GVL Demand Forecast Accuracy: Error, Bias and Worst Miss, 28 September to 28 October 2026
The day-ahead demand forecast for GVL was off by 11.5% on average (mean absolute percentage error) over 719 hours from 28 September to 28 October 2026, and 23% of hours landed within 5% of the reading. Its bias was -10.7%: it ran low on average, an under forecast. The largest miss was 159 MW (44.4%) too low at 10 Oct 2026, 17:00 EDT (UTC-04:00). Dates and times are local (America/New_York).
Key Facts
- The day-ahead demand forecast for GVL was off by 11.5% on average (mean absolute percentage error) over 719 hours from 28 September to 28 October 2026, and 23% of hours landed within 5% of the reading. Its bias was -10.7%: it ran low on average, an under forecast. The largest miss was 159 MW (44.4%) too low at 10 Oct 2026, 17:00 EDT (UTC-04:00).
- Across 53 US grids ranked by average error over their own latest 30 day windows, GVL came 45 (1 is the smallest error).
- On average the forecast differed from reported demand by 29 MW, against average demand of 239 MW.
- The forecast was above reported demand in 11% of compared hours.
Forecast Error at a Glance
719 hours from 28 September to 28 October 2026Average error11.5%
Bias-10.7%
Hours within 5%23%
Worst miss159 MW
Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (-28 MW per hour on average): the forecast ran low on average, an under forecast. The worst miss was 159 MW (44.4%) too low at 10 Oct 2026, 17:00 EDT (UTC-04:00): forecast 199 MW, reported 358 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)Data to 2026-10-28
Show the data table (168 rows)
| Local hour | Reported demand | Day-ahead forecast |
|---|---|---|
| 21 Oct, 08:00 | 183 MW | 163 MW |
| 21 Oct, 09:00 | 184 MW | 166 MW |
| 21 Oct, 10:00 | 188 MW | 171 MW |
| 21 Oct, 11:00 | 193 MW | 178 MW |
| 21 Oct, 12:00 | 200 MW | 185 MW |
| 21 Oct, 13:00 | 210 MW | 197 MW |
| 21 Oct, 14:00 | 220 MW | 208 MW |
| 21 Oct, 15:00 | 230 MW | 218 MW |
| 21 Oct, 16:00 | 242 MW | 224 MW |
| 21 Oct, 17:00 | 248 MW | 227 MW |
| 21 Oct, 18:00 | 247 MW | 225 MW |
| 21 Oct, 19:00 | 245 MW | 226 MW |
| 21 Oct, 20:00 | 234 MW | 218 MW |
| 21 Oct, 21:00 | 220 MW | 204 MW |
| 21 Oct, 22:00 | 199 MW | 186 MW |
| 21 Oct, 23:00 | 180 MW | 169 MW |
| 22 Oct, 00:00 | 164 MW | 154 MW |
| 22 Oct, 01:00 | 153 MW | 143 MW |
| 22 Oct, 02:00 | 145 MW | 137 MW |
| 22 Oct, 03:00 | 142 MW | 133 MW |
| 22 Oct, 04:00 | 143 MW | 133 MW |
| 22 Oct, 05:00 | 150 MW | 139 MW |
| 22 Oct, 06:00 | 168 MW | 155 MW |
| 22 Oct, 07:00 | 179 MW | 166 MW |
| 22 Oct, 08:00 | 185 MW | 171 MW |
| 22 Oct, 09:00 | 187 MW | 171 MW |
| 22 Oct, 10:00 | 188 MW | 173 MW |
| 22 Oct, 11:00 | 191 MW | 176 MW |
| 22 Oct, 12:00 | 194 MW | 181 MW |
| 22 Oct, 13:00 | 199 MW | 186 MW |
