UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 603 ANNEX 3: Other Detailed Methodological Descriptions for Individual Source or Sink Categories 750 A 3.1.2 Commonly used references 750 A 3.1.3 Feedstocks and Non-Energy Use (NEU) of fuels 753 A 3.1.6 Upstream oil and gas production (1A1cii, 1B2) 767 A 3.3.1 Enteric Fermentation (3A) 809 A 3.3.2 Manure Management (3B) 810 A 3.3.3 Agricultural Soils (3D) 816 A 3.3.6 Distribution of manure in different management systems 830 A 3.3.7 Description of the UK Agriculture Inventory Model 831 A 3.4.1 Carbon stock changes due to afforestation and forest management (4A) A 3.4.2 Alignment of CARBINE to the IPCC suggestions for “Use of Models in Good Practice National Greenhouse Gas Inventories” 875 A 3.4.3 Land Use Change and Soils (4B, 4C, 4E) 887 A 3.4.4 Changes in stocks of carbon in non-forest biomass due to management and land use change (4B2, 4C2, 4E2) 902 A 3.4.5 Carbon stock changes and biomass burning emissions due to Deforestation (4B, 4C, 4E, 4G) 907 A 3.4.6 Biomass Burning – Forest and Non-Forest Wildfires (4A, 4B, 4C) 911 A 3.4.7 Emissions from organic soils (4A, 4B, 4C, 4D, 4E, 4(II)) 917 A 3.4.8 On-site and off-site emissions from peat extraction (4D) 926 A 3.4.9 Flooded Lands (4D) 930

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 606 ANNEX 9: End User Emissions 1067 ANNEX 10: Reporting on consistency of the reported data on air emissions (including LULUCF) – UNFCCC scope ................................ ..... 620 emissions (excluding LULUCF) – UNFCCC scope ................................ .... 628 of emissions (including LULUCF) – UNFCCC scope ................................ . 634 of emissions (excluding LULUCF) – UNFCCC scope ................................ 642 year to latest reported year, including LULUCF) – UNFCCC scope ........... 649 year to latest reported year, excluding LULUCF) – UNFCCC scope .......... 657 Categories Shaded in Grey – UNFCCC scope ................................ .......... 665 LULUCF) with Key Categories Shaded in Grey – UNFCCC scope ............ 671 Key Categories Shaded in Grey – UNFCCC scope ................................ ... 676 LULUCF) with Key Categories Shaded in Grey – UNFCCC scope ............ 680 Shaded in Grey – UNFCCC scope ................................ ............................ 685

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 607 Categories Shaded in Grey – UNFCCC scope ................................ .......... 690 year to the latest reported year ................................ ................................ .. 700 carbon dioxide (CO2) inventory ................................ ................................ .. 713 methane (CH4) inventory ................................ ................................ ........... 727 nitrous oxide (N2O) inventory ................................ ................................ ..... 732 F-gas inventory ................................ ................................ .......................... 736 (Approach 2) uncertainty analyses ................................ ............................ 749 UK Energy Statistics ................................ ................................ .................. 755 aircraft types ................................ ................................ .............................. 762 Use, including cooking appliances, gas fires and boilers ........................... 766 (1990-2021) ................................ ................................ ............................... 811 Animal types, 2021 ................................ ................................ .................... 813 ................................ ................................ ................................ .................. 816

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 608 digestates ................................ ................................ ................................ .. 816 UK crops, 1990-2021 ................................ ................................ ................. 820 emissions ................................ ................................ ................................ .. 828 leaching and run-off and associated N2O emissions ................................ .. 828 emissions ................................ ................................ ................................ .. 828 uptake by planting of forests of Sitka spruce (P. Sitchensis), yield class 12. ................................ ................................ ................................ .................. 871 models................................ ................................ ................................ ....... 875 Kingdom since 1500 based on estimates of woodland area by age from the NFI and administrative records. ................................ ................................ . 884 England, Scotland, Wales, Northern Ireland, United Kingdom of Great Britain and Northern Ireland) ................................ ......... 889 non-organic soil carbon density (t ha-1) to 1 m deep for changes between different land types in England ................................ ................................ .. 897 non-organic soil carbon density (t ha-1) to 1 m deep for changes between different land types in Scotland ................................ ................................ .. 898

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 609 non-organic soil carbon density (t ha-1) to 1 m deep for changes between different land types in Wales ................................ ................................ ...... 898 non-organic soil carbon density (t ha-1) to 1 m deep for changes between different land types in Northern Ireland ................................ ...................... 898 land use in England (E), Scotland (S), Wales (W) and Northern Ireland (NI) ................................ ................................ ................................ .................. 899 stock changes from Cropland Management ................................ .............. 903 carbon stock changes from Grassland Management ................................ . 904 changes between different land types in England ................................ ...... 906 changes between different land types in Scotland. ................................ .... 906 changes between different land types in Wales. ................................ ........ 907 changes between different land types in Northern Ireland. ........................ 907 administration in 1990 and 2021. ................................ ............................... 919 use change, drainage and rewetting between 1990 and 2021 ................... 919 ha-1 y-1, kg CH4 ha-1 yr-1, and kg N2O-N ha-1 yr-1, respectively (updated from Evans et al (2017) and Brown et. al. 2020, 2021). Total fluxes are shown in tCO2e ha-1 yr-1 using AR5 GWP with no feedbacks (CH4= 28, N2O = 265).A

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 610 positive EF indicates net GHG emission, and a negative EF indicates net GHG removal. Note that the EFs for Direct CH4 include a correction for CH4 lost in ditches (1-fraction of ditches in the landscape) as per Equation 2.6 and standard errors are shown for the Total EFs in brackets. ........................... 922 Raised Inquiry/Mineral Extraction in Great Britain reports, and GMA, 2021) ................................ ................................ ................................ .................. 928 1990 and 2021. ................................ ................................ ......................... 932 Territories and Crown Dependencies ................................ ........................ 935 Overseas Territories and Crown Dependencies ................................ ........ 936 oxidised and emitted ................................ ................................ .................. 955 crown dependencies ................................ ................................ .................. 957 Emission Factors ................................ ................................ ....................... 965 Estimates (kt CH4) ................................ ................................ ..................... 966 Parameters (5D1) ................................ ................................ ...................... 967 sector (5D2)................................ ................................ ............................... 967

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 611 equivalent) ................................ ................................ ................................ .
969 (Mt CO2 equivalent) ................................ ................................ ................... 971 GHGs (Mt CO2 equivalent) ................................ ................................ ........ 971 ................................ ................................ ................................ .................. 971 Agricultural Soils (Mt CO2 equivalent) ................................ ........................ 973 fertilizer applied ................................ ................................ ......................... 973 (Gg) ................................ ................................ ................................ ........... 975 Waste activity data (Gg) ................................ ................................ ............ 975 basis) ................................ ................................ ................................ ........ 977 (TJ net) ................................ ................................ ................................ ...... 984 consumption (for 2021) ................................ ................................ .............. 998

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 612 (Emission Factors in kt / Mt for Coal & Fuel Oil, kt / Mth for Gases) ......... 1048 Factors in kt / Mt for Fuel Oil and kt / Mth for OPG and Natural Gas) ...... 1051 (Emission Factors in kt/Mt for solid & liquid fuels, kt/Mth for gases) ......... 1054 GHGI and the EU/UK ETS ................................ ................................ ....... 1058 Solid Fuels and kt / Mth for Gases) ................................ .......................... 1059 produced) ................................ ................................ ................................ 1060 Combustion Plant (Emission Factors in kt / Mt for Coal & Fuel Oil, kt / Mth for Natural Gas) ................................ ................................ ............................ 1061 emissions/removals from LULUCF (Mt CO2eq) – National Statistics coverage (UK only) ................................ ................................ ................................ . 1066 from LULUCF (Mt CO2eq) – National Statistics coverage (UK only) ........ 1066 names used in the emission calculation ................................ ................... 1076 equivalent ................................ ................................ ................................ 1150 equivalent ................................ ................................ ................................ 1150 equivalent ................................ ................................ ................................ 1151 equivalent ................................ ................................ ................................ 1152

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 613 between (i) 4A and 4G, (ii) 4B, (iii) 4C, (iv) 4D, (v) 4E .................. 865 land uses 1951-2020, showing the observations and posterior distribution of estimates. The grey shaded band is the 2.5-97.5 percentiles of the posterior distribution, with the MAP the black line within this. (Levy et al. 2021). ...... 892 showing the observations and posterior distribution of estimates. The grey shaded band is the 2.5-97.5 percentiles of the posterior distribution, with the MAP the black line within this. (Levy et al. 2021). The thin coloured lines are the corrected observations, after accounting for systematic uncertainty, and interpolating. ................................ ................................ .............................. 893 confidence limits and the 1990-2019 inventory LUC time series, based on Countryside Survey and historic datasets. ................................ ................. 895 soil carbon stocks. ................................ ................................ ..................... 901 anomalies were filtered to exclude those recorded over urban/industrial areas). ................................ ................................ ................................ ....... 914 year ................................ ................................ ................................ ........... 915 amended from Evans et al (2017) ................................ .............................. 918 from Evans et al (2017) ± standard error. Note that an EF for Forest is not shown as the Tier 3 method employed results in a range of EFs for forests on organic soils, which is due to changes in the age of forests and differences in afforestation over time. (All fluxes are shown in tCO2-C ha-1 yr-1. Note that a

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 614 positive EF indicates net GHG emission, and a negative EF indicates net GHG removal). ................................ ................................ .......................... 923 updated from Evans et al (2017) ± standard error. Note that the EFs for Direct CH4 include a correction for CH4 lost in ditches (1-fraction of ditches in applicable (i.e. drained status). (All fluxes are shown in Kg CH4 ha-1 yr-1). . 924 updated from Evans et al (2017) ± standard error. (All fluxes are shown in Kg N2O-N ha-1 yr-1). ................................ ................................ ......................... 924 fuel to allocate to bottom-up NRMM estimates ................................ .......... 992 enough fuel to allocate to bottom-up NRMM estimates .............................. 993 N2O, estimated from MHD, Ireland observations are shown in red, and background Southern Hemisphere monthly concentrations from CGO, Tasmania are shown in blue. Grey shading represents unratified data. ... 1005 (a) from 1990 and (b) from 2006. GHGI estimates are shown in black. InTEM 2-site 2-year estimates are shown in green (±1σ). InTEM full network, 1- month annualised, estimates are shown in blue (±1σ). InTEM 7-site, 2-month annualised, estimates are shown in red (±1σ). ................................ ........ 1006 month-1 from 2006. GHGI estimates are shown in black. InTEM 2-month estimates are shown in red (±1σ). InTEM 1-month estimates are shown in blue (±1σ). ................................ ................................ ............................... 1007 2019-2022 by (a) Spring (b) Summer (c) Autumn and (d) Winter. The observation stations are shown as blue triangles. Major cities are shown as red circles. ................................ ................................ ............................... 1008 (a) from 1990 and (b) from 2012. GHGI estimates are shown in black. InTEM 1-site, 3-year estimates are shown in green (±1σ), InTEM full network, 1- month, annualised, estimates are shown in blue (±1σ). ........................... 1009 month-1 from 2012. GHGI estimates are shown in black. InTEM 1-month estimates are shown in blue (±1σ). ................................ .......................... 1010 2019-2022 by (a) Spring (b) Summer (c) Autumn and (d) Winter. The observation stations are shown as blue triangles. Major cities are shown as red circles. ................................ ................................ ............................... 1010

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 615 152a, HFC-23, HFC-32, HFC-227ea, HFC-245fa, HFC-365mfc and HFC-43- 10mee) in Tg CO2-eq yr−1 from the GHGI (black) and InTEM, annualised 2- year inversion (blue) and 1-year inversion (orange). Note HFC-43-10mee (< 0.2 Tg CO2-eq yr−1) is included from 2011 when the observations start. The uncertainty bars represent ±1σ. ................................ ............................... 1011 estimated from MHD, Ireland observations are shown in red, and background Southern Hemisphere monthly concentrations from CGO, Tasmania are shown in blue. Grey shading represents unratified data. ......................... 1012 estimated from MHD, Ireland observations are shown in red, and background Southern Hemisphere monthly concentrations from CGO, Tasmania are shown in blue. Grey shading represents unratified data. ......................... 1013 CO2-eq yr-1 from 1990. GHGI estimates are shown in black. InTEM 2-year estimates are shown in blue (±1σ), InTEM 1-year estimates are shown in orange (±1σ). ................................ ................................ ........................... 1014 CO2-eq yr-1 from 1990. GHGI estimates are shown in black. InTEM 2-year estimates are shown in blue (±1σ), InTEM 1-year estimates are shown in orange (±1σ). ................................ ................................ ........................... 1015 2022. The observation stations are shown as blue triangles. Major cities are shown as red circles.
................................ ................................ ............... 1016 The observation stations are shown as blue triangles. Major cities are shown as red circles. ................................ ................................ .......................... 1017 in Tg CO2-eq yr−1 from the GHGI (black) and InTEM, annualised 2-year inversion (blue) and 1-year inversion (orange). The InTEM uncertainty bounds represent 1-σ. ................................ ................................ ............. 1022 estimated from MHD, Ireland observations are shown in red, and background Southern Hemisphere monthly concentrations from CGO, Tasmania are shown in blue. Grey shading represents unratified data. ......................... 1023 yr-1 from 1990. GHGI estimates are shown in black. InTEM 2-year estimates are shown in blue (±1σ), InTEM 1-year estimates are shown in orange (±1σ). ................................ ................................ ................................ ................ 1024 The observation stations are shown as blue triangles. Major cities are shown as red circles. ................................ ................................ .......................... 1025

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 616 NF3 estimated from MHD, Ireland observations are shown in red, and background Southern Hemisphere monthly concentrations from CGO, Tasmania are shown in blue. Grey shading represents unratified data. ... 1027 from (a) 1990 and (b) 2012. GHGI estimates are shown in black. InTEM 2- year estimates are shown in green (1σ), InTEM annualised 1-month estimates are shown in blue (1σ). ................................ .......................... 1027 from 2012. GHGI estimates are shown in black. InTEM 1-month estimates are shown in blue (1σ). ................................ ................................ .......... 1028 2022. The observation stations are shown as blue triangles. Major cities are shown as red circles. ................................ ................................ ............... 1029 from 2012. GHGI estimates are too small to see. InTEM 2-year estimates are shown in blue (1σ), InTEM 1-year estimates are shown in orange (1σ). ................................ ................................ ................................ ................ 1030 2022. The observation stations are shown as blue triangles. Major cities are shown as red circles. ................................ ................................ ............... 1030 from MHD, Ireland observations (data obtained from LSCE equipment through a data sharing agreement) are shown in red, and background Southern Hemisphere monthly concentrations from CGO, Tasmania are shown in blue. Grey shading represents unratified data. ......................... 1031 sectors considered in the end user example ................................ ............ 1072

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 617 This annex contains the key category analysis for the latest GHG inventory1. It • A description of the methodology used for identifying key categories • Information on the level of disaggregation • Information to fulfil the reporting requirements of Tables 4.2 and 4.3 of Volume 1 of the 2006 IPCC Guidelines, including and excluding land use, land-use change and forestry (LULUCF). In the UK inventory, certain source categories are particularly significant in terms of their contribution to the overall unc ertainty of the inventory. These key source categories have been identified so that the resources available for inventory preparation may be prioritised, and the best possible estimates prepared for the most significant source categories. The UK completes both quantitative and qualitative Key Category Analyses (KCAs). The UK has used the method set out in Section 4.3.1 and Section 4.3.2 of the 2006 IPCC Guidelines Volume 1 General Guidance and Reporting (Approach 1 to identify key categories, and Approach 2 to identify key categories respectively) to quantitatively determine the key source 1 Following the requirements to report information about uncertainties as set out in FCCC/CP/2013/10/Add.3. Report of the Conference of the Parties on its nineteenth session, held in Warsaw from 11 to 23 November 2013. Addendum Part Action taken by the Conference of the Parties at its nineteenth session. UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 618 Following IPCC good practice, a qualitative analysis of the inventory has been made to identify any additional key source categories, which may not have been identified using the quantitative anal ysis. The approach set out in Section 4.3.3 of the IPCC 2006 Guidelines has been applied, using the four criteria set out in the guidance, to judge whether a category is a key category. The criteria 1. (Use of) mitigation techniques and technologies; 2. Emissions growth (increase or decrease); 3. No quantitative assessment of uncertainties performed; 4. Completeness (examine qualitatively potential key categories that are not yet estimated quantitatively by applying the qualit ative In addition, additional criteria have also been taken in account 5. High uncertainty (links to point 3 above); 6. Unexpectedly low or high emissions; 7. External recommendation has also been used as an additional criterion to identify key categories. The results of the qualitative analysis did not identify any categories that were not already identified by the quantitative key category analysis. A key category analysis has been completed for both level and trend. This KCA has been created using the 2006 IPCC Guidelines Approach 1 methodology. The factors that make a source a key category • A high contribution to the level of emissions; and • A high contribution to the trend; For example, transport fuel (1A3b) is a key category for carbon dioxide because it is a large source of emissions and nitric acid production (2B2) because it shows a significant trend. UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 619 The category groupings are largely aligned to those suggested in Tables 4.5 and 4.6 in Volume 1, Chapter 4 of the 2006 IPCC guidelines, although we deviate in a number of cases, in • Agriculture and LULUCF. In the 2006 guidelines a different nomenclature for categorising agriculture and LULUCF sources and sinks was used compared to the adopted nomenclat ure, which means that it would be challenging and confusing to retain this categorisation when sources are grouped differently in the adopted nomenclature. The UK Inventory Agency considers that the level of aggregation used in the UK method for the KCA is sufficiently detailed to target inventory improvements whilst not introducing unnecessary computational difficulties (e.g. use of “miscellaneous” categories to mop up the remainder within a sector).
Further, the level of source/s ink category aggregations in the KCA are aligned to how individual methods or models are used to derive the UK inventory estimates, and are therefore at an appropriate level of detail for the UK inventory • Fugitive Emissions. The suggested categories are at a much more granular leve l (e.g. 1B2aii) than other sectors. We considered that this would lead to an undue diminishing of these sectors, decreasing their likelihood of being considered key, so have adopte d a level of aggregation more consistent with other sectors • Miscellaneous emissions. The suggested approach was to group a large number of small sources into one category. We considered that this would lead to an undue increase in the significance of these sources, increasing their likelihood of being considered key, so have adopted a level of aggregation more consistent with other sectors The results of the key category analysis with and without LULUCF, for the base year and the latest reported year and for both Approaches 1 and 2 KCA, are summarised by sector and gases in Section 1.5.1. The tables indicate whether a key category arises from the level (L1) assessment The results of the level assessment (based on Approach 1) with and without LULUCF for the base year and the latest reported year are shown final column after this sorting process, which according to the 2006 IPCC guidelines, should account for 90% of the uncertainty in level. The results of the trend assessment (based on Approach 1) with and without LULUCF for the base year to the latest reported year are shown in using the absolute value of the result; an absolute function is used since Land Use, Land Use Change and Forestry contains negative sources (sinks) and the absolute function is necessary to produce positive uncertainty contributions for these sinks. The source cate gories (i.e. rows of

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 620 The key source categories are those whose contributions add up to 95% of the sum of the trend parameters in the final column after this sorting process, which according to the 2006 IPCC guidelines, should account for 90% of the uncertainty in trend. Note that the tables in chapter 1 of the NIR summarise the key categories from both the approach 1 and approach 2 key categories analyses and the aggregations used are slightly different for the two approaches. For example, the category "3A" is therefore total emissions from category 3A, whilst categories 3A1 and 3A2 have also been identified as key categories in their own right.
Level Assessment Cumulative Total 1A1 Energy solid fuels CO2 185,488.39 185,488.39 0.2173 0.2173 1A3b Road liquid fuels CO2 109,173.97 109,173.97 0.1279 0.3453 1A4 Other gaseous fuels CO2 70,371.86 70,371.86 0.0825 0.4277 5A Solid waste disposal CH4 67,633.35 67,633.35 0.0793 0.5070 1A1 Energy liquid fuels CO2 40,387.53 40,387.53 0.0473 0.5543 1A2 Manufacturing industries and liquid fuels CO2 27,665.96 27,665.96 0.0324 0.5867 1A2 Manufacturing industries and gaseous fuels CO2 27,291.18 27,291.18 0.0320 0.6187 1B1 Coal mining and handling CH4 24,446.08 24,446.08 0.0286 0.6474 2C1 Iron and steel production CO2 23,628.28 23,628.28 0.0277 0.6750 1A4 Other liquid fuels CO2 21,465.76 21,465.76 0.0252 0.7002 3A1 Enteric fermentation from Cattle CH4 21,166.02 21,166.02 0.0248 0.7250 1A2 Manufacturing industries and solid fuels CO2 20,209.42 20,209.42 0.0237 0.7487 1A4 Other solid fuels CO2 19,824.90 19,824.90 0.0232 0.7719

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 621 Level Assessment Cumulative Total 2B3 Adipic acid production N2O 17,727.08 17,727.08 0.0208 0.7927 2B9 Fluorochemical production HFCs, PFCs, SF6 14,911.66 14,911.66 0.0175 0.8101 4B Cropland CO2 14,230.88 14,230.88 0.0167 0.8268 4A Forest land CO2 -13,940.16 13,940.16 0.0163 0.8432 1B2 Oil and gas extraction CH4 13,835.90 13,835.90 0.0162 0.8594 3D Agricultural soils N2O 13,428.41 13,428.41 0.0157 0.8751 1A1 Energy gaseous fuels CO2 11,939.20 11,939.20 0.0140 0.8891 1A3d Domestic liquid fuels CO2 7,611.13 7,611.13 0.0089 0.8980 2A1 Cement production CO2 7,295.26 7,295.26 0.0085 0.9066 3A2 Enteric fermentation from Sheep CH4 5,858.92 5,858.92 0.0069 0.9134 4E Settlements CO2 5,426.53 5,426.53 0.0064 0.9198 1A5 liquid fuels CO2 5,293.44 5,293.44 0.0062 0.9260 1B2 Oil and gas extraction CO2 5,088.53 5,088.53 0.0060 0.9320 2B8 Petrochemical and carbon black production CO2 4,751.56 4,751.56 0.0056 0.9375 3B1 Manure management from Cattle CH4 4,646.15 4,646.15 0.0054 0.9430 2B2 Nitric acid production N2O 3,432.78 3,432.78 0.0040 0.9470 3B2 Manure management from Sheep N2O 3,038.90 3,038.90 0.0036 0.9505 4C Grassland CH4 2,807.05 2,807.05 0.0033 0.9538 5D Wastewater treatment and discharge CH4 2,365.31 2,365.31 0.0028 0.9566

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 622 Level Assessment Cumulative Total 4D Wetlands CH4 2,313.24 2,313.24 0.0027 0.9593 4G Harvested wood products CO2 -2,096.17 2,096.17 0.0025 0.9618 2B1 Ammonia production CO2 1,895.00 1,895.00 0.0022 0.9640 1A3a Domestic liquid fuels CO2 1,869.71 1,869.71 0.0022 0.9662 1B1 Coal mining and handling CO2 1,698.56 1,698.56 0.0020 0.9682 1A3c liquid fuels CO2 1,469.34 1,469.34 0.0017 0.9699 5C Incineration and open burning of waste CO2 1,445.17 1,445.17 0.0017 0.9716 1A4 Other solid fuels CH4 1,440.83 1,440.83 0.0017 0.9733 1A3b Road liquid fuels CH4 1,408.61 1,408.61 0.0017 0.9749 2C6 Zinc production CO2 1,350.65 1,350.65 0.0016 0.9765 2A2 Lime production CO2 1,328.60 1,328.60 0.0016 0.9781 2A4 Other process uses of carbonates CO2 1,198.69 1,198.69 0.0014 0.9795 1A3b Road liquid fuels N2O 1,176.81 1,176.81 0.0014 0.9809 3G Liming CO2 1,019.16 1,019.16 0.0012 0.9820 1A1 Energy solid fuels N2O 939.47 939.47 0.0011 0.9831 2G1 Electrical equipment HFCs, PFCs, SF6 5D Wastewater treatment and discharge N2O 796.37 796.37 0.0009 0.9851 4D Wetlands CO2 668.77 668.77 0.0008 0.9858 4B Cropland N2O 653.25 653.25 0.0008 0.9866

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 623 Level Assessment Cumulative Total 4C Grassland CO2 -618.75 618.75 0.0007 0.9873 2D Non-energy products from fuels and solvent use CO2 552.81 552.81 0.0006 0.9880 2G3 N2O from product uses N2O 493.41 493.41 0.0006 0.9886 1A4 Other peat CO2 453.50 453.50 0.0005 0.9891 2C3 Aluminium production CO2 450.32 450.32 0.0005 0.9896 4A Forest land N2O 438.95 438.95 0.0005 0.9901 2A3 Glass production CO2 412.37 412.37 0.0005 0.9906 2C4 Magnesium production HFCs, PFCs, SF6 4E Settlements N2O 392.31 392.31 0.0005 0.9920 3A4 Enteric fermentation from Other livestock CH4 338.26 338.26 0.0004 0.9924 4B Cropland CH4 332.36 332.36 0.0004 0.9928 3A3 Enteric fermentation from Swine CH4 317.02 317.02 0.0004 0.9932 3J Agriculture activities in OTs and CDs CH4 306.10 306.10 0.0004 0.9935 2C3 Aluminium production HFCs, PFCs, SF6 3H Urea application to land CO2 293.75 293.75 0.0003 0.9942 4 Indirect N2O emissions from LULUCF N2O 271.94 271.94 0.0003 0.9945 1A1 Energy other fuels CO2 244.37 244.37 0.0003 0.9948

