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

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

The day-ahead demand forecast for LGEE was off by 7.8% on average (mean absolute percentage error) over 717 hours from 21 August to 20 September 2026, and 14% of hours landed within 5% of the reading. Its bias was -7.8%: it ran low on average, an under forecast. The largest miss was 852 MW (14.9%) too low at 12 Sept 2026, 17:00 EDT (UTC-04:00). Dates and times are local (America/New_York).

Key Facts

  • The day-ahead demand forecast for LGEE was off by 7.8% on average (mean absolute percentage error) over 717 hours from 21 August to 20 September 2026, and 14% of hours landed within 5% of the reading. Its bias was -7.8%: it ran low on average, an under forecast. The largest miss was 852 MW (14.9%) too low at 12 Sept 2026, 17:00 EDT (UTC-04:00).
  • Across 53 US grids ranked by average error over their own latest 30 day windows, LGEE came 41 (1 is the smallest error).
  • On average the forecast differed from reported demand by 394 MW, against average demand of 5,067 MW.
  • The forecast was above reported demand in 2% of compared hours.

Forecast Error at a Glance

717 hours from 21 August to 20 September 2026
Average error7.8%
Bias-7.8%
Hours within 5%14%
Worst miss852 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (-392 MW per hour on average): the forecast ran low on average, an under forecast. The worst miss was 852 MW (14.9%) too low at 12 Sept 2026, 17:00 EDT (UTC-04:00): forecast 4,877 MW, reported 5,729 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, 21:00 EDT (UTC-04:00)
LGEE day-ahead demand forecast and reported demand by hour Hourly reported demand and the day-ahead forecast for LGEE over the last 7 days of the window, to 20 Sept 2026, 21:00 EDT (UTC-04:00). Gaps are hours with a missing, zero or implausible report. 0 2,000 4,000 6,000 8,000 13 Sept, 22:0014 Sept, 22:0015 Sept, 22:0016 Sept, 22:0017 Sept, 22:0018 Sept, 22:0019 Sept, 22:00
Hourly reported demand and the day-ahead forecast for LGEE over the last 7 days of the window, to 20 Sept 2026, 21:00 EDT (UTC-04:00). Gaps are hours with a missing, zero or implausible report.
Data to 2026-09-20
LGEE day-ahead demand forecast and reported demand by hour
Local hourReported demandDay-ahead forecast
13 Sept, 22:005,146 MW4,490 MW
13 Sept, 23:004,701 MW4,161 MW
14 Sept, 00:004,411 MW3,873 MW
14 Sept, 01:004,079 MW3,625 MW
14 Sept, 02:003,939 MW3,460 MW
14 Sept, 03:003,605 MW3,363 MW
14 Sept, 04:003,571 MW3,305 MW
