The UK government published its 2026 greenhouse gas conversion factors on 11 June 2026. One number stands out. Grid electricity is now 0.13096 kg CO₂e per kWh generated, against 0.17700 in the 2025 set. That is a fall of 26% in one edition, the largest step in the series going back to 1990.
If you report in the UK, or use these factors for UK sites, your Scope 2 figure for 2026 will drop sharply even if you used exactly the same electricity. Before you put that in a report, it helps to know where the drop comes from.
What changed in the 2026 factors
| Factor | 2025 set | 2026 set | Change |
|---|---|---|---|
| Electricity generated, per kWh | 0.17700 | 0.13096 | −26% |
| Transmission and distribution losses, per kWh | 0.01853 | 0.01299 | −30% |
| Battery electric car, average, per km | 0.04047 | 0.02951 | −27% |
| National rail, per passenger km | 0.03546 | 0.03092 | −13% |
| Homeworking, office equipment, per FTE hour | 0.03144 | 0.02159 | −31% |
| Natural gas, per kWh (gross CV) | 0.18296 | 0.18231 | −0.4% |
| Diesel, average biofuel blend, per litre | 2.57082 | 2.58354 | +0.5% |
Everything that runs on grid electricity moved with it: electric cars and vans, rail, the Underground and homeworking equipment. Fuels barely moved. Aviation, water, hotel stays and heat and steam were held at earlier values, so a fall in those lines this year would point to a change in your data, not in the factors.
Why it fell so far: two years of data in one step
Until 2025, the electricity factor was built from the national greenhouse gas inventory, which runs about two years behind. The 2025 set described the grid of 2023. For 2026, DESNZ switched to its quarterly Energy Trends statistics, which cut the lag to one year. The 2026 set describes the grid of 2025, and the 2024 grid is skipped entirely.
DESNZ splits the 26% fall into three parts:
- About 16 points come from the change in the grid mix between 2023 and 2024, the year the last UK coal power station closed.
- About 3 points come from the change between 2024 and 2025.
- The remaining 6 to 7 points come from the new method itself: better treatment of electricity imports and exports, and a fix for a small double count affecting on-site generators.
Imports matter more than they used to. Net imports supplied 15.5% of UK electricity in the 2025 data, against 8.65% in the year behind the previous set.
What it does to your numbers
Take an office that uses 100,000 kWh of grid electricity a year. With the 2025 factors, that is 17.7 tonnes CO₂e in Scope 2, plus 1.9 tonnes for grid losses in Scope 3. With the 2026 factors, it is 13.1 tonnes and 1.3 tonnes. The footprint falls by more than 5 tonnes and nobody switched anything off.
That is a real change in the grid, and it is fine to report it. What is not fine is letting a reader think you cut your consumption. Show the kWh next to the tonnes, and say in one sentence that the factor changed.
What to do about your base year
DESNZ leaves the choice to you: users decide whether to adjust earlier years so the time series stays consistent, and if they do not, they should explain the skipped year. Three steps keep it clean:
- Keep each year on its own factor set. Your 2025 inventory stays on the 2025 factors, your 2026 inventory uses the 2026 factors. The grid really did change.
- Check your recalculation policy. The GHG Protocol asks you to recalculate the base year when a change in method has a significant effect, against a threshold you set yourself, often 5%. For most companies the method part of this change, 6 to 7 points of the electricity factor, will not move the total past that threshold. If electricity is most of your footprint, check.
- Disclose it. One line is enough: the 2026 UK electricity factor uses a new method with a one-year data lag, so the 2024 grid year is skipped, and our Scope 2 fell partly for that reason.
This is the location-based factor. Market-based Scope 2 follows your contracts and certificates and is not changed by it.
For more on choosing and recording factors, see our guides to emission factors and location-based and market-based Scope 2. If you report under SECR, the SECR guide covers what the annual report needs. Greener Ahead applies the 2026 UK factors to UK activity data in carbon accounting and keeps the edition used next to every line.
Joost Thissen
