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

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

The day-ahead demand forecast for SCEG was off by 5.4% on average (mean absolute percentage error) over 719 hours from 21 August to 20 September 2026, and 53% of hours landed within 5% of the reading. Its bias was -4.7%: it ran low on average, an under forecast. The largest miss was 586 MW (16.3%) too low at 16 Sept 2026, 10:00 EDT (UTC-04:00). Dates and times are local (America/New_York).

Key Facts

  • The day-ahead demand forecast for SCEG was off by 5.4% on average (mean absolute percentage error) over 719 hours from 21 August to 20 September 2026, and 53% of hours landed within 5% of the reading. Its bias was -4.7%: it ran low on average, an under forecast. The largest miss was 586 MW (16.3%) too low at 16 Sept 2026, 10:00 EDT (UTC-04:00).
  • Across 53 US grids ranked by average error over their own latest 30 day windows, SCEG came 34 (1 is the smallest error).
  • On average the forecast differed from reported demand by 182 MW, against average demand of 3,433 MW.
  • The forecast was above reported demand in 18% of compared hours.

Forecast Error at a Glance

719 hours from 21 August to 20 September 2026
Average error5.4%
Bias-4.7%
Hours within 5%53%
Worst miss586 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (-158 MW per hour on average): the forecast ran low on average, an under forecast. The worst miss was 586 MW (16.3%) too low at 16 Sept 2026, 10:00 EDT (UTC-04:00): forecast 3,019 MW, reported 3,605 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)
SCEG day-ahead demand forecast and reported demand by hour Hourly reported demand and the day-ahead forecast for SCEG 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 1,250 2,500 3,750 5,000 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 SCEG 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
SCEG day-ahead demand forecast and reported demand by hour
Local hourReported demandDay-ahead forecast
13 Sept, 22:003,464 MW3,358 MW
13 Sept, 23:003,211 MW3,110 MW
14 Sept, 00:002,998 MW2,999 MW
14 Sept, 01:002,833 MW2,855 MW
14 Sept, 02:002,740 MW2,743 MW
14 Sept, 03:002,668 MW2,668 MW
14 Sept, 04:002,618 MW2,644 MW
14 Sept, 05:002,670 MW2,709 MW
14 Sept, 06:002,850 MW2,879 MW
14 Sept, 07:002,979 MW2,975 MW
14 Sept, 08:003,272 MW3,100 MW
14 Sept, 09:003,581 MW3,339 MW
14 Sept, 10:003,889 MW3,595 MW
14 Sept, 11:004,124 MW3,849 MW
14 Sept, 12:004,239 MW4,109 MW
14 Sept, 13:004,409 MW4,317 MW
14 Sept, 14:004,488 MW4,455 MW
14 Sept, 15:004,574 MW4,561 MW
14 Sept, 16:004,639 MW4,620 MW
14 Sept, 17:004,631 MW4,607 MW
14 Sept, 18:004,535 MW4,374 MW
14 Sept, 19:004,333 MW4,217 MW
14 Sept, 20:004,176 MW4,054 MW
14 Sept, 21:003,898 MW3,806 MW
14 Sept, 22:003,596 MW3,537 MW
14 Sept, 23:003,329 MW3,281 MW
15 Sept, 00:003,108 MW3,124 MW
15 Sept, 01:002,967 MW2,942 MW
15 Sept, 02:002,842 MW2,837 MW
15 Sept, 03:002,792 MW2,762 MW
15 Sept, 04:002,777 MW2,715 MW
15 Sept, 05:002,859 MW2,758 MW
15 Sept, 06:003,017 MW2,923 MW
15 Sept, 07:003,031 MW2,954 MW
15 Sept, 08:003,111 MW3,024 MW
15 Sept, 09:003,325 MW3,156 MW
15 Sept, 10:003,538 MW3,308 MW
15 Sept, 11:003,658 MW3,489 MW
15 Sept, 12:003,723 MW3,693 MW
15 Sept, 13:003,841 MW3,878 MW
15 Sept, 14:003,961 MW3,974 MW
15 Sept, 15:004,027 MW4,065 MW
15 Sept, 16:004,054 MW4,125 MW
15 Sept, 17:004,025 MW4,085 MW
15 Sept, 18:003,914 MW3,952 MW
15 Sept, 19:003,739 MW3,781 MW
15 Sept, 20:003,625 MW3,650 MW
15 Sept, 21:003,359 MW3,424 MW
15 Sept, 22:003,103 MW3,177 MW
15 Sept, 23:002,859 MW2,953 MW
16 Sept, 00:002,666 MW2,719 MW
16 Sept, 01:002,637 MW2,560 MW
