 day windows, PACE came 40 (1 is the smallest error).
  • On average the forecast differed from reported demand by 484 MW, against average demand of 6,396 MW.
  • The forecast was above reported demand in 71% of compared hours.

Forecast Error at a Glance

719 hours from 21 August to 20 September 2026
Average error7.8%
Bias+5.3%
Hours within 5%43%
Worst miss2,006 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (+307 MW per hour on average): the forecast ran high on average, an over forecast. The worst miss was 2,006 MW (27.9%) too high at 27 Aug 2026, 19:00 MDT (UTC-06:00): forecast 9,194 MW, reported 7,188 MW.

Source: U.S. Energy Information Administration (EIA). (US Government work, public domain) 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, 19:00 MDT (UTC-06:00)
PACE day-ahead demand forecast and reported demand by hour Hourly reported demand and the day-ahead forecast for PACE over the last 7 days of the window, to 20 Sept 2026, 19:00 MDT (UTC-06:00). Gaps are hours with a missing, zero or implausible report. 0 2,000 4,000 6,000 8,000 13 Sept, 20:0014 Sept, 20:0015 Sept, 20:0016 Sept, 20:0017 Sept, 20:0018 Sept, 20:0019 Sept, 20:00
Hourly reported demand and the day-ahead forecast for PACE over the last 7 days of the window, to 20 Sept 2026, 19:00 MDT (UTC-06:00). Gaps are hours with a missing, zero or implausible report.
Data to 2026-09-20
PACE day-ahead demand forecast and reported demand by hour
Local hourReported demandDay-ahead forecast
13 Sept, 20:006,495 MW7,005 MW
13 Sept, 21:006,322 MW6,754 MW
13 Sept, 22:006,203 MW6,401 MW
13 Sept, 23:006,231 MW6,036 MW
14 Sept, 00:006,003 MW5,734 MW
14 Sept, 01:005,577 MW5,535 MW
14 Sept, 02:005,389 MW5,398 MW
14 Sept, 03:005,283 MW5,322 MW
14 Sept, 04:005,329 MW5,333 MW
14 Sept, 05:005,469 MW5,501 MW
14 Sept, 06:005,518 MW5,770 MW
14 Sept, 07:005,804 MW6,002 MW
14 Sept, 08:006,079 MW6,157 MW
14 Sept, 09:006,214 MW6,289 MW
14 Sept, 10:006,747 MW6,436 MW
14 Sept, 11:006,863 MW6,581 MW
14 Sept, 12:007,037 MW6,754 MW
14 Sept, 13:007,192 MW6,944 MW
14 Sept, 14:007,582 MW7,100 MW
14 Sept, 15:007,318 MW7,210 MW
14 Sept, 16:007,446 MW7,319 MW
14 Sept, 17:007,466 MW7,415 MW
14 Sept, 18:006,913 MW7,383 MW
14 Sept, 19:006,058 MW7,245 MW
14 Sept, 20:005,496 MW7,014 MW
14 Sept, 21:005,175 MW6,712 MW
14 Sept, 22:004,851 MW6,305 MW
14 Sept, 23:005,053 MW5,916 MW
15 Sept, 00:005,241 MW5,624 MW
15 Sept, 01:004,977 MW5,396 MW
15 Sept, 02:004,853 MW5,485 MW
15 Sept, 03:004,807 MW5,418 MW
15 Sept, 04:004,781 MW5,384 MW
15 Sept, 05:004,907 MW5,528 MW
15 Sept, 06:005,119 MW5,825 MW
15 Sept, 07:005,079 MW5,955 MW
15 Sept, 08:005,837 MW6,056 MW
15 Sept, 09:005,982 MW6,163 MW
15 Sept, 10:006,341 MW6,312 MW
15 Sept, 11:006,708 MW6,419 MW
15 Sept, 12:006,939 MW6,586 MW
15 Sept, 13:006,712 MW6,845 MW
15 Sept, 14:006,759 MW7,131 MW
15 Sept, 15:006,877 MW7,404 MW
15 Sept, 16:006,855 MW7,685 MW
15 Sept, 17:006,770 MW7,878 MW
15 Sept, 18:006,309 MW7,849 MW
15 Sept, 19:005,790 MW7,590 MW
15 Sept, 20:005,941 MW7,319 MW
15 Sept, 21:005,807 MW6,992 MW
15 Sept, 22:006,144 MW6,622 MW
15 Sept, 23:005,889 MW6,220 MW
16 Sept, 00:005,861 MW5,875 MW
16 Sept, 01:005,239 MW5,648 MW
16 Sept, 02:005,137 MW5,361 MW
16 Sept, 03:005,055 MW5,224 MW
16 Sept, 04:005,238 MW5,250 MW
16 Sept, 05:005,359 MW5,409 MW
16 Sept, 06:005,359 MW5,672 MW
16 Sept, 07:005,610 MW5,918 MW
16 Sept, 08:006,045 MW6,102 MW
