SEC Demand Forecast Accuracy: Error, Bias and Worst Miss, 28 September to 28 October 2026

The day-ahead demand forecast for SEC was off by 25.4% on average (mean absolute percentage error) over 695 hours from 28 September to 28 October 2026, and 12% of hours landed within 5% of the reading. Its bias was -21.2%: it ran low on average, an under forecast. The largest miss was 179 MW (37.1%) too low at 12 Oct 2026, 16:00 EDT (UTC-04:00). Dates and times are local (America/New_York).

Key Facts

The day-ahead demand forecast for SEC was off by 25.4% on average (mean absolute percentage error) over 695 hours from 28 September to 28 October 2026, and 12% of hours landed within 5% of the reading. Its bias was -21.2%: it ran low on average, an under forecast. The largest miss was 179 MW (37.1%) too low at 12 Oct 2026, 16:00 EDT (UTC-04:00).
Across 53 US grids ranked by average error over their own latest 30 day windows, SEC came 50 (1 is the smallest error).
On average the forecast differed from reported demand by 70 MW, against average demand of 268 MW.
The forecast was above reported demand in 10% of compared hours.

Forecast Error at a Glance

695 hours from 28 September to 28 October 2026

Average error25.4%

Bias-21.2%

Hours within 5%12%

Worst miss179 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (-61 MW per hour on average): the forecast ran low on average, an under forecast. The worst miss was 179 MW (37.1%) too low at 12 Oct 2026, 16:00 EDT (UTC-04:00): forecast 303 MW, reported 482 MW.

Source: U.S. Energy Information Administration (EIA). (US Government work, public domain) Data as of 2026-10-28. 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 28 Oct 2026, 07:00 EDT (UTC-04:00)

Hourly reported demand and the day-ahead forecast for SEC over the last 7 days of the window, to 28 Oct 2026, 07:00 EDT (UTC-04:00). Gaps are hours with a missing, zero or implausible report.

Data to 2026-10-28

Show the data table (168 rows)

