EPA groups US electricity into 27 eGRID subregions. These subregion factors are the GHG Protocol Scope 2 location-based factors; each ZIP code maps to one subregion.
| Code | Name (EPA) | States | CO₂e lb/MWh | kg/kWh | Carbon-free | Rating |
|---|---|---|---|---|---|---|
| NYUP | NPCC Upstate NY | NY, NJ | 242.776 | 0.1101 | 74.06% | Very Clean |
| CAMX | WECC California | CA | 429.983 | 0.1950 | 54.56% | Clean |
| AKMS | ASCC Miscellaneous | AK | 522.4 | 0.2370 | 68.98% | Clean |
| NEWE | NPCC New England | MA, ME, CT, VT, NH, RI | 543.178 | 0.2464 | 41.84% | Clean |
| SRVC | SERC Virginia/Carolina | NC, VA, SC | 596.326 | 0.2705 | 49.89% | Clean |
| RFCE | RFC East | PA, NJ, MD, DE, DC, VA | 599.17 | 0.2718 | 40.35% | Clean |
| NWPP | WECC Northwest | WA, OR, MT, UT, ID, NV, WY, CA, AZ, NM | 635.267 | 0.2882 | 58.25% | Average |
| AZNM | WECC Southwest | AZ, NM, NV, TX, CA | 706.189 | 0.3203 | 40.27% | Average |
| ERCT | ERCOT All | TX | 736.629 | 0.3341 | 37.24% | Average |
| SRMV | SERC Mississippi Valley | AR, LA, MS, TX, MO | 741.741 | 0.3364 | 25.1% | Average |
| FRCC | FRCC All | FL | 784.785 | 0.3560 | 18.54% | Average |
| SRSO | SERC South | GA, AL, MS, FL | 846.007 | 0.3837 | 29.88% | Dirty |
| NYCW | NPCC NYC/Westchester | NY | 865.744 | 0.3927 | 0.59% | Dirty |
| SPNO | SPP North | KS, MO | 867.74 | 0.3936 | 54.17% | Dirty |
| SPSO | SPP South | OK, TX, LA, AR, NM, MO, KS | 875.567 | 0.3972 | 36.74% | Dirty |
| SRTV | SERC Tennessee Valley | KY, TN, MS, AL, VA, NC, GA | 903.306 | 0.4097 | 41.93% | Dirty |
| AKGD | ASCC Alaska Grid | AK | 905.109 | 0.4106 | 16.29% | Dirty |
| RFCW | RFC West | OH, IN, WV, IL, PA, VA, WI, KY, MD, MI | 916.054 | 0.4155 | 36.06% | Dirty |
| MROW | MRO West | IA, MN, NE, ND, SD, WI, MT, IL | 926.552 | 0.4203 | 51.34% | Dirty |
| RFCM | RFC Michigan | MI | 975.978 | 0.4427 | 21.38% | Dirty |
| RMPA | WECC Rockies | CO, WY, NE, SD, MT | 1042.539 | 0.4729 | 41.85% | Very Dirty |
| HIMS | HICC Miscellaneous | HI | 1133.294 | 0.5141 | 34.19% | Very Dirty |
| NYLI | NPCC Long Island | NY | 1189.333 | 0.5395 | 6.49% | Very Dirty |
| SRMW | SERC Midwest | IL, MO, IA | 1248.582 | 0.5663 | 31.62% | Very Dirty |
| MROE | MRO East | WI, MI | 1404.963 | 0.6373 | 17.33% | Very Dirty |
| HIOA | HICC Oahu | HI | 1498.947 | 0.6799 | 14.24% | Very Dirty |
| PRMS | Puerto Rico Miscellaneous | PR | 1548.53 | 0.7024 | 2.31% | Very Dirty |
Source: EPA eGRID2023 Rev2 (released June 2025). States: those with at least 1% of the subregion's ZIP codes in this site's ZIP mapping. Rating (this site's scale, lb CO2e/MWh): Very Clean <400, Clean <600, Average <800, Dirty <1,000, Very Dirty 1,000+.
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