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

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

The day-ahead demand forecast for LDWP was off by 7.4% on average (mean absolute percentage error) over 718 hours from 21 August to 20 September 2026, and 36% of hours landed within 5% of the reading. Its bias was -6.2%: it ran low on average, an under forecast. The largest miss was 1,441 MW (28.0%) too low at 10 Sept 2026, 00:00 PDT (UTC-07:00). Dates and times are local (America/Los_Angeles).

Key Facts

  • The day-ahead demand forecast for LDWP was off by 7.4% on average (mean absolute percentage error) over 718 hours from 21 August to 20 September 2026, and 36% of hours landed within 5% of the reading. Its bias was -6.2%: it ran low on average, an under forecast. The largest miss was 1,441 MW (28.0%) too low at 10 Sept 2026, 00:00 PDT (UTC-07:00).
  • Across 53 US grids ranked by average error over their own latest 30 day windows, LDWP came 38 (1 is the smallest error).
  • On average the forecast differed from reported demand by 276 MW, against average demand of 3,691 MW.
  • The forecast was above reported demand in 8% of compared hours.

Forecast Error at a Glance

718 hours from 21 August to 20 September 2026
Average error7.4%
Bias-6.2%
Hours within 5%36%
Worst miss1,441 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (-236 MW per hour on average): the forecast ran low on average, an under forecast. The worst miss was 1,441 MW (28.0%) too low at 10 Sept 2026, 00:00 PDT (UTC-07:00): forecast 3,699 MW, reported 5,140 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, 17:00 PDT (UTC-07:00)
LDWP day-ahead demand forecast and reported demand by hour Hourly reported demand and the day-ahead forecast for LDWP over the last 7 days of the window, to 20 Sept 2026, 17:00 PDT (UTC-07:00). Gaps are hours with a missing, zero or implausible report. 0 1,250 2,500 3,750 5,000 13 Sept, 18:0014 Sept, 18:0015 Sept, 18:0016 Sept, 18:0017 Sept, 18:0018 Sept, 18:0019 Sept, 18:00
Hourly reported demand and the day-ahead forecast for LDWP over the last 7 days of the window, to 20 Sept 2026, 17:00 PDT (UTC-07:00). Gaps are hours with a missing, zero or implausible report.
Data to 2026-09-20
LDWP day-ahead demand forecast and reported demand by hour
Local hourReported demandDay-ahead forecast
13 Sept, 18:004,125 MW4,054 MW
13 Sept, 19:004,036 MW3,883 MW
13 Sept, 20:003,861 MW3,745 MW
13 Sept, 21:003,636 MW3,546 MW
13 Sept, 22:003,506 MW3,310 MW
13 Sept, 23:003,243 MW3,058 MW
14 Sept, 00:003,096 MW2,814 MW