Local hour	Reported demand	Day-ahead forecast
21 Oct, 08:00	234 MW	168 MW
21 Oct, 09:00	236 MW	161 MW
21 Oct, 10:00	239 MW	159 MW
21 Oct, 11:00	250 MW	163 MW
21 Oct, 12:00	266 MW	174 MW
21 Oct, 13:00	284 MW	187 MW
21 Oct, 14:00	300 MW	195 MW
21 Oct, 15:00	321 MW	210 MW
21 Oct, 16:00	338 MW	221 MW
21 Oct, 17:00	339 MW	234 MW
21 Oct, 18:00	328 MW	229 MW
21 Oct, 19:00	322 MW	221 MW
21 Oct, 20:00	317 MW	210 MW
21 Oct, 21:00	275 MW	193 MW
21 Oct, 22:00	231 MW	171 MW
21 Oct, 23:00	205 MW	149 MW
22 Oct, 00:00	183 MW	131 MW
22 Oct, 01:00	175 MW	123 MW
22 Oct, 02:00	165 MW	118 MW
22 Oct, 03:00	164 MW	118 MW
22 Oct, 04:00	173 MW	123 MW
22 Oct, 05:00	193 MW	138 MW
22 Oct, 06:00	218 MW	159 MW
22 Oct, 07:00	227 MW	169 MW
22 Oct, 08:00	241 MW	168 MW
22 Oct, 09:00	238 MW	164 MW
22 Oct, 10:00	241 MW	162 MW
22 Oct, 11:00	243 MW	167 MW
22 Oct, 12:00	256 MW	174 MW
22 Oct, 13:00	271 MW	183 MW
22 Oct, 14:00	285 MW	193 MW
22 Oct, 15:00	304 MW	206 MW
22 Oct, 16:00	322 MW	219 MW
22 Oct, 17:00	327 MW	227 MW
22 Oct, 18:00	311 MW	224 MW
22 Oct, 19:00	309 MW	218 MW
22 Oct, 20:00	289 MW	208 MW
22 Oct, 21:00	266 MW	192 MW
22 Oct, 22:00	232 MW	169 MW
22 Oct, 23:00	204 MW	148 MW
23 Oct, 00:00	185 MW	131 MW
23 Oct, 01:00	173 MW	123 MW
23 Oct, 02:00	166 MW	118 MW
23 Oct, 03:00	167 MW	118 MW
23 Oct, 04:00	174 MW	123 MW
23 Oct, 05:00	194 MW	137 MW
23 Oct, 06:00	220 MW	156 MW
23 Oct, 07:00	235 MW	167 MW
23 Oct, 08:00	246 MW	167 MW
23 Oct, 09:00	247 MW	164 MW
23 Oct, 10:00	251 MW	162 MW
23 Oct, 11:00	255 MW	166 MW
23 Oct, 12:00	264 MW	174 MW
23 Oct, 13:00	273 MW	181 MW
23 Oct, 14:00	285 MW	190 MW
23 Oct, 15:00	298 MW	200 MW
23 Oct, 16:00	305 MW	209 MW
23 Oct, 17:00	306 MW	216 MW
23 Oct, 18:00	286 MW	212 MW
23 Oct, 19:00	279 MW	206 MW
23 Oct, 20:00	267 MW	196 MW
23 Oct, 21:00	252 MW	184 MW
23 Oct, 22:00	228 MW	166 MW
23 Oct, 23:00	207 MW	149 MW
24 Oct, 00:00	187 MW	136 MW
24 Oct, 01:00	173 MW	127 MW
24 Oct, 02:00	165 MW	122 MW
24 Oct, 03:00	160 MW	120 MW
24 Oct, 04:00	160 MW	121 MW
24 Oct, 05:00	168 MW	125 MW
24 Oct, 06:00	181 MW	135 MW
24 Oct, 07:00	197 MW	148 MW
24 Oct, 08:00	218 MW	162 MW
24 Oct, 09:00	236 MW	166 MW
24 Oct, 10:00	226 MW	168 MW
24 Oct, 11:00	212 MW	172 MW
24 Oct, 12:00	264 MW	177 MW
24 Oct, 13:00	253 MW	184 MW
24 Oct, 14:00	273 MW	188 MW
24 Oct, 15:00	278 MW	197 MW
24 Oct, 16:00	282 MW	205 MW
24 Oct, 17:00	280 MW	211 MW
24 Oct, 18:00	269 MW	208 MW
24 Oct, 19:00	271 MW	203 MW
24 Oct, 20:00	266 MW	195 MW
24 Oct, 21:00	254 MW	183 MW
24 Oct, 22:00	237 MW	168 MW
24 Oct, 23:00	219 MW	152 MW
25 Oct, 00:00	204 MW	141 MW
25 Oct, 01:00	185 MW	130 MW
25 Oct, 02:00	179 MW	122 MW
25 Oct, 03:00	176 MW	119 MW
25 Oct, 04:00	174 MW	118 MW
25 Oct, 05:00	177 MW	120 MW
25 Oct, 06:00	186 MW	126 MW
25 Oct, 07:00	199 MW	138 MW
25 Oct, 08:00	222 MW	157 MW
25 Oct, 09:00	245 MW	171 MW
25 Oct, 10:00	267 MW	179 MW
25 Oct, 11:00	278 MW	188 MW
25 Oct, 12:00	286 MW	197 MW
25 Oct, 13:00	294 MW	204 MW
25 Oct, 14:00	297 MW	209 MW
25 Oct, 15:00	291 MW	213 MW
