# UK ETS (/docs/regulations/uk-ets)



<Callout title="Calculation Preview">
  UK ETS will take effect on July 1st.
  For preview purposes, we currently apply the calculation to all consumption.
  We will later switch to only accounting for fuels combusted after July 1st.
</Callout>

<Callout type="warning" title="Regulatory Questions Ahead">
  Please note that the handling of biofuels under the UK ETS regulation is not yet fully clarified.
  In the meantime, we handle biofuels as we do under the EU ETS, but we will update our approach as soon as more
  information
  becomes available.
</Callout>

Ships of **5,000 gross tonnage and above** operating between UK ports must report emissions and surrender UK Allowances (UKAs) in proportion to the emitted greenhouse gases.

Emission+ calculates exactly how many allowances you need.

## What You Get [#what-you-get]

Emission+ continuously calculates the amount of UKAs required for your ship.

You don't need to worry about any of the following:

* ### Emission Types [#emission-types]

We automatically calculate CO₂, CH₄, and N₂O emissions using the correct emission factors and Global Warming Potential (GWP) values per fuel type.

* ### Methane Slip [#methane-slip]

For LNG-fuelled vessels, we automatically apply the correct methane slip factor based on the engine class (e.g. Otto dual-fuel medium-speed, Otto dual-fuel slow-speed, diesel dual-fuel slow-speed, LBSI).

* ### Fuel Blends [#fuel-blends]

You report a blend, and we automatically split it into its constituent fuels.

* ### Biofuels [#biofuels]

Sustainable fuels (biofuels with a Proof of Sustainability) have their CO₂ emission factor set to zero — CH₄ and N₂O are still fully accounted for.

* ### Voyage Types [#voyage-types]

Emission+ determines the correct voyage scope and rating based on your departure and arrival ports.
Vessels are only required to surrender UK allowances for emissions resulting from voyages between UK ports.

## Regulation Specifics [#regulation-specifics]

The UK ETS for maritime shipping is established by:

* [The Greenhouse Gas Emissions Trading Scheme (Amendment) (No. 2) Order 2026, No. 392](https://www.legislation.gov.uk/uksi/2026/392/schedule/1/made)
  — Schedule 1 contains the calculation rules, default emission factors, GWP values, and methane slip factors used by Emission+.

## Voyage Types and Ratings [#voyage-types-and-ratings]

The UK ETS applies only to voyages **within** or **between** UK ports. Each voyage is classified and assigned a rating that determines how much of its emissions are accounted for:

| Voyage Type     | Description                                   | Rating |
| --------------- | --------------------------------------------- | ------ |
| Non-UK voyage   | Both ports outside the UK                     | 0%     |
| UK entry voyage | Non-UK port → UK port                         | 0%     |
| UK exit voyage  | UK port → non-UK port                         | 0%     |
| Inner GB voyage | Great Britain port → Great Britain port       | 100%   |
| Inner NI voyage | Northern Ireland port → Northern Ireland port | 100%   |
| GB ↔ NI voyage  | Between Great Britain and Northern Ireland    | 50%    |

Unlike the EU ETS, international voyages to or from UK ports are **not** partially in scope — vessels are only required to surrender allowances for emissions resulting from domestic UK voyages.