14 Sept, 05:003,709 MW3,387 MW
14 Sept, 06:003,889 MW3,646 MW
14 Sept, 07:004,103 MW3,819 MW
14 Sept, 08:004,179 MW3,958 MW
14 Sept, 09:004,364 MW4,148 MW
14 Sept, 10:004,522 MW4,353 MW
14 Sept, 11:004,716 MW4,575 MW
14 Sept, 12:004,992 MW4,765 MW
14 Sept, 13:005,243 MW4,954 MW
14 Sept, 14:005,344 MW5,106 MW
14 Sept, 15:005,487 MW5,231 MW
14 Sept, 16:005,663 MW5,295 MW
14 Sept, 17:005,684 MW5,312 MW
14 Sept, 18:005,626 MW5,224 MW
14 Sept, 19:005,366 MW5,035 MW
14 Sept, 20:005,222 MW4,846 MW
14 Sept, 21:004,926 MW4,620 MW
14 Sept, 22:004,562 MW4,290 MW
14 Sept, 23:004,235 MW3,954 MW
15 Sept, 00:003,958 MW3,668 MW
15 Sept, 01:003,801 MW3,436 MW
15 Sept, 02:003,629 MW3,313 MW
15 Sept, 03:003,542 MW3,184 MW
15 Sept, 04:003,476 MW3,154 MW
15 Sept, 05:003,571 MW3,237 MW
15 Sept, 06:003,724 MW3,422 MW
15 Sept, 07:003,960 MW3,573 MW
15 Sept, 08:003,945 MW3,767 MW
15 Sept, 09:004,373 MW3,997 MW
15 Sept, 10:004,803 MW4,331 MW
15 Sept, 11:005,259 MW4,723 MW
15 Sept, 12:005,771 MW5,179 MW
15 Sept, 13:006,228 MW5,540 MW
15 Sept, 14:006,608 MW5,883 MW
15 Sept, 15:006,740 MW6,120 MW
15 Sept, 16:006,842 MW6,294 MW
15 Sept, 17:006,883 MW6,345 MW
15 Sept, 18:006,852 MW6,254 MW
15 Sept, 19:006,507 MW6,014 MW
15 Sept, 20:006,287 MW5,804 MW
15 Sept, 21:005,960 MW5,467 MW
15 Sept, 22:005,563 MW5,060 MW
15 Sept, 23:005,271 MW4,704 MW
16 Sept, 00:004,978 MW4,365 MW
16 Sept, 01:004,673 MW4,251 MW
16 Sept, 02:004,451 MW4,057 MW
16 Sept, 03:004,336 MW3,915 MW
16 Sept, 04:004,259 MW3,833 MW
16 Sept, 05:004,267 MW3,891 MW
16 Sept, 06:004,426 MW4,085 MW
16 Sept, 07:004,662 MW4,235 MW
16 Sept, 08:004,757 MW4,421 MW
16 Sept, 09:005,121 MW4,703 MW
16 Sept, 10:005,482 MW5,090 MW
16 Sept, 11:005,894 MW5,494 MW
16 Sept, 12:006,430 MW5,879 MW
16 Sept, 13:006,683 MW6,182 MW
16 Sept, 14:006,920 MW6,412 MW
16 Sept, 15:007,193 MW6,553 MW
16 Sept, 16:007,264 MW6,605 MW
16 Sept, 17:007,251 MW6,602 MW
16 Sept, 18:007,091 MW6,478 MW
16 Sept, 19:006,664 MW6,228 MW
16 Sept, 20:006,541 MW5,970 MW
16 Sept, 21:006,234 MW5,681 MW
16 Sept, 22:005,797 MW5,308 MW
16 Sept, 23:005,341 MW4,956 MW
17 Sept, 00:005,135 MW4,657 MW
17 Sept, 01:004,699 MW4,369 MW
17 Sept, 02:004,483 MW4,163 MW
17 Sept, 03:004,309 MW3,996 MW
17 Sept, 04:004,252 MW3,926 MW
17 Sept, 05:004,269 MW3,971 MW
17 Sept, 06:004,455 MW4,181 MW
17 Sept, 07:004,585 MW4,319 MW
17 Sept, 08:004,698 MW4,534 MW
17 Sept, 09:005,138 MW4,897 MW
17 Sept, 10:005,543 MW5,339 MW
17 Sept, 11:006,023 MW5,800 MW
17 Sept, 12:006,520 MW6,195 MW
17 Sept, 13:006,833 MW6,489 MW
17 Sept, 14:006,922 MW6,691 MW
17 Sept, 15:006,903 MW6,821 MW