25 Oct, 16:00	300 MW	217 MW
25 Oct, 17:00	296 MW	220 MW
25 Oct, 18:00	296 MW	221 MW
25 Oct, 19:00	300 MW	218 MW
25 Oct, 20:00	288 MW	210 MW
25 Oct, 21:00	269 MW	196 MW
25 Oct, 22:00	244 MW	175 MW
25 Oct, 23:00	218 MW	154 MW
26 Oct, 00:00	201 MW	138 MW
26 Oct, 01:00	184 MW	128 MW
26 Oct, 02:00	177 MW	123 MW
26 Oct, 03:00	178 MW	120 MW
26 Oct, 04:00	187 MW	124 MW
26 Oct, 05:00	200 MW	135 MW
26 Oct, 06:00	226 MW	151 MW
26 Oct, 07:00	240 MW	159 MW
26 Oct, 08:00	248 MW	162 MW
26 Oct, 09:00	263 MW	168 MW
26 Oct, 10:00	275 MW	175 MW
26 Oct, 11:00	287 MW	182 MW
26 Oct, 12:00	297 MW	189 MW
26 Oct, 13:00	307 MW	195 MW
26 Oct, 14:00	312 MW	200 MW
26 Oct, 15:00	321 MW	208 MW
26 Oct, 16:00	332 MW	218 MW
26 Oct, 17:00	328 MW	228 MW
26 Oct, 18:00	327 MW	228 MW
26 Oct, 19:00	327 MW	224 MW
26 Oct, 20:00	311 MW	215 MW
26 Oct, 21:00	284 MW	198 MW
26 Oct, 22:00	253 MW	175 MW
26 Oct, 23:00	221 MW	154 MW
27 Oct, 00:00	196 MW	136 MW
27 Oct, 01:00	188 MW	125 MW
27 Oct, 02:00	178 MW	120 MW
27 Oct, 03:00	172 MW	117 MW
27 Oct, 04:00	178 MW	120 MW
27 Oct, 05:00	200 MW	131 MW
27 Oct, 06:00	222 MW	147 MW
27 Oct, 07:00	237 MW	155 MW
27 Oct, 08:00	244 MW	158 MW
27 Oct, 09:00	253 MW	164 MW
27 Oct, 10:00	266 MW	172 MW
27 Oct, 11:00	273 MW	181 MW
27 Oct, 12:00	289 MW	192 MW
27 Oct, 13:00	306 MW	202 MW
27 Oct, 14:00	313 MW	210 MW
27 Oct, 15:00	329 MW	219 MW
27 Oct, 16:00	338 MW	235 MW
27 Oct, 17:00	340 MW	241 MW
27 Oct, 18:00	334 MW	238 MW
27 Oct, 19:00	331 MW	234 MW
27 Oct, 20:00	314 MW	223 MW
27 Oct, 21:00	283 MW	205 MW
27 Oct, 22:00	248 MW	181 MW
27 Oct, 23:00	224 MW	158 MW
28 Oct, 00:00	184 MW	140 MW
28 Oct, 01:00	173 MW	129 MW
28 Oct, 02:00	169 MW	123 MW
28 Oct, 03:00	167 MW	121 MW
28 Oct, 04:00	172 MW	125 MW
28 Oct, 05:00	185 MW	136 MW
28 Oct, 06:00	200 MW	152 MW
28 Oct, 07:00	205 MW	159 MW

Assumptions

Only hours with both a forecast and a positive demand reading count (695 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). SEC Demand Forecast Accuracy: Error, Bias and Worst Miss. https://worldpowermonitor.com/forecast-accuracy/sec/

Plain text

World Power Monitor. SEC Demand Forecast Accuracy: Error, Bias and Worst Miss. Data as of 2026-10-28. Data from U.S. Energy Information Administration. https://worldpowermonitor.com/forecast-accuracy/sec/

BibTeX

@misc{wpm_forecast_accuracy_sec_2026,
  title = {{SEC Demand Forecast Accuracy: Error, Bias and Worst Miss}},
  author = {{World Power Monitor}},
  year = {2026},
  note = {Data as of 2026-10-28. Data from U.S. Energy Information Administration.},
  url = {https://worldpowermonitor.com/forecast-accuracy/sec/}
}

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

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SEC Demand Forecast Accuracy: Error, Bias and Worst Miss, 28 September to 28 October 2026

Key Facts

Forecast Error at a Glance

Forecast and Reported Demand, Last 7 Days

Assumptions

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