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

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

The day-ahead demand forecast for JEA was off by 4.4% on average (mean absolute percentage error) over 719 hours from 21 August to 20 September 2026, and 66% of hours landed within 5% of the reading. Its bias was +2.3%: it ran high on average, an over forecast. The largest miss was 468 MW (24.8%) too high at 25 Aug 2026, 16:00 EDT (UTC-04:00). Dates and times are local (America/New_York).

Key Facts

  • The day-ahead demand forecast for JEA was off by 4.4% on average (mean absolute percentage error) over 719 hours from 21 August to 20 September 2026, and 66% of hours landed within 5% of the reading. Its bias was +2.3%: it ran high on average, an over forecast. The largest miss was 468 MW (24.8%) too high at 25 Aug 2026, 16:00 EDT (UTC-04:00).
  • Across 53 US grids ranked by average error over their own latest 30 day windows, JEA came 29 (1 is the smallest error).
  • On average the forecast differed from reported demand by 83 MW, against average demand of 1,871 MW.
  • The forecast was above reported demand in 68% of compared hours.

Forecast Error at a Glance

719 hours from 21 August to 20 September 2026
Average error4.4%
Bias+2.3%
Hours within 5%66%
Worst miss468 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (+37 MW per hour on average): the forecast ran high on average, an over forecast. The worst miss was 468 MW (24.8%) too high at 25 Aug 2026, 16:00 EDT (UTC-04:00): forecast 2,353 MW, reported 1,885 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)
JEA day-ahead demand forecast and reported demand by hour Hourly reported demand and the day-ahead forecast for JEA 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. 0 750 1,500 2,250 3,000 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 JEA 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
JEA day-ahead demand forecast and reported demand by hour
Local hourReported demandDay-ahead forecast
13 Sept, 22:001,803 MW1,902 MW
13 Sept, 23:001,657 MW1,756 MW
14 Sept, 00:001,539 MW1,625 MW
14 Sept, 01:001,452 MW1,532 MW
14 Sept, 02:001,396 MW1,451 MW
14 Sept, 03:001,369 MW1,411 MW
14 Sept, 04:001,381 MW1,421 MW
14 Sept, 05:001,439 MW1,492 MW
14 Sept, 06:001,538 MW1,584 MW
14 Sept, 07:001,582 MW1,623 MW
14 Sept, 08:001,659 MW1,768 MW
14 Sept, 09:001,805 MW1,938 MW
14 Sept, 10:001,991 MW2,123 MW
14 Sept, 11:002,176 MW2,300 MW
14 Sept, 12:002,334 MW2,448 MW
14 Sept, 13:002,459 MW2,516 MW
14 Sept, 14:002,530 MW2,565 MW
14 Sept, 15:002,534 MW2,593 MW
14 Sept, 16:002,508 MW2,518 MW
14 Sept, 17:002,468 MW2,496 MW
14 Sept, 18:002,421 MW2,428 MW
14 Sept, 19:002,335 MW2,346 MW
14 Sept, 20:002,289 MW2,295 MW
14 Sept, 21:002,151 MW2,185 MW
14 Sept, 22:001,991 MW2,054 MW
14 Sept, 23:001,794 MW1,901 MW
15 Sept, 00:001,677 MW1,776 MW
15 Sept, 01:001,579 MW1,670 MW
15 Sept, 02:001,492 MW1,599 MW
15 Sept, 03:001,471 MW1,549 MW
15 Sept, 04:001,478 MW1,547 MW
15 Sept, 05:001,523 MW1,619 MW
15 Sept, 06:001,624 MW1,702 MW
15 Sept, 07:001,665 MW1,721 MW
15 Sept, 08:001,722 MW1,848 MW
15 Sept, 09:001,761 MW1,974 MW
15 Sept, 10:001,850 MW2,074 MW
15 Sept, 11:001,988 MW2,195 MW
15 Sept, 12:002,092 MW2,282 MW
15 Sept, 13:002,101 MW2,345 MW
15 Sept, 14:002,071 MW2,382 MW
15 Sept, 15:002,129 MW2,410 MW
15 Sept, 16:002,154 MW2,442 MW
15 Sept, 17:002,148 MW2,382 MW
15 Sept, 18:002,079 MW2,351 MW
15 Sept, 19:002,038 MW2,282 MW
15 Sept, 20:002,030 MW2,222 MW
15 Sept, 21:001,945 MW2,129 MW
15 Sept, 22:001,840 MW1,991 MW
15 Sept, 23:001,734 MW1,851 MW
16 Sept, 00:001,631 MW1,632 MW
16 Sept, 01:001,539 MW1,549 MW