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 624 Level Assessment Cumulative Total 1A1 Energy gaseous fuels N2O 232.10 232.10 0.0003 0.9951 2B7 Soda ash production CO2 224.40 224.40 0.0003 0.9954 1A4 Other solid fuels N2O 218.14 218.14 0.0003 0.9956 2B10 Other Chemical Industry CH4 214.15 214.15 0.0003 0.9959 5C Incineration and open burning of waste CH4 213.78 213.78 0.0003 0.9961 3F Field burning of agricultural residues CH4 209.47 209.47 0.0002 0.9964 2F1 Refrigeration and air conditioning HFCs, PFCs, SF6 2G2 SF6 and PFCs from other product use HFCs, PFCs, SF6 1A4 Other gaseous fuels CH4 176.56 176.56 0.0002 0.9970 2F2 Foam blowing agents HFCs, PFCs, SF6 3J Agriculture activities in OTs and CDs N2O 155.42 155.42 0.0002 0.9974 1A1 Energy gaseous fuels CH4 144.26 144.26 0.0002 0.9976 4C Grassland N2O 134.86 134.86 0.0002 0.9977 1A2 Manufacturing industries and solid fuels N2O 125.66 125.66 0.0001 0.9979 2B6 Titanium dioxide production CO2 104.63 104.63 0.0001 0.9980 1A2 Manufacturing industries and liquid fuels N2O 102.15 102.15 0.0001 0.9981 1A4 Other biomass CH4 100.88 100.88 0.0001 0.9982 1A1 Energy liquid fuels N2O 99.98 99.98 0.0001 0.9984

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 625 Level Assessment Cumulative Total 4A Forest land CH4 99.49 99.49 0.0001 0.9985 1A3e Other liquid fuels CO2 98.14 98.14 0.0001 0.9986 1A3d Domestic liquid fuels N2O 93.38 93.38 0.0001 0.9987 1A4 Other liquid fuels N2O 83.51 83.51 0.0001 0.9988 1A4 Other liquid fuels CH4 73.07 73.07 0.0001 0.9989 1A2 Manufacturing industries and other fuels CO2 70.61 70.61 0.0001 0.9990 5C Incineration and open burning of waste N2O 61.44 61.44 0.0001 0.9990 1A1 Energy solid fuels CH4 56.99 56.99 0.0001 0.9991 3F Field burning of agricultural residues N2O 51.40 51.40 0.0001 0.9992 1A2 Manufacturing industries and solid fuels CH4 50.06 50.06 0.0001 0.9992 1A5 liquid fuels N2O 49.91 49.91 0.0001 0.9993 2C1 Iron and steel production CH4 43.92 43.92 0.0001 0.9993 2G4 Other product manufacture and use N2O 40.20 40.20 0.0000 0.9994 1B2 Oil and gas extraction N2O 39.74 39.74 0.0000 0.9994 1A1 Energy liquid fuels CH4 38.63 38.63 0.0000 0.9995 1A4 Other peat CH4 35.94 35.94 0.0000 0.9995 1A2 Manufacturing industries and liquid fuels CH4 35.43 35.43 0.0000 0.9996 2A4 Other process uses of carbonates CH4 34.84 34.84 0.0000 0.9996 2B8 Petrochemical and carbon black production CH4 33.79 33.79 0.0000 0.9996 1A4 Other gaseous fuels N2O 33.42 33.42 0.0000 0.9997

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 626 Level Assessment Cumulative Total 2F6 Other product uses as substitutes for ODS HFCs, PFCs, SF6 5B Biological treatment of solid waste CH4 21.89 21.89 0.0000 0.9997 1A1 Energy other fuels CH4 20.77 20.77 0.0000 0.9998 1A2 Manufacturing industries and biomass N2O 19.38 19.38 0.0000 0.9998 4E Settlements CH4 19.03 19.03 0.0000 0.9998 4D Wetlands N2O 18.90 18.90 0.0000 0.9998 2C1 Iron and steel production N2O 18.43 18.43 0.0000 0.9998 1A3a Domestic liquid fuels N2O 15.74 15.74 0.0000 0.9999 1A2 Manufacturing industries and biomass CH4 15.36 15.36 0.0000 0.9999 1A2 Manufacturing industries and gaseous fuels CH4 13.69 13.69 0.0000 0.9999 1A2 Manufacturing industries and gaseous fuels N2O 12.95 12.95 0.0000 0.9999 5B Biological treatment of solid waste N2O 12.36 12.36 0.0000 0.9999 1A4 Other biomass N2O 12.04 12.04 0.0000 0.9999 2E1 Integrated circuit or semiconductor HFCs, PFCs, SF6 1A3a Domestic liquid fuels CH4 7.69 7.69 0.0000 1.0000 1A1 Energy other fuels N2O 5.96 5.96 0.0000 1.0000 1A3d Domestic liquid fuels CH4 4.10 4.10 0.0000 1.0000 1A5 liquid fuels CH4 3.98 3.98 0.0000 1.0000 1A3c liquid fuels N2O 2.93 2.93 0.0000 1.0000

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 627 Level Assessment Cumulative Total 1A3c liquid fuels CH4 2.75 2.75 0.0000 1.0000 2B8 Petrochemical and carbon black production N2O 1.96 1.96 0.0000 1.0000 1A4 Other peat N2O 1.59 1.59 0.0000 1.0000 2F3 Fire protection HFCs, PFCs, SF6 1A3e Other liquid fuels N2O 1.05 1.05 0.0000 1.0000 1A1 Energy biomass CH4 0.53 0.53 0.0000 1.0000 1A2 Manufacturing industries and other fuels N2O 0.30 0.30 0.0000 1.0000 2B1 Ammonia production CH4 0.29 0.29 0.0000 1.0000 2B1 Ammonia production N2O 0.27 0.27 0.0000 1.0000 1A1 Energy biomass N2O 0.22 0.22 0.0000 1.0000 1A2 Manufacturing industries and other fuels CH4 0.17 0.17 0.0000 1.0000 1A3e Other liquid fuels CH4 0.14 0.14 0.0000 1.0000 1B1 Coal mining and handling N2O 0.08 0.08 0.0000 1.0000 Total 820,103.31 853,413.47 1.0000

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 628 Level Assessment Cumulative Total 1A1 Energy solid fuels CO2 185,488.39 185,488.39 0.2293 0.3643 1A3b Road liquid fuels CO2 109,173.97 109,173.97 0.1350 0.3643 1A4 Other gaseous fuels CO2 70,371.86 70,371.86 0.0870 0.4512 5A Solid waste disposal CH4 67,633.35 67,633.35 0.0836 0.5349 1A1 Energy liquid fuels CO2 40,387.53 40,387.53 0.0499 0.5848 1A2 Manufacturing industries and liquid fuels CO2 27,665.96 27,665.96 0.0342 0.6190 1A2 Manufacturing industries and gaseous fuels CO2 27,291.18 27,291.18 0.0337 0.6527 1B1 Coal mining and handling CH4 24,446.08 24,446.08 0.0302 0.6829 2C1 Iron and steel production CO2 23,628.28 23,628.28 0.0292 0.7121 1A4 Other liquid fuels CO2 21,465.76 21,465.76 0.0265 0.7387 3A1 Enteric fermentation from Cattle CH4 21,166.02 21,166.02 0.0262 0.7648 1A2 Manufacturing industries and solid fuels CO2 20,209.42 20,209.42 0.0250 0.7898 1A4 Other solid fuels CO2 19,824.90 19,824.90 0.0245 0.8143 2B3 Adipic acid production N2O 17,727.08 17,727.08 0.0219 0.8362 2B9 Fluorochemical production HFCs, PFCs, SF6 14,911.66 14,911.66 0.0184 0.8547 1B2 Oil and gas extraction CH4 13,835.90 13,835.90 0.0171 0.8718 3D Agricultural soils N2O 13,428.41 13,428.41 0.0166 0.8884 1A1 Energy gaseous fuels CO2 11,939.20 11,939.20 0.0148 0.9031

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 629 Level Assessment Cumulative Total 1A3d Domestic liquid fuels CO2 7,611.13 7,611.13 0.0094 0.9125 2A1 Cement production CO2 7,295.26 7,295.26 0.0090 0.9216 3A2 Enteric fermentation from Sheep CH4 5,858.92 5,858.92 0.0072 0.9288 1A5 liquid fuels CO2 5,293.44 5,293.44 0.0065 0.9354 1B2 Oil and gas extraction CO2 5,088.53 5,088.53 0.0063 0.9416 2B8 Petrochemical and carbon black production CO2 4,751.56 4,751.56 0.0059 0.9475 3B1 Manure management from Cattle CH4 4,646.15 4,646.15 0.0057 0.9533 2B2 Nitric acid production N2O 3,432.78 3,432.78 0.0042 0.9575 3B2 Manure management from Sheep N2O 3,038.90 3,038.90 0.0038 0.9613 5D Wastewater treatment and discharge CH4 2,365.31 2,365.31 0.0029 0.9642 2B1 Ammonia production CO2 1,895.00 1,895.00 0.0023 0.9665 1A3a Domestic liquid fuels CO2 1,869.71 1,869.71 0.0023 0.9688 1B1 Coal mining and handling CO2 1,698.56 1,698.56 0.0021 0.9709 1A3c liquid fuels CO2 1,469.34 1,469.34 0.0018 0.9728 5C Incineration and open burning of waste CO2 1,445.17 1,445.17 0.0018 0.9745 1A4 Other solid fuels CH4 1,440.83 1,440.83 0.0018 0.9763 1A3b Road liquid fuels CH4 1,408.61 1,408.61 0.0017 0.9781 2C6 Zinc production CO2 1,350.65 1,350.65 0.0017 0.9797 2A2 Lime production CO2 1,328.60 1,328.60 0.0016 0.9814 2A4 Other process uses of carbonates CO2 1,198.69 1,198.69 0.0015 0.9829

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 630 Level Assessment Cumulative Total 1A3b Road liquid fuels N2O 1,176.81 1,176.81 0.0015 0.9843 3G Liming CO2 1,019.16 1,019.16 0.0013 0.9856 1A1 Energy solid fuels N2O 939.47 939.47 0.0012 0.9867 2G1 Electrical equipment HFCs, PFCs, SF6 5D Wastewater treatment and discharge N2O 796.37 796.37 0.0010 0.9887 2D Non-energy products from fuels and solvent use CO2 552.81 552.81 0.0007 0.9894 2G3 N2O from product uses N2O 493.41 493.41 0.0006 0.9900 1A4 Other peat CO2 453.50 453.50 0.0006 0.9906 2C3 Aluminium production CO2 450.32 450.32 0.0006 0.9912 2A3 Glass production CO2 412.37 412.37 0.0005 0.9917 2C4 Magnesium production HFCs, PFCs, SF6 3A4 Enteric fermentation from Other livestock CH4 338.26 338.26 0.0004 0.9931 3A3 Enteric fermentation from Swine CH4 317.02 317.02 0.0004 0.9935 3J Agriculture activities in OTs and CDs CH4 306.10 306.10 0.0004 0.9938 2C3 Aluminium production HFCs, PFCs, SF6 3H Urea application to land CO2 293.75 293.75 0.0004 0.9946 1A1 Energy other fuels CO2 244.37 244.37 0.0003 0.9949

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 631 Level Assessment Cumulative Total 1A1 Energy gaseous fuels N2O 232.10 232.10 0.0003 0.9952 2B7 Soda ash production CO2 224.40 224.40 0.0003 0.9954 1A4 Other solid fuels N2O 218.14 218.14 0.0003 0.9957 2B10 Other Chemical Industry CH4 214.15 214.15 0.0003 0.9960 5C Incineration and open burning of waste CH4 213.78 213.78 0.0003 0.9962 3F Field burning of agricultural residues CH4 209.47 209.47 0.0003 0.9965 2F1 Refrigeration and air conditioning HFCs, PFCs, SF6 2G2 SF6 and PFCs from other product use HFCs, PFCs, SF6 1A4 Other gaseous fuels CH4 176.56 176.56 0.0002 0.9972 2F2 Foam blowing agents HFCs, PFCs, SF6 3J Agriculture activities in OTs and CDs N2O 155.42 155.42 0.0002 0.9976 1A1 Energy gaseous fuels CH4 144.26 144.26 0.0002 0.9978 1A2 Manufacturing industries and solid fuels N2O 125.66 125.66 0.0002 0.9979 2B6 Titanium dioxide production CO2 104.63 104.63 0.0001 0.9981 1A2 Manufacturing industries and liquid fuels N2O 102.15 102.15 0.0001 0.9982 1A4 Other biomass CH4 100.88 100.88 0.0001 0.9983 1A1 Energy liquid fuels N2O 99.98 99.98 0.0001 0.9984 1A3e Other liquid fuels CO2 98.14 98.14 0.0001 0.9986 1A3d Domestic liquid fuels N2O 93.38 93.38 0.0001 0.9987

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 632 Level Assessment Cumulative Total 1A4 Other liquid fuels N2O 83.51 83.51 0.0001 0.9988 1A4 Other liquid fuels CH4 73.07 73.07 0.0001 0.9989 1A2 Manufacturing industries and other fuels CO2 70.61 70.61 0.0001 0.9990 5C Incineration and open burning of waste N2O 61.44 61.44 0.0001 0.9990 1A1 Energy solid fuels CH4 56.99 56.99 0.0001 0.9991 3F Field burning of agricultural residues N2O 51.40 51.40 0.0001 0.9992 1A2 Manufacturing industries and solid fuels CH4 50.06 50.06 0.0001 0.9992 1A5 liquid fuels N2O 49.91 49.91 0.0001 0.9993 2C1 Iron and steel production CH4 43.92 43.92 0.0001 0.9994 2G4 Other product manufacture and use N2O 40.20 40.20 0.0000 0.9994 1B2 Oil and gas extraction N2O 39.74 39.74 0.0000 0.9995 1A1 Energy liquid fuels CH4 38.63 38.63 0.0000 0.9995 1A4 Other peat CH4 35.94 35.94 0.0000 0.9995 1A2 Manufacturing industries and liquid fuels CH4 35.43 35.43 0.0000 0.9996 2A4 Other process uses of carbonates CH4 34.84 34.84 0.0000 0.9996 2B8 Petrochemical and carbon black production CH4 33.79 33.79 0.0000 0.9997 1A4 Other gaseous fuels N2O 33.42 33.42 0.0000 0.9997 2F6 Other product uses as substitutes for ODS HFCs, PFCs, SF6 5B Biological treatment of solid waste CH4 21.89 21.89 0.0000 0.9998 1A1 Energy other fuels CH4 20.77 20.77 0.0000 0.9998

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 633 Level Assessment Cumulative Total 1A2 Manufacturing industries and biomass N2O 19.38 19.38 0.0000 0.9998 2C1 Iron and steel production N2O 18.43 18.43 0.0000 0.9998 1A3a Domestic liquid fuels N2O 15.74 15.74 0.0000 0.9999 1A2 Manufacturing industries and biomass CH4 15.36 15.36 0.0000 0.9999 1A2 Manufacturing industries and gaseous fuels CH4 13.69 13.69 0.0000 0.9999 1A2 Manufacturing industries and gaseous fuels N2O 12.95 12.95 0.0000 0.9999 5B Biological treatment of solid waste N2O 12.36 12.36 0.0000 0.9999 1A4 Other biomass N2O 12.04 12.04 0.0000 0.9999 2E1 Integrated circuit or semiconductor HFCs, PFCs, SF6 1A3a Domestic liquid fuels CH4 7.69 7.69 0.0000 1.0000 1A1 Energy other fuels N2O 5.96 5.96 0.0000 1.0000 1A3d Domestic liquid fuels CH4 4.10 4.10 0.0000 1.0000 1A5 liquid fuels CH4 3.98 3.98 0.0000 1.0000 1A3c liquid fuels N2O 2.93 2.93 0.0000 1.0000 1A3c liquid fuels CH4 2.75 2.75 0.0000 1.0000 2B8 Petrochemical and carbon black production N2O 1.96 1.96 0.0000 1.0000 1A4 Other peat N2O 1.59 1.59 0.0000 1.0000 2F3 Fire protection HFCs, PFCs, SF6 1A3e Other liquid fuels N2O 1.05 1.05 0.0000 1.0000

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 634 Level Assessment Cumulative Total 1A1 Energy biomass CH4 0.53 0.53 0.0000 1.0000 1A2 Manufacturing industries and other fuels N2O 0.30 0.30 0.0000 1.0000 2B1 Ammonia production CH4 0.29 0.29 0.0000 1.0000 2B1 Ammonia production N2O 0.27 0.27 0.0000 1.0000 1A1 Energy biomass N2O 0.22 0.22 0.0000 1.0000 1A2 Manufacturing industries and other fuels CH4 0.17 0.17 0.0000 1.0000 1A3e Other liquid fuels CH4 0.14 0.14 0.0000 1.0000 1B1 Coal mining and handling N2O 0.08 0.08 0.0000 1.0000 Total 808,950.83 808,950.83 1.0000 Level Assessment Cumulative Total 1A3b Road liquid fuels CO2 99,276.69 99,276.69 0.2084 0.2084 1A4 Other gaseous fuels CO2 76,850.07 76,850.07 0.1613 0.3697 1A1 Energy gaseous fuels CO2 54,199.83 54,199.83 0.1138 0.4835 1A2 Manufacturing industries and gaseous fuels CO2 24,871.53 24,871.53 0.0522 0.5357 3A1 Enteric fermentation from Cattle CH4 18,085.60 18,085.60 0.0380 0.5737 4A Forest land CO2 -18,082.25 18,082.25 0.0380 0.6116

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 635 Level Assessment Cumulative Total 1A2 Manufacturing industries and liquid fuels CO2 14,227.59 14,227.59 0.0299 0.6415 1A4 Other liquid fuels CO2 13,868.78 13,868.78 0.0291 0.6706 5A Solid waste disposal CH4 13,777.09 13,777.09 0.0289 0.6995 4B Cropland CO2 12,690.21 12,690.21 0.0266 0.7262 1A1 Energy liquid fuels CO2 11,869.05 11,869.05 0.0249 0.7511 3D Agricultural soils N2O 10,999.18 10,999.18 0.0231 0.7742 2C1 Iron and steel production CO2 10,605.21 10,605.21 0.0223 0.7964 2F1 Refrigeration and air conditioning HFCs, PFCs, SF6 9,161.95 9,161.95 0.0192 0.8157 1A1 Energy other fuels CO2 6,559.20 6,559.20 0.0138 0.8294 1A1 Energy solid fuels CO2 6,414.00 6,414.00 0.0135 0.8429 1A3d Domestic liquid fuels CO2 4,862.02 4,862.02 0.0102 0.8531 3A2 Enteric fermentation from Sheep CH4 4,714.58 4,714.58 0.0099 0.8630 1B2 Oil and gas extraction CH4 4,541.72 4,541.72 0.0095 0.8725 3B1 Manure management from Cattle CH4 4,290.16 4,290.16 0.0090 0.8816 2A1 Cement production CO2 4,215.15 4,215.15 0.0088 0.8904 4E Settlements CO2 3,799.29 3,799.29 0.0080 0.8984 1A2 Manufacturing industries and solid fuels CO2 3,482.14 3,482.14 0.0073 0.9057 4C Grassland CH4 2,861.40 2,861.40 0.0060 0.9117 4C Grassland CO2 -2,738.53 2,738.53 0.0057 0.9174 1B2 Oil and gas extraction CO2 2,682.64 2,682.64 0.0056 0.9231

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 636 Level Assessment Cumulative Total 3B2 Manure management from Sheep N2O 2,493.71 2,493.71 0.0052 0.9283 4D Wetlands CH4 2,382.01 2,382.01 0.0050 0.9333 4G Harvested wood products CO2 -2,037.46 2,037.46 0.0043 0.9376 5D Wastewater treatment and discharge CH4 1,959.38 1,959.38 0.0041 0.9417 1A4 Other solid fuels CO2 1,952.53 1,952.53 0.0041 0.9458 1A5 liquid fuels CO2 1,567.97 1,567.97 0.0033 0.9491 2B8 Petrochemical and carbon black production CO2 1,529.70 1,529.70 0.0032 0.9523 1A3c liquid fuels CO2 1,522.80 1,522.80 0.0032 0.9555 5B Biological treatment of solid waste CH4 1,373.84 1,373.84 0.0029 0.9584 2B1 Ammonia production CO2 1,178.74 1,178.74 0.0025 0.9609 3G Liming CO2 1,177.94 1,177.94 0.0025 0.9633 2A2 Lime production CO2 1,092.26 1,092.26 0.0023 0.9656 5D Wastewater treatment and discharge N2O 903.51 903.51 0.0019 0.9695 1A3a Domestic liquid fuels CO2 897.03 897.03 0.0019 0.9714 1A3b Road liquid fuels N2O 880.35 880.35 0.0018 0.9732 1A2 Manufacturing industries and other fuels CO2 683.27 683.27 0.0014 0.9747 5B Biological treatment of solid waste N2O 660.50 660.50 0.0014 0.9760 2G3 N2O from product uses N2O 593.71 593.71 0.0012 0.9773 4D Wetlands CO2 550.11 550.11 0.0012 0.9785

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 637 Level Assessment Cumulative Total 3A4 Enteric fermentation from Other livestock CH4 521.04 521.04 0.0011 0.9795 1B1 Coal mining and handling CH4 514.50 514.50 0.0011 0.9806 2A4 Other process uses of carbonates CO2 423.46 423.46 0.0009 0.9815 2D Non-energy products from fuels and solvent use CO2 402.41 402.41 0.0008 0.9824 4A Forest land N2O 377.40 377.40 0.0008 0.9832 4B Cropland N2O 354.68 354.68 0.0007 0.9839 2F2 Foam blowing agents HFCs, PFCs, SF6 2A3 Glass production CO2 340.25 340.25 0.0007 0.9854 5C Incineration and open burning of waste CO2 335.70 335.70 0.0007 0.9861 1A4 Other biomass CH4 335.24 335.24 0.0007 0.9868 2G1 Electrical equipment HFCs, PFCs, SF6 4B Cropland CH4 317.96 317.96 0.0007 0.9881 2F3 Fire protection HFCs, PFCs, SF6 4E Settlements N2O 254.78 254.78 0.0005 0.9893 3H Urea application to land CO2 252.57 252.57 0.0005 0.9898 3J Agriculture activities in OTs and CDs CH4 228.23 228.23 0.0005 0.9903 3A3 Enteric fermentation from Swine CH4 223.56 223.56 0.0005 0.9908 1A1 Energy gaseous fuels N2O 215.74 215.74 0.0005 0.9912 1A1 Energy biomass N2O 205.14 205.14 0.0004 0.9916

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 638 Level Assessment Cumulative Total 1B1 Coal mining and handling CO2 203.99 203.99 0.0004 0.9921 1A4 Other gaseous fuels CH4 191.50 191.50 0.0004 0.9925 1A3b Road gaseous fuels CO2 178.51 178.51 0.0004 0.9928 1A3b Road biomass CO2 166.35 166.35 0.0003 0.9932 1A4 Other solid fuels CH4 166.31 166.31 0.0003 0.9935 1A1 Energy biomass CH4 163.29 163.29 0.0003 0.9939 1A1 Energy other fuels CH4 161.15 161.15 0.0003 0.9942 2B6 Titanium dioxide production CO2 155.29 155.29 0.0003 0.9945 4 Indirect N2O emissions from LULUCF N2O 152.89 152.89 0.0003 0.9949 2B7 Soda ash production CO2 131.33 131.33 0.0003 0.9951 1A3e Other liquid fuels CO2 129.66 129.66 0.0003 0.9954 4C Grassland N2O 127.67 127.67 0.0003 0.9957 2G2 SF6 and PFCs from other product use HFCs, PFCs, SF6 2B9 Fluorochemical production HFCs, PFCs, SF6 1A2 Manufacturing industries and biomass N2O 113.93 113.93 0.0002 0.9964 1A1 Energy other fuels N2O 111.67 111.67 0.0002 0.9967 4A Forest land CH4 104.50 104.50 0.0002 0.9969 3J Agriculture activities in OTs and CDs N2O 103.91 103.91 0.0002 0.9971 1A1 Energy gaseous fuels CH4 98.42 98.42 0.0002 0.9973

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 639 Level Assessment Cumulative Total 1A2 Manufacturing industries and biomass CH4 90.53 90.53 0.0002 0.9975 1A3b Road liquid fuels CH4 82.08 82.08 0.0002 0.9977 1A4 Other liquid fuels N2O 81.50 81.50 0.0002 0.9978 1A2 Manufacturing industries and liquid fuels N2O 74.24 74.24 0.0002 0.9980 2G4 Other product manufacture and use N2O 72.46 72.46 0.0002 0.9981 5C Incineration and open burning of waste CH4 59.15 59.15 0.0001 0.9983 2C3 Aluminium production CO2 57.94 57.94 0.0001 0.9984 1A3d Domestic liquid fuels N2O 56.78 56.78 0.0001 0.9985 1A1 Energy liquid fuels N2O 44.07 44.07 0.0001 0.9986 1A4 Other biomass N2O 41.07 41.07 0.0001 0.9987 2C4 Magnesium production HFCs, PFCs, SF6 1A3c solid fuels CO2 38.41 38.41 0.0001 0.9989 1A4 Other gaseous fuels N2O 36.25 36.25 0.0001 0.9989 5C Incineration and open burning of waste N2O 35.35 35.35 0.0001 0.9990 1A4 Other liquid fuels CH4 31.09 31.09 0.0001 0.9991 2B10 Other Chemical Industry CH4 30.69 30.69 0.0001 0.9991 2F6 Other product uses as substitutes for ODS HFCs, PFCs, SF6 1A1 Energy solid fuels N2O 29.27 29.27 0.0001 0.9993 4E Settlements CH4 28.19 28.19 0.0001 0.9993

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 640 Level Assessment Cumulative Total 2B2 Nitric acid production N2O 28.09 28.09 0.0001 0.9994 1A2 Manufacturing industries and solid fuels N2O 24.82 24.82 0.0001 0.9994 1A4 Other solid fuels N2O 23.16 23.16 0.0000 0.9995 1B2 Oil and gas extraction N2O 22.21 22.21 0.0000 0.9995 4D Wetlands N2O 21.42 21.42 0.0000 0.9996 2E1 Integrated circuit or semiconductor HFCs, PFCs, SF6 1A5 liquid fuels N2O 15.03 15.03 0.0000 0.9997 1A2 Manufacturing industries and liquid fuels CH4 14.75 14.75 0.0000 0.9997 2C1 Iron and steel production CH4 12.93 12.93 0.0000 0.9997 1A2 Manufacturing industries and gaseous fuels CH4 12.40 12.40 0.0000 0.9998 1A2 Manufacturing industries and gaseous fuels N2O 11.73 11.73 0.0000 0.9998 1A2 Manufacturing industries and solid fuels CH4 10.29 10.29 0.0000 0.9998 2B8 Petrochemical and carbon black production CH4 9.90 9.90 0.0000 0.9998 1A2 Manufacturing industries and other fuels N2O 9.18 9.18 0.0000 0.9999 1A1 Energy liquid fuels CH4 8.73 8.73 0.0000 0.9999 1A4 Other peat CO2 7.71 7.71 0.0000 0.9999 1A3a Domestic liquid fuels N2O 7.55 7.55 0.0000 0.9999 1A3d Domestic liquid fuels CH4 7.39 7.39 0.0000 0.9999

