The 2026 UK GHG Conversion Factors Are Here

Every June, the Department for Energy Security and Net Zero (DESNZ) releases updated greenhouse gas conversion factors for the coming reporting year. The 2026 edition is now live on GOV.UK.

For most businesses, this lands quietly. It shouldn't. These factors are the foundation of your carbon data. Get them wrong - or leave them unchanged from last year - and every figure in your GHG inventory, your SECR report, or your net-zero disclosure is inaccurate. That matters when clients, procurement teams, or auditors are looking at the numbers.

This post explains what conversion factors are, what has changed in the latest release, and what you should actually do with that information.

Why this annual update actually matters

The conversion factors are not just an administrative formality. They are a direct reflection of how the UK's energy system is changing. The most visible of these is the grid electricity factor - the number used to calculate Scope 2 emissions from purchased electricity.

Over the last several years, that figure has been falling consistently. In the most recent prior release, the UK grid electricity conversion factor dropped by approximately 15% year-on-year - from 0.149 to around 0.128 kgCO₂e per kWh - driven by lower natural gas use in power generation and an increase in net electricity imports from lower-carbon sources.

If your business consumes 500,000 kWh of electricity per year, that single factor change reduces your reported Scope 2 figure by roughly 10.5 tonnes CO₂e on paper - without any change to your actual consumption.

That is not a bad thing. It reflects a genuinely cleaner grid. But it does mean that year-on-year comparisons in your carbon reporting need to use consistent, correctly dated factors - and that using the right year's factors is not optional.

Key changes in the recent factors

The table below summarises the significant changes in the 2025 factors (the most recently fully documented release), which provide important context for understanding the trajectory of the 2026 update.

Source: DESNZ Greenhouse Gas Reporting: Conversion Factors 2026 and the 2025 major changes document. Previous years available from the GOV.UK conversion factors archive.

What this means if you report under SECR

Under the Streamlined Energy and Carbon Reporting (SECR) regulations, qualifying UK companies must report their energy consumption and associated carbon emissions in their annual directors' report. The regulations require you to use the methodology and conversion factors published by DESNZ.

In practice, this means:

• If your financial year runs January to December 2026, you should use the 2026 conversion factors.
• If you have a non-standard year-end (say, March 2026), you should use the factors that correspond to the majority of your reporting period - typically the current year's factors.
• You should not mix years within a single report.
• Year-on-year comparisons should note if material changes in factors (rather than consumption) have driven changes in reported figures.

The same principle applies if you report for procurement purposes under PPN 006 or contribute carbon data to a supply chain assessment.

A lower grid factor does not mean your emissions have fallen

This is the most common misunderstanding we see in client reporting. When the grid electricity factor falls by 15%, companies using a lot of electricity see a significant reduction in their reported Scope 2 emissions - even if they have not changed their consumption at all.

That reduction is real in a systems sense: the UK grid is generating fewer emissions per kWh, and that benefit flows through to users. But it tells you nothing about what your business has done to reduce its own impact.

If you are reporting against a net-zero or reduction target, the relevant metric is what you are consuming - not just what the grid factor happens to be this year. Procurement teams and auditors are increasingly sophisticated about this distinction. Presenting a lower Scope 2 figure without noting that it reflects a factor change - rather than an efficiency improvement - will not hold up to scrutiny.

Four things to do now

1. Update your conversion factors. If you are already tracking energy and carbon data, check that your calculation tool or spreadsheet is using 2026 factors for any 2026 activity data. If you are still using 2025 factors, your current-year figures are already incorrect. The 2026 dataset is available on GOV.UK - condensed set recommended for most users.

2. Check your freight and logistics data. The increase in HGV articulated freight factors is one of the larger Scope 3 changes. If you report on goods transported by road haulage - either direct or in your supply chain - your per-tonne emission figures will increase under the new factors.

3. Review bioenergy and biofuel calculations. Well-to-tank factors for a range of biofuels have shifted substantially. If your business uses biomethane, biodiesel, or operates any bioenergy equipment, you should recalculate your upstream (WTT) emissions using the latest figures.

4. Document the change in your next report. If the factor updates cause a material shift in your reported emissions versus the prior year, include a brief note in your disclosure explaining that the change reflects updated conversion factors, not a change in consumption. This is standard practice and protects the integrity of your data.

Common questions

What are the UK government GHG conversion factors?

They are the official emission factors published annually by DESNZ. Organisations use them to convert activity data - such as kWh of electricity used or litres of fuel consumed - into tonnes of CO₂e for carbon reporting under frameworks including SECR, PPN 006, and CDP.

When were the 2026 conversion factors published?

The 2026 conversion factors were published by DESNZ in June 2026. They should be used for reporting on emissions generated during the 2026 calendar year. The full dataset - condensed set, full set and flat file - is available to download from the GOV.UK publication page.

Do I have to update my conversion factors every year?

Yes. For SECR, PPN 006 procurement compliance, and most recognised reporting frameworks, you must use the conversion factors that correspond to the year in which your emissions occurred. Using out-of-date factors undermines the accuracy and credibility of your carbon data.

What if the new factors change my emissions figures significantly?

That is normal and expected. Year-on-year factor changes reflect genuine shifts in the UK's energy system. When you report, you should use the appropriate factors for each reporting year - and where there is a significant change, you can note the reason in your disclosure. This is standard practice and does not affect your net-zero trajectory.

Does a lower electricity grid factor mean our Scope 2 emissions have actually fallen?

Not necessarily. A lower grid factor reduces your calculated Scope 2 emissions on paper, but it reflects a change in the UK grid rather than a reduction in your own electricity consumption. To genuinely reduce Scope 2 emissions you need to reduce energy use, switch to renewable tariffs backed by REGOs, or procure matched renewable power.