14 Sept, 01:002,841 MW2,634 MW
14 Sept, 02:002,749 MW2,501 MW
14 Sept, 03:002,704 MW2,423 MW
14 Sept, 04:002,773 MW2,412 MW
14 Sept, 05:002,869 MW2,489 MW
14 Sept, 06:002,963 MW2,642 MW
14 Sept, 07:003,033 MW2,781 MW
14 Sept, 08:003,449 MW2,948 MW
14 Sept, 09:003,489 MW3,085 MW
14 Sept, 10:003,560 MW3,194 MW
14 Sept, 11:003,711 MW3,332 MW
14 Sept, 12:003,945 MW3,515 MW
14 Sept, 13:004,308 MW3,735 MW
14 Sept, 14:004,181 MW3,939 MW
14 Sept, 15:004,255 MW4,123 MW
14 Sept, 16:004,419 MW4,216 MW
14 Sept, 17:004,372 MW4,195 MW
14 Sept, 18:004,272 MW3,978 MW
14 Sept, 19:004,104 MW3,830 MW
14 Sept, 20:003,878 MW3,665 MW
14 Sept, 21:003,642 MW3,469 MW
14 Sept, 22:003,493 MW3,222 MW
14 Sept, 23:003,236 MW2,965 MW
15 Sept, 00:002,926 MW2,733 MW
15 Sept, 01:002,742 MW2,557 MW
15 Sept, 02:002,537 MW2,433 MW
15 Sept, 03:002,413 MW2,354 MW
15 Sept, 04:002,427 MW2,341 MW
15 Sept, 05:002,510 MW2,424 MW
15 Sept, 06:002,715 MW2,587 MW
15 Sept, 07:002,878 MW2,699 MW
15 Sept, 08:003,289 MW2,832 MW
15 Sept, 09:003,370 MW2,914 MW
15 Sept, 10:003,401 MW2,957 MW
15 Sept, 11:003,479 MW3,064 MW
15 Sept, 12:003,583 MW3,179 MW
15 Sept, 13:003,712 MW3,346 MW
15 Sept, 14:003,689 MW3,536 MW
15 Sept, 15:003,874 MW3,711 MW
15 Sept, 16:004,088 MW3,802 MW
15 Sept, 17:004,016 MW3,795 MW
15 Sept, 18:003,769 MW3,601 MW
15 Sept, 19:003,705 MW3,521 MW
15 Sept, 20:003,728 MW3,381 MW
15 Sept, 21:003,562 MW3,211 MW
15 Sept, 22:003,239 MW3,006 MW
15 Sept, 23:002,995 MW2,796 MW
16 Sept, 00:002,832 MW2,614 MW
16 Sept, 01:002,633 MW2,455 MW
16 Sept, 02:002,550 MW2,340 MW
16 Sept, 03:002,518 MW2,271 MW
16 Sept, 04:002,468 MW2,265 MW
16 Sept, 05:002,551 MW2,350 MW
16 Sept, 06:002,696 MW2,516 MW
16 Sept, 07:002,803 MW2,623 MW
16 Sept, 08:002,997 MW2,740 MW
16 Sept, 09:003,118 MW2,803 MW
16 Sept, 10:003,150 MW2,835 MW
16 Sept, 11:003,120 MW2,896 MW
16 Sept, 12:003,177 MW2,974 MW
16 Sept, 13:003,311 MW3,082 MW
16 Sept, 14:003,508 MW3,241 MW
16 Sept, 15:003,674 MW3,371 MW
16 Sept, 16:003,830 MW3,474 MW
16 Sept, 17:003,796 MW3,473 MW
16 Sept, 18:003,566 MW3,320 MW
16 Sept, 19:003,514 MW3,273 MW
16 Sept, 20:003,431 MW3,167 MW
16 Sept, 21:003,278 MW3,034 MW
16 Sept, 22:003,159 MW2,856 MW
16 Sept, 23:002,920 MW2,674 MW
17 Sept, 00:002,712 MW2,593 MW
17 Sept, 01:002,581 MW2,443 MW
17 Sept, 02:002,436 MW2,329 MW
17 Sept, 03:002,347 MW2,258 MW
17 Sept, 04:002,335 MW2,253 MW
17 Sept, 05:002,433 MW2,338 MW
17 Sept, 06:002,600 MW2,507 MW
17 Sept, 07:002,762 MW2,625 MW
17 Sept, 08:002,933 MW2,732 MW
17 Sept, 09:003,080 MW2,793 MW
17 Sept, 10:003,163 MW2,822 MW
17 Sept, 11:003,194 MW2,872 MW