16 Sept, 09:006,872 MW6,267 MW
16 Sept, 10:006,858 MW6,429 MW
16 Sept, 11:007,118 MW6,596 MW
16 Sept, 12:007,425 MW6,859 MW
16 Sept, 13:007,538 MW7,137 MW
16 Sept, 14:007,472 MW7,385 MW
16 Sept, 15:007,763 MW7,581 MW
16 Sept, 16:007,756 MW7,720 MW
16 Sept, 17:007,878 MW7,820 MW
16 Sept, 18:007,275 MW7,717 MW
16 Sept, 19:006,289 MW7,530 MW
16 Sept, 20:006,212 MW7,323 MW
16 Sept, 21:006,151 MW7,047 MW
16 Sept, 22:006,239 MW6,659 MW
16 Sept, 23:005,990 MW6,255 MW
17 Sept, 00:005,669 MW5,920 MW
17 Sept, 01:005,352 MW5,626 MW
17 Sept, 02:005,407 MW5,532 MW
17 Sept, 03:005,319 MW5,472 MW
17 Sept, 04:005,437 MW5,465 MW
17 Sept, 05:005,680 MW5,617 MW
17 Sept, 06:005,658 MW5,877 MW
17 Sept, 07:005,694 MW6,127 MW
17 Sept, 08:005,842 MW6,317 MW
17 Sept, 09:006,560 MW6,486 MW
17 Sept, 10:007,276 MW6,685 MW
17 Sept, 11:007,478 MW6,900 MW
17 Sept, 12:007,350 MW7,142 MW
17 Sept, 13:007,348 MW7,382 MW
17 Sept, 14:007,478 MW7,588 MW
17 Sept, 15:007,566 MW7,728 MW
17 Sept, 16:007,712 MW7,805 MW
17 Sept, 17:007,784 MW7,802 MW
17 Sept, 18:007,062 MW7,714 MW
17 Sept, 19:006,296 MW7,578 MW
17 Sept, 20:006,340 MW7,381 MW
17 Sept, 21:006,112 MW7,105 MW
17 Sept, 22:006,206 MW6,735 MW
17 Sept, 23:005,770 MW6,349 MW
18 Sept, 00:005,450 MW6,016 MW
18 Sept, 01:005,477 MW5,780 MW
18 Sept, 02:005,508 MW5,416 MW
18 Sept, 03:005,581 MW5,337 MW
18 Sept, 04:005,509 MW5,339 MW
18 Sept, 05:005,566 MW5,456 MW
18 Sept, 06:005,998 MW5,787 MW
18 Sept, 07:005,932 MW6,013 MW
18 Sept, 08:006,073 MW6,172 MW
18 Sept, 09:006,480 MW6,398 MW
18 Sept, 10:006,505 MW6,597 MW
18 Sept, 11:006,787 MW6,793 MW
18 Sept, 12:006,999 MW6,982 MW
18 Sept, 13:007,071 MW7,169 MW
18 Sept, 14:007,362 MW7,337 MW
18 Sept, 15:007,458 MW7,446 MW
18 Sept, 16:006,804 MW7,489 MW
18 Sept, 17:006,418 MW7,412 MW
18 Sept, 18:005,843 MW7,275 MW
18 Sept, 19:005,549 MW7,026 MW
18 Sept, 20:004,906 MW6,800 MW
18 Sept, 21:004,848 MW6,575 MW
18 Sept, 22:005,036 MW6,300 MW
18 Sept, 23:004,923 MW5,996 MW
19 Sept, 00:004,749 MW5,706 MW
19 Sept, 01:004,930 MW5,495 MW
19 Sept, 02:004,933 MW5,345 MW
19 Sept, 03:004,833 MW5,251 MW
19 Sept, 04:004,850 MW5,203 MW
19 Sept, 05:005,299 MW5,228 MW
19 Sept, 06:005,079 MW5,287 MW
19 Sept, 07:004,946 MW5,361 MW
19 Sept, 08:005,571 MW5,474 MW
19 Sept, 09:005,844 MW5,632 MW
19 Sept, 10:005,902 MW5,787 MW
19 Sept, 11:006,002 MW5,915 MW
19 Sept, 12:006,571 MW6,039 MW
19 Sept, 13:006,539 MW6,184 MW
19 Sept, 14:005,984 MW6,320 MW
19 Sept, 15:006,189 MW6,418 MW
19 Sept, 16:006,025 MW6,495 MW
19 Sept, 17:006,091 MW6,535 MW
19 Sept, 18:005,845 MW6,486 MW
19 Sept, 19:004,919 MW6,381 MW
19 Sept, 20:005,237 MW6,254 MW
19 Sept, 21:005,087 MW6,103 MW
19 Sept, 22:004,868 MW5,873 MW
19 Sept, 23:004,827 MW5,623 MW
20 Sept, 00:004,622 MW5,392 MW
20 Sept, 01:004,630 MW5,219 MW
20 Sept, 02:004,552 MW5,099 MW
20 Sept, 03:004,340 MW5,027 MW
20 Sept, 04:004,484 MW4,990 MW
20 Sept, 05:004,474 MW5,002 MW
20 Sept, 06:004,463 MW5,032 MW
20 Sept, 07:004,531 MW5,079 MW
20 Sept, 08:004,681 MW5,167 MW
20 Sept, 09:005,094 MW5,291 MW
20 Sept, 10:005,471 MW5,423 MW
20 Sept, 11:005,955 MW5,571 MW
20 Sept, 12:006,156 MW5,750 MW
20 Sept, 13:006,270 MW5,940 MW
20 Sept, 14:006,413 MW6,117 MW
20 Sept, 15:006,442 MW6,299 MW
20 Sept, 16:006,219 MW6,461 MW
20 Sept, 17:006,187 MW6,542 MW
20 Sept, 18:005,663 MW6,493 MW
20 Sept, 19:005,113 MW6,396 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.