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 641 Level Assessment Cumulative Total 1A2 Manufacturing industries and other fuels CH4 7.04 7.04 0.0000 0.9999 2C1 Iron and steel production N2O 6.54 6.54 0.0000 0.9999 2A4 Other process uses of carbonates CH4 4.75 4.75 0.0000 1.0000 1A3b Road gaseous fuels CH4 4.73 4.73 0.0000 1.0000 2C3 Aluminium production HFCs, PFCs, SF6 1A3c liquid fuels N2O 3.04 3.04 0.0000 1.0000 1A1 Energy solid fuels CH4 1.90 1.90 0.0000 1.0000 1A3e Other liquid fuels N2O 1.47 1.47 0.0000 1.0000 1A3a Domestic liquid fuels CH4 1.18 1.18 0.0000 1.0000 1A5 liquid fuels CH4 1.10 1.10 0.0000 1.0000 1A3c solid fuels CH4 0.98 0.98 0.0000 1.0000 2B8 Petrochemical and carbon black production N2O 0.74 0.74 0.0000 1.0000 1A4 Other peat CH4 0.61 0.61 0.0000 1.0000 1A3c liquid fuels CH4 0.54 0.54 0.0000 1.0000 2B1 Ammonia production CH4 0.23 0.23 0.0000 1.0000 2B1 Ammonia production N2O 0.22 0.22 0.0000 1.0000 1A3b Road gaseous fuels N2O 0.08 0.08 0.0000 1.0000 1A3c solid fuels N2O 0.07 0.07 0.0000 1.0000 1A4 Other peat N2O 0.03 0.03 0.0000 1.0000 1A3e Other liquid fuels CH4 0.02 0.02 0.0000 1.0000

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 642 Level Assessment Cumulative Total 1B1 Coal mining and handling N2O 0.02 0.02 0.0000 1.0000 Total 430,653.74 476,370.21 1.0000 Level Assessment Cumulative Total 1A3b Road liquid fuels CO2 99,276.69 99,276.69 0.2312 0.2312 1A4 Other gaseous fuels CO2 76,850.07 76,850.07 0.1789 0.4101 1A1 Energy gaseous fuels CO2 54,199.83 54,199.83 0.1262 0.5363 1A2 Manufacturing industries and gaseous fuels CO2 24,871.53 24,871.53 0.0579 0.5942 3A1 Enteric fermentation from Cattle CH4 18,085.60 18,085.60 0.0421 0.6363 1A2 Manufacturing industries and liquid fuels CO2 14,227.59 14,227.59 0.0331 0.6694 1A4 Other liquid fuels CO2 13,868.78 13,868.78 0.0323 0.7017 5A Solid waste disposal CH4 13,777.09 13,777.09 0.0321 0.7338 1A1 Energy liquid fuels CO2 11,869.05 11,869.05 0.0276 0.7614 3D Agricultural soils N2O 10,999.18 10,999.18 0.0256 0.7870 2C1 Iron and steel production CO2 10,605.21 10,605.21 0.0247 0.8117 2F1 Refrigeration and air conditioning HFCs, PFCs, SF6 9,161.95 9,161.95 0.0213 0.8331 1A1 Energy other fuels CO2 6,559.20 6,559.20 0.0153 0.8483

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 643 Level Assessment Cumulative Total 1A1 Energy solid fuels CO2 6,414.00 6,414.00 0.0149 0.8633 1A3d Domestic liquid fuels CO2 4,862.02 4,862.02 0.0113 0.8746 3A2 Enteric fermentation from Sheep CH4 4,714.58 4,714.58 0.0110 0.8856 1B2 Oil and gas extraction CH4 4,541.72 4,541.72 0.0106 0.8961 3B1 Manure management from Cattle CH4 4,290.16 4,290.16 0.0100 0.9061 2A1 Cement production CO2 4,215.15 4,215.15 0.0098 0.9159 1A2 Manufacturing industries and solid fuels CO2 3,482.14 3,482.14 0.0081 0.9241 1B2 Oil and gas extraction CO2 2,682.64 2,682.64 0.0062 0.9303 3B2 Manure management from Sheep N2O 2,493.71 2,493.71 0.0058 0.9361 5D Wastewater treatment and discharge CH4 1,959.38 1,959.38 0.0046 0.9407 1A4 Other solid fuels CO2 1,952.53 1,952.53 0.0045 0.9452 1A5 liquid fuels CO2 1,567.97 1,567.97 0.0037 0.9489 2B8 Petrochemical and carbon black production CO2 1,529.70 1,529.70 0.0036 0.9524 1A3c liquid fuels CO2 1,522.80 1,522.80 0.0035 0.9560 5B Biological treatment of solid waste CH4 1,373.84 1,373.84 0.0032 0.9592 2B1 Ammonia production CO2 1,178.74 1,178.74 0.0027 0.9619 3G Liming CO2 1,177.94 1,177.94 0.0027 0.9647 2A2 Lime production CO2 1,092.26 1,092.26 0.0025 0.9672 5D Wastewater treatment and discharge N2O 903.51 903.51 0.0021 0.9715

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 644 Level Assessment Cumulative Total 1A3a Domestic liquid fuels CO2 897.03 897.03 0.0021 0.9736 1A3b Road liquid fuels N2O 880.35 880.35 0.0020 0.9756 1A2 Manufacturing industries and other fuels CO2 683.27 683.27 0.0016 0.9772 5B Biological treatment of solid waste N2O 660.50 660.50 0.0015 0.9788 2G3 N2O from product uses N2O 593.71 593.71 0.0014 0.9801 3A4 Enteric fermentation from Other livestock CH4 521.04 521.04 0.0012 0.9814 1B1 Coal mining and handling CH4 514.50 514.50 0.0012 0.9826 2A4 Other process uses of carbonates CO2 423.46 423.46 0.0010 0.9835 2D Non-energy products from fuels and solvent use CO2 402.41 402.41 0.0009 0.9845 2F2 Foam blowing agents HFCs, PFCs, SF6 2A3 Glass production CO2 340.25 340.25 0.0008 0.9861 5C Incineration and open burning of waste CO2 335.70 335.70 0.0008 0.9869 1A4 Other biomass CH4 335.24 335.24 0.0008 0.9877 2G1 Electrical equipment HFCs, PFCs, SF6 2F3 Fire protection HFCs, PFCs, SF6 3H Urea application to land CO2 252.57 252.57 0.0006 0.9897 3J Agriculture activities in OTs and CDs CH4 228.23 228.23 0.0005 0.9902 3A3 Enteric fermentation from Swine CH4 223.56 223.56 0.0005 0.9908 1A1 Energy gaseous fuels N2O 215.74 215.74 0.0005 0.9913

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 645 Level Assessment Cumulative Total 1A1 Energy biomass N2O 205.14 205.14 0.0005 0.9917 1B1 Coal mining and handling CO2 203.99 203.99 0.0005 0.9922 1A4 Other gaseous fuels CH4 191.50 191.50 0.0004 0.9927 1A3b Road gaseous fuels CO2 178.51 178.51 0.0004 0.9931 1A3b Road biomass CO2 166.35 166.35 0.0004 0.9935 1A4 Other solid fuels CH4 166.31 166.31 0.0004 0.9938 1A1 Energy biomass CH4 163.29 163.29 0.0004 0.9942 1A1 Energy other fuels CH4 161.15 161.15 0.0004 0.9946 2B6 Titanium dioxide production CO2 155.29 155.29 0.0004 0.9950 2B7 Soda ash production CO2 131.33 131.33 0.0003 0.9953 1A3e Other liquid fuels CO2 129.66 129.66 0.0003 0.9956 2G2 SF6 and PFCs from other product use HFCs, PFCs, SF6 2B9 Fluorochemical production HFCs, PFCs, SF6 1A2 Manufacturing industries and biomass N2O 113.93 113.93 0.0003 0.9964 1A1 Energy other fuels N2O 111.67 111.67 0.0003 0.9967 3J Agriculture activities in OTs and CDs N2O 103.91 103.91 0.0002 0.9969 1A1 Energy gaseous fuels CH4 98.42 98.42 0.0002 0.9971 1A2 Manufacturing industries and biomass CH4 90.53 90.53 0.0002 0.9973 1A3b Road liquid fuels CH4 82.08 82.08 0.0002 0.9975

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 646 Level Assessment Cumulative Total 1A4 Other liquid fuels N2O 81.50 81.50 0.0002 0.9977 1A2 Manufacturing industries and liquid fuels N2O 74.24 74.24 0.0002 0.9979 2G4 Other product manufacture and use N2O 72.46 72.46 0.0002 0.9981 5C Incineration and open burning of waste CH4 59.15 59.15 0.0001 0.9982 2C3 Aluminium production CO2 57.94 57.94 0.0001 0.9983 1A3d Domestic liquid fuels N2O 56.78 56.78 0.0001 0.9985 1A1 Energy liquid fuels N2O 44.07 44.07 0.0001 0.9986 1A4 Other biomass N2O 41.07 41.07 0.0001 0.9987 2C4 Magnesium production HFCs, PFCs, SF6 1A3c solid fuels CO2 38.41 38.41 0.0001 0.9988 1A4 Other gaseous fuels N2O 36.25 36.25 0.0001 0.9989 5C Incineration and open burning of waste N2O 35.35 35.35 0.0001 0.9990 1A4 Other liquid fuels CH4 31.09 31.09 0.0001 0.9991 2B10 Other Chemical Industry CH4 30.69 30.69 0.0001 0.9992 2F6 Other product uses as substitutes for ODS HFCs, PFCs, SF6 1A1 Energy solid fuels N2O 29.27 29.27 0.0001 0.9993 2B2 Nitric acid production N2O 28.09 28.09 0.0001 0.9994 1A2 Manufacturing industries and solid fuels N2O 24.82 24.82 0.0001 0.9994 1A4 Other solid fuels N2O 23.16 23.16 0.0001 0.9995

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 647 Level Assessment Cumulative Total 1B2 Oil and gas extraction N2O 22.21 22.21 0.0001 0.9995 2E1 Integrated circuit or semiconductor HFCs, PFCs, SF6 1A5 liquid fuels N2O 15.03 15.03 0.0000 0.9996 1A2 Manufacturing industries and liquid fuels CH4 14.75 14.75 0.0000 0.9997 2C1 Iron and steel production CH4 12.93 12.93 0.0000 0.9997 1A2 Manufacturing industries and gaseous fuels CH4 12.40 12.40 0.0000 0.9997 1A2 Manufacturing industries and gaseous fuels N2O 11.73 11.73 0.0000 0.9998 1A2 Manufacturing industries and solid fuels CH4 10.29 10.29 0.0000 0.9998 2B8 Petrochemical and carbon black production CH4 9.90 9.90 0.0000 0.9998 1A2 Manufacturing industries and other fuels N2O 9.18 9.18 0.0000 0.9998 1A1 Energy liquid fuels CH4 8.73 8.73 0.0000 0.9999 1A4 Other peat CO2 7.71 7.71 0.0000 0.9999 1A3a Domestic liquid fuels N2O 7.55 7.55 0.0000 0.9999 1A3d Domestic liquid fuels CH4 7.39 7.39 0.0000 0.9999 1A2 Manufacturing industries and other fuels CH4 7.04 7.04 0.0000 0.9999 2C1 Iron and steel production N2O 6.54 6.54 0.0000 0.9999 2A4 Other process uses of carbonates CH4 4.75 4.75 0.0000 1.0000 1A3b Road gaseous fuels CH4 4.73 4.73 0.0000 1.0000

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 648 Level Assessment Cumulative Total 2C3 Aluminium production HFCs, PFCs, SF6 1A3c liquid fuels N2O 3.04 3.04 0.0000 1.0000 1A1 Energy solid fuels CH4 1.90 1.90 0.0000 1.0000 1A3e Other liquid fuels N2O 1.47 1.47 0.0000 1.0000 1A3a Domestic liquid fuels CH4 1.18 1.18 0.0000 1.0000 1A5 liquid fuels CH4 1.10 1.10 0.0000 1.0000 1A3c solid fuels CH4 0.98 0.98 0.0000 1.0000 2B8 Petrochemical and carbon black production N2O 0.74 0.74 0.0000 1.0000 1A4 Other peat CH4 0.61 0.61 0.0000 1.0000 1A3c liquid fuels CH4 0.54 0.54 0.0000 1.0000 2B1 Ammonia production CH4 0.23 0.23 0.0000 1.0000 2B1 Ammonia production N2O 0.22 0.22 0.0000 1.0000 1A3b Road gaseous fuels N2O 0.08 0.08 0.0000 1.0000 1A3c solid fuels N2O 0.07 0.07 0.0000 1.0000 1A4 Other peat N2O 0.03 0.03 0.0000 1.0000 1A3e Other liquid fuels CH4 0.02 0.02 0.0000 1.0000 1B1 Coal mining and handling N2O 0.02 0.02 0.0000 1.0000 Total 429,489.47 429,489.47 1.0000

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 649 Trend Assessment Contribution to 1A1 Energy solid fuels CO2 185,488.39 6,414.00 0.1066 0.2385 0.2385 1A1 Energy gaseous fuels CO2 11,939.20 54,199.83 0.0562 0.1257 0.3642 1A3b Road liquid fuels CO2 109,173.97 99,276.69 0.0492 0.1100 0.4742 1A4 Other gaseous fuels CO2 70,371.86 76,850.07 0.0467 0.1046 0.5788 5A Solid waste disposal CH4 67,633.35 13,777.09 0.0255 0.0570 0.6358 1B1 Coal mining and handling CH4 24,446.08 514.50 0.0144 0.0323 0.6681 1A2 Manufacturing industries and 1A1 Energy liquid fuels CO2 40,387.53 11,869.05 0.0109 0.0245 0.7202 2B3 Adipic acid production N2O 17,727.08 - 0.0109 0.0244 0.7446 2F1 Refrigeration and air conditioning HFCs, PFCs, SF6 201.39 9,161.95 0.0106 0.0237 0.7683 1A4 Other solid fuels CO2 19,824.90 1,952.53 0.0099 0.0222 0.7905 2B9 Fluorochemical production HFCs, PFCs, SF6 14,911.66 120.85 0.0090 0.0202 0.8107 1A2 Manufacturing industries and 3A1 Enteric fermentation from Cattle CH4 21,166.02 18,085.60 0.0082 0.0183 0.8477 1A1 Energy other fuels CO2 244.37 6,559.20 0.0075 0.0169 0.8645 4B Cropland CO2 14,230.88 12,690.21 0.0061 0.0137 0.8782

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 650 Trend Assessment Contribution to 3D Agricultural soils N2O 13,428.41 10,999.18 0.0046 0.0103 0.8886 1B2 Oil and gas extraction CH4 13,835.90 4,541.72 0.0032 0.0071 0.8957 1A4 Other liquid fuels CO2 21,465.76 13,868.78 0.0030 0.0068 0.9025 4A Forest land CO2 -13,940.16 -18,082.25 0.0029 0.0065 0.9090 3B1 Manure management from Cattle CH4 4,646.15 4,290.16 0.0022 0.0049 0.9139 4C Grassland CO2 -618.75 -2,738.53 0.0021 0.0048 0.9186 2C1 Iron and steel production CO2 23,628.28 10,605.21 0.0021 0.0047 0.9234 2B2 Nitric acid production N2O 3,432.78 28.09 0.0021 0.0047 0.9280 3A2 Enteric fermentation from Sheep CH4 5,858.92 4,714.58 0.0019 0.0043 0.9323 4C Grassland CH4 2,807.05 2,861.40 0.0016 0.0036 0.9360 5B Biological treatment of solid waste CH4 21.89 1,373.84 0.0016 0.0036 0.9395 1A5 liquid fuels CO2 5,293.44 1,567.97 0.0014 0.0032 0.9427 4D Wetlands CH4 2,313.24 2,382.01 0.0014 0.0031 0.9458 4G Harvested wood products CO2 -2,096.17 -2,037.46 0.0012 0.0028 0.9485 2B8 Petrochemical and carbon black 4E Settlements CO2 5,426.53 3,799.29 0.0011 0.0025 0.9535 3B2 Manure management from Sheep N2O 3,038.90 2,493.71 0.0011 0.0024 0.9559 1A3d Domestic liquid fuels CO2 7,611.13 4,862.02 0.0010 0.0023 0.9582 1A3c liquid fuels CO2 1,469.34 1,522.80 0.0009 0.0020 0.9601

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 651 Trend Assessment Contribution to 407.71 942.13 0.0009 0.0019 0.9620 5D Wastewater treatment and discharge CH4 2,365.31 1,959.38 0.0008 0.0019 0.9639 2C6 Zinc production CO2 1,350.65 - 0.0008 0.0019 0.9658 1B1 Coal mining and handling CO2 1,698.56 203.99 0.0008 0.0018 0.9676 1A3b Road liquid fuels CH4 1,408.61 82.08 0.0008 0.0017 0.9693 5B Biological treatment of solid waste N2O 12.36 660.50 0.0008 0.0017 0.9710 1A2 Manufacturing industries and 3G Liming CO2 1,019.16 1,177.94 0.0008 0.0017 0.9744 1A4 Other solid fuels CH4 1,440.83 166.31 0.0007 0.0015 0.9760 5D Wastewater treatment and discharge N2O 796.37 903.51 0.0006 0.0013 0.9772 1A1 Energy solid fuels N2O 939.47 29.27 0.0005 0.0012 0.9784 5C Incineration and open burning of waste CO2 1,445.17 335.70 0.0005 0.0011 0.9796 2A2 Lime production CO2 1,328.60 1,092.26 0.0005 0.0010 0.9806 2A1 Cement production CO2 7,295.26 4,215.15 0.0005 0.0010 0.9816 3A4 Enteric fermentation from Other livestock CH4 338.26 521.04 0.0004 0.0009 0.9825 2G3 N2O from product uses N2O 493.41 593.71 0.0004 0.0009 0.9834 1A2 Manufacturing industries and 2F3 Fire protection HFCs, PFCs, SF6 1.47 293.92 0.0003 0.0008 0.9849

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 652 Trend Assessment Contribution to 1A4 Other biomass CH4 100.88 335.24 0.0003 0.0007 0.9857 2F2 Foam blowing agents HFCs, PFCs, SF6 167.80 353.92 0.0003 0.0007 0.9864 1A3b Road liquid fuels N2O 1,176.81 880.35 0.0003 0.0007 0.9871 1A4 Other peat CO2 453.50 7.71 0.0003 0.0006 0.9877 2A4 Other process uses of carbonates CO2 1,198.69 423.46 0.0002 0.0005 0.9882 1A1 Energy biomass N2O 0.22 205.14 0.0002 0.0005 0.9887 4D Wetlands CO2 668.77 550.11 0.0002 0.0005 0.9893 2B1 Ammonia production CO2 1,895.00 1,178.74 0.0002 0.0005 0.9897 2C3 Aluminium production CO2 450.32 57.94 0.0002 0.0005 0.9902 1A3b Road gaseous fuels CO2 - 178.51 0.0002 0.0005 0.9907 2C4 Magnesium production HFCs, PFCs, SF6 399.06 40.68 0.0002 0.0004 0.9911 1A3b Road biomass CO2 - 166.35 0.0002 0.0004 0.9916 1A1 Energy biomass CH4 0.53 163.29 0.0002 0.0004 0.9920 2C3 Aluminium production HFCs, PFCs, SF6 299.84 4.32 0.0002 0.0004 0.9924 1A1 Energy other fuels CH4 20.77 161.15 0.0002 0.0004 0.9928 4A Forest land N2O 438.95 377.40 0.0002 0.0004 0.9932 4B Cropland CH4 332.36 317.96 0.0002 0.0004 0.9935 2A3 Glass production CO2 412.37 340.25 0.0001 0.0003 0.9939

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 653 Trend Assessment Contribution to 2D Non-energy products from fuels and 3F Field burning of agricultural residues CH4 209.47 - 0.0001 0.0003 0.9944 1A1 Energy other fuels N2O 5.96 111.67 0.0001 0.0003 0.9947 2G1 Electrical equipment HFCs, PFCs, SF6 828.89 330.09 0.0001 0.0003 0.9950 1A2 Manufacturing industries and 2B6 Titanium dioxide production CO2 104.63 155.29 0.0001 0.0003 0.9955 1A4 Other gaseous fuels CH4 176.56 191.50 0.0001 0.0003 0.9958 3H Urea application to land CO2 293.75 252.57 0.0001 0.0003 0.9961 1A1 Energy gaseous fuels N2O 232.10 215.74 0.0001 0.0002 0.9963 1A4 Other solid fuels N2O 218.14 23.16 0.0001 0.0002 0.9965 1A3a Domestic liquid fuels CO2 1,869.71 897.03 0.0001 0.0002 0.9968 1A2 Manufacturing industries and 2B10 Other Chemical Industry CH4 214.15 30.69 0.0001 0.0002 0.9972 1A3e Other liquid fuels CO2 98.14 129.66 0.0001 0.0002 0.9974 3J Agriculture activities in OTs and CDs CH4 306.10 228.23 0.0001 0.0002 0.9976 3A3 Enteric fermentation from Swine CH4 317.02 223.56 0.0001 0.0001 0.9977 4C Grassland N2O 134.86 127.67 0.0001 0.0001 0.9979 5C Incineration and open burning of waste CH4 213.78 59.15 0.0001 0.0001 0.9980

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 654 Trend Assessment Contribution to 4A Forest land CH4 99.49 104.50 0.0001 0.0001 0.9982 2G4 Other product manufacture and use N2O 40.20 72.46 0.0001 0.0001 0.9983 4E Settlements N2O 392.31 254.78 0.0001 0.0001 0.9984 1A2 Manufacturing industries and 1A3c solid fuels CO2 - 38.41 0.0000 0.0001 0.9986 1A4 Other liquid fuels N2O 83.51 81.50 0.0000 0.0001 0.9987 1A4 Other biomass N2O 12.04 41.07 0.0000 0.0001 0.9988 1A1 Energy solid fuels CH4 56.99 1.90 0.0000 0.0001 0.9989 3F Field burning of agricultural residues N2O 51.40 - 0.0000 0.0001 0.9990 1A1 Energy gaseous fuels CH4 144.26 98.42 0.0000 0.0001 0.9990 3J Agriculture activities in OTs and CDs N2O 155.42 103.91 0.0000 0.0001 0.9991 1A2 Manufacturing industries and 2G2 SF6 and PFCs from other product use HFCs, PFCs, SF6 191.54 121.01 0.0000 0.0001 0.9992 1A4 Other gaseous fuels N2O 33.42 36.25 0.0000 0.0000 0.9992 1A4 Other peat CH4 35.94 0.61 0.0000 0.0000 0.9993 4E Settlements CH4 19.03 28.19 0.0000 0.0000 0.9993 2F6 Other product uses as substitutes for ODS HFCs, PFCs, SF6 23.59 30.08 0.0000 0.0000 0.9994

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 655 Trend Assessment Contribution to 1A2 Manufacturing industries and 2E1 Integrated circuit or semiconductor HFCs, PFCs, SF6 11.10 19.44 0.0000 0.0000 0.9995 2A4 Other process uses of carbonates CH4 34.84 4.75 0.0000 0.0000 0.9995 2B7 Soda ash production CO2 224.40 131.33 0.0000 0.0000 0.9996 4B Cropland N2O 653.25 354.68 0.0000 0.0000 0.9996 1A1 Energy liquid fuels CH4 38.63 8.73 0.0000 0.0000 0.9996 4D Wetlands N2O 18.90 21.42 0.0000 0.0000 0.9997 1A5 liquid fuels N2O 49.91 15.03 0.0000 0.0000 0.9997 1B2 Oil and gas extraction CO2 5,088.53 2,682.64 0.0000 0.0000 0.9997 2C1 Iron and steel production CH4 43.92 12.93 0.0000 0.0000 0.9997 4 Indirect N2O emissions from LULUCF N2O 271.94 152.89 0.0000 0.0000 0.9998 1A2 Manufacturing industries and 1A1 Energy liquid fuels N2O 99.98 44.07 0.0000 0.0000 0.9998 2B8 Petrochemical and carbon black 1A3d Domestic liquid fuels N2O 93.38 56.78 0.0000 0.0000 0.9999 1A4 Other liquid fuels CH4 73.07 31.09 0.0000 0.0000 0.9999 1A2 Manufacturing industries and 1A3d Domestic liquid fuels CH4 4.10 7.39 0.0000 0.0000 0.9999

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 656 Trend Assessment Contribution to 1A2 Manufacturing industries and 1A2 Manufacturing industries and 1A3b Road gaseous fuels CH4 - 4.73 0.0000 0.0000 0.9999 1A2 Manufacturing industries and 2C1 Iron and steel production N2O 18.43 6.54 0.0000 0.0000 1.0000 5C Incineration and open burning of waste N2O 61.44 35.35 0.0000 0.0000 1.0000 1A3a Domestic liquid fuels CH4 7.69 1.18 0.0000 0.0000 1.0000 1A3c liquid fuels N2O 2.93 3.04 0.0000 0.0000 1.0000 1B2 Oil and gas extraction N2O 39.74 22.21 0.0000 0.0000 1.0000 1A5 liquid fuels CH4 3.98 1.10 0.0000 0.0000 1.0000 1A3c solid fuels CH4 - 0.98 0.0000 0.0000 1.0000 1A3e Other liquid fuels N2O 1.05 1.47 0.0000 0.0000 1.0000 1A3c liquid fuels CH4 2.75 0.54 0.0000 0.0000 1.0000 1A4 Other peat N2O 1.59 0.03 0.0000 0.0000 1.0000 1A3a Domestic liquid fuels N2O 15.74 7.55 0.0000 0.0000 1.0000 2B8 Petrochemical and carbon black 1A3b Road gaseous fuels N2O - 0.08 0.0000 0.0000 1.0000 2B1 Ammonia production CH4 0.29 0.23 0.0000 0.0000 1.0000