| 22 Oct, 14:00 | 207 MW | 194 MW |
| 22 Oct, 15:00 | 219 MW | 204 MW |
| 22 Oct, 16:00 | 232 MW | 214 MW |
| 22 Oct, 17:00 | 237 MW | 221 MW |
| 22 Oct, 18:00 | 235 MW | 222 MW |
| 22 Oct, 19:00 | 236 MW | 223 MW |
| 22 Oct, 20:00 | 228 MW | 214 MW |
| 22 Oct, 21:00 | 215 MW | 200 MW |
| 22 Oct, 22:00 | 196 MW | 183 MW |
| 22 Oct, 23:00 | 179 MW | 166 MW |
| 23 Oct, 00:00 | 163 MW | 151 MW |
| 23 Oct, 01:00 | 152 MW | 140 MW |
| 23 Oct, 02:00 | 144 MW | 133 MW |
| 23 Oct, 03:00 | 141 MW | 130 MW |
| 23 Oct, 04:00 | 142 MW | 132 MW |
| 23 Oct, 05:00 | 149 MW | 138 MW |
| 23 Oct, 06:00 | 167 MW | 154 MW |
| 23 Oct, 07:00 | 178 MW | 164 MW |
| 23 Oct, 08:00 | 184 MW | 171 MW |
| 23 Oct, 09:00 | 186 MW | 177 MW |
| 23 Oct, 10:00 | 187 MW | 184 MW |
| 23 Oct, 11:00 | 191 MW | 192 MW |
| 23 Oct, 12:00 | 196 MW | 199 MW |
| 23 Oct, 13:00 | 202 MW | 208 MW |
| 23 Oct, 14:00 | 209 MW | 211 MW |
| 23 Oct, 15:00 | 218 MW | 213 MW |
| 23 Oct, 16:00 | 226 MW | 216 MW |
| 23 Oct, 17:00 | 229 MW | 223 MW |
| 23 Oct, 18:00 | 225 MW | 230 MW |
| 23 Oct, 19:00 | 224 MW | 225 MW |
| 23 Oct, 20:00 | 216 MW | 217 MW |
| 23 Oct, 21:00 | 205 MW | 206 MW |
| 23 Oct, 22:00 | 191 MW | 192 MW |
| 23 Oct, 23:00 | 177 MW | 176 MW |
| 24 Oct, 00:00 | 164 MW | 156 MW |
| 24 Oct, 01:00 | 153 MW | 145 MW |
| 24 Oct, 02:00 | 146 MW | 136 MW |
| 24 Oct, 03:00 | 141 MW | 131 MW |
| 24 Oct, 04:00 | 140 MW | 127 MW |
| 24 Oct, 05:00 | 142 MW | 128 MW |
| 24 Oct, 06:00 | 151 MW | 132 MW |
| 24 Oct, 07:00 | 159 MW | 137 MW |
| 24 Oct, 08:00 | 169 MW | 147 MW |
| 24 Oct, 09:00 | 175 MW | 161 MW |
| 24 Oct, 10:00 | 182 MW | 175 MW |
| 24 Oct, 11:00 | 194 MW | 193 MW |
| 24 Oct, 12:00 | 198 MW | 213 MW |
| 24 Oct, 13:00 | 204 MW | 222 MW |
| 24 Oct, 14:00 | 210 MW | 217 MW |
| 24 Oct, 15:00 | 213 MW | 225 MW |
| 24 Oct, 16:00 | 220 MW | 229 MW |
| 24 Oct, 17:00 | 221 MW | 234 MW |
| 24 Oct, 18:00 | 221 MW | 236 MW |
| 24 Oct, 19:00 | 224 MW | 237 MW |
| 24 Oct, 20:00 | 217 MW | 229 MW |
| 24 Oct, 21:00 | 210 MW | 219 MW |
| 24 Oct, 22:00 | 201 MW | 204 MW |
| 24 Oct, 23:00 | 188 MW | 187 MW |
| 25 Oct, 00:00 | 177 MW | 165 MW |
| 25 Oct, 01:00 | 166 MW | 154 MW |
| 25 Oct, 02:00 | 158 MW | 146 MW |
| 25 Oct, 03:00 | 153 MW | 141 MW |
| 25 Oct, 04:00 | 150 MW | 139 MW |
| 25 Oct, 05:00 | 150 MW | 140 MW |
| 25 Oct, 06:00 | 156 MW | 145 MW |
| 25 Oct, 07:00 | 161 MW | 151 MW |
| 25 Oct, 08:00 | 170 MW | 163 MW |
| 25 Oct, 09:00 | 182 MW | 176 MW |
| 25 Oct, 10:00 | 194 MW | 191 MW |
| 25 Oct, 11:00 | 202 MW | 209 MW |
| 25 Oct, 12:00 | 211 MW | 222 MW |
| 25 Oct, 13:00 | 215 MW | 232 MW |
| 25 Oct, 14:00 | 215 MW | 238 MW |
| 25 Oct, 15:00 | 223 MW | 238 MW |
| 25 Oct, 16:00 | 228 MW | 238 MW |
| 25 Oct, 17:00 | 232 MW | 241 MW |
| 25 Oct, 18:00 | 235 MW | 237 MW |
