GCPD Demand Forecast Accuracy: Error, Bias and Worst Miss, 13 October to 12 November 2026

The day-ahead demand forecast for GCPD was off by 1.8% on average (mean absolute percentage error) over 719 hours from 13 October to 12 November 2026, and 98% of hours landed within 5% of the reading. Its bias was -1.3%: it ran low on average, an under forecast. The largest miss was 76 MW (13.3%) too high at 7 Nov 2026, 13:00 PST (UTC-08:00). Dates and times are local (America/Los_Angeles).

Key Facts

The day-ahead demand forecast for GCPD was off by 1.8% on average (mean absolute percentage error) over 719 hours from 13 October to 12 November 2026, and 98% of hours landed within 5% of the reading. Its bias was -1.3%: it ran low on average, an under forecast. The largest miss was 76 MW (13.3%) too high at 7 Nov 2026, 13:00 PST (UTC-08:00).
Across 53 US grids ranked by average error over their own latest 30 day windows, GCPD came 5 (1 is the smallest error).
On average the forecast differed from reported demand by 13 MW, against average demand of 703 MW.
The forecast was above reported demand in 21% of compared hours.

Forecast Error at a Glance

719 hours from 13 October to 12 November 2026

Average error1.8%

Bias-1.3%

Hours within 5%98%

Worst miss76 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (-9 MW per hour on average): the forecast ran low on average, an under forecast. The worst miss was 76 MW (13.3%) too high at 7 Nov 2026, 13:00 PST (UTC-08:00): forecast 649 MW, reported 573 MW.

Source: U.S. Energy Information Administration (EIA). (US Government work, public domain) Data as of 2026-11-12. 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 12 Nov 2026, 04:00 PST (UTC-08:00)

Hourly reported demand and the day-ahead forecast for GCPD over the last 7 days of the window, to 12 Nov 2026, 04:00 PST (UTC-08:00). Gaps are hours with a missing, zero or implausible report.

Data to 2026-11-12

Show the data table (168 rows)

