IMOS - UK ETS in the Carbon Calculator

Introduction

The UK Emissions Trading Scheme (UK ETS) expands to maritime from 1 July 2026. This article summarizes the scheme's scope and compliance mechanics as they apply to shipping, alongside how UK ETS modifiers and carbon pricing are intended to be handled in the Carbon Calculator. Like EU ETS, UK ETS percentages apply to the Carbon Cost calculation per voyage leg, determined by the relevant ports.

This feature requires the configuration flag CFGEnableUkEts to be enabled.

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UK ETS Scope

From 1 July 2026, the UK ETS applies to cargo and passenger vessels of 5,000 GT and above. Offshore ships are brought into scope later, from 1 January 2027. The scheme covers emissions on domestic voyages between UK ports and emissions generated while in UK ports of call.

Phase-in and Reporting Timeline

Unlike EU ETS, which phases in surrender obligations over several years, the UK ETS applies a 100% surrender obligation from the start, but the first scheme year is a half-year.

Period

Notes

1 Jul – 31 Dec 2026

First (partial) scheme year; reporting begins 1 July

2027 onward

Standard reporting year, 1 Jan – 31 Dec


Greenhouse Gases Covered

The greenhouse gases covered align with EU ETS and include combustion and slippage emissions of:

  • Carbon dioxide (CO₂)

  • Methane (CH₄)

  • Nitrous oxide (N₂O)

Emissions are calculated on a tank-to-wake basis. Methane and nitrous oxide are reported using IPCC AR5 global warming potential values: CH₄ = 28 and N₂O = 265. (Note: this is the same GWP convention used for EU ETS and differs FuelEU - AR4)

Domestic Voyages and Ports of Call

A domestic voyage includes any voyage from one UK port to another, as well as a voyage that starts and ends at the same UK port. Emissions generated during ports of call are also in scope, including time at berth, whether moored or anchored, at UK ports and offshore installations.

Because port-of-call emissions are captured, the port stay portion of an international route calling at a UK port is also within scope, even though the international voyage leg itself is not a domestic voyage.

Northern Ireland <–> Great Britain Deduction

Coming Soon - this feature will be available shortly

A 50% deduction applies to the surrender obligation for voyages between Northern Ireland and Great Britain. Port stays in both Northern Ireland and Great Britain remain subject to a 100% surrender obligation.

For comparison, on a voyage between a non-UK port (e.g. France) and Great Britain, the voyage leg carries no (0%) surrender obligation, while the Great Britain port stay remains at 100%.

UK ETS in the Carbon Calculator

This feature requires the configuration flags CFGEnableUkEts and CFGDefaultIncludeUKETSExpInPnl to be enabled. Schema version 53.4 is also a requirement.

The UK ETS Calculator is available in the Carbon Calculator on the Estimate and Voyage level to aid in commercial decision-making regarding the impact of UK ETS, and to apply a price to carbon emissions. The percentage values for each leg of an itinerary will apply to the Carbon Cost calculation by default and will be determined by the Load and Discharge ports. You can also view the total UK ETS emissions in MT.

Select the Include in PnL checkbox to add the UK ETS costs to the Estimate PnL. A future release includes adding these costs to the Voyage PnL as well.

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Contract Settlement Type Options

Cash or allowance settlement type options are available for selection in the UK ETS tab in the Cargo contract, VC In contract, Time Charter contract, or Head Fixture added to the Estimate.

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Coming Soon - include UK ETS costs in the voyage PnL, creating cash/allowance invoices, accruals, reporting, and other financial workflows.


Configuration Flags

Related Configuration Flags

Name/Flag

Description

Enable UK ETS
CFGEnableUkEts

When enabled, a tab in the Estimate's Carbon Calculator appears to calculate the UK ETS.

*Minimum Schema Required: 502

UKETS Default Price

CFGUKETSDefaultPrice

Specifies the default UK ETS carbon price used in carbon cost calculations when no price has been manually entered. When not set, the UK ETS price defaults to zero. Mirrors the behavior of CFGCo2DefaultPrice for EU ETS.

Default Include UKETS Expense in P&L

CFGDefaultIncludeUKETSExpInPnl

When CFGEnableUkEts is enabled along with this flag, UK ETS Expenses will be included in the PnL by default for estimates.

Default TC Out Cargo UKETS Settlement Type

CFGDefaultTCOutCargoUKETSSettlementType

Used to set the default UK ETS Settlement Type for Time Charter Out and Cargo contracts. Accepted values are N/A and Cash. Only contracts that are created after updating this default will be impacted.

Default TC in VC in UKETS Settlement Type

CFGDefaultTCInVCInUKETSSettlementType

Used to set the default UK ETS Settlement Type for Time Charter In, Head Fixture and VC In contracts. Accepted values are N/A and Cash. Only contracts that are created after updating this default will be impacted.