16 Sept, 02:001,487 MW1,468 MW
16 Sept, 03:001,436 MW1,435 MW
16 Sept, 04:001,430 MW1,431 MW
16 Sept, 05:001,473 MW1,515 MW
16 Sept, 06:001,568 MW1,603 MW
16 Sept, 07:001,583 MW1,626 MW
16 Sept, 08:001,659 MW1,741 MW
16 Sept, 09:001,774 MW1,842 MW
16 Sept, 10:001,870 MW1,945 MW
16 Sept, 11:001,959 MW2,056 MW
16 Sept, 12:002,071 MW2,167 MW
16 Sept, 13:002,157 MW2,218 MW
16 Sept, 14:002,232 MW2,242 MW
16 Sept, 15:002,284 MW2,295 MW
16 Sept, 16:002,301 MW2,296 MW
16 Sept, 17:002,241 MW2,251 MW
16 Sept, 18:002,176 MW2,192 MW
16 Sept, 19:002,122 MW2,118 MW
16 Sept, 20:002,065 MW2,087 MW
16 Sept, 21:001,944 MW1,999 MW
16 Sept, 22:001,789 MW1,877 MW
16 Sept, 23:001,673 MW1,742 MW
17 Sept, 00:001,553 MW1,646 MW
17 Sept, 01:001,473 MW1,531 MW
17 Sept, 02:001,407 MW1,460 MW
17 Sept, 03:001,378 MW1,402 MW
17 Sept, 04:001,372 MW1,391 MW
17 Sept, 05:001,398 MW1,462 MW
17 Sept, 06:001,463 MW1,551 MW
17 Sept, 07:001,496 MW1,583 MW
17 Sept, 08:001,560 MW1,683 MW
17 Sept, 09:001,678 MW1,800 MW
17 Sept, 10:001,846 MW1,909 MW
17 Sept, 11:001,962 MW2,020 MW
17 Sept, 12:002,018 MW2,120 MW
17 Sept, 13:002,107 MW2,194 MW
17 Sept, 14:002,190 MW2,221 MW
17 Sept, 15:002,235 MW2,264 MW
17 Sept, 16:002,239 MW2,291 MW
17 Sept, 17:002,222 MW2,248 MW
17 Sept, 18:002,151 MW2,195 MW
17 Sept, 19:002,083 MW2,103 MW
17 Sept, 20:002,034 MW2,049 MW
17 Sept, 21:001,914 MW1,966 MW
17 Sept, 22:001,796 MW1,840 MW
17 Sept, 23:001,638 MW1,711 MW
18 Sept, 00:001,520 MW1,583 MW
18 Sept, 01:001,417 MW1,478 MW
18 Sept, 02:001,354 MW1,396 MW
18 Sept, 03:001,335 MW1,351 MW
18 Sept, 04:001,340 MW1,333 MW
18 Sept, 05:001,410 MW1,398 MW
18 Sept, 06:001,492 MW1,493 MW
18 Sept, 07:001,530 MW1,528 MW
18 Sept, 08:001,548 MW1,641 MW
18 Sept, 09:001,663 MW1,775 MW
18 Sept, 10:001,797 MW1,925 MW
18 Sept, 11:001,884 MW2,031 MW
18 Sept, 12:001,959 MW2,153 MW
18 Sept, 13:002,011 MW2,225 MW
18 Sept, 14:002,069 MW2,303 MW
18 Sept, 15:002,142 MW2,326 MW
18 Sept, 16:002,195 MW2,353 MW
18 Sept, 17:002,215 MW2,279 MW
18 Sept, 18:002,161 MW2,215 MW
18 Sept, 19:002,052 MW2,122 MW
18 Sept, 20:001,961 MW2,050 MW
18 Sept, 21:001,850 MW1,962 MW
18 Sept, 22:001,722 MW1,835 MW
18 Sept, 23:001,607 MW1,720 MW
19 Sept, 00:001,484 MW1,598 MW
19 Sept, 01:001,407 MW1,490 MW
19 Sept, 02:001,327 MW1,408 MW
19 Sept, 03:001,288 MW1,354 MW
19 Sept, 04:001,281 MW1,321 MW
19 Sept, 05:001,287 MW1,313 MW
19 Sept, 06:001,280 MW1,341 MW
19 Sept, 07:001,311 MW1,398 MW
19 Sept, 08:001,457 MW1,552 MW
19 Sept, 09:001,633 MW1,702 MW
19 Sept, 10:001,812 MW1,847 MW
19 Sept, 11:001,993 MW1,978 MW
19 Sept, 12:002,141 MW2,095 MW
19 Sept, 13:002,253 MW2,163 MW
19 Sept, 14:002,343 MW2,230 MW
19 Sept, 15:002,395 MW2,268 MW
19 Sept, 16:002,410 MW2,276 MW
19 Sept, 17:002,387 MW2,234 MW
19 Sept, 18:002,276 MW2,164 MW
19 Sept, 19:002,182 MW2,066 MW
19 Sept, 20:002,102 MW2,010 MW
19 Sept, 21:001,973 MW1,919 MW
19 Sept, 22:001,855 MW1,824 MW
19 Sept, 23:001,709 MW1,717 MW
20 Sept, 00:001,595 MW1,616 MW
20 Sept, 01:001,495 MW1,505 MW
20 Sept, 02:001,422 MW1,422 MW
20 Sept, 03:001,377 MW1,361 MW
20 Sept, 04:001,353 MW1,326 MW
20 Sept, 05:001,314 MW1,285 MW
20 Sept, 06:001,326 MW1,286 MW
20 Sept, 07:001,359 MW1,330 MW
20 Sept, 08:001,447 MW1,499 MW
20 Sept, 09:001,553 MW1,629 MW
20 Sept, 10:001,647 MW1,739 MW
20 Sept, 11:001,733 MW1,845 MW
20 Sept, 12:001,850 MW1,953 MW
20 Sept, 13:001,924 MW2,001 MW
20 Sept, 14:001,963 MW2,035 MW
20 Sept, 15:001,993 MW2,057 MW
20 Sept, 16:002,021 MW2,073 MW
20 Sept, 17:002,034 MW2,034 MW
20 Sept, 18:001,986 MW1,986 MW
20 Sept, 19:001,925 MW1,925 MW
20 Sept, 20:001,881 MW1,881 MW
20 Sept, 21:001,804 MW1,804 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.