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 657 Trend Assessment Contribution to 2B1 Ammonia production N2O 0.27 0.22 0.0000 0.0000 1.0000 1A3c solid fuels N2O - 0.07 0.0000 0.0000 1.0000 1A3e Other liquid fuels CH4 0.14 0.02 0.0000 0.0000 1.0000 1B1 Coal mining and handling N2O 0.08 0.02 0.0000 0.0000 1.0000 Total 820,103.31 430,653.74 0.4470 1.0000 Trend Assessment Contribution to 1A1 Energy solid fuels CO2 185,488.39 6,414.00 0.1066 0.2482 0.2482 1A1 Energy gaseous fuels CO2 11,939.20 54,199.83 0.0562 0.1307 0.3789 1A3b Road liquid fuels CO2 109,173.97 99,276.69 0.0492 0.1144 0.4933 1A4 Other gaseous fuels CO2 70,371.86 76,850.07 0.0467 0.1088 0.6021 5A Solid waste disposal CH4 67,633.35 13,777.09 0.0255 0.0593 0.6614 1B1 Coal mining and handling CH4 24,446.08 514.50 0.0144 0.0336 0.6950 1A2 Manufacturing industries and 1A1 Energy liquid fuels CO2 40,387.53 11,869.05 0.0109 0.0255 0.7492 2B3 Adipic acid production N2O 17,727.08 - 0.0109 0.0254 0.7746

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 658 Trend Assessment Contribution to 2F1 Refrigeration and air conditioning HFCs, PFCs, SF6 201.39 9,161.95 0.0106 0.0247 0.7993 1A4 Other solid fuels CO2 19,824.90 1,952.53 0.0099 0.0231 0.8224 2B9 Fluorochemical production HFCs, PFCs, SF6 14,911.66 120.85 0.0090 0.0210 0.8434 1A2 Manufacturing industries and 3A1 Enteric fermentation from Cattle CH4 21,166.02 18,085.60 0.0082 0.0190 0.8818 1A1 Energy other fuels CO2 244.37 6,559.20 0.0075 0.0175 0.8994 3D Agricultural soils N2O 13,428.41 10,999.18 0.0046 0.0108 0.9101 1B2 Oil and gas extraction CH4 13,835.90 4,541.72 0.0032 0.0074 0.9176 1A4 Other liquid fuels CO2 21,465.76 13,868.78 0.0030 0.0071 0.9247 3B1 Manure management from Cattle CH4 4,646.15 4,290.16 0.0022 0.0050 0.9297 2C1 Iron and steel production CO2 23,628.28 10,605.21 0.0021 0.0049 0.9346 2B2 Nitric acid production N2O 3,432.78 28.09 0.0021 0.0048 0.9395 3A2 Enteric fermentation from Sheep CH4 5,858.92 4,714.58 0.0019 0.0045 0.9439 5B Biological treatment of solid waste CH4 21.89 1,373.84 0.0016 0.0037 0.9476 1A5 liquid fuels CO2 5,293.44 1,567.97 0.0014 0.0033 0.9509 2B8 Petrochemical and carbon black production CO2 4,751.56 1,529.70 0.0011 0.0026 0.9536 3B2 Manure management from Sheep N2O 3,038.90 2,493.71 0.0011 0.0024 0.9560 1A3d Domestic liquid fuels CO2 7,611.13 4,862.02 0.0010 0.0024 0.9584 1A3c liquid fuels CO2 1,469.34 1,522.80 0.0009 0.0020 0.9604

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 659 Trend Assessment Contribution to 407.71 942.13 0.0009 0.0020 0.9624 5D Wastewater treatment and discharge CH4 2,365.31 1,959.38 0.0008 0.0020 0.9644 2C6 Zinc production CO2 1,350.65 - 0.0008 0.0019 0.9663 1B1 Coal mining and handling CO2 1,698.56 203.99 0.0008 0.0019 0.9682 1A3b Road liquid fuels CH4 1,408.61 82.08 0.0008 0.0018 0.9700 5B Biological treatment of solid waste N2O 12.36 660.50 0.0008 0.0018 0.9718 1A2 Manufacturing industries and 3G Liming CO2 1,019.16 1,177.94 0.0008 0.0018 0.9753 1A4 Other solid fuels CH4 1,440.83 166.31 0.0007 0.0016 0.9769 5D Wastewater treatment and discharge N2O 796.37 903.51 0.0006 0.0013 0.9782 1A1 Energy solid fuels N2O 939.47 29.27 0.0005 0.0013 0.9795 5C Incineration and open burning of waste CO2 1,445.17 335.70 0.0005 0.0012 0.9806 2A2 Lime production CO2 1,328.60 1,092.26 0.0005 0.0011 0.9817 2A1 Cement production CO2 7,295.26 4,215.15 0.0005 0.0010 0.9828 3A4 Enteric fermentation from Other livestock CH4 338.26 521.04 0.0004 0.0009 0.9837 2G3 N2O from product uses N2O 493.41 593.71 0.0004 0.0009 0.9846 1A2 Manufacturing industries and 2F3 Fire protection HFCs, PFCs, SF6 1.47 293.92 0.0003 0.0008 0.9862

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 660 Trend Assessment Contribution to 1A4 Other biomass CH4 100.88 335.24 0.0003 0.0008 0.9870 2F2 Foam blowing agents HFCs, PFCs, SF6 167.80 353.92 0.0003 0.0007 0.9877 1A3b Road liquid fuels N2O 1,176.81 880.35 0.0003 0.0007 0.9884 1A4 Other peat CO2 453.50 7.71 0.0003 0.0006 0.9891 2A4 Other process uses of carbonates CO2 1,198.69 423.46 0.0002 0.0006 0.9896 1A1 Energy biomass N2O 0.22 205.14 0.0002 0.0006 0.9902 2B1 Ammonia production CO2 1,895.00 1,178.74 0.0002 0.0005 0.9907 2C3 Aluminium production CO2 450.32 57.94 0.0002 0.0005 0.9912 1A3b Road gaseous fuels CO2 - 178.51 0.0002 0.0005 0.9917 2C4 Magnesium production HFCs, PFCs, SF6 399.06 40.68 0.0002 0.0005 0.9921 1A3b Road biomass CO2 - 166.35 0.0002 0.0005 0.9926 1A1 Energy biomass CH4 0.53 163.29 0.0002 0.0004 0.9930 2C3 Aluminium production HFCs, PFCs, SF6 299.84 4.32 0.0002 0.0004 0.9934 1A1 Energy other fuels CH4 20.77 161.15 0.0002 0.0004 0.9938 2A3 Glass production CO2 412.37 340.25 0.0001 0.0003 0.9942 2D Non-energy products from fuels and 3F Field burning of agricultural residues CH4 209.47 - 0.0001 0.0003 0.9948 1A1 Energy other fuels N2O 5.96 111.67 0.0001 0.0003 0.9951

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 661 Trend Assessment Contribution to 2G1 Electrical equipment HFCs, PFCs, SF6 828.89 330.09 0.0001 0.0003 0.9954 1A2 Manufacturing industries and 2B6 Titanium dioxide production CO2 104.63 155.29 0.0001 0.0003 0.9959 1A4 Other gaseous fuels CH4 176.56 191.50 0.0001 0.0003 0.9962 3H Urea application to land CO2 293.75 252.57 0.0001 0.0003 0.9965 1A1 Energy gaseous fuels N2O 232.10 215.74 0.0001 0.0003 0.9967 1A4 Other solid fuels N2O 218.14 23.16 0.0001 0.0002 0.9970 1A3a Domestic liquid fuels CO2 1,869.71 897.03 0.0001 0.0002 0.9972 1A2 Manufacturing industries and 2B10 Other Chemical Industry CH4 214.15 30.69 0.0001 0.0002 0.9977 1A3e Other liquid fuels CO2 98.14 129.66 0.0001 0.0002 0.9979 3J Agriculture activities in OTs and CDs CH4 306.10 228.23 0.0001 0.0002 0.9981 3A3 Enteric fermentation from Swine CH4 317.02 223.56 0.0001 0.0002 0.9982 5C Incineration and open burning of waste CH4 213.78 59.15 0.0001 0.0001 0.9984 2G4 Other product manufacture and use N2O 40.20 72.46 0.0001 0.0001 0.9985 1A2 Manufacturing industries and 1A3c solid fuels CO2 - 38.41 0.0000 0.0001 0.9987 1A4 Other liquid fuels N2O 83.51 81.50 0.0000 0.0001 0.9988

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 662 Trend Assessment Contribution to 1A4 Other biomass N2O 12.04 41.07 0.0000 0.0001 0.9989 1A1 Energy solid fuels CH4 56.99 1.90 0.0000 0.0001 0.9990 3F Field burning of agricultural residues N2O 51.40 - 0.0000 0.0001 0.9991 1A1 Energy gaseous fuels CH4 144.26 98.42 0.0000 0.0001 0.9991 3J Agriculture activities in OTs and CDs N2O 155.42 103.91 0.0000 0.0001 0.9992 1A2 Manufacturing industries and 2G2 SF6 and PFCs from other product use HFCs, PFCs, SF6 191.54 121.01 0.0000 0.0001 0.9993 1A4 Other gaseous fuels N2O 33.42 36.25 0.0000 0.0001 0.9993 1A4 Other peat CH4 35.94 0.61 0.0000 0.0000 0.9994 2F6 Other product uses as substitutes for ODS HFCs, PFCs, SF6 23.59 30.08 0.0000 0.0000 0.9994 1A2 Manufacturing industries and 2E1 Integrated circuit or semiconductor HFCs, PFCs, SF6 11.10 19.44 0.0000 0.0000 0.9996 2A4 Other process uses of carbonates CH4 34.84 4.75 0.0000 0.0000 0.9996 2B7 Soda ash production CO2 224.40 131.33 0.0000 0.0000 0.9996 1A1 Energy liquid fuels CH4 38.63 8.73 0.0000 0.0000 0.9997 1A5 liquid fuels N2O 49.91 15.03 0.0000 0.0000 0.9997

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 663 Trend Assessment Contribution to 1B2 Oil and gas extraction CO2 5,088.53 2,682.64 0.0000 0.0000 0.9997 2C1 Iron and steel production CH4 43.92 12.93 0.0000 0.0000 0.9998 1A2 Manufacturing industries and 1A1 Energy liquid fuels N2O 99.98 44.07 0.0000 0.0000 0.9998 2B8 Petrochemical and carbon black production CH4 33.79 9.90 0.0000 0.0000 0.9998 1A3d Domestic liquid fuels N2O 93.38 56.78 0.0000 0.0000 0.9998 1A4 Other liquid fuels CH4 73.07 31.09 0.0000 0.0000 0.9999 1A2 Manufacturing industries and 1A3d Domestic liquid fuels CH4 4.10 7.39 0.0000 0.0000 0.9999 1A2 Manufacturing industries and 1A2 Manufacturing industries and 1A3b Road gaseous fuels CH4 - 4.73 0.0000 0.0000 0.9999 1A2 Manufacturing industries and 2C1 Iron and steel production N2O 18.43 6.54 0.0000 0.0000 1.0000 5C Incineration and open burning of waste N2O 61.44 35.35 0.0000 0.0000 1.0000 1A3a Domestic liquid fuels CH4 7.69 1.18 0.0000 0.0000 1.0000 1A3c liquid fuels N2O 2.93 3.04 0.0000 0.0000 1.0000 1B2 Oil and gas extraction N2O 39.74 22.21 0.0000 0.0000 1.0000

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 664 Trend Assessment Contribution to 1A5 liquid fuels CH4 3.98 1.10 0.0000 0.0000 1.0000 1A3c solid fuels CH4 - 0.98 0.0000 0.0000 1.0000 1A3e Other liquid fuels N2O 1.05 1.47 0.0000 0.0000 1.0000 1A3c liquid fuels CH4 2.75 0.54 0.0000 0.0000 1.0000 1A4 Other peat N2O 1.59 0.03 0.0000 0.0000 1.0000 1A3a Domestic liquid fuels N2O 15.74 7.55 0.0000 0.0000 1.0000 2B8 Petrochemical and carbon black production N2O 1.96 0.74 0.0000 0.0000 1.0000 1A3b Road gaseous fuels N2O - 0.08 0.0000 0.0000 1.0000 2B1 Ammonia production CH4 0.29 0.23 0.0000 0.0000 1.0000 2B1 Ammonia production N2O 0.27 0.22 0.0000 0.0000 1.0000 1A3c solid fuels N2O - 0.07 0.0000 0.0000 1.0000 1A3e Other liquid fuels CH4 0.14 0.02 0.0000 0.0000 1.0000 1B1 Coal mining and handling N2O 0.08 0.02 0.0000 0.0000 1.0000 Total 808,950.83 429,489.47 0.4296 1.0000 Following the 2006 IPCC Guidelines, the UK has also completed an Approach 2 KCA for both level and trend, which takes into ac count

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 665 The results of the level assessment (based on Approach 2) with and without LULUCF for the base year and the latest reported year are shown in final column after this sorting process, which accounts for 90% of the uncertainty in level.
The results of the trend assessment (based on Approach 2) with and without LULUCF for the base year to the latest reported year, are shown in result; an absolute function is used since Land Use, Land Use Change and Forestry contains negative sources (sinks) and the absolute function key source categories are those whose contributions add up to 90% of the sum of the level parameter in the final column after this sorting process, which accounts for 90% of the uncertainty in trend. Any methodological improvements to the uncertainty analysis are discussed in ANNEX 2:.
Level Assessment Cumulative Total 5A 5A Solid Waste Disposal CH4 67633.35 67633.35 0.3161 0.3161 1A 1A Coal CO2 225522.71 225522.71 0.0801 0.3962 1A 1A (Stationary) Oil CO2 94802.30 94802.30 0.0588 0.4551 1B2 1B2 Natural Gas Transmission CH4 11880.19 11880.19 0.0577 0.5127 1B1 1B1 Coal Mining CH4 24445.88 24445.88 0.0475 0.5602

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 666 Level Assessment Cumulative Total 5C 5C Waste Incineration CO2 1445.17 1445.17 0.0344 0.5946 4B 4B Cropland CO2 14230.88 14230.88 0.0275 0.6221 4E 4E Settlements CO2 5426.53 5426.53 0.0236 0.6457 1A 1A Natural Gas CO2 109602.23 109602.23 0.0212 0.6670 3D 3D Agricultural Soils N2O 13428.41 13428.41 0.0212 0.6881 2B 2B Chemical industries N2O 21162.10 21162.10 0.0205 0.7086 4A 4A Forest Land CO2 -13940.16 13940.16 0.0202 0.7288 2C 2C Metal Industries CO2 25429.25 25429.25 0.0169 0.7457 5D 5D Wastewater Handling N2O 796.37 796.37 0.0167 0.7624 1B2 1B2 Offshore Oil& Gas CH4 1955.71 1955.71 0.0166 0.7790 1A3b 1A3b Gasoline/ LPG CO2 75379.45 75379.45 0.0162 0.7952 2B 2B Chemical industry HFCs 14807.32 14807.32 0.0143 0.8095 1A3d 1A3d Marine fuel CO2 7611.13 7611.13 0.0132 0.8227 1A1 & 1A2 & 1A4 & 1A5 Other Combustion N2O 1936.80 1936.80 0.0122 0.8349 5D 5D Wastewater Handling CH4 2365.31 2365.31 0.0120 0.8468 4C 4C Grassland CH4 2807.05 2807.05 0.0109 0.8577 2B 2B Chemical industries CO2 6975.59 6975.59 0.0105 0.8681 1A3b 1A3b Gasoline/ LPG CH4 1308.55 1308.55 0.0095 0.8776 3A 3A Enteric Fermentation CH4 27680.22 27680.22 0.0091 0.8867

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 667 Level Assessment Cumulative Total 4D 4D Wetland CH4 2313.24 2313.24 0.0078 0.8945 1A3b 1A3b DERV CO2 33792.87 33792.87 0.0073 0.9018 2G 2G Other Product Manufacture and Use N2O 533.61 533.61 0.0073 0.9091 1A1 & 1A2 & 1A4 & 1A5 Other Combustion CH4 2207.13 2207.13 0.0070 0.9162 3B 3B Manure Management N2O 3038.90 3038.90 0.0067 0.9228 1A3b 1A3b Gasoline/ LPG N2O 887.83 887.83 0.0064 0.9292 5C 5C Waste Incineration CH4 213.78 213.78 0.0056 0.9348 4E 4E Settlements N2O 392.31 392.31 0.0049 0.9397 4 4 Indirect LULUCF Emissions N2O 271.94 271.94 0.0043 0.9441 1A3b 1A3b DERV N2O 288.98 288.98 0.0036 0.9477 4A 4A Forest land N2O 438.95 438.95 0.0036 0.9513 1A3a 1A3a Aviation Fuel CO2 1869.71 1869.71 0.0035 0.9548 1B2 1B2 Oil & Natural Gas CO2 5088.53 5088.53 0.0031 0.9579 4G 4G Other Activities CO2 -2096.17 2096.17 0.0030 0.9609 3B 3B Manure Management CH4 4646.15 4646.15 0.0030 0.9640 2D 2D Non Energy Products from Fuels and Solvent Use CO2 552.81 552.81 0.0030 0.9670 4B 4B Cropland CH4 332.36 332.36 0.0029 0.9699 2A 2A Mineral Industries CO2 10234.92 10234.92 0.0024 0.9722 4B 4B Cropland N2O 653.25 653.25 0.0022 0.9744

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 668 Level Assessment Cumulative Total 3J 3J OT & CD Agriculture CH4 306.10 306.10 0.0021 0.9765 1A3 1A3 Other diesel CO2 1567.49 1567.49 0.0021 0.9786 3G 3G Liming CO2 1019.16 1019.16 0.0021 0.9807 3H 3H Urea application to agriculture CO2 293.75 293.75 0.0014 0.9821 1A4 1A4 Peat CO2 453.50 453.50 0.0014 0.9835 5C 5C Waste Incineration N2O 61.44 61.44 0.0014 0.9848 4D 4D Wetland CO2 668.77 668.77 0.0013 0.9861 1A3b 1A3b DERV CH4 100.06 100.06 0.0013 0.9874 1B1 1B1 Solid Fuel Transformation CO2 1698.56 1698.56 0.0012 0.9886 4C 4C Grassland CO2 -618.75 618.75 0.0012 0.9898 3J 3J OT & CD Agriculture N2O 155.42 155.42 0.0011 0.9909 1A3d 1A3d Marine fuel N2O 93.38 93.38 0.0011 0.9919 2F 2F Product Uses as Substitutes for ODS HFCs 801.49 801.49 0.0009 0.9928 4A 4A Forest Land CH4 99.49 99.49 0.0008 0.9937 4C 4C Grassland N2O 134.86 134.86 0.0006 0.9942 2G 2G Other Product Manufacture and Use PFCs 128.63 128.63 0.0006 0.9948 2C 2C Metal Industries PFCs 299.84 299.84 0.0006 0.9954 3F 3F Field Burning CH4 209.47 209.47 0.0005 0.9959 2B 2B Chemical Industry CH4 248.23 248.23 0.0005 0.9964 2G 2G Other Product Manufacture and Use SF6 891.81 891.81 0.0005 0.9969

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 669 Level Assessment Cumulative Total 1B2 1B2 Oil & Natural Gas N2O 39.74 39.74 0.0004 0.9973 2A 2A Mineral Industries CH4 34.84 34.84 0.0003 0.9976 1A 1A Other (waste) CO2 245.37 245.37 0.0003 0.9979 2C 2C Metal Industries SF6 399.06 399.06 0.0003 0.9982 5B 5B Biological treatment of solid waste CH4 21.89 21.89 0.0002 0.9984 2C 2C Iron & Steel N2O 18.43 18.43 0.0002 0.9986 1A4 1A4 Petroleum Coke CO2 81.64 81.64 0.0002 0.9988 2C 2C Iron & Steel Production CH4 43.92 43.92 0.0002 0.9990 4D 4D Wetland N2O 18.90 18.90 0.0002 0.9992 1A3a 1A3a Aviation Fuel N2O 15.74 15.74 0.0002 0.9993 3F 3F Field Burning N2O 51.40 51.40 0.0001 0.9995 5B 5B Biological treatment of solid waste N2O 12.36 12.36 0.0001 0.9996 2B 2B Chemical industry PFCs 104.34 104.34 0.0001 0.9997 4E 4E Settlements CH4 19.03 19.03 0.0001 0.9998 1A3d 1A3d Marine fuel CH4 4.10 4.10 0.0001 0.9998 1A3 1A3 Other diesel N2O 3.98 3.98 0.0001 0.9999 2E 2E Electronics Industry HFCs 10.84 10.84 0.0000 0.9999 1A3a 1A3a Aviation Fuel CH4 7.69 7.69 0.0000 1.0000 1A3 1A3 Other diesel CH4 2.88 2.88 0.0000 1.0000 2E 2E Electronics Industry NF3 0.26 0.26 0.0000 1.0000

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 670 Level Assessment Cumulative Total 2F 2F Product Uses as Substitutes for ODS PFCs 0.46 0.46 0.0000 1.0000 1B1 1B1 Solid Fuel Transformation CH4 0.20 0.20 0.0000 1.0000 1B1 1B1 Fugitive Emissions from Solid Fuels N2O 0.08 0.08 0.0000 1.0000 1A3 1A3 Natural Gas CO2 0.00 0.00 0.0000 1.0000 1A3c 1A3c Coal CO2 0.00 0.00 0.0000 1.0000 1B2 1B2 Other Energy Industries CO2 0.00 0.00 0.0000 1.0000 4F 4F Other Land CO2 0.00 0.00 0.0000 1.0000 1A3 1A3 Natural Gas CH4 0.00 0.00 0.0000 1.0000 1A3c 1A3c Coal CH4 0.00 0.00 0.0000 1.0000 2D 2D Non-energy Products from Fuels and Solvent Use CH4 0.00 0.00 0.0000 1.0000 1A3 1A3 Natural Gas N2O 0.00 0.00 0.0000 1.0000 1A3c 1A3c Coal N2O 0.00 0.00 0.0000 1.0000 2D 2D Non-energy Products from Fuels and Solvent Use N2O 0.00 0.00 0.0000 1.0000 2C 2C Metal Industries HFCs 0.00 0.00 0.0000 1.0000 Total 820,103.31 853,413.47 1

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 671 emissions (Gg CO2e) Level Assessment Cumulative Total 5A 5A Solid Waste Disposal CH4 13777.09 13777.09 0.1381 0.1381 1A 1A Natural Gas CO2 155921.42 155921.42 0.0647 0.2028 4A 4A Forest Land CO2 -18082.25 18082.25 0.0563 0.2591 1A 1A (Stationary) Oil CO2 41428.77 41428.77 0.0551 0.3143 4B 4B Cropland CO2 12690.21 12690.21 0.0526 0.3669 5D 5D Wastewater Handling N2O 903.51 903.51 0.0406 0.4075 1B2 1B2 Natural Gas Transmission CH4 3711.37 3711.37 0.0386 0.4462 3D 3D Agricultural Soils N2O 10999.18 10999.18 0.0372 0.4834 4E 4E Settlements CO2 3799.29 3799.29 0.0354 0.5188 1A3b 1A3b DERV CO2 68500.76 68500.76 0.0317 0.5505 5B 5B Biological treatment of solid waste CH4 1373.84 1373.84 0.0296 0.5801 2F 2F Product Uses as Substitutes for ODS HFCs 10798.35 10798.35 0.0270 0.6071 4C 4C Grassland CH4 2861.40 2861.40 0.0237 0.6308 1A3b 1A3b DERV N2O 805.91 805.91 0.0217 0.6525 5D 5D Wastewater Handling CH4 1959.38 1959.38 0.0213 0.6738 1A 1A Other (waste) CO2 7042.63 7042.63 0.0205 0.6943 2G 2G Other Product Manufacture and Use N2O 666.17 666.17 0.0195 0.7138 1A3d 1A3d Marine fuel CO2 4862.02 4862.02 0.0181 0.7319

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 672 emissions (Gg CO2e) Level Assessment Cumulative Total 4D 4D Wetland CH4 2382.01 2382.01 0.0173 0.7492 5C 5C Waste Incineration CO2 335.70 335.70 0.0171 0.7663 3A 3A Enteric Fermentation CH4 23544.77 23544.77 0.0166 0.7829 2C 2C Metal Industries CO2 10663.15 10663.15 0.0152 0.7981 1B2 1B2 Offshore Oil& Gas CH4 830.35 830.35 0.0151 0.8132 1A3b 1A3b Gasoline/ LPG CO2 30775.54 30775.54 0.0142 0.8273 1A1 & 1A2 & 1A4 & 1A5 Other Combustion N2O 1036.85 1036.85 0.0140 0.8413 5B 5B Biological treatment of solid waste N2O 660.50 660.50 0.0130 0.8543 3B 3B Manure Management N2O 2493.71 2493.71 0.0117 0.8660 4C 4C Grassland CO2 -2738.53 2738.53 0.0114 0.8774 2B 2B Chemical industries CO2 2995.07 2995.07 0.0096 0.8870 1A 1A Coal CO2 11848.67 11848.67 0.0090 0.8960 1A1 & 1A2 & 1A4 & 1A5 Other Combustion CH4 1294.38 1294.38 0.0089 0.9049 4E 4E Settlements N2O 254.78 254.78 0.0069 0.9117 4A 4A Forest land N2O 377.40 377.40 0.0066 0.9184 4G 4G Other Activities CO2 -2037.46 2037.46 0.0063 0.9247 3B 3B Manure Management CH4 4290.16 4290.16 0.0060 0.9307 4B 4B Cropland CH4 317.96 317.96 0.0059 0.9367

