GCPD Demand Forecast Accuracy: Error, Bias and Worst Miss, 6 October to 5 November 2026

The day-ahead demand forecast for GCPD was off by 2.1% on average (mean absolute percentage error) over 719 hours from 6 October to 5 November 2026, and 97% of hours landed within 5% of the reading. Its bias was -1.8%: it ran low on average, an under forecast. The largest miss was 52 MW (6.7%) too low at 21 Oct 2026, 13:00 PDT (UTC-07:00). Dates and times are local (America/Los_Angeles).

Key Facts

The day-ahead demand forecast for GCPD was off by 2.1% on average (mean absolute percentage error) over 719 hours from 6 October to 5 November 2026, and 97% of hours landed within 5% of the reading. Its bias was -1.8%: it ran low on average, an under forecast. The largest miss was 52 MW (6.7%) too low at 21 Oct 2026, 13:00 PDT (UTC-07:00).
Across 53 US grids ranked by average error over their own latest 30 day windows, GCPD came 10 (1 is the smallest error).
On average the forecast differed from reported demand by 15 MW, against average demand of 710 MW.
The forecast was above reported demand in 13% of compared hours.

Forecast Error at a Glance

719 hours from 6 October to 5 November 2026

Average error2.1%

Bias-1.8%

Hours within 5%97%

Worst miss52 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (-13 MW per hour on average): the forecast ran low on average, an under forecast. The worst miss was 52 MW (6.7%) too low at 21 Oct 2026, 13:00 PDT (UTC-07:00): forecast 728 MW, reported 780 MW.

Source: U.S. Energy Information Administration (EIA). (US Government work, public domain) Data as of 2026-11-05. 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 5 Nov 2026, 05:00 PST (UTC-08:00)

Hourly reported demand and the day-ahead forecast for GCPD over the last 7 days of the window, to 5 Nov 2026, 05:00 PST (UTC-08:00). Gaps are hours with a missing, zero or implausible report.

Data to 2026-11-05

Show the data table (168 rows)