Local hour	Reported demand	Day-ahead forecast
5 Nov, 05:00	713 MW	717 MW
5 Nov, 06:00	738 MW	734 MW
5 Nov, 07:00	739 MW	736 MW
5 Nov, 08:00	739 MW	733 MW
5 Nov, 09:00	734 MW	724 MW
5 Nov, 10:00	731 MW	717 MW
5 Nov, 11:00	719 MW	708 MW
5 Nov, 12:00	711 MW	694 MW
5 Nov, 13:00	705 MW	691 MW
5 Nov, 14:00	696 MW	686 MW
5 Nov, 15:00	702 MW	687 MW
5 Nov, 16:00	716 MW	699 MW
5 Nov, 17:00	732 MW	712 MW
5 Nov, 18:00	734 MW	716 MW
5 Nov, 19:00	732 MW	717 MW
5 Nov, 20:00	731 MW	717 MW
5 Nov, 21:00	720 MW	709 MW
5 Nov, 22:00	706 MW	700 MW
5 Nov, 23:00	697 MW	691 MW
6 Nov, 00:00	698 MW	696 MW
6 Nov, 01:00	694 MW	693 MW
6 Nov, 02:00	695 MW	695 MW
6 Nov, 03:00	699 MW	701 MW
6 Nov, 04:00	705 MW	719 MW
6 Nov, 05:00	723 MW	742 MW
6 Nov, 06:00	735 MW	759 MW
6 Nov, 07:00	735 MW	761 MW
6 Nov, 08:00	735 MW	757 MW
6 Nov, 09:00	733 MW	746 MW
6 Nov, 10:00	717 MW	731 MW
6 Nov, 11:00	714 MW	717 MW
6 Nov, 12:00	705 MW	706 MW
6 Nov, 13:00	700 MW	696 MW
6 Nov, 14:00	697 MW	685 MW
6 Nov, 15:00	696 MW	684 MW
6 Nov, 16:00	703 MW	694 MW
6 Nov, 17:00	706 MW	705 MW
6 Nov, 18:00	703 MW	704 MW
6 Nov, 19:00	698 MW	697 MW
6 Nov, 20:00	688 MW	690 MW
6 Nov, 21:00	683 MW	679 MW
6 Nov, 22:00	669 MW	671 MW
6 Nov, 23:00	662 MW	665 MW
7 Nov, 00:00	659 MW	663 MW
7 Nov, 01:00	659 MW	660 MW
7 Nov, 02:00	662 MW	660 MW
7 Nov, 03:00	665 MW	664 MW
7 Nov, 04:00	673 MW	670 MW
7 Nov, 05:00	686 MW	682 MW
7 Nov, 06:00	698 MW	692 MW
7 Nov, 07:00	705 MW	701 MW
7 Nov, 08:00	706 MW	699 MW
7 Nov, 09:00	696 MW	694 MW
7 Nov, 10:00	683 MW	682 MW
7 Nov, 11:00	671 MW	671 MW
7 Nov, 12:00	662 MW	657 MW
7 Nov, 13:00	573 MW	649 MW
7 Nov, 14:00	613 MW	641 MW
7 Nov, 15:00	650 MW	642 MW
7 Nov, 16:00	663 MW	652 MW
7 Nov, 17:00	675 MW	662 MW
7 Nov, 18:00	673 MW	664 MW
7 Nov, 19:00	672 MW	663 MW
7 Nov, 20:00	670 MW	658 MW
7 Nov, 21:00	666 MW	654 MW
7 Nov, 22:00	663 MW	649 MW
7 Nov, 23:00	660 MW	643 MW
8 Nov, 00:00	655 MW	653 MW
8 Nov, 01:00	651 MW	649 MW
8 Nov, 02:00	648 MW	646 MW
8 Nov, 03:00	644 MW	642 MW
8 Nov, 04:00	645 MW	646 MW
8 Nov, 05:00	653 MW	659 MW
8 Nov, 06:00	659 MW	666 MW
8 Nov, 07:00	666 MW	672 MW
8 Nov, 08:00	680 MW	678 MW
8 Nov, 09:00	678 MW	675 MW
8 Nov, 10:00	670 MW	668 MW
8 Nov, 11:00	665 MW	659 MW
8 Nov, 12:00	656 MW	650 MW
8 Nov, 13:00	650 MW	643 MW
8 Nov, 14:00	647 MW	630 MW
8 Nov, 15:00	649 MW	643 MW
8 Nov, 16:00	660 MW	656 MW
8 Nov, 17:00	675 MW	667 MW
8 Nov, 18:00	675 MW	668 MW
8 Nov, 19:00	675 MW	668 MW
8 Nov, 20:00	674 MW	665 MW
8 Nov, 21:00	673 MW	661 MW
8 Nov, 22:00	665 MW	654 MW
8 Nov, 23:00	656 MW	649 MW
9 Nov, 00:00	651 MW	653 MW
9 Nov, 01:00	653 MW	652 MW
9 Nov, 02:00	660 MW	657 MW
9 Nov, 03:00	669 MW	661 MW
9 Nov, 04:00	674 MW	667 MW
9 Nov, 05:00	693 MW	686 MW
9 Nov, 06:00	712 MW	706 MW
9 Nov, 07:00	717 MW	715 MW
9 Nov, 08:00	720 MW	719 MW
9 Nov, 09:00	709 MW	716 MW
9 Nov, 10:00	692 MW	708 MW
9 Nov, 11:00	681 MW	703 MW
9 Nov, 12:00	675 MW	693 MW