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 673 emissions (Gg CO2e) Level Assessment Cumulative Total 4 4 Indirect LULUCF Emissions N2O 152.89 152.89 0.0052 0.9419 1A3 1A3 Other diesel CO2 1818.80 1818.80 0.0052 0.9471 3G 3G Liming CO2 1177.94 1177.94 0.0051 0.9522 2D 2D Non Energy Products from Fuels and Solvent Use CO2 402.41 402.41 0.0047 0.9569 1A3a 1A3a Aviation Fuel CO2 897.03 897.03 0.0036 0.9605 1B2 1B2 Oil & Natural Gas CO2 2658.99 2658.99 0.0035 0.9639 3J 3J OT & CD Agriculture CH4 228.23 228.23 0.0033 0.9673 5C 5C Waste Incineration CH4 59.15 59.15 0.0033 0.9706 2A 2A Mineral Industries CO2 6071.12 6071.12 0.0030 0.9736 3H 3H Urea application to agriculture CO2 252.57 252.57 0.0026 0.9762 4B 4B Cropland N2O 354.68 354.68 0.0026 0.9788 4D 4D Wetland CO2 550.11 550.11 0.0023 0.9811 1B1 1B1 Coal Mining CH4 510.23 510.23 0.0021 0.9832 4A 4A Forest Land CH4 104.50 104.50 0.0018 0.9850 5C 5C Waste Incineration N2O 35.35 35.35 0.0017 0.9867 1A4 1A4 Petroleum Coke CO2 304.86 304.86 0.0016 0.9883 3J 3J OT & CD Agriculture N2O 103.91 103.91 0.0015 0.9898 1A3d 1A3d Marine fuel N2O 56.78 56.78 0.0014 0.9912 4C 4C Grassland N2O 127.67 127.67 0.0012 0.9924 1A3b 1A3b Gasoline/ LPG CH4 75.05 75.05 0.0012 0.9936

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 674 emissions (Gg CO2e) Level Assessment Cumulative Total 1A3b 1A3b Gasoline/ LPG N2O 74.45 74.45 0.0012 0.9947 2G 2G Other Product Manufacture and Use PFCs 67.70 67.70 0.0007 0.9954 1B2 1B2 Oil & Natural Gas N2O 22.21 22.21 0.0005 0.9958 2G 2G Other Product Manufacture and Use SF6 383.40 383.40 0.0004 0.9963 4D 4D Wetland N2O 21.42 21.42 0.0004 0.9967 1B2 1B2 Other Energy Industries CO2 23.65 23.65 0.0003 0.9970 1B1 1B1 Solid Fuel Transformation CO2 203.99 203.99 0.0003 0.9973 2B 2B Chemical industry PFCs 120.85 120.85 0.0003 0.9976 4E 4E Settlements CH4 28.19 28.19 0.0002 0.9978 1A3 1A3 Natural Gas CO2 178.51 178.51 0.0002 0.9980 1A3d 1A3d Marine fuel CH4 7.39 7.39 0.0002 0.9982 1A3b 1A3b DERV CH4 7.04 7.04 0.0002 0.9984 2E 2E Electronics Industry HFCs 19.10 19.10 0.0002 0.9986 2B 2B Chemical Industry CH4 40.83 40.83 0.0002 0.9987 1A3a 1A3a Aviation Fuel N2O 7.55 7.55 0.0002 0.9989 1A3c 1A3c Coal CO2 38.41 38.41 0.0002 0.9991 2C 2C Iron & Steel N2O 6.54 6.54 0.0002 0.9992 1A3 1A3 Natural Gas CH4 4.73 4.73 0.0001 0.9994 1A3 1A3 Other diesel N2O 4.51 4.51 0.0001 0.9995 2C 2C Iron & Steel Production CH4 12.93 12.93 0.0001 0.9996

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 675 emissions (Gg CO2e) Level Assessment Cumulative Total 2A 2A Mineral Industries CH4 4.75 4.75 0.0001 0.9997 2B 2B Chemical industries N2O 29.05 29.05 0.0001 0.9998 2C 2C Metal Industries SF6 38.42 38.42 0.0001 0.9998 1A4 1A4 Peat CO2 7.71 7.71 0.0001 0.9999 1B1 1B1 Solid Fuel Transformation CH4 4.27 4.27 0.0000 0.9999 1A3c 1A3c Coal CH4 0.98 0.98 0.0000 0.9999 2C 2C Metal Industries PFCs 4.32 4.32 0.0000 1.0000 1A3 1A3 Other diesel CH4 0.57 0.57 0.0000 1.0000 1A3a 1A3a Aviation Fuel CH4 1.18 1.18 0.0000 1.0000 2C 2C Metal Industries HFCs 2.26 2.26 0.0000 1.0000 2E 2E Electronics Industry NF3 0.34 0.34 0.0000 1.0000 1A3 1A3 Natural Gas N2O 0.08 0.08 0.0000 1.0000 1A3c 1A3c Coal N2O 0.07 0.07 0.0000 1.0000 1B1 1B1 Fugitive Emissions from Solid Fuels N2O 0.02 0.02 0.0000 1.0000 4F 4F Other Land CO2 0.00 0.00 0.0000 1.0000 2D 2D Non-energy Products from Fuels and Solvent Use CH4 0.00 0.00 0.0000 1.0000 3F 3F Field Burning CH4 0.00 0.00 0.0000 1.0000 2D 2D Non-energy Products from Fuels and Solvent Use N2O 0.00 0.00 0.0000 1.0000 3F 3F Field Burning N2O 0.00 0.00 0.0000 1.0000 2B 2B Chemical industry HFCs 0.00 0.00 0.0000 1.0000

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 676 emissions (Gg CO2e) Level Assessment Cumulative Total 2F 2F Product Uses as Substitutes for ODS PFCs 0.00 0.00 0.0000 1.0000 Total 430,653.74 476,370.21 1 Level Assessment Cumulative Total 5A 5A Solid Waste Disposal CH4 67633.35 67633.35 0.3573 0.3573 1A 1A Coal CO2 225522.71 225522.71 0.0905 0.4478 1A 1A (Stationary) Oil CO2 94802.30 94802.30 0.0665 0.5143 1B2 1B2 Natural Gas Transmission CH4 11880.19 11880.19 0.0652 0.5795 1B1 1B1 Coal Mining CH4 24445.88 24445.88 0.0536 0.6331 5C 5C Waste Incineration CO2 1445.17 1445.17 0.0389 0.6720 1A 1A Natural Gas CO2 109602.23 109602.23 0.0240 0.6960 3D 3D Agricultural Soils N2O 13428.41 13428.41 0.0239 0.7199 2B 2B Chemical industries N2O 21162.10 21162.10 0.0231 0.7431 2C 2C Metal Industries CO2 25429.25 25429.25 0.0191 0.7622 5D 5D Wastewater Handling N2O 796.37 796.37 0.0188 0.7810 1B2 1B2 Offshore Oil& Gas CH4 1955.71 1955.71 0.0187 0.7997

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 677 Level Assessment Cumulative Total 1A3b 1A3b Gasoline/ LPG CO2 75379.45 75379.45 0.0183 0.8180 2B 2B Chemical industry HFCs 14807.32 14807.32 0.0162 0.8342 1A3d 1A3d Marine fuel CO2 7611.13 7611.13 0.0149 0.8491 1A1 & 1A2 & 1A4 & 1A5 Other Combustion N2O 1936.80 1936.80 0.0138 0.8629 5D 5D Wastewater Handling CH4 2365.31 2365.31 0.0135 0.8764 2B 2B Chemical industries CO2 6975.59 6975.59 0.0118 0.8882 1A3b 1A3b Gasoline/ LPG CH4 1308.55 1308.55 0.0107 0.8989 3A 3A Enteric Fermentation CH4 27680.22 27680.22 0.0103 0.9092 1A3b 1A3b DERV CO2 33792.87 33792.87 0.0082 0.9175 2G 2G Other Product Manufacture and Use N2O 533.61 533.61 0.0082 0.9257 1A1 & 1A2 & 1A4 & 1A5 Other Combustion CH4 2207.13 2207.13 0.0080 0.9337 3B 3B Manure Management N2O 3038.90 3038.90 0.0075 0.9412 1A3b 1A3b Gasoline/ LPG N2O 887.83 887.83 0.0072 0.9484 5C 5C Waste Incineration CH4 213.78 213.78 0.0063 0.9547 1A3b 1A3b DERV N2O 288.98 288.98 0.0041 0.9588 1A3a 1A3a Aviation Fuel CO2 1869.71 1869.71 0.0040 0.9628 1B2 1B2 Oil & Natural Gas CO2 5088.53 5088.53 0.0035 0.9663 3B 3B Manure Management CH4 4646.15 4646.15 0.0034 0.9697 2D 2D Non Energy Products from Fuels and Solvent Use CO2 552.81 552.81 0.0034 0.9731

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 678 Level Assessment Cumulative Total 2A 2A Mineral Industries CO2 10234.92 10234.92 0.0027 0.9758 3J 3J OT & CD Agriculture CH4 306.10 306.10 0.0024 0.9781 1A3 1A3 Other diesel CO2 1567.49 1567.49 0.0024 0.9805 3G 3G Liming CO2 1019.16 1019.16 0.0023 0.9828 3H 3H Urea application to agriculture CO2 293.75 293.75 0.0016 0.9844 1A4 1A4 Peat CO2 453.50 453.50 0.0016 0.9860 5C 5C Waste Incineration N2O 61.44 61.44 0.0015 0.9875 1A3b 1A3b DERV CH4 100.06 100.06 0.0014 0.9890 1B1 1B1 Solid Fuel Transformation CO2 1698.56 1698.56 0.0014 0.9903 3J 3J OT & CD Agriculture N2O 155.42 155.42 0.0012 0.9915 1A3d 1A3d Marine fuel N2O 93.38 93.38 0.0012 0.9927 2F 2F Product Uses as Substitutes for ODS HFCs 801.49 801.49 0.0011 0.9938 2G 2G Other Product Manufacture and Use PFCs 128.63 128.63 0.0007 0.9944 2C 2C Metal Industries PFCs 299.84 299.84 0.0007 0.9951 3F 3F Field Burning CH4 209.47 209.47 0.0006 0.9957 2B 2B Chemical Industry CH4 248.23 248.23 0.0005 0.9962 2G 2G Other Product Manufacture and Use SF6 891.81 891.81 0.0005 0.9967 1B2 1B2 Oil & Natural Gas N2O 39.74 39.74 0.0004 0.9972 2A 2A Mineral Industries CH4 34.84 34.84 0.0004 0.9976 1A 1A Other (waste) CO2 245.37 245.37 0.0004 0.9979

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 679 Level Assessment Cumulative Total 2C 2C Metal Industries SF6 399.06 399.06 0.0003 0.9982 5B 5B Biological treatment of solid waste CH4 21.89 21.89 0.0002 0.9985 2C 2C Iron & Steel N2O 18.43 18.43 0.0002 0.9987 1A4 1A4 Petroleum Coke CO2 81.64 81.64 0.0002 0.9990 2C 2C Iron & Steel Production CH4 43.92 43.92 0.0002 0.9992 1A3a 1A3a Aviation Fuel N2O 15.74 15.74 0.0002 0.9993 3F 3F Field Burning N2O 51.40 51.40 0.0001 0.9995 5B 5B Biological treatment of solid waste N2O 12.36 12.36 0.0001 0.9996 2B 2B Chemical industry PFCs 104.34 104.34 0.0001 0.9997 1A3d 1A3d Marine fuel CH4 4.10 4.10 0.0001 0.9998 1A3 1A3 Other diesel N2O 3.98 3.98 0.0001 0.9998 2E 2E Electronics Industry HFCs 10.84 10.84 0.0001 0.9999 1A3a 1A3a Aviation Fuel CH4 7.69 7.69 0.0001 1.0000 1A3 1A3 Other diesel CH4 2.88 2.88 0.0000 1.0000 2E 2E Electronics Industry NF3 0.26 0.26 0.0000 1.0000 2F 2F Product Uses as Substitutes for ODS PFCs 0.46 0.46 0.0000 1.0000 1B1 1B1 Solid Fuel Transformation CH4 0.20 0.20 0.0000 1.0000 1B1 1B1 Fugitive Emissions from Solid Fuels N2O 0.08 0.08 0.0000 1.0000 1A3 1A3 Natural Gas CO2 0.00 0.00 0.0000 1.0000 1A3c 1A3c Coal CO2 0.00 0.00 0.0000 1.0000

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 680 Level Assessment Cumulative Total 1B2 1B2 Other Energy Industries CO2 0.00 0.00 0.0000 1.0000 1A3 1A3 Natural Gas CH4 0.00 0.00 0.0000 1.0000 1A3c 1A3c Coal CH4 0.00 0.00 0.0000 1.0000 2D 2D Non-energy Products from Fuels and Solvent Use CH4 0.00 0.00 0.0000 1.0000 1A3 1A3 Natural Gas N2O 0.00 0.00 0.0000 1.0000 1A3c 1A3c Coal N2O 0.00 0.00 0.0000 1.0000 2D 2D Non-energy Products from Fuels and Solvent Use N2O 0.00 0.00 0.0000 1.0000 2C 2C Metal Industries HFCs 0.00 0.00 0.0000 1.0000 Total 808,950.83 808,950.83 1 emissions (Gg CO2e) Level Assessment Cumulative Total 5A 5A Solid Waste Disposal CH4 13777.09 13777.09 0.1808 0.1808 1A 1A Natural Gas CO2 155921.42 155921.42 0.0848 0.2656 1A 1A (Stationary) Oil CO2 41428.77 41428.77 0.0722 0.3378 5D 5D Wastewater Handling N2O 903.51 903.51 0.0531 0.3909 1B2 1B2 Natural Gas Transmission CH4 3711.37 3711.37 0.0506 0.4415

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 681 emissions (Gg CO2e) Level Assessment Cumulative Total 3D 3D Agricultural Soils N2O 10999.18 10999.18 0.0487 0.4902 1A3b 1A3b DERV CO2 68500.76 68500.76 0.0416 0.5318 5B 5B Biological treatment of solid waste CH4 1373.84 1373.84 0.0387 0.5705 2F 2F Product Uses as Substitutes for ODS HFCs 10798.35 10798.35 0.0353 0.6059 1A3b 1A3b DERV N2O 805.91 805.91 0.0284 0.6343 5D 5D Wastewater Handling CH4 1959.38 1959.38 0.0278 0.6621 1A 1A Other (waste) CO2 7042.63 7042.63 0.0268 0.6889 2G 2G Other Product Manufacture and Use N2O 666.17 666.17 0.0256 0.7145 1A3d 1A3d Marine fuel CO2 4862.02 4862.02 0.0237 0.7382 5C 5C Waste Incineration CO2 335.70 335.70 0.0224 0.7606 3A 3A Enteric Fermentation CH4 23544.77 23544.77 0.0217 0.7823 2C 2C Metal Industries CO2 10663.15 10663.15 0.0199 0.8022 1B2 1B2 Offshore Oil& Gas CH4 830.35 830.35 0.0198 0.8220 1A3b 1A3b Gasoline/ LPG CO2 30775.54 30775.54 0.0186 0.8406 1A1 & 1A2 & 1A4 & 1A5 Other Combustion N2O 1036.85 1036.85 0.0183 0.8589 5B 5B Biological treatment of solid waste N2O 660.50 660.50 0.0170 0.8759 3B 3B Manure Management N2O 2493.71 2493.71 0.0153 0.8912 2B 2B Chemical industries CO2 2995.07 2995.07 0.0126 0.9038 1A 1A Coal CO2 11848.67 11848.67 0.0118 0.9156

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 682 emissions (Gg CO2e) Level Assessment Cumulative Total 1A1 & 1A2 & 1A4 & 1A5 Other Combustion CH4 1294.38 1294.38 0.0116 0.9272 3B 3B Manure Management CH4 4290.16 4290.16 0.0079 0.9351 1A3 1A3 Other diesel CO2 1818.80 1818.80 0.0068 0.9419 3G 3G Liming CO2 1177.94 1177.94 0.0067 0.9485 2D 2D Non Energy Products from Fuels and Solvent Use CO2 402.41 402.41 0.0061 0.9547 1A3a 1A3a Aviation Fuel CO2 897.03 897.03 0.0047 0.9594 1B2 1B2 Oil & Natural Gas CO2 2658.99 2658.99 0.0045 0.9639 3J 3J OT & CD Agriculture CH4 228.23 228.23 0.0044 0.9683 5C 5C Waste Incineration CH4 59.15 59.15 0.0043 0.9726 2A 2A Mineral Industries CO2 6071.12 6071.12 0.0040 0.9766 3H 3H Urea application to agriculture CO2 252.57 252.57 0.0034 0.9800 1B1 1B1 Coal Mining CH4 510.23 510.23 0.0028 0.9828 5C 5C Waste Incineration N2O 35.35 35.35 0.0022 0.9850 1A4 1A4 Petroleum Coke CO2 304.86 304.86 0.0021 0.9871 3J 3J OT & CD Agriculture N2O 103.91 103.91 0.0020 0.9891 1A3d 1A3d Marine fuel N2O 56.78 56.78 0.0018 0.9909 1A3b 1A3b Gasoline/ LPG CH4 75.05 75.05 0.0015 0.9924 1A3b 1A3b Gasoline/ LPG N2O 74.45 74.45 0.0015 0.9939 2G 2G Other Product Manufacture and Use PFCs 67.70 67.70 0.0009 0.9948

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 683 emissions (Gg CO2e) Level Assessment Cumulative Total 1B2 1B2 Oil & Natural Gas N2O 22.21 22.21 0.0006 0.9954 2G 2G Other Product Manufacture and Use SF6 383.40 383.40 0.0006 0.9959 1B2 1B2 Other Energy Industries CO2 23.65 23.65 0.0005 0.9964 1B1 1B1 Solid Fuel Transformation CO2 203.99 203.99 0.0004 0.9968 2B 2B Chemical industry PFCs 120.85 120.85 0.0003 0.9971 1A3 1A3 Natural Gas CO2 178.51 178.51 0.0003 0.9974 1A3d 1A3d Marine fuel CH4 7.39 7.39 0.0003 0.9976 1A3b 1A3b DERV CH4 7.04 7.04 0.0002 0.9979 2E 2E Electronics Industry HFCs 19.10 19.10 0.0002 0.9981 2B 2B Chemical Industry CH4 40.83 40.83 0.0002 0.9984 1A3a 1A3a Aviation Fuel N2O 7.55 7.55 0.0002 0.9986 1A3c 1A3c Coal CO2 38.41 38.41 0.0002 0.9988 2C 2C Iron & Steel N2O 6.54 6.54 0.0002 0.9990 1A3 1A3 Natural Gas CH4 4.73 4.73 0.0002 0.9992 1A3 1A3 Other diesel N2O 4.51 4.51 0.0002 0.9993 2C 2C Iron & Steel Production CH4 12.93 12.93 0.0002 0.9995 2A 2A Mineral Industries CH4 4.75 4.75 0.0001 0.9996 2B 2B Chemical industries N2O 29.05 29.05 0.0001 0.9997 2C 2C Metal Industries SF6 38.42 38.42 0.0001 0.9998 1A4 1A4 Peat CO2 7.71 7.71 0.0001 0.9998

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 684 emissions (Gg CO2e) Level Assessment Cumulative Total 1B1 1B1 Solid Fuel Transformation CH4 4.27 4.27 0.0001 0.9999 1A3c 1A3c Coal CH4 0.98 0.98 0.0000 0.9999 2C 2C Metal Industries PFCs 4.32 4.32 0.0000 0.9999 1A3 1A3 Other diesel CH4 0.57 0.57 0.0000 1.0000 1A3a 1A3a Aviation Fuel CH4 1.18 1.18 0.0000 1.0000 2C 2C Metal Industries HFCs 2.26 2.26 0.0000 1.0000 2E 2E Electronics Industry NF3 0.34 0.34 0.0000 1.0000 1A3 1A3 Natural Gas N2O 0.08 0.08 0.0000 1.0000 1A3c 1A3c Coal N2O 0.07 0.07 0.0000 1.0000 1B1 1B1 Fugitive Emissions from Solid Fuels N2O 0.02 0.02 0.0000 1.0000 2D 2D Non-energy Products from Fuels and Solvent Use CH4 0.00 0.00 0.0000 1.0000 3F 3F Field Burning CH4 0.00 0.00 0.0000 1.0000 2D 2D Non-energy Products from Fuels and Solvent Use N2O 0.00 0.00 0.0000 1.0000 3F 3F Field Burning N2O 0.00 0.00 0.0000 1.0000 2B 2B Chemical industry HFCs 0.00 0.00 0.0000 1.0000 2F 2F Product Uses as Substitutes for ODS PFCs 0.00 0.00 0.0000 1.0000 Total 429,489.47 429,489.47 1

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 685 Trend Uncertainty Cumulative Total 5A 5A Solid Waste Disposal CH4 67633.35 13777.09 0.0123 26.5% 0.2655 1A 1A Coal CO2 225522.71 11848.67 0.0046 9.9% 0.3644 1B1 1B1 Coal Mining CH4 24445.88 510.23 0.0029 6.3% 0.4269 1A 1A Natural Gas CO2 109602.23 155921.42 0.0023 5.0% 0.4767 5B 5B Biological treatment of solid waste CH4 21.89 1373.84 0.0017 3.6% 0.5124 1B2 1B2 Natural Gas Transmission CH4 11880.19 3711.37 0.0015 3.2% 0.5444 2F 2F Product Uses as Substitutes for ODS HFCs 801.49 10798.35 0.0015 3.2% 0.5760 1A3b 1A3b DERV CO2 33792.87 68500.76 0.0013 2.9% 0.6047 2B 2B Chemical industries N2O 21162.10 29.05 0.0013 2.8% 0.6327 5D 5D Wastewater Handling N2O 796.37 903.51 0.0012 2.7% 0.6592 4B 4B Cropland CO2 14230.88 12690.21 0.0012 2.6% 0.6856 5C 5C Waste Incineration CO2 1445.17 335.70 0.0012 2.6% 0.7119 1A 1A Other (waste) CO2 245.37 7042.63 0.0011 2.4% 0.7364 1A3b 1A3b DERV N2O 288.98 805.91 0.0010 2.1% 0.7579 2B 2B Chemical industry HFCs 14807.32 0.00 0.0009 2.0% 0.7775 3D 3D Agricultural Soils N2O 13428.41 10999.18 0.0008 1.6% 0.7938 5B 5B Biological treatment of solid waste N2O 12.36 660.50 0.0007 1.6% 0.8094 4C 4C Grassland CH4 2807.05 2861.40 0.0007 1.4% 0.8234

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 686 Trend Uncertainty Cumulative Total 2G 2G Other Product Manufacture and Use N2O 533.61 666.17 0.0006 1.4% 0.8372 1A 1A (Stationary) Oil CO2 94802.30 41428.77 0.0006 1.4% 0.8508 1A3b 1A3b Gasoline/ LPG CH4 1308.55 75.05 0.0005 1.2% 0.8623 4E 4E Settlements CO2 5426.53 3799.29 0.0005 1.1% 0.8731 4D 4D Wetland CH4 2313.24 2382.01 0.0005 1.0% 0.8834 5D 5D Wastewater Handling CH4 2365.31 1959.38 0.0004 0.9% 0.8929 4A 4A Forest Land CO2 -13940.16 -18082.25 0.0004 0.9% 0.9023 4C 4C Grassland CO2 -618.75 -2738.53 0.0004 0.9% 0.9116 3A 3A Enteric Fermentation CH4 27680.22 23544.77 0.0004 0.8% 0.9193 1A3b 1A3b Gasoline/ LPG N2O 887.83 74.45 0.0003 0.7% 0.9267 3B 3B Manure Management N2O 3038.90 2493.71 0.0002 0.5% 0.9318 1A3b 1A3b Gasoline/ LPG CO2 75379.45 30775.54 0.0002 0.5% 0.9367 2C 2C Metal Industries CO2 25429.25 10663.15 0.0002 0.5% 0.9414 1B2 1B2 Offshore Oil& Gas CH4 1955.71 830.35 0.0002 0.4% 0.9458 4G 4G Other Activities CO2 -2096.17 -2037.46 0.0002 0.4% 0.9498 1A3d 1A3d Marine fuel CO2 7611.13 4862.02 0.0002 0.4% 0.9537 5C 5C Waste Incineration CH4 213.78 59.15 0.0002 0.4% 0.9573 1A3 1A3 Other diesel CO2 1567.49 1818.80 0.0002 0.3% 0.9608 3G 3G Liming CO2 1019.16 1177.94 0.0002 0.3% 0.9642 4B 4B Cropland CH4 332.36 317.96 0.0002 0.3% 0.9674

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 687 Trend Uncertainty Cumulative Total 3B 3B Manure Management CH4 4646.15 4290.16 0.0001 0.3% 0.9706 4A 4A Forest land N2O 438.95 377.40 0.0001 0.3% 0.9737 2B 2B Chemical industries CO2 6975.59 2995.07 0.0001 0.3% 0.9763 1A4 1A4 Peat CO2 453.50 7.71 0.0001 0.2% 0.9782 1A4 1A4 Petroleum Coke CO2 81.64 304.86 0.0001 0.2% 0.9798 4E 4E Settlements N2O 392.31 254.78 0.0001 0.2% 0.9814 2D 2D Non Energy Products from Fuels and Solvent 1A3b 1A3b DERV CH4 100.06 7.04 0.0001 0.1% 0.9845 1B1 1B1 Solid Fuel Transformation CO2 1698.56 203.99 0.0001 0.1% 0.9858 3H 3H Urea application to agriculture CO2 293.75 252.57 0.0001 0.1% 0.9870 3J 3J OT & CD Agriculture CH4 306.10 228.23 0.0001 0.1% 0.9882 1A1 & 1A2 & 1A4 & 1A5 Other Combustion CH4 2207.13 1294.38 0.0001 0.1% 0.9894 4A 4A Forest Land CH4 99.49 104.50 0.0001 0.1% 0.9905 4D 4D Wetland CO2 668.77 550.11 0.0000 0.1% 0.9915 2C 2C Metal Industries PFCs 299.84 4.32 0.0000 0.1% 0.9923 3F 3F Field Burning CH4 209.47 0.00 0.0000 0.1% 0.9930 4C 4C Grassland N2O 134.86 127.67 0.0000 0.1% 0.9936 2B 2B Chemical Industry CH4 248.23 40.83 0.0000 0.0% 0.9941