Local hour	Reported demand	Day-ahead forecast
29 Oct, 07:00	792 MW	764 MW
29 Oct, 08:00	785 MW	763 MW
29 Oct, 09:00	767 MW	744 MW
29 Oct, 10:00	750 MW	728 MW
29 Oct, 11:00	729 MW	718 MW
29 Oct, 12:00	711 MW	713 MW
29 Oct, 13:00	703 MW	704 MW
29 Oct, 14:00	691 MW	690 MW
29 Oct, 15:00	686 MW	680 MW
29 Oct, 16:00	686 MW	681 MW
29 Oct, 17:00	698 MW	691 MW
29 Oct, 18:00	713 MW	699 MW
29 Oct, 19:00	708 MW	697 MW
29 Oct, 20:00	712 MW	701 MW
29 Oct, 21:00	710 MW	698 MW
29 Oct, 22:00	697 MW	694 MW
29 Oct, 23:00	688 MW	684 MW
30 Oct, 00:00	684 MW	676 MW
30 Oct, 01:00	683 MW	677 MW
30 Oct, 02:00	681 MW	672 MW
30 Oct, 03:00	681 MW	674 MW
30 Oct, 04:00	686 MW	682 MW
30 Oct, 05:00	705 MW	707 MW
30 Oct, 06:00	725 MW	720 MW
30 Oct, 07:00	735 MW	724 MW
30 Oct, 08:00	736 MW	721 MW
30 Oct, 09:00	731 MW	714 MW
30 Oct, 10:00	721 MW	707 MW
30 Oct, 11:00	707 MW	698 MW
30 Oct, 12:00	697 MW	690 MW
30 Oct, 13:00	687 MW	677 MW
30 Oct, 14:00	676 MW	661 MW
30 Oct, 15:00	666 MW	656 MW
30 Oct, 16:00	670 MW	656 MW
30 Oct, 17:00	673 MW	666 MW
30 Oct, 18:00	684 MW	672 MW
30 Oct, 19:00	688 MW	672 MW
30 Oct, 20:00	689 MW	676 MW
30 Oct, 21:00	688 MW	674 MW
30 Oct, 22:00	683 MW	672 MW
30 Oct, 23:00	682 MW	670 MW
31 Oct, 00:00	680 MW	665 MW
31 Oct, 01:00	683 MW	669 MW
31 Oct, 02:00	685 MW	671 MW
31 Oct, 03:00	693 MW	675 MW
31 Oct, 04:00	700 MW	682 MW
31 Oct, 05:00	711 MW	702 MW
31 Oct, 06:00	726 MW	711 MW
31 Oct, 07:00	740 MW	723 MW
31 Oct, 08:00	745 MW	721 MW
31 Oct, 09:00	731 MW	710 MW
31 Oct, 10:00	713 MW	697 MW
31 Oct, 11:00	696 MW	685 MW
31 Oct, 12:00	682 MW	669 MW
31 Oct, 13:00	669 MW	653 MW
31 Oct, 14:00	660 MW	640 MW
31 Oct, 15:00	659 MW	633 MW
31 Oct, 16:00	658 MW	635 MW
31 Oct, 17:00	661 MW	648 MW
31 Oct, 18:00	665 MW	656 MW
31 Oct, 19:00	666 MW	656 MW
31 Oct, 20:00	670 MW	657 MW
31 Oct, 21:00	670 MW	653 MW
31 Oct, 22:00	664 MW	652 MW
31 Oct, 23:00	661 MW	648 MW
1 Nov, 00:00	656 MW	655 MW
1 Nov, 01:00	655 MW	661 MW
1 Nov, 01:00	654 MW	661 MW
1 Nov, 02:00	657 MW	663 MW
1 Nov, 03:00	664 MW	667 MW
1 Nov, 04:00	675 MW	679 MW
1 Nov, 05:00	687 MW	691 MW
1 Nov, 06:00	695 MW	705 MW
1 Nov, 07:00	704 MW	711 MW
1 Nov, 08:00	705 MW	711 MW
1 Nov, 09:00	694 MW	696 MW
1 Nov, 10:00	673 MW	683 MW
1 Nov, 11:00	661 MW	669 MW
1 Nov, 12:00	651 MW	656 MW
1 Nov, 13:00	646 MW	652 MW
1 Nov, 14:00	641 MW	644 MW
1 Nov, 15:00	643 MW	645 MW
1 Nov, 16:00	650 MW	653 MW
1 Nov, 17:00	667 MW	666 MW
1 Nov, 18:00	672 MW	672 MW
1 Nov, 19:00	675 MW	676 MW
1 Nov, 20:00	677 MW	677 MW
1 Nov, 21:00	679 MW	673 MW
1 Nov, 22:00	675 MW	668 MW
1 Nov, 23:00	670 MW	667 MW
2 Nov, 00:00	673 MW	671 MW
2 Nov, 01:00	680 MW	676 MW
2 Nov, 02:00	689 MW	683 MW
2 Nov, 03:00	698 MW	692 MW
2 Nov, 04:00	713 MW	715 MW
2 Nov, 05:00	745 MW	740 MW
2 Nov, 06:00	769 MW	762 MW
2 Nov, 07:00	770 MW	766 MW
2 Nov, 08:00	752 MW	763 MW
2 Nov, 09:00	735 MW	744 MW
2 Nov, 10:00	716 MW	726 MW
2 Nov, 11:00	699 MW	710 MW
2 Nov, 12:00	694 MW	696 MW
2 Nov, 13:00	690 MW	692 MW
2 Nov, 14:00	683 MW	685 MW
2 Nov, 15:00	687 MW	687 MW
2 Nov, 16:00	702 MW	694 MW
2 Nov, 17:00	715 MW	704 MW
2 Nov, 18:00	716 MW	706 MW
2 Nov, 19:00	713 MW	705 MW
2 Nov, 20:00	707 MW	701 MW
2 Nov, 21:00	702 MW	695 MW
2 Nov, 22:00	694 MW	689 MW
2 Nov, 23:00	684 MW	684 MW
3 Nov, 00:00	682 MW	680 MW
3 Nov, 01:00	681 MW	680 MW
3 Nov, 02:00	679 MW	683 MW
3 Nov, 03:00	681 MW	685 MW
3 Nov, 04:00	687 MW	693 MW
3 Nov, 05:00	707 MW	710 MW
3 Nov, 06:00	726 MW	727 MW
3 Nov, 07:00	725 MW	729 MW
3 Nov, 08:00	716 MW	729 MW
3 Nov, 09:00	768 MW	723 MW
3 Nov, 10:00	698 MW	713 MW
3 Nov, 11:00	688 MW	705 MW
3 Nov, 12:00	691 MW	693 MW
3 Nov, 13:00	682 MW	687 MW
3 Nov, 14:00	683 MW	680 MW
3 Nov, 15:00	686 MW	681 MW
3 Nov, 16:00	698 MW	690 MW
3 Nov, 17:00	705 MW	701 MW
3 Nov, 18:00	704 MW	704 MW
3 Nov, 19:00	695 MW	702 MW
3 Nov, 20:00	693 MW	698 MW
3 Nov, 21:00	688 MW	694 MW
3 Nov, 22:00	677 MW	686 MW
3 Nov, 23:00	672 MW	680 MW
4 Nov, 00:00	677 MW	670 MW
4 Nov, 01:00	676 MW	670 MW
4 Nov, 02:00	682 MW	676 MW
4 Nov, 03:00	688 MW	685 MW
4 Nov, 04:00	701 MW	698 MW
4 Nov, 05:00	726 MW	723 MW
4 Nov, 06:00	751 MW	744 MW
4 Nov, 07:00	753 MW	749 MW
4 Nov, 08:00	743 MW	742 MW
4 Nov, 09:00	734 MW	729 MW
4 Nov, 10:00	724 MW	714 MW
4 Nov, 11:00	718 MW	704 MW
4 Nov, 12:00	716 MW	694 MW
4 Nov, 13:00	718 MW	688 MW
4 Nov, 14:00	710 MW	685 MW
4 Nov, 15:00	709 MW	691 MW
4 Nov, 16:00	722 MW	706 MW
4 Nov, 17:00	738 MW	716 MW
4 Nov, 18:00	739 MW	718 MW
4 Nov, 19:00	732 MW	713 MW
4 Nov, 20:00	731 MW	710 MW
4 Nov, 21:00	722 MW	703 MW
4 Nov, 22:00	709 MW	692 MW
4 Nov, 23:00	700 MW	684 MW
5 Nov, 00:00	696 MW	699 MW
5 Nov, 01:00	689 MW	693 MW
5 Nov, 02:00	687 MW	695 MW
5 Nov, 03:00	688 MW	694 MW
5 Nov, 04:00	694 MW	705 MW
5 Nov, 05:00	713 MW	720 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 2026-11-05. 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 2026-11-05. 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, 6 October to 5 November 2026

Key Facts

Forecast Error at a Glance

Forecast and Reported Demand, Last 7 Days

Assumptions

Related