17 Sept, 12:003,191 MW2,950 MW
17 Sept, 13:003,322 MW3,060 MW
17 Sept, 14:003,378 MW3,204 MW
17 Sept, 15:003,429 MW3,346 MW
17 Sept, 16:003,502 MW3,443 MW
17 Sept, 17:003,582 MW3,436 MW
17 Sept, 18:003,515 MW3,291 MW
17 Sept, 19:003,480 MW3,249 MW
17 Sept, 20:003,395 MW3,160 MW
17 Sept, 21:003,298 MW3,024 MW
17 Sept, 22:003,159 MW2,840 MW
17 Sept, 23:002,922 MW2,656 MW
18 Sept, 00:002,648 MW2,517 MW
18 Sept, 01:002,599 MW2,369 MW
18 Sept, 02:002,459 MW2,258 MW
18 Sept, 03:002,351 MW2,187 MW
18 Sept, 04:002,322 MW2,178 MW
18 Sept, 05:002,452 MW2,253 MW
18 Sept, 06:002,482 MW2,404 MW
18 Sept, 07:002,520 MW2,507 MW
18 Sept, 08:002,664 MW2,605 MW
18 Sept, 09:002,677 MW2,662 MW
18 Sept, 10:002,771 MW2,685 MW
18 Sept, 11:002,885 MW2,735 MW
18 Sept, 12:002,949 MW2,819 MW
18 Sept, 13:003,070 MW2,954 MW
18 Sept, 14:003,207 MW3,132 MW
18 Sept, 15:003,346 MW3,302 MW
18 Sept, 16:003,535 MW3,418 MW
18 Sept, 17:003,524 MW3,416 MW
18 Sept, 18:003,398 MW3,262 MW
18 Sept, 19:003,331 MW3,207 MW
18 Sept, 20:003,283 MW3,113 MW
18 Sept, 21:003,197 MW2,984 MW
18 Sept, 22:003,009 MW2,818 MW
18 Sept, 23:002,750 MW2,650 MW
19 Sept, 00:002,600 MW2,504 MW
19 Sept, 01:002,437 MW2,366 MW
19 Sept, 02:002,344 MW2,257 MW
19 Sept, 03:002,294 MW2,179 MW
19 Sept, 04:002,296 MW2,143 MW
19 Sept, 05:002,333 MW2,153 MW
19 Sept, 06:002,315 MW2,196 MW
19 Sept, 07:002,281 MW2,220 MW
19 Sept, 08:002,320 MW2,297 MW
19 Sept, 09:002,384 MW2,360 MW
19 Sept, 10:002,500 MW2,400 MW
19 Sept, 11:002,587 MW2,464 MW
19 Sept, 12:002,667 MW2,574 MW
19 Sept, 13:002,871 MW2,721 MW
19 Sept, 14:003,088 MW2,917 MW
19 Sept, 15:003,302 MW3,116 MW
19 Sept, 16:003,425 MW3,266 MW
19 Sept, 17:003,594 MW3,300 MW
19 Sept, 18:003,532 MW3,208 MW
19 Sept, 19:003,515 MW3,187 MW
19 Sept, 20:003,397 MW3,106 MW
19 Sept, 21:003,210 MW2,987 MW
19 Sept, 22:002,996 MW2,835 MW
19 Sept, 23:002,776 MW2,666 MW
20 Sept, 00:002,645 MW2,501 MW
20 Sept, 01:002,446 MW2,358 MW
20 Sept, 02:002,313 MW2,247 MW
20 Sept, 03:002,246 MW2,169 MW
20 Sept, 04:002,206 MW2,130 MW
20 Sept, 05:002,199 MW2,137 MW
20 Sept, 06:002,214 MW2,180 MW
20 Sept, 07:002,198 MW2,215 MW
20 Sept, 08:002,511 MW2,319 MW
20 Sept, 09:002,509 MW2,419 MW
20 Sept, 10:002,623 MW2,491 MW
20 Sept, 11:002,670 MW2,584 MW
20 Sept, 12:002,782 MW2,708 MW
20 Sept, 13:003,121 MW2,875 MW
20 Sept, 14:003,305 MW3,057 MW
20 Sept, 15:003,060 MW3,211 MW
20 Sept, 16:003,087 MW3,276 MW
20 Sept, 17:003,241 MW3,264 MW

Assumptions

  • Only hours with both a forecast and a positive demand reading count (718 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.