16 Sept, 02:002,520 MW2,431 MW
16 Sept, 03:002,440 MW2,371 MW
16 Sept, 04:002,521 MW2,345 MW
16 Sept, 05:002,530 MW2,414 MW
16 Sept, 06:002,700 MW2,570 MW
16 Sept, 07:002,839 MW2,619 MW
16 Sept, 08:003,040 MW2,694 MW
16 Sept, 09:003,311 MW2,845 MW
16 Sept, 10:003,605 MW3,019 MW
16 Sept, 11:003,738 MW3,219 MW
16 Sept, 12:003,755 MW3,435 MW
16 Sept, 13:003,925 MW3,652 MW
16 Sept, 14:003,949 MW3,792 MW
16 Sept, 15:003,961 MW3,917 MW
16 Sept, 16:004,141 MW3,975 MW
16 Sept, 17:004,044 MW3,959 MW
16 Sept, 18:003,904 MW3,819 MW
16 Sept, 19:003,717 MW3,609 MW
16 Sept, 20:003,544 MW3,478 MW
16 Sept, 21:003,312 MW3,250 MW
16 Sept, 22:003,036 MW3,021 MW
16 Sept, 23:002,764 MW2,789 MW
17 Sept, 00:002,550 MW2,488 MW
17 Sept, 01:002,401 MW2,362 MW
17 Sept, 02:002,339 MW2,242 MW
17 Sept, 03:002,304 MW2,187 MW
17 Sept, 04:002,302 MW2,181 MW
17 Sept, 05:002,371 MW2,257 MW
17 Sept, 06:002,550 MW2,429 MW
17 Sept, 07:002,612 MW2,505 MW
17 Sept, 08:002,766 MW2,610 MW
17 Sept, 09:003,181 MW2,768 MW
17 Sept, 10:003,476 MW2,961 MW
17 Sept, 11:003,571 MW3,172 MW
17 Sept, 12:003,567 MW3,402 MW
17 Sept, 13:003,723 MW3,627 MW
17 Sept, 14:003,867 MW3,822 MW
17 Sept, 15:004,024 MW3,954 MW
17 Sept, 16:004,109 MW4,000 MW
17 Sept, 17:004,142 MW3,970 MW
17 Sept, 18:004,042 MW3,860 MW
17 Sept, 19:003,866 MW3,687 MW
17 Sept, 20:003,674 MW3,522 MW
17 Sept, 21:003,431 MW3,320 MW
17 Sept, 22:003,159 MW3,081 MW
17 Sept, 23:002,880 MW2,843 MW
18 Sept, 00:002,669 MW2,533 MW
18 Sept, 01:002,685 MW2,386 MW
18 Sept, 02:002,680 MW2,304 MW
18 Sept, 03:002,702 MW2,201 MW
18 Sept, 04:002,666 MW2,209 MW
18 Sept, 05:002,768 MW2,278 MW
18 Sept, 06:002,855 MW2,454 MW
18 Sept, 07:002,805 MW2,515 MW
18 Sept, 08:003,024 MW2,611 MW
18 Sept, 09:003,226 MW2,806 MW
18 Sept, 10:003,356 MW3,046 MW
18 Sept, 11:003,361 MW3,269 MW
18 Sept, 12:003,564 MW3,690 MW
18 Sept, 13:003,822 MW3,935 MW
18 Sept, 14:004,034 MW4,114 MW
18 Sept, 15:004,177 MW4,226 MW
18 Sept, 16:004,260 MW4,300 MW
18 Sept, 17:004,215 MW4,244 MW
18 Sept, 18:004,076 MW4,115 MW
18 Sept, 19:003,935 MW3,878 MW
18 Sept, 20:003,768 MW3,693 MW
18 Sept, 21:003,542 MW3,488 MW
18 Sept, 22:003,308 MW3,252 MW
18 Sept, 23:003,073 MW3,031 MW
19 Sept, 00:002,874 MW2,899 MW
19 Sept, 01:002,709 MW2,742 MW
19 Sept, 02:002,663 MW2,620 MW
19 Sept, 03:002,653 MW2,540 MW
19 Sept, 04:002,658 MW2,492 MW
19 Sept, 05:002,607 MW2,487 MW
19 Sept, 06:002,655 MW2,520 MW
19 Sept, 07:002,705 MW2,540 MW
19 Sept, 08:002,879 MW2,702 MW
19 Sept, 09:003,138 MW2,934 MW
19 Sept, 10:003,376 MW3,181 MW
19 Sept, 11:003,617 MW3,432 MW
19 Sept, 12:003,836 MW3,695 MW
19 Sept, 13:004,052 MW3,848 MW
19 Sept, 14:004,132 MW3,968 MW
19 Sept, 15:004,093 MW4,040 MW
19 Sept, 16:004,072 MW4,075 MW
19 Sept, 17:003,816 MW4,018 MW
19 Sept, 18:003,661 MW3,875 MW
19 Sept, 19:003,540 MW3,717 MW
19 Sept, 20:003,425 MW3,579 MW
19 Sept, 21:003,296 MW3,393 MW
19 Sept, 22:003,124 MW3,220 MW
19 Sept, 23:002,936 MW2,986 MW
20 Sept, 00:002,738 MW2,800 MW
20 Sept, 01:002,590 MW2,669 MW
20 Sept, 02:002,487 MW2,562 MW
20 Sept, 03:002,438 MW2,473 MW
20 Sept, 04:002,387 MW2,421 MW
20 Sept, 05:002,379 MW2,399 MW
20 Sept, 06:002,397 MW2,430 MW
20 Sept, 07:002,457 MW2,445 MW
20 Sept, 08:002,600 MW2,591 MW
20 Sept, 09:002,803 MW2,804 MW
20 Sept, 10:002,994 MW3,040 MW
20 Sept, 11:003,238 MW3,254 MW
20 Sept, 12:003,450 MW3,502 MW
20 Sept, 13:003,645 MW3,646 MW
20 Sept, 14:003,759 MW3,766 MW
20 Sept, 15:003,849 MW3,895 MW
20 Sept, 16:003,925 MW3,950 MW
20 Sept, 17:003,909 MW3,917 MW
20 Sept, 18:003,834 MW3,842 MW
20 Sept, 19:003,710 MW3,707 MW
20 Sept, 20:003,588 MW3,589 MW
20 Sept, 21:003,408 MW3,404 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.