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 688 Trend Uncertainty Cumulative Total 2A 2A Mineral Industries CO2 10234.92 6071.12 0.0000 0.0% 0.9945 1B2 1B2 Other Energy Industries CO2 0.00 23.65 0.0000 0.0% 0.9949 4 4 Indirect LULUCF Emissions N2O 271.94 152.89 0.0000 0.0% 0.9953 1A3a 1A3a Aviation Fuel CO2 1869.71 897.03 0.0000 0.0% 0.9958 3J 3J OT & CD Agriculture N2O 155.42 103.91 0.0000 0.0% 0.9962 2A 2A Mineral Industries CH4 34.84 4.75 0.0000 0.0% 0.9965 1A1 & 1A2 & 1A4 & 1A5 Other Combustion N2O 1936.80 1036.85 0.0000 0.0% 0.9968 2C 2C Metal Industries SF6 399.06 38.42 0.0000 0.0% 0.9971 4D 4D Wetland N2O 18.90 21.42 0.0000 0.0% 0.9974 1A3 1A3 Natural Gas CO2 0.00 178.51 0.0000 0.0% 0.9976 1A3d 1A3d Marine fuel N2O 93.38 56.78 0.0000 0.0% 0.9979 1A3c 1A3c Coal CO2 0.00 38.41 0.0000 0.0% 0.9981 4E 4E Settlements CH4 19.03 28.19 0.0000 0.0% 0.9982 5C 5C Waste Incineration N2O 61.44 35.35 0.0000 0.0% 0.9984 3F 3F Field Burning N2O 51.40 0.00 0.0000 0.0% 0.9986 1A3d 1A3d Marine fuel CH4 4.10 7.39 0.0000 0.0% 0.9988 2B 2B Chemical industry PFCs 104.34 120.85 0.0000 0.0% 0.9989 2E 2E Electronics Industry HFCs 10.84 19.10 0.0000 0.0% 0.9991 1A3 1A3 Natural Gas CH4 0.00 4.73 0.0000 0.0% 0.9992

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 689 Trend Uncertainty Cumulative Total 2G 2G Other Product Manufacture and Use SF6 891.81 383.40 0.0000 0.0% 0.9994 2C 2C Iron & Steel Production CH4 43.92 12.93 0.0000 0.0% 0.9995 4B 4B Cropland N2O 653.25 354.68 0.0000 0.0% 0.9996 2C 2C Iron & Steel N2O 18.43 6.54 0.0000 0.0% 0.9997 1A3 1A3 Other diesel N2O 3.98 4.51 0.0000 0.0% 0.9998 1B1 1B1 Solid Fuel Transformation CH4 0.20 4.27 0.0000 0.0% 0.9998 1A3a 1A3a Aviation Fuel CH4 7.69 1.18 0.0000 0.0% 0.9998 1B2 1B2 Oil & Natural Gas N2O 39.74 22.21 0.0000 0.0% 0.9999 1A3 1A3 Other diesel CH4 2.88 0.57 0.0000 0.0% 0.9999 1A3c 1A3c Coal CH4 0.00 0.98 0.0000 0.0% 0.9999 1B2 1B2 Oil & Natural Gas CO2 5088.53 2658.99 0.0000 0.0% 1.0000 1A3a 1A3a Aviation Fuel N2O 15.74 7.55 0.0000 0.0% 1.0000 2C 2C Metal Industries HFCs 0.00 2.26 0.0000 0.0% 1.0000 1A3 1A3 Natural Gas N2O 0.00 0.08 0.0000 0.0% 1.0000 2E 2E Electronics Industry NF3 0.26 0.34 0.0000 0.0% 1.0000 1A3c 1A3c Coal N2O 0.00 0.07 0.0000 0.0% 1.0000 2G 2G Other Product Manufacture and Use PFCs 128.63 67.70 0.0000 0.0% 1.0000 2F 2F Product Uses as Substitutes for ODS PFCs 0.46 0.00 0.0000 0.0% 1.0000 1B1 1B1 Fugitive Emissions from Solid Fuels N2O 0.08 0.02 0.0000 0.0% 1.0000 4F 4F Other Land CO2 0.00 0.00 0.0000 0.0% 1.0000

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 690 Trend Uncertainty Cumulative Total 2D 2D Non-energy Products from Fuels and Solvent 2D 2D Non-energy Products from Fuels and Solvent Total 820,103.31 430,653.74 1 Trend Uncertainty Cumulative Total 5A 5A Solid Waste Disposal CH4 67633.35 13777.09 0.0123 29.4% 0.2936 1A 1A Coal CO2 225522.71 11848.67 0.0046 10.9% 0.4030 1B1 1B1 Coal Mining CH4 24445.88 510.23 0.0029 6.9% 0.4722 1A 1A Natural Gas CO2 109602.23 155921.42 0.0023 5.5% 0.5272 5B 5B Biological treatment of solid waste CH4 21.89 1373.84 0.0017 4.0% 0.5667 1B2 1B2 Natural Gas Transmission CH4 11880.19 3711.37 0.0015 3.5% 0.6022 2F 2F Product Uses as Substitutes for ODS HFCs 801.49 10798.35 0.0015 3.5% 0.6371 1A3b 1A3b DERV CO2 33792.87 68500.76 0.0013 3.2% 0.6688 2B 2B Chemical industries N2O 21162.10 29.05 0.0013 3.1% 0.6998 5D 5D Wastewater Handling N2O 796.37 903.51 0.0012 2.9% 0.7291 5C 5C Waste Incineration CO2 1445.17 335.70 0.0012 2.9% 0.7583

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 691 Trend Uncertainty Cumulative Total 1A 1A Other (waste) CO2 245.37 7042.63 0.0011 2.7% 0.7853 1A3b 1A3b DERV N2O 288.98 805.91 0.0010 2.4% 0.8091 2B 2B Chemical industry HFCs 14807.32 0.00 0.0009 2.2% 0.8308 3D 3D Agricultural Soils N2O 13428.41 10999.18 0.0008 1.8% 0.8488 5B 5B Biological treatment of solid waste N2O 12.36 660.50 0.0007 1.7% 0.8661 2G 2G Other Product Manufacture and Use N2O 533.61 666.17 0.0006 1.5% 0.8813 1A 1A (Stationary) Oil CO2 94802.30 41428.77 0.0006 1.5% 0.8963 1A3b 1A3b Gasoline/ LPG CH4 1308.55 75.05 0.0005 1.3% 0.9091 5D 5D Wastewater Handling CH4 2365.31 1959.38 0.0004 1.0% 0.9196 3A 3A Enteric Fermentation CH4 27680.22 23544.77 0.0004 0.9% 0.9281 1A3b 1A3b Gasoline/ LPG N2O 887.83 74.45 0.0003 0.8% 0.9363 3B 3B Manure Management N2O 3038.90 2493.71 0.0002 0.6% 0.9420 1A3b 1A3b Gasoline/ LPG CO2 75379.45 30775.54 0.0002 0.5% 0.9475 2C 2C Metal Industries CO2 25429.25 10663.15 0.0002 0.5% 0.9526 1B2 1B2 Offshore Oil& Gas CH4 1955.71 830.35 0.0002 0.5% 0.9574 1A3d 1A3d Marine fuel CO2 7611.13 4862.02 0.0002 0.4% 0.9618 5C 5C Waste Incineration CH4 213.78 59.15 0.0002 0.4% 0.9658 1A3 1A3 Other diesel CO2 1567.49 1818.80 0.0002 0.4% 0.9696 3G 3G Liming CO2 1019.16 1177.94 0.0002 0.4% 0.9734 3B 3B Manure Management CH4 4646.15 4290.16 0.0001 0.3% 0.9768

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 692 Trend Uncertainty Cumulative Total 2B 2B Chemical industries CO2 6975.59 2995.07 0.0001 0.3% 0.9797 1A4 1A4 Peat CO2 453.50 7.71 0.0001 0.2% 0.9818 1A4 1A4 Petroleum Coke CO2 81.64 304.86 0.0001 0.2% 0.9836 2D 2D Non Energy Products from Fuels and Solvent 1A3b 1A3b DERV CH4 100.06 7.04 0.0001 0.2% 0.9870 1B1 1B1 Solid Fuel Transformation CO2 1698.56 203.99 0.0001 0.1% 0.9884 3H 3H Urea application to agriculture CO2 293.75 252.57 0.0001 0.1% 0.9898 3J 3J OT & CD Agriculture CH4 306.10 228.23 0.0001 0.1% 0.9911 1A1 & 1A2 & 1A4 & 1A5 Other Combustion CH4 2207.13 1294.38 0.0001 0.1% 0.9924 2C 2C Metal Industries PFCs 299.84 4.32 0.0000 0.1% 0.9932 3F 3F Field Burning CH4 209.47 0.00 0.0000 0.1% 0.9940 2B 2B Chemical Industry CH4 248.23 40.83 0.0000 0.0% 0.9945 2A 2A Mineral Industries CO2 10234.92 6071.12 0.0000 0.0% 0.9950 1B2 1B2 Other Energy Industries CO2 0.00 23.65 0.0000 0.0% 0.9954 1A3a 1A3a Aviation Fuel CO2 1869.71 897.03 0.0000 0.0% 0.9959 3J 3J OT & CD Agriculture N2O 155.42 103.91 0.0000 0.0% 0.9963 2A 2A Mineral Industries CH4 34.84 4.75 0.0000 0.0% 0.9967

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 693 Trend Uncertainty Cumulative Total 1A1 & 1A2 & 1A4 & 1A5 Other Combustion N2O 1936.80 1036.85 0.0000 0.0% 0.9971 2C 2C Metal Industries SF6 399.06 38.42 0.0000 0.0% 0.9974 1A3 1A3 Natural Gas CO2 0.00 178.51 0.0000 0.0% 0.9977 1A3d 1A3d Marine fuel N2O 93.38 56.78 0.0000 0.0% 0.9979 1A3c 1A3c Coal CO2 0.00 38.41 0.0000 0.0% 0.9982 5C 5C Waste Incineration N2O 61.44 35.35 0.0000 0.0% 0.9984 3F 3F Field Burning N2O 51.40 0.00 0.0000 0.0% 0.9986 1A3d 1A3d Marine fuel CH4 4.10 7.39 0.0000 0.0% 0.9987 2B 2B Chemical industry PFCs 104.34 120.85 0.0000 0.0% 0.9989 2E 2E Electronics Industry HFCs 10.84 19.10 0.0000 0.0% 0.9991 1A3 1A3 Natural Gas CH4 0.00 4.73 0.0000 0.0% 0.9993 2G 2G Other Product Manufacture and Use SF6 891.81 383.40 0.0000 0.0% 0.9994 2C 2C Iron & Steel Production CH4 43.92 12.93 0.0000 0.0% 0.9995 2C 2C Iron & Steel N2O 18.43 6.54 0.0000 0.0% 0.9996 1A3 1A3 Other diesel N2O 3.98 4.51 0.0000 0.0% 0.9997 1B1 1B1 Solid Fuel Transformation CH4 0.20 4.27 0.0000 0.0% 0.9998 1A3a 1A3a Aviation Fuel CH4 7.69 1.18 0.0000 0.0% 0.9998 1B2 1B2 Oil & Natural Gas N2O 39.74 22.21 0.0000 0.0% 0.9999 1A3 1A3 Other diesel CH4 2.88 0.57 0.0000 0.0% 0.9999

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 694 Trend Uncertainty Cumulative Total 1A3c 1A3c Coal CH4 0.00 0.98 0.0000 0.0% 0.9999 1B2 1B2 Oil & Natural Gas CO2 5088.53 2658.99 0.0000 0.0% 1.0000 1A3a 1A3a Aviation Fuel N2O 15.74 7.55 0.0000 0.0% 1.0000 2C 2C Metal Industries HFCs 0.00 2.26 0.0000 0.0% 1.0000 1A3 1A3 Natural Gas N2O 0.00 0.08 0.0000 0.0% 1.0000 2E 2E Electronics Industry NF3 0.26 0.34 0.0000 0.0% 1.0000 1A3c 1A3c Coal N2O 0.00 0.07 0.0000 0.0% 1.0000 2G 2G Other Product Manufacture and Use PFCs 128.63 67.70 0.0000 0.0% 1.0000 2F 2F Product Uses as Substitutes for ODS PFCs 0.46 0.00 0.0000 0.0% 1.0000 1B1 1B1 Fugitive Emissions from Solid Fuels N2O 0.08 0.02 0.0000 0.0% 1.0000 2D 2D Non-energy Products from Fuels and Solvent 2D 2D Non-energy Products from Fuels and Solvent Total 808,950.83 429,489.47 1 The Key Category Analysis (KCA) ranking system is an additional tool that the UK has developed to aid in the prioritisation of improvement work.
The KCA ranking system works by allocating a score based on how high categories rank in the base year and most recent year level assessments and the trend assessment for the approach 1 KCA including LULUCF. For example, if CO2 from road transport liquid fuel use is the 4th highest by the base year level assessment, 3rd highest by the most recent year level assessment and h as the 5th highest trend assessment then it’s score

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 695 would be 4+3+5=12.
The categories are then ranked from lowest score to highest, with scores that are equal resolved by the mo st recent year The assessments used in this ranking exercise are only those including LULUCF, because if the additional excluding LULUCF assessments were also used, the LULUCF sectors would only be included in half of the assessments and would therefore give an unrepresentative weighting. IPCC Code IPCC Category Greenhouse Gas 1 1A3b Road liquid fuels CO2 2 1A4 Other gaseous fuels CO2 3 1A2 Manufacturing industries and gaseous fuels CO2 4 5A Solid waste disposal CH4 5 1A1 Energy solid fuels CO2 6 1A1 Energy liquid fuels CO2 7 1A1 Energy gaseous fuels CO2 8 3A1 Enteric fermentation from Cattle CH4 9 1A4 Other liquid fuels CO2 12 2C1 Iron and steel production CO2 14 1A2 Manufacturing industries and solid fuels CO2

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 696 IPCC Code IPCC Category Greenhouse Gas 15 1B2 Oil and gas extraction CH4 16 1A4 Other solid fuels CO2 17 1B1 Coal mining and handling CH4 18 1A2 Manufacturing industries and liquid fuels CO2 19 3A2 Enteric fermentation from Sheep CH4 20 3B1 Manure management from Cattle CH4 21 1A3d Domestic liquid fuels CO2 24 1A5 liquid fuels CO2 25 3B2 Manure management from Sheep N2O 27 2B8 Petrochemical and carbon black production CO2 29 4G Harvested wood products CO2 30 1A1 Energy other fuels CO2 32 5D Wastewater treatment and discharge CH4 33 2F1 Refrigeration and air conditioning HFCs, PFCs, SF6 and NF3 34 2B9 Fluorochemical production HFCs, PFCs, SF6 and NF3 35 2B2 Nitric acid production N2O

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 697 IPCC Code IPCC Category Greenhouse Gas 36 2B3 Adipic acid production N2O 37 1B2 Oil and gas extraction CO2 38 5B Biological treatment of solid waste CH4 The key category analysis is used to prioritise and plan improvements.
The approach the UK takes to achieve this is described in Section 1.2.2.5. UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 698 ANNEX 2: Assessment of Uncertainty Uncertainty estimates are calculated using two Approach 1 (error propagation) and Approach 2 (Monte Carlo simulation).
These are not to be confused with Approaches 1 and 2 for Key Category Analysis (KCA), of which Approach 2 KCA uses Approach 1 uncertainties to account for uncertainty in determining Key Categories. Uncertainties have been estimated by IPCC sector and direct greenhouse gas.
It may be possible to estimate uncertainty at higher levels of sectoral detail, however this would require further understanding of the dependencies between sub-sectors and greatly increase the complexity of the Approach 2 model. Aggregation has therefore been used as a method to avoid the risk of unaccounted for correlations and retain accuracy in uncertainty estimates, as advised in the 2006 IPCC guidelines (vol.
1, chap. 3, pg.
3.25). Uncertainty estimates for the sector breakdown used in UK Official Statistics are also not reported here, since the categories are not consistent with the requirements of the UK’s commitments under the UNFCCC and Uncertainty parameters for new sources and sources which have been significantly revised are reviewed each year, particularly for sources which have a significant impact on overall uncertainties.
The overall method used to estimate uncertainties is described below, and the work to improve the accuracy of the uncertainty analysis continues. The key category analysis used data from the uncertainty analysis, and the results of the key category analysis are given in The IPCC 2006 Guidelines defines error propagation and Monte Carlo modelling approaches to estimating uncertainties in national greenhouse gas inven tories.
The results of the error approach are not exactly the same as those used in the Monte Carlo Simulation since the error propagation source categorisation is less detail ed and has a more simplistic approach to uncertainties. The Approach 1 uncertainties assumes all parameters are normally distributed (which means it doesn’t account for the skew, kurtosis or any other non -normal features of the expected distributions), and does not account for variations in uncertainty in the time series unlike the Monte Carlo approach which takes into account these factors.
The parameters used for the Approach 1 uncertainties for both the base year and the most recent year are the values g iven Certain source categories are particularly significant in terms of their contribution to the overall uncertainty of the inventory. Key source categories in this respect are identified using Approach 1 uncertainties in the Approach 2 KCA.
These have been identified so that the resources available for inventory preparation may be prioritised, and the best possible estimates prepared for the most significant source categories. We have used tThe method used for key category analysis is described in Section 4.3.2 of the 2006 IPCC Guidelines Volume 1 General Guidance and

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 699 Reporting (Approach 2 to identify key categories)and.
The results of this key category analysis A 2.1.1.1 Uncertainty in the Trend Trend uncertainties are estimated using two sensitivities. These are described in the 2006 IPCC • Type A the change in the difference in overall emissions between the base year and the current year, expressed as a percentage, resulting from a 1 percent increase in emissions or removals of a given category and gas in both the base year and the current year.
Type B the change in the difference in overall emissions between the base year and the current year, expressed as a percentage, resulting from a 1 percent increase in emissions or removals of a given category and gas in the current year only. Conceptually, Type A sensitivity arises from uncertainties that affect emissions or removals in the base year and the current year equally, and Type B sensitivity arises from uncertainties that affect emissions or removals in the current year only.
Uncertainties that are fully correlated between years will be associated with Type A sensitivities, and uncertainties that are not correlated between years will be associated with Type B sensitivities. Once the uncertainties introduced into the national inventory by Type A and Type B sensitivities have been calculated, they can be summed using the error propagation equation to give the overall uncertainty in the

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 700 A 2.1.2 Tables of uncertainty estimates from the error propagation approach 1A Coal CO2 225,522.71 11,848.67 1.78% 3.22% 3.7% 0.0000 12.960% 1.445% 0.4174% 0.0363% 0.0018% 1A3b DERV CO2 33,792.87 68,500.76 1.00% 2.00% 2.2% 0.0000 6.186% 8.353% 0.1237% 0.1181% 0.0003% 2 Emissions presented are for UNFCCC geographical coverage.
UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 701 1A3c Coal CO2 - 38.41 20.00% 6.00% 20.9% 0.0000 0.005% 0.005% 0.0003% 0.0013% 0.0000% 1A4 Peat CO2 453.50 7.71 30.00% 10.00% 31.6% 0.0000 0.028% 0.001% 0.0028% 0.0004% 0.0000%

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 702 3G Liming CO2 1,019.16414 1,177.94 0.00% 20.90% 20.9% 0.0000 0.078% 0.144% 0.0164% 0.0000% 0.0000% 4B Cropland CO2 14,230.88 12,690.21 1.00% 20.00% 20.0% 0.0000 0.636% 1.547% 0.1272% 0.0219% 0.0002% 4C Grassland CO2 -618.75 -2,738.53 1.00% 20.00% 20.0% 0.0000 0.294% 0.334% 0.0589% 0.0047% 0.0000% 4D Wetland CO2 668.77 550.11 1.00% 20.00% 20.0% 0.0000 0.024% 0.067% 0.0049% 0.0009% 0.0000% 4F Other Land CO2 - - 0.00% 0.00% 0.0% - 0.000% 0.000% 0.0000% 0.0000% 0.0000%

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 703 1A3b DERV CH4 100.06 7.04 1.00% 130.00% 130.0% 0.0000 0.006% 0.001% 0.0072% 0.0000% 0.0000% 1A3c Coal CH4 - 0.98 20.00% 110.00% 111.8% 0.0000 0.000% 0.000% 0.0001% 0.0000% 0.0000%

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 704 4B Cropland CH4 332.36 317.96 1.00% 90.00% 90.0% 0.0000 0.017% 0.039% 0.0157% 0.0005% 0.0000%

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 705 4C Grassland CH4 2,807.05 2,861.40 1.00% 40.00% 40.0% 0.0000 0.169% 0.349% 0.0677% 0.0049% 0.0000% 4D Wetland CH4 2,313.24 2,382.01 1.00% 35.00% 35.0% 0.0000 0.142% 0.290% 0.0498% 0.0041% 0.0000%

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 706 1A3b DERV N2O 288.98 805.91 1.00% 130.00% 130.0% 0.0000 0.080% 0.098% 0.1037% 0.0014% 0.0001% 1A3c Coal N2O - 0.07 20.00% 110.00% 111.8% 0.0000 0.000% 0.000% 0.0000% 0.0000% 0.0000%

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 707 4A Forest land N2O 438.95 377.40 1.00% 85.00% 85.0% 0.0000 0.018% 0.046% 0.0152% 0.0007% 0.0000% 4B Cropland N2O 653.25 354.68 1.00% 35.00% 35.0% 0.0000 0.001% 0.043% 0.0005% 0.0006% 0.0000% 4C Grassland N2O 134.86 127.67 1.00% 45.00% 45.0% 0.0000 0.007% 0.016% 0.0031% 0.0002% 0.0000% 4D Wetland N2O 18.90 21.42 1.00% 90.00% 90.0% 0.0000 0.001% 0.003% 0.0013% 0.0000% 0.0000%

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 708 HFCs 14,807.32 - 0.00% 10.00% 10.0% - 0.948% 0.000% 0.0948% 0.0000% 0.0001% HFCs - 2.26 5.00% 10.00% 11.2% 0.0000 0.000% 0.000% 0.0000% 0.0000% 0.0000% HFCs 10.84 19.10 0.00% 47.15% 47.1% 0.0000 0.002% 0.002% 0.0008% 0.0000% 0.0000% HFCs 801.49 10,798.35 8.50% 8.57% 12.1% 0.0000 1.265% 1.317% 0.1084% 0.1582% 0.0004% PFCs 104.34 120.85 0.00% 10.00% 10.0% 0.0000 0.008% 0.015% 0.0008% 0.0000% 0.0000% PFCs 299.84 4.32 0.00% 20.00% 20.0% 0.0000 0.019% 0.001% 0.0037% 0.0000% 0.0000%

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 709 PFCs 0.46 - 0.00% 25.00% 25.0% - 0.000% 0.000% 0.0000% 0.0000% 0.0000% PFCs 128.63 67.70 0.00% 47.15% 47.1% 0.0000 0.0000% 0.0083% 0.0000% 0.0000% 0.0000%

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 710 A 2.2.1 Overview of the Method Quantitative estimates of the uncertainties in the emissions were calculated using a Monte Carlo simulation. This corresponds to the IPCC Approach 2 method, discussed in the 2006 Guidelines (IPCC, 2006).
The background to the implementation of the Monte Carlo simulation is described in detail by Eggleston et al (1998), with the estimates reported here revised to reflect changes in the latest inventory and improvements made in the model. This section gives a brief summary of the methodology, assumptions and results of the simulation.
The computational procedure is detailed below. • A probability distribution function (PDF) was allocated to each unique emission factor and piece of activity data.
The PDFs were mostly normal or log -normal, with more specific distributions given to a handful of sources. The parameters of the PDFs were set by analysing the available data on emission factors and activity data, and by expert • A calculation was set up to estimate the total emissions of each gas for the years 1990 • Each PDF was sampled at least 20,000 times, such that the emission calculations performed produced a converged output distribution; • The distribution of errors in the parameter values was calculated from the difference between 2.5 and 97.5 percentile values in the distribution, as a percentage of the • The uncertainty in the trend between 1990 and the latest reported year, according to gas, was also estimated.
This was calculated as the latest year sample minus the 1990 sample, A 2.2.2 Methodological details of the Monte Carlo model A 2.2.2.1 Uncertainty Distributions Nearly all of the distributions of emissions from sources in the inventory are modelled used normal or log normal distributions, with more specific distributions given to a handful of sources. The specific distributions include log -logistic and gamma distributions.
The primary use of custom distributions is for agriculture; these are fitted distributions that reflect the results of an agriculture- specific Monte Carlo analysis done by Rothamsted Research which accounts for the various factors that influence the modelled agriculture emissions. Emissions from landfill have been modelled using a custom distribution.
Aitchison et al. (cited in Eggleston et al., 1998) estimated the uncertainty for landfill emissions using Monte Carlo analysis and found it to be skewed.
The distribution histogram was used to generate an empirical distribution of emissions. We examined the distribution and fitted a log normal distribution to Aitchison’s data.
The emissions are scaled according to the mean estimate of landfill emissions There are a couple of other specific distributions for F-gases and wastewater which reflect specific distributions we expect for those sources. UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 711 The Monte Carlo model contains a number of correlations.
If A and B are correlated, then if emissions are under or overestimated from A it would be expected to be over or underestimated The type and implementation of the correlations has been examined as part of a review (Abbott et al., 2007). The sensitivity analysis that we have completed on the Monte Carlo model suggest that the uncertainties are not sensitive to the correlations between emission factors for fuel used, In running this simulation, it was necessary to make assumptions about the degree of correlation between sources in 1990 and the latest reported year.
If source emission factors are correlated this will have the effect of reducing the trend uncertainty but will not affect uncertainties on emission totals in 1990 or the latest inventory year. The trend estimated by the Monte Carlo model is particularly sensitive to N2O emissions from agricultural soils.
A 2.2.2.2.2 Between Sources in the same year In many cases the same factors, or factors derived on the same basis are used for multiple sources. In these cases, we’d say that the emission factors are correlated.
For example, the coal emissions factors for N 2O used for cement industry use may be the same as coal use in other industrial combustion due to lack of a more specific factor, in this case we may say the two factors are correlated. Omitting these correlations leads to an underestimate of uncertainty in any given Following recommendations in the 2006 IPCC Guidelines, the model uses a true Monte Carlo A 2.2.3 Quality Control Checks on the Monte Carlo Model Output A number of quality control checks are completed as part of the uncertainty analysis.
A 2.2.3.1 Checks against totals of the national emissions To ensure the emissions in the Monte Carlo model closely agree with the reported totals in the NIR, the emissions in the model were checked against the national totals both before and after the simulation was run. The central estimates from the model are expected to be similar to the reported emissions totals but are not expected to match exactly.
A 2.2.3.2 Inter-comparison between the output of the error propagation and Monte A formal check to compare the output of the error propagation and Monte Carlo model is completed. The results of this comparison are discussed in Section A 2.6.
A 2.2.3.3 Calculation of uncertainty on the total The uncertainty on the 1990 and the most recent year emissions was calculated using two