9 Nov, 13:00	677 MW	688 MW
9 Nov, 14:00	683 MW	683 MW
9 Nov, 15:00	689 MW	693 MW
9 Nov, 16:00	696 MW	705 MW
9 Nov, 17:00	702 MW	709 MW
9 Nov, 18:00	701 MW	706 MW
9 Nov, 19:00	694 MW	700 MW
9 Nov, 20:00	692 MW	693 MW
9 Nov, 21:00	686 MW	683 MW
9 Nov, 22:00	675 MW	672 MW
9 Nov, 23:00	670 MW	666 MW
10 Nov, 00:00	667 MW	666 MW
10 Nov, 01:00	665 MW	670 MW
10 Nov, 02:00	672 MW	680 MW
10 Nov, 03:00	678 MW	688 MW
10 Nov, 04:00	689 MW	693 MW
10 Nov, 05:00	707 MW	709 MW
10 Nov, 06:00	725 MW	722 MW
10 Nov, 07:00	713 MW	726 MW
10 Nov, 08:00	713 MW	728 MW
10 Nov, 09:00	706 MW	724 MW
10 Nov, 10:00	720 MW	715 MW
10 Nov, 11:00	717 MW	710 MW
10 Nov, 12:00	714 MW	701 MW
10 Nov, 13:00	717 MW	697 MW
10 Nov, 14:00	710 MW	693 MW
10 Nov, 15:00	716 MW	699 MW
10 Nov, 16:00	720 MW	705 MW
10 Nov, 17:00	722 MW	704 MW
10 Nov, 18:00	716 MW	700 MW
10 Nov, 19:00	708 MW	692 MW
10 Nov, 20:00	697 MW	685 MW
10 Nov, 21:00	689 MW	678 MW
10 Nov, 22:00	677 MW	668 MW
10 Nov, 23:00	666 MW	662 MW
11 Nov, 00:00	663 MW	658 MW
11 Nov, 01:00	657 MW	651 MW
11 Nov, 02:00	653 MW	650 MW
11 Nov, 03:00	644 MW	655 MW
11 Nov, 04:00	646 MW	666 MW
11 Nov, 05:00	664 MW	677 MW
11 Nov, 06:00	675 MW	689 MW
11 Nov, 07:00	679 MW	694 MW
11 Nov, 08:00	690 MW	700 MW
11 Nov, 09:00	691 MW	700 MW
11 Nov, 10:00	687 MW	698 MW
11 Nov, 11:00	679 MW	691 MW
11 Nov, 12:00	676 MW	679 MW
11 Nov, 13:00	668 MW	674 MW
11 Nov, 14:00	663 MW	668 MW
11 Nov, 15:00	671 MW	673 MW
11 Nov, 16:00	682 MW	680 MW
11 Nov, 17:00	689 MW	693 MW
11 Nov, 18:00	686 MW	692 MW
11 Nov, 19:00	682 MW	688 MW
11 Nov, 20:00	677 MW	681 MW
11 Nov, 21:00	673 MW	674 MW
11 Nov, 22:00	659 MW	665 MW
11 Nov, 23:00	648 MW	657 MW
12 Nov, 00:00	645 MW	652 MW
12 Nov, 01:00	640 MW	653 MW
12 Nov, 02:00	641 MW	655 MW
12 Nov, 03:00	644 MW	652 MW
12 Nov, 04:00	655 MW	666 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.

Cite this page

APA 7

World Power Monitor. (2026). GCPD Demand Forecast Accuracy: Error, Bias and Worst Miss. https://worldpowermonitor.com/forecast-accuracy/gcpd/

Plain text

World Power Monitor. GCPD Demand Forecast Accuracy: Error, Bias and Worst Miss. Data as of 2026-11-12. Data from U.S. Energy Information Administration. https://worldpowermonitor.com/forecast-accuracy/gcpd/

BibTeX

@misc{wpm_forecast_accuracy_gcpd_2026,
  title = {{GCPD Demand Forecast Accuracy: Error, Bias and Worst Miss}},
  author = {{World Power Monitor}},
  year = {2026},
  note = {Data as of 2026-11-12. Data from U.S. Energy Information Administration.},
  url = {https://worldpowermonitor.com/forecast-accuracy/gcpd/}
}

Permalink: https://worldpowermonitor.com/forecast-accuracy/gcpd/

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GCPD Demand Forecast Accuracy: Error, Bias and Worst Miss, 13 October to 12 November 2026

Key Facts

Forecast Error at a Glance

Forecast and Reported Demand, Last 7 Days

Assumptions

Related