Oahu island grid serving Honolulu - transitioning from oil to solar and wind. This page provides the official EPA eGRID2023 electricity emission factors for the HIOA subregion, used for GHG Protocol Scope 2 location-based emissions reporting.
The HIOA subregion is 94% dirtier than the US average (770.9 lb CO2e/MWh).
| Pollutant | lb / MWh | kg / kWh | Scope |
|---|---|---|---|
| CO2e (total GHG) | 1498.947 | 0.6799 | Scope 2 |
| CO2 | 1489.548 | 0.6756 | Scope 2 |
| CH4 (methane) | 0.134 | 0.00006078 | Scope 2 |
| N2O (nitrous oxide) | 0.021 | 0.00000953 | Scope 2 |
| NOx | 3.908 | 0.00177264 | Air quality |
| SO2 | 4.28 | 0.00194138 | Air quality |
| CO2 non-baseload | 1753.441 | 0.7953 | Scope 2 (marginal) |
Using HIOA emission factor: 1498.947 lb CO2e/MWh = 0.6799 kg/kWh. Source: EPA eGRID2023.
These emission factors are from EPA eGRID2023 Rev2 (released June 2025), the official US government source for grid electricity emission rates. eGRID uses annual net generation and emissions data from all US power plants to calculate subregion-level output emission rates.
For GHG Protocol Scope 2 reporting, use the CO2e total output emission rate: 1498.947 lb/MWh or 0.6799 kg/kWh.
Primary utility: Hawaii Electric Light Company
Query HIOA emission factors by ZIP code:
curl "https://emission-factors.com/api/lookup?zip=YOUR_ZIP"
Read the API docs - free, no key, no signup.
The HIOA eGRID2023 Scope 2 location-based emission factor is 1498.947 lb CO2e per MWh (0.6799 kg CO2e per kWh). This is the value to use in GHG Protocol location-based Scope 2 calculations for facilities in the Hawaii Oahu subregion.
The HIOA (Hawaii Oahu) eGRID subregion covers: HI. Oahu island grid serving Honolulu - transitioning from oil to solar and wind.
Multiply kWh by 0.6799. Example: 50,000 kWh × 0.6799 = 33995 kg CO2e (33.99 tonnes).
Query any US ZIP code via API
33,616 ZIP codes · All 27 eGRID subregions · EPA eGRID2023 + 2024 preliminary
Read the API docs · Scope 2 guide