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 712 The first method uses the standard deviation calculated by the simulation and the mean to give a percentage uncertainty, while the second method uses the 95% confidence interval given by the percentiles quoted. When a distribution is completely nor mally distributed, the two methods should give the same results.
However, when a distribution is skewed the two methods diverge, since the variance is dominated by outliers which aren’t necessarily accounted for in the 95% Calculating the uncertainty using both of these methods allows us to check that the Monte Carlo analysis is behaving in the way we would expect, and that convergence of the distributions is being achieved. Comparing the results using both calculations showed that the uncertainties were almost the same for gases where the distributions used were predominantly normal, but higher for N2O and the GWP weighted total, as expected.
The following sections present the uncertainties in emissions, and the trend in emissions A 2.3.1 Uncertainty Parameters used and 2 uncertainties. For all of these tables the following • Uncertainties expressed as 0.5*R/E where R is the difference between 2.5 and 97.5 percentiles and E is the mean; • Where custom distributions are used for the Approach 2 uncertainties the parameters are not used directly, but the below parameters should still be a reasonable indicator of the uncertainty in the distribution used for Approach 2; • (r) means revised in comparison to previous NIR; • (n) represents a new uncertainty parameter, either because sources are considered at a more granular level, or because a new source is included in the inventory; and • (a) means uncertainty for emission factors and activity cannot be separated, so one uncertainty that represents both is displayed.
UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 713 1A Lubricants 50.00% 5.00% 50.00% 5.00% It's challenging to determine the proportion of lubricant used as a fuel, hence a high activity uncertainty. 1A1 Blast Furnace Gas 1.50% 10.00% 1.00% 10.00% Overall uncertainty for all coke & steelmaking emissions is quite low but allocation to individual sources is definitely 1A1 Coke Oven Coke 1.00% 10.00% 1.00% 10.00% Overall uncertainty for all coke & steelmaking emissions is quite low but allocation to individual sources is definitely 1A1 Coke Oven Gas 1.50% 10.00% 1.00% 10.00% Overall uncertainty for all coke & steelmaking emissions is quite low but allocation to individual sources is definitely 1A1 Colliery Methane 5.00% 5.00% 5.00% 5.00% (Minor fuel in sector context) 1A1 Gas/Diesel Oil 20.00% 2.00% 5.00% 2.00% Dominated by activity in 1A1cii.
There may be limited gas oil use unreported by e.g. MODUs in latest year; base year notably higher as the inventory AD are derived from sector- wide reported data, to address known under-reports in DUKES.
Typically, gas oil Carbon emission factors reported are within 1% of each other but occasional deviations further. 1A1 Liquefied Petroleum Gas 25.70% 2.10% 2.50% 2.10% The DUKES data from 2009 onwards were revised considerably in the energy / NEU split for LPG, and we have created a new split for earlier years.
Chosen 2.1% Emission Factor (EF) uncertainty to be consistent with gas oil - the makeup of LPG is well understood and documented

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 714 1A1 Motor Gasoline 2.50% 2.10% 2.50% 2.10% Outside of 1A3, the motor gasoline allocations are probably much more uncertain as they are reliant on the off-road 1A1 Municipal Solid Waste 1.00% 15.00% 1.00% 15.00% MSW quantity is known accurately. Uncertainty is in mass of fossil carbon per tonne of residual MSW.
This is based on reasonable waste composition data from peer reviewed sources, adapted from landfill data. 1A1 Naphtha 50.00% 5.00% 50.00% 5.00% DUKES are uncertain about where naphtha is used (or not), so a high activity uncertainty has been chosen.
EF uncertainty chosen as 5%. The content of naphtha is quite variable - it contains a huge range of hydrocarbons from C5 up to C70+, so the exact carbon content is variable and there are about 5 different grades of naphtha according to UKPIA.
1A1 Natural Gas 20.00% 2.00% 1.00% 2.00% ETS-based data, so low uncertainties. Base year activity is dominated by 1A1cii, where uncertainty is notably higher as the inventory AD are derived from sector-wide reported data, to address known under-reports in DUKES.
1A1 Orimulsion 5.00% 5.00% 5.00% 5.00% (Minor fuel in sector context) 1A1 Other Bituminous Coal 2.00% 2.00% 2.00% 2.00% ETS-based data, so low uncertainties. 1A1 Other Kerosene 1.25% 5.00% 1.25% 5.00% ETS-based data, so low uncertainties.
1A1 Other Other 11.90% 5.00% 10.00% 5.00% (Minor fuel in sector context)

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 715 1A1 Petroleum Coke 7.80% 10.00% 5.00% 10.00% ETS-based data, so low uncertainties. 10% chosen for EF uncertainty as there is only a small dataset for the quality of petcoke used in the sector and the CEF could be quite variable depending on the source of the petcoke.
1A1 Refinery Gas 50.00% 20.00% 25.00% 15.00% Comparisons between EU ETS and DUKES are variable over time. Risk that in earlier years the “own use” may have been mis-reported to energy stats.
High uncertainty on AD. Also, a variable quality fuel, so the EF is also uncertain.
1A1 Residual Fuel Oil 5.50% 2.55% 1.25% 2.55% ETS-based data, so low uncertainties. 1A1 Scrap Tyres 15.00% 10.00% 15.00% 10.00% Limited reported use of this fuel; only a small amount of reporting (typically cement kilns) within EU ETS and a modest number of fuel quality analyses either through the BCA/MPA (trade body) or the EU ETS.
Also, some variability in the fossil C versus bio-C content of the tyres adds to EF 1A2 Blast Furnace Gas 1.50% 10.00% 1.00% 10.00% Overall uncertainty for all coke & steelmaking emissions is quite low but allocation to individual sources is definitely 1A2 Coke Oven Coke 3.00% 10.00% 1.00% 10.00% Overall uncertainty for all coke & steelmaking emissions is quite low but allocation to individual sources is definitely 1A2 Coke Oven Gas 3.00% 10.00% 1.00% 10.00% Overall uncertainty for all coke & steelmaking emissions is quite low but allocation to individual sources is definitely 1A2 Colliery Methane 5.00% 5.00% 5.00% 5.00% (Minor fuel in sector context)

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 716 1A2 Gas/Diesel Oil 20.00% 2.00% 20.00% 2.00% Low EF uncertainty as the composition of gas oil is well understood across the time series. The AD for stationary combustion in industrial sectors is quite uncertain, however.
DUKES does not distinguish between mobile and stationary sources, and other AD data sources (e.g. EU ETS) have limited coverage of gas oil use across all of 1A2.
1A2 Liquefied Petroleum Gas 25.70% 2.10% 2.50% 2.10% The DUKES data from 2009 onwards were revised considerably in the energy / NEU split for LPG, and we have created a new split for earlier years. Chosen 2.1% EF uncertainty to be consistent with gas oil - the makeup of LPG is well understood and documented 1A2 Motor Gasoline 20.00% 2.10% 20.00% 2.10% Outside of 1A3, the motor gasoline allocations are probably much more uncertain.
Chosen 2.1% EF uncertainty to be consistent with gas oil - the makeup of motor gasoline is well 1A2 Municipal Solid Waste 5.00% 15.00% 5.00% 15.00% MSW quantity is known accurately. Uncertainty is in mass of fossil carbon per tonne of residual MSW.
This is based on reasonable waste composition data from peer reviewed sources, adapted from landfill data. 1A2 Natural Gas 2.80% 3.00% 1.00% 3.00% Low EF uncertainty as gas composition is monitored and reported across much of the time series, and the fuel has narrow compositional range.
AD are also well understood and low uncertainty. Gas supplier data to DUKES can be checked against periodic data matching (meter point data against industry sector information).
1A2 non-fuel combustion 50.00% 100.00% 50.00% 100.00% (Minor emission source in sector context)

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 717 1A2 Other Bituminous Coal 5.00% 10.00% 5.00% 10.00% Limited compositional data over time (e.g. EU ETS data for coal is incomplete), so EF uncertainty reflects the range of composition of coal types in 1A2.
AD uncertainty is moderate for 1A2, reflecting energy supplier reporting to DESNZ. 1A2 Other Kerosene 6.00% 2.00% 6.00% 2.00% (Minor fuel in sector context) 1A2 Other Other 5.00% 50.00% 5.00% 3.00% (Minor fuel in sector context) 1A2 Patent Fuel 10.00% 3.00% 10.00% 3.00% (Minor fuel in sector context) 1A2 Petroleum Coke 25.00% 15.00% 20.00% 15.00% EF uncertainty reflects range of petcock composition that may be used for fuel in 1A2.
AD uncertainty is quite high as we have limited data from DUKES and not much AD from EU 1A2 Refinery Gas 50.00% 15.00% 50.00% 15.00% (Minor fuel in sector context) 1A2 Residual Fuel Oil 5.50% 2.10% 1.50% 2.10% Low EF uncertainty as the composition of fuel oil is well understood across the time series. The AD uncertainty is low in recent years as the fuel is not widely used other than by larger operators that report under EU ETS.
Moderate uncertainty in earlier years when fewer routine annual AD 1A2 Scrap Tyres 15.00% 10.00% 15.00% 10.00% (See 1A1 comment – same applies here.) 1A3 Aviation Gasoline 20.00% 3.30% 20.00% 3.30% Activity uncertainty is higher than many other similar fuels because of the uncertainty in the international-domestic split 1A3 Jet Gasoline 20.00% 3.30% 20.00% 3.30% Activity uncertainty is higher than many other similar fuels because of the uncertainty in the international-domestic split

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 718 1A3 liquid biofuels 5.00% 5.00% 5.00% 5.00% Activity data are not very uncertain, as it's taken from RTFO data.
There is a total potential range of 10% variability in the fossil fuel carbon content of FAME (i.e. judging from the contents of the different fatty acid types used to synthesize the FAME, the highest content is around 44.8g/kg, whilst the lowest is 40.2g/kg).
In reality, these are the extremes, so a lower overall uncertainty is expected. the other liquid biofuels are consumed in much smaller quantities than FAME.
1A3 Other Bituminous Coal 20.00% 6.00% 20.00% 6.00% (Minor fuel in sector context) 1A3 Other Gas/Diesel Oil 15.00% 2.00% 15.00% 2.00% (Minor fuel in sector context) 1A3 Natural Gas 5.00% 2.00% 5.00% 2.00% Using parameters for road transport LPG; note that source is 1A3b Gas/Diesel Oil 1.80% 2.00% 1.00% 2.00% Low EF uncertainty as the composition of gas oil is well understood across the time series. Low AD uncertainty as good corroboration between fuel sales data and estimates based on vehicle movement data.
1A3b Liquefied Petroleum Gas 5.00% 2.00% 5.00% 2.00% EF uncertainty is consistent with gas oil - the makeup of LPG is well understood and documented. Not a major fuel in the sector but AD are considered moderately uncertain.
1A3b Motor Gasoline 1.00% 2.00% 1.00% 2.00% Low EF uncertainty as the composition of petrol is well understood across the time series. Low AD uncertainty as good corroboration between fuel sales data and estimates based on vehicle movement data.
1A3d Gas/Diesel Oil 20.00% 2.00% 20.00% 2.00% Activity uncertainty is higher than many other similar fuels because of the uncertainty in the international-domestic split

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 719 1A3d Residual Fuel Oil 20.00% 2.00% 20.00% 2.00% Activity uncertainty is higher than many other similar fuels because of the uncertainty in the international-domestic split 1A4 Anthracite 1.50% 6.00% 1.00% 6.00% Low AD uncertainty as tax data helps establish residential use. EF uncertainty reflects variability in anthracite 1A4 Coke Oven Coke 3.00% 10.00% 1.00% 10.00% (Minor fuel in sector context) 1A4 Gas/Diesel Oil 30.00% 2.00% 30.00% 2.00% Low EF uncertainty as the composition of gas oil is well understood across the time series.
High AD uncertainty as scarce data on use of this fuel, e.g. in mobile machinery, in 1A4 Gas Works Gas 5.00% 5.00% 5.00% 5.00% (Minor fuel in sector context) 1A4 Liquefied Petroleum Gas 25.70% 2.10% 2.50% 2.10% The DUKES data from 2009 onwards were revised considerably in the energy / NEU split for LPG, and we have created a new split for earlier years.
Chosen 2.1% EF uncertainty to be consistent with gas oil - the makeup of LPG is well understood and documented 1A4 Motor Gasoline 50.00% 2.00% 50.00% 2.00% Low EF uncertainty as the composition of petrol is well understood across the time series. High AD uncertainty as scarce data on use of this fuel in mobile machinery in 1A4.
1A4 Natural Gas 2.80% 3.00% 2.00% 3.00% (As for 1A2) 1A4 Other Bituminous Coal 3.00% 10.00% 3.00% 10.00% Chosen 3% activity uncertainty as we know that there are some limitations on the coal allocation to small-scale users. UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 720 1A4 Other Kerosene 3.00% 2.00% 3.00% 2.00% Low AD uncertainty as tax data helps establish residential use.
EF uncertainty reflects narrow range of fuel 1A4 Patent Fuel 3.30% 3.00% 2.00% 3.00% (Minor fuel in sector context) 1A4 Peat 30.00% 10.00% 30.00% 10.00% (Minor fuel in sector context) 1A4 Petroleum Coke 20.00% 15.00% 20.00% 15.00% Limited information on the AD of use in domestic fuels which increases uncertainty. Moderate emission factor uncertainty as there is only a small dataset for the quality of petcoke used in the sector and the CEF could be quite variable depending on the source of the petcoke.
1A4 Residual Fuel Oil 5.50% 2.10% 3.00% 2.10% (Minor fuel in sector context) 1A5 Gas/Diesel Oil 6.25% 2.05% 6.25% 2.05% Moderate AD uncertainty as data from very few data suppliers. EF uncertainty reflects narrow range of fuel 1A5 Jet Gasoline 10.00% 3.00% 10.00% 3.00% Activity Data comes directly from fuel users so should have 1B1 Coke Oven Gas 1.50% 10.00% 1.00% 10.00% (Minor fuel in sector context) 1B1 Other Bituminous Coal 1.50% 6.00% 1.50% 6.00% EF uncertainty reflects the range of composition of coal types in SSF manufacture.
AD uncertainty is quite low, reflecting the small number of operators and high level of AD 1B1 petroleum coke 20.00% 10.00% 20.00% 10.00% (Minor fuel in sector context)

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 721 1B2a non-fuel combustion 15.00% 20.00% 10.00% 30.00% The dominant sources are onshore oil production (latest year) and offshore oil well testing (base year). The PPRS data underpin the oil production data and whilst they are very consistent across years, it is plausible that up to 10% error may occur if one of the larger site’s mis-reports as these dominate.
For the base year, the AD for well testing is extrapolated to 1990 using well drilling statistics so introduces some additional uncertainty. The dominant source in recent years is onshore oil production which applies an IPCC 2019 Refinement Tier 1 EF which cites a 30% uncertainty margin.
In the base year due to the (large) dominance of oil well testing, a lower overall EF uncertainty 1B2b non-fuel combustion 15.00% 20.00% 2.00% 10.00% The dominant sources are direct process releases from both offshore gas rigs and terminals (latest year) and gas well testing (base year). The installation-level reporting underpins latest year estimates, and hence low AD estimates and the EF reflects that there is a good dataset with known sites contributing fairly consistently but there may be a reasonably high measurement uncertainty at source.
For the base year, the AD for well testing is well documented back to 1995, and then extrapolated to 1990 introducing some additional uncertainty. For the base year, the CEF is only based on operator guidance rather than any monitoring, making it

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 722 1B2c non-fuel combustion 20.00% 5.00% 5.00% 5.00% Flaring emissions dominate this sector in all years.
There has been high quality reporting of flaring since around 1995, but the monitoring of gas to flare and need for assumptions to estimate the mass will undermine that to an extent. For the Base Year we have extrapolated back from 1995 so the uncertainty in AD is higher.
There is a large dataset on the composition of gas to flare and recent evidence that 98% combustion is accurate3. However, if a few sites have notably lower oxidation, this would significantly impact the 2A1 non-fuel combustion 1.00% 3.00% 1.00% 3.00% EU ETS-type data collected from BCA for all sites so assume very good quality and complete.
2A2 non-fuel combustion 10.00% 5.00% (a) 5.00% High level of reporting in EU ETS for recent years and EF reflects small range of data for carbonates used in lime production. AD uncertainty higher in earlier years.
2A3 non-fuel combustion (a) 5.00% (a) 5.00% Mostly based on ETS data. Very small sites outside EU ETS; it's not certain how well EU ETS factor will apply to these 2A4 non-fuel combustion 2.00% 3.00% 2.00% 3.00% (Minor source in UK context) 2B Coke 1.00% 20.00% 1.00% 10.00% (Minor source in UK context) 2B coke oven coke (a) 20.00% (a) 20.00% (Minor source in UK context) 3 Shaw et al., 2022.
Through the analysis of emission plumes in the North Sea between 2018 and 2019, it was found that 98.4% of carbon in flared gas is converted to CO2. UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 723 2B Natural Gas 2.80% 1.25% 1.75% 1.25% Covers both feedstock and fuel (i.e.
total fuel used at the sites), so AD should be very good. 2B non-fuel combustion 2.00% 5.00% 2.00% 5.00% (Minor source in UK context) 2B OPG (a) 5.00% (a) 5.00% Moderate uncertainty in EF reflecting good level of reporting of fuel quality in EU ETS but range of variability of process off-gases that are generated and used in the chemical 2B petroleum coke 1.00% 10.00% 1.00% 10.00% (Minor source in UK context) 2B refinery gas 30.00% 5.00% 30.00% 5.00% High uncertainty, as we deviate from DUKES.
Low emission factor uncertainty, but not a well-characterised fuel. 2C Blast Furnace Gas 2.00% 10.00% 2.00% 10.00% Overall uncertainty in 2C is quite low and uncertainty is more about where the carbon input (from the coking coal) ends up being emitted, and less about the overall amount of carbon 2C Coke 2.00% 10.00% 2.00% 10.00% Good level of reporting from I&S operators across the time 2C coke oven coke 2.00% 5.00% 2.00% 5.00% Activity data has low uncertainty since it's based on ETS/ISSB/DUKES.
Emissions are based on regulator data, 2C non-fuel combustion 2.00% 10.00% 2.00% 10.00% Overall uncertainty in 2C is quite low and uncertainty is more about where the carbon input (from the coking coal) ends up being emitted, and less about the overall amount of carbon 2C Petroleum Coke 10.00% 7.50% 10.00% 7.50% (Minor source in UK context)

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 724 2D Lubricants 50.00% 50.00% 50.00% 50.00% It's challenging to determine the size of the recovered lubricant market, as this is outside the scope of energy statistics, hence a high activity uncertainty. The fraction of lubricant incidentally oxidised is also highly uncertain, so should be reflected in a high EF uncertainty.
2D non-fuel combustion 25.00% 2.00% 25.00% 2.00% Some uncertainty as to the proportion of HDVs requiring urea and how much is needed per vehicle. Very low EF uncertainty because carbon content of urea solution known 2D Petroleum Coke 20.00% 30.00% 20.00% 30.00% (Minor source in UK context) 2D Petroleum Waxes 10.00% 50.00% 10.00% 50.00% (Minor source in UK context) 2G 25.00% 2.00% 25.00% 2.00% High activity uncertainty due to it being unclear if bicarbonate of soda is used for emissive or non-emissive applications.
Low uncertainty in emission factors as it's determined from 3G non-fuel combustion (a) 20.90% (a) 20.90% Reflects overall uncertainty of AD and EF for carbonate 3H non-fuel combustion (a) 50.00% (a) 50.00% (Minor source in UK context)

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 725 4A non-fuel combustion 5.00% 20.00% 5.00% 20.00% In order to assess the uncertainties for Forest Land a Monte Carlo analysis was performed using the CARBINE model. The probability density functions (PDFs) assigned to the various CARBINE input parameters were based on information from the literature and expert judgement.
A selection of 100 sets of input parameters were generated using a Latin hypercube, as this was considered to be the minimum number of model runs to get a reasonable estimate 4B non-fuel combustion 1.00% 25.00% 1.00% 25.00% High uncertainty reflects modelled assumptions and limited AD and is focussed in the EF parameter. 4C non-fuel combustion 1.00% 30.00% 1.00% 30.00% High uncertainty reflects modelled assumptions and limited AD and is focussed in the EF parameter.
4D non-fuel combustion 1.00% 25.00% 1.00% 25.00% High uncertainty reflects modelled assumptions and limited AD and is focussed in the EF parameter. 4E non-fuel combustion 1.00% 25.00% 1.00% 25.00% High uncertainty reflects modelled assumptions and limited AD and is focussed in the EF parameter.
4F non-fuel combustion (a) 50.00% (a) 50.00% High uncertainty reflects modelled assumptions and limited AD and is focussed in the EF parameter. UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 726 4G non-fuel combustion 1.00% 20.00% 1.00% 15.00% In order to assess the uncertainties for Forest Land a Monte Carlo analysis was performed using the CARBINE model.
The probability density functions (PDFs) assigned to the various CARBINE input parameters were based on information from the literature and expert judgement. A selection of 100 sets of input parameters were generated using a Latin hypercube, as this was considered to be the minimum number of model runs to get a reasonable estimate 5C Chemical waste 300.00% 40.00% 10.00% 30.00% (Minor source in UK context) 5C Clinical waste 300.00% 40.00% 5.00% 20.00% (Minor source in UK context) 5C Municipal Solid Waste 300.00% 40.00% 1.00% 15.00% (Minor source in UK context) 5C non-fuel combustion 300.00% 40.00% 300.00% 40.00% Unauthorised and widely dispersed activity estimated from indirect data sources so high uncertainty.
Significant uncertainty in the composition of material burnt. 5C Small scale waste burning 300.00% (n) 100.00% (n) 300.00% (n) 100.00% (n) Activity data taken from a relatively new survey with high uncertainty (confidence in this source may improve in future years).
High EF uncertainty due to the variability of waste being burnt and its biogenic content. UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 727 1A1 All Fuels 10.00% 50.00% 1.00% 50.00% Minor source but uncertainty mainly reflects uncertainty in the EF from combustion of biomass.
A large proportion of base year emissions are associated with 1A1ciii data which are extrapolated based on production trends, therefore has a higher uncertainty than the 1A1a- dominated emissions in later years. 1A2 All Fuels 1.50% 50.00% 1.00% 50.00% As above.
1A3 Aviation Gasoline 20.00% 78.50% 20.00% 78.50% (Minor source in UK context) 1A3 Jet Gasoline 20.00% 78.50% 20.00% 78.50% (Minor source in UK context) 1A3 Other Bituminous Coal 20.00% 110.00% 20.00% 110.00% (Minor source in UK context) 1A3 Other Gas/Diesel Oil 15.00% 130.00% 15.00% 130.00% (Minor source in UK context) 1A3 Natural Gas 5.00% 130.00% 5.00% 130.00% Using parameters for road transport LPG; note that source is 1A3b Gas/Diesel Oil 1.80% 130.00% 1.00% 130.00% Road transport fuel sales well documented, so uncertainty in AD should be low. Uncertainty in EF reflects the variability in EFs for the range of vehicle (car, van, HGV) and road types.
1A3b Liquefied Petroleum Gas 5.00% 130.00% 5.00% 130.00% (Minor source in UK context)

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 728 1A3b Motor Gasoline 1.00% 75.00% 1.00% 75.00% Road transport dominates consumption of these fuels, so uncertainty in AD should be low. Uncertainty in EF reflects the variability in EFs for petrol cars and road types.
Lower uncertainty than diesel vehicles because consumption dominated by only one vehicle type. 1A3d Gas/Diesel Oil 20.00% 130.00% 20.00% 130.00% Uncertainty in AD due to uncertainty in getting domestic/international split from bottom-up method.
Uncertainty in EF should be consistent with other 1A3 gas oil 1A3d Residual Fuel Oil 20.00% 130.00% 20.00% 130.00% Uncertainty in AD due to uncertainty in getting domestic/international split from bottom-up method. 1.50% 50.00% 1.00% 50.00% Minor source but uncertainty mainly reflects uncertainty in the EF from combustion of biomass.
7.07% 65.55% 7.07% 65.55% (Minor source in UK context) 1B1 Coke Oven Gas 1.50% 50.00% 1.00% 50.00% (Minor source in UK context) 1B1 non-fuel combustion 2.00% 20.00% 2.00% 20.00% High EF uncertainty reflects the modelled estimates of 1B1 wood (a) 50.00% (a) 50.00% (Minor source in UK context)

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 729 1B2a non-fuel combustion 20.00% 50.00% 5.00% 50.00% Latest year methane 1B2a is dominated by direct process fugitives from offshore oil rigs and oil terminals and oil loading. In all cases the AD are of reasonable quality from installation-level reporting (the oil loading AD are from production stats, of good quality).
Base year AD are more uncertain; industry reporting is not source-specific and IPCC good practice gap-filling methods are used to derive 1990- 1994 estimates. The 2019 Refinement cites 50% uncertainty for direct process / fugitive EFs.
1B2b non-fuel combustion 20.00% 50.00% 5.00% 50.00% Latest year methane 1B2b is dominated by direct process fugitives from offshore gas rigs gas oil terminals and from onshore gas production and gathering. In all cases the AD are of reasonable quality from installation-level reporting.
Base year AD are more uncertain; industry reporting is not source-specific and IPCC good practice gap-filling methods are used to derive 1990-1994 estimates. The 2019 Refinement cites 10-20% uncertainty for direct process / fugitives EFs whilst the IPCC default uncertainty for process fugitives is 100%.
The UK applies 50% as a compromise