| 25 Oct, 19:00 | 240 MW | 230 MW |
| 25 Oct, 20:00 | 234 MW | 220 MW |
| 25 Oct, 21:00 | 224 MW | 211 MW |
| 25 Oct, 22:00 | 210 MW | 196 MW |
| 25 Oct, 23:00 | 194 MW | 180 MW |
| 26 Oct, 00:00 | 179 MW | 169 MW |
| 26 Oct, 01:00 | 167 MW | 156 MW |
| 26 Oct, 02:00 | 158 MW | 147 MW |
| 26 Oct, 03:00 | 154 MW | 142 MW |
| 26 Oct, 04:00 | 155 MW | 141 MW |
| 26 Oct, 05:00 | 162 MW | 147 MW |
| 26 Oct, 06:00 | 179 MW | 163 MW |
| 26 Oct, 07:00 | 190 MW | 173 MW |
| 26 Oct, 08:00 | 196 MW | 181 MW |
| 26 Oct, 09:00 | 202 MW | 191 MW |
| 26 Oct, 10:00 | 209 MW | 202 MW |
| 26 Oct, 11:00 | 214 MW | 208 MW |
| 26 Oct, 12:00 | 225 MW | 218 MW |
| 26 Oct, 13:00 | 232 MW | 223 MW |
| 26 Oct, 14:00 | 237 MW | 232 MW |
| 26 Oct, 15:00 | 244 MW | 236 MW |
| 26 Oct, 16:00 | 251 MW | 239 MW |
| 26 Oct, 17:00 | 255 MW | 239 MW |
| 26 Oct, 18:00 | 253 MW | 240 MW |
| 26 Oct, 19:00 | 257 MW | 237 MW |
| 26 Oct, 20:00 | 247 MW | 228 MW |
| 26 Oct, 21:00 | 231 MW | 215 MW |
| 26 Oct, 22:00 | 209 MW | 198 MW |
| 26 Oct, 23:00 | 190 MW | 180 MW |
| 27 Oct, 00:00 | 174 MW | 157 MW |
| 27 Oct, 01:00 | 161 MW | 146 MW |
| 27 Oct, 02:00 | 152 MW | 138 MW |
| 27 Oct, 03:00 | 147 MW | 134 MW |
| 27 Oct, 04:00 | 148 MW | 134 MW |
| 27 Oct, 05:00 | 156 MW | 139 MW |
| 27 Oct, 06:00 | 173 MW | 153 MW |
| 27 Oct, 07:00 | 185 MW | 163 MW |
| 27 Oct, 08:00 | 190 MW | 168 MW |
| 27 Oct, 09:00 | 195 MW | 175 MW |
| 27 Oct, 10:00 | 200 MW | 180 MW |
| 27 Oct, 11:00 | 206 MW | 183 MW |
| 27 Oct, 12:00 | 208 MW | 190 MW |
| 27 Oct, 13:00 | 208 MW | 194 MW |
| 27 Oct, 14:00 | 237 MW | 206 MW |
| 27 Oct, 15:00 | 244 MW | 212 MW |
| 27 Oct, 16:00 | 251 MW | 221 MW |
| 27 Oct, 17:00 | 255 MW | 225 MW |
| 27 Oct, 18:00 | 253 MW | 225 MW |
| 27 Oct, 19:00 | 257 MW | 228 MW |
| 27 Oct, 20:00 | 247 MW | 221 MW |
| 27 Oct, 21:00 | 231 MW | 210 MW |
| 27 Oct, 22:00 | 209 MW | 195 MW |
| 27 Oct, 23:00 | 190 MW | 179 MW |
| 28 Oct, 00:00 | 174 MW | 160 MW |
| 28 Oct, 01:00 | 161 MW | 149 MW |
| 28 Oct, 02:00 | 152 MW | 140 MW |
| 28 Oct, 03:00 | 147 MW | 136 MW |
| 28 Oct, 04:00 | 148 MW | 136 MW |
| 28 Oct, 05:00 | 156 MW | 143 MW |
| 28 Oct, 06:00 | 173 MW | 158 MW |
| 28 Oct, 07:00 | 185 MW | 169 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.
Related
Cite this page
APA 7
World Power Monitor. (2026). GVL Demand Forecast Accuracy: Error, Bias and Worst Miss. https://worldpowermonitor.com/forecast-accuracy/gvl/
Plain text
World Power Monitor. GVL 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/gvl/
BibTeX
@misc{wpm_forecast_accuracy_gvl_2026,
title = {{GVL 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/gvl/}
} Permalink: https://worldpowermonitor.com/forecast-accuracy/gvl/
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