17 Sept, 16:006,842 MW6,831 MW
17 Sept, 17:006,857 MW6,801 MW
17 Sept, 18:006,746 MW6,648 MW
17 Sept, 19:006,529 MW6,379 MW
17 Sept, 20:006,328 MW6,164 MW
17 Sept, 21:005,947 MW5,811 MW
17 Sept, 22:005,571 MW5,450 MW
17 Sept, 23:005,214 MW5,061 MW
18 Sept, 00:004,976 MW4,741 MW
18 Sept, 01:004,718 MW4,390 MW
18 Sept, 02:004,560 MW4,189 MW
18 Sept, 03:004,321 MW4,038 MW
18 Sept, 04:004,142 MW3,955 MW
18 Sept, 05:004,188 MW3,988 MW
18 Sept, 06:004,380 MW4,167 MW
18 Sept, 07:004,540 MW4,296 MW
18 Sept, 08:004,738 MW4,478 MW
18 Sept, 09:005,133 MW4,774 MW
18 Sept, 10:005,407 MW5,131 MW
18 Sept, 11:005,896 MW5,500 MW
18 Sept, 12:006,203 MW5,817 MW
18 Sept, 13:006,661 MW6,050 MW
18 Sept, 14:006,566 MW6,211 MW
18 Sept, 15:006,621 MW6,277 MW
18 Sept, 16:006,609 MW6,269 MW
18 Sept, 17:006,377 MW6,193 MW
18 Sept, 18:006,150 MW6,010 MW
18 Sept, 19:005,919 MW5,737 MW
18 Sept, 20:005,694 MW5,506 MW
18 Sept, 21:005,375 MW5,214 MW
18 Sept, 22:005,139 MW4,894 MW
18 Sept, 23:004,725 MW4,559 MW
19 Sept, 00:004,453 MW4,267 MW
19 Sept, 01:004,251 MW3,978 MW
19 Sept, 02:004,051 MW3,778 MW
19 Sept, 03:003,814 MW3,627 MW
19 Sept, 04:003,660 MW3,513 MW
19 Sept, 05:003,759 MW3,467 MW
19 Sept, 06:003,811 MW3,498 MW
19 Sept, 07:003,823 MW3,533 MW
19 Sept, 08:004,000 MW3,698 MW
19 Sept, 09:004,363 MW4,021 MW
19 Sept, 10:004,719 MW4,377 MW
19 Sept, 11:005,106 MW4,761 MW
19 Sept, 12:005,424 MW5,115 MW
19 Sept, 13:005,756 MW5,395 MW
19 Sept, 14:006,129 MW5,629 MW
19 Sept, 15:006,456 MW5,759 MW
19 Sept, 16:006,518 MW5,854 MW
19 Sept, 17:006,496 MW5,857 MW
19 Sept, 18:006,293 MW5,750 MW
19 Sept, 19:005,963 MW5,514 MW
19 Sept, 20:005,771 MW5,289 MW
19 Sept, 21:005,472 MW5,022 MW
19 Sept, 22:005,122 MW4,715 MW
19 Sept, 23:00n/a4,402 MW
20 Sept, 00:00n/a4,111 MW
20 Sept, 01:004,242 MW3,895 MW
20 Sept, 02:004,010 MW3,711 MW
20 Sept, 03:003,980 MW3,575 MW
20 Sept, 04:003,876 MW3,488 MW
20 Sept, 05:003,906 MW3,447 MW
20 Sept, 06:003,824 MW3,466 MW
20 Sept, 07:003,896 MW3,501 MW
20 Sept, 08:003,985 MW3,678 MW
20 Sept, 09:004,289 MW4,009 MW
20 Sept, 10:004,749 MW4,415 MW
20 Sept, 11:005,113 MW4,838 MW
20 Sept, 12:005,512 MW5,219 MW
20 Sept, 13:005,871 MW5,546 MW
20 Sept, 14:006,190 MW5,769 MW
20 Sept, 15:006,369 MW5,944 MW
20 Sept, 16:006,452 MW6,053 MW
20 Sept, 17:006,444 MW6,054 MW
20 Sept, 18:006,228 MW5,948 MW
20 Sept, 19:006,017 MW5,744 MW
20 Sept, 20:005,804 MW5,514 MW
20 Sept, 21:005,116 MW5,216 MW

Assumptions

  • Only hours with both a forecast and a positive demand reading count (717 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.