# The Greenhouse Gas Emissions Trading Scheme Order 2020, Paragraph 35: Formulae to be used when calculating maritime emissions


(1) For the purposes of calculating maritime emissions, a maritime operator must use the following formula—
MEETS=CO2ETS+CH4ETS×GWPCH4+N2OETS×GWPN2O
(2) In the application of the formula referred to in sub-paragraph (1)—
(a) a maritime operator must calculate CO2 emissions by adding the CO2 emissions of all fuels i used, applying the following formula—
CO2ETS=∑iMi-Mi,NC×EFCO2,i
(b) a maritime operator must calculate CH4 emissions by adding the CH4 emissions resulting from the combustion of all fuels i used together with the emissions caused by CH4 slippage, applying the following formula—
CH4ETS=∑iMi-Mi,NC×EFCH4,i+CH4S
(c) a maritime operator must calculate N2O emissions by adding the N2O emissions of all fuels i used applying the following formula—
N2OETS=∑iMi-Mi,NC×EFN2O,i
(3) The terms used in the equations are to be interpreted in accordance with Table C1.
Table C1
Explanation of terms used in relation to the equations
Term
Explanation
ME ETS
Maritime emissions to be reported under this Schedule, expressed in tonnes CO 2 equivalent, where “CO 2 equivalent” means the metric measure used to compute the emissions from CO 2, CH 4 and N 2O on the basis of their global warming potential, by converting amounts of CH 4 and N 2O to the equivalent amount of carbon dioxide with the same global warming potential.
CO 2ETS
Total aggregated CO 2 emitted.
CH 4ETS
Total aggregated CH 4 emitted.
N 2O ETS
Total aggregated N 2O emitted.
GWP CH4
Global warming potential of CH 4 over 100 years which is 28tCO 2(e)/tCH 4.
GWP N20
Global warming potential of N 2O over 100 years which is 265tCO 2(e)/tN 2O.
i
Index corresponding to the fuels used on board the ship in the scheme year.
j
Index corresponding to emission sources on board the ship. For the purpose of this Schedule, the sources include the main engines, auxiliary engines, gas turbines, boilers and inert gas generators.
M i
Fuel consumption, as total mass of the specific fuel i used (total for all emission sources).
M i, j
Fuel consumption, as mass of the specific fuel i used in emission source j.
C j
Tank to Wake emission factor of slipped fuel (slippage coefficient) as a percentage of the mass of the fuel i used by the emission source j [%].
Cj includes fugitive and slipped emissions. Fugitive and slipped emissions are emissions caused by the amount of fuel that does not reach the combustion chamber of the emission source or that is not consumed by the emission source because they are un-combusted, vented or leaked from the system.
M i,NC
Total mass of fuel i not combusted but released into the atmosphere. For the purpose of determining such amount, a maritime operator must apply the following formula—
Mi,NC=∑i∑jMi,j×Cj100
CH 4S
Amount of CH4 non combusted released into the atmosphere. For the purpose of determining such amount, a maritime operator must apply the following formula—
CH4S=Mi,NC
EF CO2,i
Tank to Wake CO 2 emission factor by fuel i, as defined in Table C2.
EF CH4,i
Tank to Wake CH 4 emission factor by fuel i, as defined in Table C2.
EF N2O,i
Tank to Wake N 2O emission factor by fuel i, as defined in Table C2.
(4) For the purposes of calculating maritime emissions, fuel consumption must be calculated separately for—
(a) voyages;
(b) in-port activities.

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Source: https://www.legislation.gov.uk/uksi/2020/1265/schedule/2A/paragraph/35 (the official version)
Page: https://openlegislation.uk/greenhouse-gas-emissions-trading-scheme-order-2020/schedule-2A/paragraph-35
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.