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 730 1B2c non-fuel combustion 20.00% 100.00% 5.00% 100.00% Flaring and venting both contribute a high share of total sector emissions in all years. Operator reporting informs flaring and venting emissions since 1995; accuracy will be limited by measurement uncertainty on gas to flare/vent and assumptions applied.
Base year AD are more uncertain; industry reporting is not source-specific and IPCC good practice gap-filling methods are used to derive 1990-1994 estimates. Flaring uncertainty dominates as operators assume that flare gas is 98% oxidised.
This is supported by recent evidence4, however emissions would increase greatly if the largest sites have notably lower oxidation. (a) 100.00% (a) 100.00% (Minor source in UK context) (a) 20.00% (a) 20.00% (Minor source in UK context) 2C Blast Furnace Gas 2.00% 50.00% 2.00% 50.00% (Minor source in UK context) 2C coke oven coke 2.00% 50.00% 2.00% 50.00% Activity data has low uncertainty since it's based on ETS/ISSB/DUKES.
Emissions are based on literature factors, 2C non-fuel combustion 1.00% 50.00% 1.00% 50.00% (Minor source in UK context) 50.00% 50.00% 50.00% 50.00% (Minor source in UK context) 3A non-fuel combustion 13.73% (a) 13.73% (a) Based on monte Carlo analysis for the agriculture model 3B non-fuel combustion (a) 8.37% (a) 8.37% Based on monte Carlo analysis for the agriculture model 4 Shaw et al., 2022. Through the analysis of emission plumes in the North Sea between 2018 and 2019, it was found that 98.4% of carbon in flared gas is converted to CO2.
UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 731 3F non-fuel combustion 25.61% (a) 25.61% (a) Based on monte Carlo analysis for the agriculture model 4A non-fuel combustion 5.00% 90.00% 5.00% 70.00% (Minor source in UK context) 4B non-fuel combustion 1.00% 90.00% 1.00% 90.00% (Minor source in UK context) 4C non-fuel combustion 1.00% 40.00% 1.00% 40.00% (Minor source in UK context) 4D non-fuel combustion 1.00% 40.00% 1.00% 35.00% (Minor source in UK context) 4E non-fuel combustion 1.00% 50.00% 1.00% 40.00% (Minor source in UK context) 5A non-fuel combustion 15.00% 46.00% 15.00% 46.00% Moderate/high uncertainty in historical waste data, rates of decomposition and generation of methane in the modelled approach. Some extrapolation of data needed for methane utilisation, hence high uncertainty overall, across AD and EF.
5B 30.00% 99.50% 30.00% 99.50% Scarce data for UK biological treatments. High uncertainty.
5C Municipal Solid Waste 5.00% 75.00% 1.00% 75.00% (Minor source in UK context) 5C non-fuel combustion 5.00% 50.00% 5.00% 50.00% (Minor source in UK context) 5C Small scale waste burning 300.00% (n) 100.00% (n) 300.00% (n) 100.00% (n) Activity data taken from a relatively new survey with high uncertainty (confidence in this source may improve in future years). The EF uncertainty is the default suggested in the 5C wood 300.00% (r) 50.00% 300.00% (r) 40.00% (r) (Minor source in UK context) 5D1 non-fuel combustion 10.00% 25.00% 10.00% 25.00% UK industry research and model.
Moderate-high uncertainty. UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 732 5D2 25.00% 82.54% 25.00% 82.54% Calculated based on 2006 IPCC guidelines ranges for model parameters and weighted depending on their contribution to 1A3 Aviation Gasoline 20.00% 110.00% 20.00% 110.00% 1A3 Jet Gasoline 20.00% 110.00% 20.00% 110.00% 1A3 Other Bituminous Coal 20.00% 110.00% 20.00% 110.00% 1A3 Other Gas/Diesel Oil 15.00% 130.00% 15.00% 130.00% 1A3 Natural Gas 5.00% 130.00% 5.00% 130.00% Using parameters for road transport LPG; note that source is 1A3b Gas/Diesel Oil 1.80% 130.00% 1.00% 130.00% Road transport dominates consumption of these fuels, so uncertainty in AD should be low.
Uncertainty in EF reflects the variability in EFs for different diesel vehicle types and road

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 733 1A3b Liquefied Petroleum Gas 5.00% 130.00% 5.00% 130.00% 1A3b Motor Gasoline 1.00% 75.00% 1.00% 75.00% Road transport dominates consumption of these fuels, so uncertainty in AD should be low. Uncertainty in EF reflects the variability in EFs for petrol cars and road types.
Lower uncertainty than diesel vehicles because consumption dominated by only one vehicle type. 1A3d Gas/Diesel Oil 20.00% 130.00% 20.00% 130.00% Uncertainty in AD due to uncertainty in getting domestic/international split from bottom-up method.
Uncertainty in EF should be consistent with other 1A3 gas oil 1A3d Residual Fuel Oil 20.00% 130.00% 20.00% 130.00% Uncertainty in AD due to uncertainty in getting domestic/international split from bottom-up method. 1B2a non-fuel combustion 15.00% 100.00% 10.00% 200.00% Assume same AD uncertainty as carbon.
Most UK reporting is based on operator guidance EFs with very little or no monitoring, so it is only marginally better than using IPCC defaults. The IPCC default uncertainty for nitrous oxide from such process sources is typically 100% or higher.
Also note that for onshore oil production (~half of more recent emissions) we use the IPCC default which is -10 to +1000% uncertainty range, so the latest year is more uncertain. UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 734 1B2b non-fuel combustion 15.00% 100.00% 2.00% 100.00% Assume same AD uncertainty as carbon.
Most UK reporting is based on operator guidance EFs with very little or no monitoring, so it is only marginally better than using IPCC defaults. The IPCC default uncertainty for nitrous oxide from such process sources is typically 100% or higher.
1B2c non-fuel combustion 20.00% 100.00% 5.00% 100.00% Assume same AD uncertainty as carbon. Most UK reporting is based on operator guidance EFs with very little or no monitoring, so it is only marginally better than using IPCC defaults.
The IPCC default uncertainty for nitrous oxide from such process sources is typically 100% or higher. 2.00% 50.00% 2.00% 50.00% Strong activity data, so low activity uncertainty.
Assume a high uncertainty for the literature factor. 10.00% 100.00% (a) 10.00% Emission estimates for recent years have been based partially (1998-2008) or wholly (2009-2017) on continuous monitoring, and therefore will be subject to low uncertainty.
The monitoring systems used at the 2 sites currently in operation are subject to an uncertainty of 5-10%. Uncertainty in earlier years is much higher due to more limited information 100.00% 100.00% 100.00% 100.00%

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 735 (a) 68.07% (a) 9.53% Based on separate monte Carlo analysis for the agriculture (a) 53.28% (a) 11.16% Based on separate monte Carlo analysis for the agriculture 4A non-fuel combustion 1.00% 80.00% 1.00% 80.00% 4B non-fuel combustion 1.00% 40.00% 1.00% 40.00% 4C non-fuel combustion 1.00% 50.00% 1.00% 45.00% 4D non-fuel combustion 1.00% 120.00% 1.00% 65.00% 4E non-fuel combustion 1.00% 135.00% 1.00% 130.00%% 4only non-fuel combustion 1.00% 165.00% 1.00% 165.00% 5D2 25.00% 129.37% 25.00% 129.37% Calculated based on 2006 IPCC guidelines ranges for model parameters and weighted depending on their contribution to

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 736 HFCs 2B9 (a) 15.00% (a) 10.00% HFCs 2C4 5.00% 10.00% 5.00% 10.00% HFCs 2E1 (a) 44.
50% (a) 47.15% HFCs 2F1 10.00% 10.00% 10.00% 10.00% Good UK data on refrigerant supply is used to tune the model of emissions for this sector, which means that there is a high confidence in the overall estimates of an activity for this sector. Good activity data helps mitigate the uncertainty in emissions, as leakage and disposal is directly HFCs 2F2 (a) 15.00% (a) 15.00% HFCs 2F3 (a) 25.00% (a) 25.00% HFCs 2F4a 5.00% 10.00% 5.00% 10.00% HFCs 2F4b (a) 10.00% (a) 10.00% HFCs 2F5 (a) 25.50% (a) 25.50% HFCs 2F6 (a) 51.00% (a) 42.00% PFCs 2B9 (a) 15.00% (a) 10.00% PFCs 2C3 (a) 20.00% (a) 20.00% PFCs 2F3 (a) 25.00% (a) 25.00% PFCs 2G2e (a) 44.50% (a) 47.15%

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 737 SF6 2G2a (a) 50.00% (a) 50.00% SF6 2G2b (a) 17.50% (a) 15.50% SF6 2G2e (a) 40.00% (a) 10.00%

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 738 A 2.3.2 General Considerations The uncertainty parameters presented above are based primarily on expert judgment, but where • The uncertainty range presented for data (for example the confidence interval in the 2006 IPCC guidelines for default factors) • Monte Carlo Analysis of some of the more sophisticated models, most notably for agriculture, LULUCF and F-gases In some cases, the individual uncertainties for the activity data and the emission factor are difficult to separate, but the uncertainty on the total emission can more easily be estimated.
In these cases, the uncertainties are listed in the columns for emission factor uncertainties. The analysis of the uncertainties i n the nitrous oxide emissions is particularly difficult because emissions sources are diverse, and few data are available to form an assessment of the uncertainties in each source.
Emission factor data for the combustion sources are scarce and for some fuels are not available. The uncertainty assumed for agricultural soils (IPCC category 3D) uses a custom distribution.
These parameterised functions have been defined and provided by Rothamsted Research as the best possible fit to the expected distribution of uncertainties in 1990 and the most recent year’s emissions, and are normalised in the Approach 2 methodology such that the resultant mean is consistent with the current inventory emissions in 1990 and the most Many of the uncertainties in the emissions of HFCs, PFCs, NF3 and SF6 (collectively known as F- gases) are based on the study to update emissions and projections of F-gases (ICF, 2014) in line with the 2006 IPCC guidelines. Some sources have been updated since then and the uncertainties for those sources have been revisited accordingly.
We assume that all F-gas emissions are independent between years as the technologies, gases (which have a very wide range of GWPs) used and regulations have changed drastically between the base year and the most recent year. Many HFCs in particular were not in use until the early A 2.3.3 Uncertainty in the Trend In simulatin g trend uncertainty , it was necessary to make assumptions about the degree of correlation between sources and between 1990 and the most recent year.
The assumptions were • Activity data are uncorrelated; • Emission factors of some similar fuels are correlated; • Land Use Change and forestry emission factors are correlated (e.g. 1990 4A CO2 with 4A CO2 for the most recent year); • Emission factors covered by the Carbon Factors Review (Baggott et al, 2004) are not • Process emissions from blast furnaces, coke ovens and ammonia plants are not • Landfill emissions were partly correlated across years in the simulation.
It is likely that the emission factors used in the model will be correlated, and also the historical estimates of waste arisings will be correlated since they are estimated by extrap olation from the year

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 739 of the study. However, the reduction in emissions is due to flaring and utilisation systems installed since 1990 and this is unlikely to be correlated.
As a simple estimate it was assumed that the degree of correlation should reflect the reduction in emissions since • Emissions from agricultural soils and manure management are correlated in the base and • The emission factor used for sewage treatment was assumed to be correlated between years, though the protein consumption data used as activity data were assumed not to be correlated between years; and, • Nitric acid production emission factors were assumed not to be correlated, since the mix of operating plants is very different in the most recent year compared with 1990 – only two of the original eight units are still operating in the latest inventory year, all of which now have differing levels of abatement fitted. A 2.4.1 Uncertainty in the emissions uncertainties for each of the seven categorised GHGs.
This is calculated as half of the 95% confidence range, i.e. the limits between which there is a 95% probability that the actual value of emissions falls.
Note that the uncertainty in the GWP is not accounted for. A 2.4.2 Uncertainty in the Trend 𝑙𝑎𝑡𝑒𝑠𝑡 𝑦𝑒𝑎𝑟 𝑠𝑎𝑚𝑝𝑙𝑒 − 1990 𝑠𝑎𝑚𝑝𝑙𝑒 1990 𝑚𝑒𝑎𝑛 and the 2.5 and 97.5 percentiles are shown to indicate a 95% confidence range .
This can produce different results from a trend calculated as 𝑙𝑎𝑡𝑒𝑠𝑡 𝑦𝑒𝑎𝑟 𝑠𝑎𝑚𝑝𝑙𝑒 − 1990 𝑠𝑎𝑚𝑝𝑙𝑒 1990 𝑠𝑎𝑚𝑝𝑙𝑒 , particularly where simulations of 1990 emissions are near or can go Note that the uncertainty in the GWP is not accounted for. UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 740 Gg CO2e Gg CO2e Gg CO2e Gg CO2e % Gg CO2e Gg CO2e % % % % TOTAL CO2 (net) 607,318 342,572 596,771 617,961 1.7% 336,120 348,923 1.9% -44% -45% -42% All 817,297 430,594 782,557 863,689 5.0% 420,684 441,909 2.5% -47% -53% -43% Uncertainty calculated as 0.5*R/E where R is the difference between 2.5 and 97.5 percentiles and E is the mean calculated in the simulation.
Emissions of CO2 are net emissions (i.e. sum of emissions and removals).
UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 741 identical to the emission estimates in the inventory. The Executive Summary of this NIR and the accompanying CRF tables present the agreed national GHG emissions and removals reported to the UNFCCC.
a What is specifically presented here is the 95% confidence interval for the change in emissions as a percentage of 1990 emissions; this is different to the 95% confidence interval of the percentage changes since 1990. b Note that for categories where emissions have completely or almost completely stopped being generated in the latest year (i.e. has a trend of near -100%), the 2.5 percentile for the trend might be presented as a decline of over 100%.
This should not be interpreted to mean that emissions might now be negative, instead this reflects that due to uncertainty in the emission estimates, the decline in emissions might be greater than the mean estimate for the base year. The below simplified example illustrates how this might occur.
• Base year emissions for a category is estimated to be 1 Mt CO2e • Latest year emissions for a category is estimated to be 0 Mt CO2e • Uncertainty in the base year and latest year emissions estimate is 10% • The central estimate for the trend is -100% • The lower limit for the trend (in Mt CO2e) would be lower bound for latest year emissions estimated [i.e. 0 Mt CO2e * (100% - 10%)] minus the upper bound for base year estimated emissions [i.e.
1 Mt CO2e * • Using the formula described at the beginning of section A 2.4.2, the lower limit is divided by the base year mean [i.e. -1.1 Mt CO2e / 1 Mt CO2e] which results in -110%

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 742 A 2.5.1 Overview of the Method Sectoral uncertainties were calculated from the same base data used for the “by gas” analysis.
presented in IPCC categories, which is consistent with the reporting format used within this submission to the UNFCCC, but we recommend that these estimates should only be considered

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 743 1A1a 205,265 56,239 54,578 57,920 3.0% -73% -75% -70% 1A1b 17,866 11,101 9,626 12,660 13.7% -38% -62% -15% 1A1c 16,419 12,745 12,485 13,046 2.2% -22% -37% -7% 1A2a 3,653 1,169 1,114 1,225 4.8% -68% -74% -62% 1A2b 4,371 695 660 731 5.1% -84% -103% -66% 1A2c 12,331 5,093 4,831 5,358 5.2% -59% -67% -51% 1A2d 4,694 1,322 1,246 1,400 5.8% -72% -83% -62% 1A2e 7,885 4,110 3,897 4,327 5.2% -48% -55% -41% 1A2f 6,695 2,520 2,237 2,812 11.4% -62% -86% -40% 1A2g 35,986 28,728 27,394 30,060 4.6% -20% -28% -12% 1A3a 1,895 906 730 1,083 19.5% -52% -74% -31% 1A3b 111,756 100,592 98,854 102,376 1.8% -10% -12% -8% 1A3c 1,474 1,567 1,321 1,816 15.8% 6% -17% 29% 1A3d 7,711 4,921 4,046 5,784 17.7% -36% -55% -18% 1A3e 99 131 110 152 16.2% 32% 6% 59%

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 744 1A4a 28,683 19,119 18,503 19,746 3.3% -33% -43% -26% 1A4b 80,540 68,554 65,854 71,311 4.0% -15% -20% -10% 1A4c 5,077 5,928 4,074 7,775 31.2% 17% -34% 63% 1A5b 5,349 1,584 1,469 1,698 7.2% -70% -78% -62% 2B3 17,729 - - - n/a -100% -100% -100%

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 745 3F 261 - - - n/a -100% -100% -100% 4 273 153 51 360 101.4% -44% -182% 58%

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 746 4F - - - - n/a n/a n/a n/a 817,297 430,594 420,684 441,909 2.5% -47% -53% -43% very similar but not identical to the emission estimates in the inventory. The Executive Summary of this NIR and the accompanying CRF tables present the agreed national GHG emissions and removals reported to the UNFCCC.
a What is specifically presented here is the 95% confidence interval for the change in emissions as a percentage of 1990 emissions; this is different to the 95% confidence interval of the percentage changes since 1990. Further detail can be found in section A 2.4.2. b Note that for categories where emissions have completely or almost completely stopped being generated in the latest year (i.e.
has a trend of near -100%), the 2.5 percentile for the trend might be presented as a decline of over 100%. This should not be interpreted to mean that emissions might now be negative, instead this reflects that due to uncertainty in the emission estimates, the decline in emissions might be greater than the mean estimate for the base year.
The below simplified example illustrates how this might occur. UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 747 • Base year emissions for a category is estimated to be 1 Mt CO2e • Latest year emissions for a category is estimated to be 0 Mt CO2e • Uncertainty in the base year and latest year emissions estimate is 10% • The central estimate for the trend is -100% • The lower limit for the trend (in Mt CO2e) would be lower bound for latest year emissions estimated [i.e.
0 Mt CO2e * (100% - 10%)] minus the upper bound for base year estimated emissions [i.e. 1 Mt CO2e * • Using the formula described at the beginning of section A 2.4.2, the lower limit is divided by the base year mean [i.e.
-1.1 Mt CO2e / 1 Mt CO2e] which results in -110%

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 748 Comparing the results of the error propagation approach, and the Monte Carlo estimation of uncertainty by simulation, is a useful quality control check on the behaviour of the Monte Carlo The reason that the error propagation approach is used as a reference is because the approach to the error propagation approach has been defined and checked by the IPCC, and is clearly set out in the IPCC 2000 Good Practice Guidance and the 2006 Guidelines. The UK has implemented the IPCC error propagation approach as set out in this guidance.
The implementation of an uncertainty estimation by simulation cannot be prescriptive, and will depend on how the country constructs its model, and the correlations included within that model. Therefore, there is a greater likelihood of errors being introduced in the model used to estimate uncertainty by Monte Carlo If all the distributions in the Monte Carlo model were normal, and the assumed correlations were identical, the estimated errors on the trend from the Monte Carlo model should approach those estimated by the error propagation approach if enough iterations are done.
The error propagation approach assumes 100% correlation between EFs in the base and inventory year, and no correlation between sources, however in reality the nature and degree of correlation varies by source, and many distributions are not normal but heavily skewed, particularly those with very high uncertainty. These differences interact in various ways, but would be expected broadly to result in higher trend uncertainty, and lower uncertainty on the most recent year’s total in the Monte Carlo uncertainty estimates compared to the error propagation approach.
This comparison propagation and Monte Carlo approaches. These differences mostly arise from the fact that the error propagation approach only uses normal distributions, cannot account for different uncertainty parameters between the 1990 and the latest inventory year, cannot account for correlations between sources, and automatically assumes a correlation between the emission factor uncertainty in 1990 and the most recent year.
The central estimates of emi ssions generated by the Monte Carlo model in 1990, and those in the latest inventory year, are very close. We would not expect the central estimates from the two methods to be identical, but with a very large number of iterations we would expect the difference to tend to zero.
To note, the base year is 1990 for N2O, CH4 and CO2, and 1995 for the F-gases. UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 749 (Approach 2) uncertainty analyses Error propagation 820,103 430,654 2.4% 1.6% Monte Carlo 819,946 430,594 2.5% 5.1% a Calculated as half the difference between 2.5 and 97.5 percentiles, assuming a normal distribution is equal to ±1.96 standard deviations on the central estimate.
b Net emissions, including emissions and removals from LULUCF

Other Detailed Methodological Descriptions A3 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 750 Methodological Descriptions for Individual Source or Sink Categories This Annex contains background information about methods used to estimate emissions in the UK GHG inventory. This information has not been incorporated in the main body of the report because of the level of detail, and because the methods used to estimate emissions cut across This Annex provides background information on the fuels used in the UK GHG inventory, mapping between IPCC and NAEI source categories and detailed description of methods used to estimate GHG emissions, and emission factors used in those methods.
Methods for calculating emissions within the energy sector are detailed in the method statements set out in Chapter 3 . This Annex details the emission factors used and their source, and elaborates on references commonly used within the Energy sector.
The national energy balance (and how it is used) is described in ANNEX 4:. Emission factors used for the 2023 submission for sectors 1A and 1B can be found in the accompanying excel ‘Energy_background_data_uk_2023.xlsx’.
This can be found as one of the additional documents Note that there can be a delay between the NIR being published on the NAEI website after official A 3.1.2 Commonly used references This section describes data sources that are used across multiple emission sources within the energy sector, and how they are used. A 3.1.2.1 Baggott et al., 2004 – Carbon factors review A review of the carbon factors used in the UK GHG inventory was carried out in 2004.
The report detailing this study is available This aimed to validate existing emission factors and seek new data for country specific emission factors for the UK. At the time of publication this reference provided new emission factors • fuels used in the cement industry; • a number of petroleum based fuels;

Other Detailed Methodological Descriptions A3 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 751 • coke oven and blast furnace gas.
Since then following updates are made to the following emission factors based on new 1. Coal emission factors are adjusted based on the annual variations in the GCV of the fuels using methods developed as part of the 2004 analysis (Baggott et al., 2004).
EFy is the emission factor (EF) in year y EFref is the EF in the reference year (the year for which data are available) GCVref is the GCV in the reference year 2. Since the advent of EU ETS in 2005, a number of sources of emissions from coal which had previously been reliant on Baggott et al., 2004 have now been replaced with data from the ETS, where the data set was considered suitable (high proportion of source included, and high proportion of T3 plant specific data).
In addition, in 2 014 the use of oxidation factors from this report was reviewed, and where suitable background evidence to support the factors used were not available, the IPCC default (of 1, IPCC 2006) has been used. 3.
Emission factors for petroleum based fuels (where ETS d ata are not available) are still largely based on Baggott et al., 2004. These were reviewed in 2014 and compared with the defaults in the 2006 IPCC Guidelines and found to be largely within the range of the 2006 Guidelines.
No new data for the UK has been identified and the emission factors from Baggott et al., 2004 are still considered to be relevant country specific emission 4. During 2017-18, a review of the UK’s shipping inventory was conducted (Scarborough et al., 2018).
This identified new carbon emission factors for marine fuels, which replace the factors identified as part of Baggot et al., 2004. 5.
Emission factors for natural gas are updated annually based on analyses from the gas network operators (Personal Communications from network operator s, 2019). As part of the systems improvements made to the inventory database in 2020 (moving from mass to energy units, and from gross to net), data from the gas operators has been further analysed and a revised gross to net conversion has been derived.
This has been applied to the data from the early part of the time series, which came from Baggott et al., 2004. 6.
Emission factors for coke oven gas and blast furnace gas are estimated based on a carbon balance approach (as described in Chapter 3, MS 4). 7.
The Mineral Products Association provide data for fuels used in the cement industry annually on a confidential basis, and these are validated with EU ETS data (Personal Communication, MPA, 2021). For the 2020 submission, data received for the 2004 review was reconsidered for cement, and revised coal factors for the early part of the time series (that were not received in time for inclusion in the final review report) have now been incorporated into the inventory.
A new review of carbon emission factors was con ducted during 2017, focusing on those factors retained from the 2004 review (Brown et al., 2017). This concluded that the factors that are currently in use are slightly more conservative than more recent values identified, and that there

Other Detailed Methodological Descriptions A3 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 752 was no new robust evidence upon which we could justify changing the current factors.
There were also recommendations on which emission factors might be the highest priority for further research in future. This report is available A 3.1.2.2 The Pollution Inventory and other regulators' inventories The Pollution Inventory (PI) has, since 1998, provided emission data for the six Kyoto gases (NF3 is not included) and other air pollutant for installations regulated by the Environment Agency (EA) in England and Natural Resources Wales (NRW) in Wales.
This is part of the UK’s process for managing regulated emissions from industry processes under the IPCC permitting system. The PI does contain earlier data of carbon dioxide emissions at some sites reported from 1994 onwards.
The Scottish Pollutant Release Inventory (SPRI) covers processes regulated by the Scottish Environment Protection Agency (SEPA), and contains data from 2002 and 2004 onwards. The Northern Ireland Pollution Inventory (NIPI) covers processes regulated by the Northern Ireland Environment Agency and includes data for 1999 onwards.
These data are subject to some very significant • Emissions of each pollutant are reported for each permitted installation as a whole, so emissions data for carbon dioxide, for example, can cover emissions from fuel use as well as from an industrial process. No information is given on what the source of emissions is, so a judgement has to be made about the scope of reporting; • Permitting arrangements have changed over time, so the reporting of data is not on a consistent basis across the time-series.
In general, the tendency has been to reduce the number of permits, so that whereas in the early 1990s there might have been separate permits at an industrial installation covering the boiler plant and the chemical processes, from the late 1990s onwards the tendency would be to issue a single permit to cover both. Therefore, the problems with the scope of emissions data mentioned in the first bullet point are most severe for the second half of the GHGI time series; and, • Since 1998, process operators need only report emissions of each pollutant if those emissions exceed a reporting threshold.
For example, where emissions from an installation are less than 10,000 tonnes of CO 2, or 10 tonnes of methane, the operator does not need to report any emissions data for that substance in that year. Reporting thresholds are irrelevant for many of the sectors of interest to this study, since emissions would be many times higher than the thresholds, but the reporting thresholds do mean that it is necessary to consider whether the data available in the PI (and in the SPRI & NIPI for later years) will be complete.
Despite these limitations, these data are still a useful source of information for the UK GHG inventory. A considerable amount of effort is put into manually interpreting the individual returns and allocating these to appropriate categories for use in the inventory estimates by the Inventory A 3.1.2.3 The Environmental and Emissions Monitoring System (EEMS) Reporting Emissions from upstream oil and gas producti on facilities, including onshore terminals, are estimated based on operator reporting via EEMS, managed by the Offshore Petroleum Regulator for Environment and Decommissioning (OPRED) and developed in conjunction with the trade association Oil & Gas UK (formerly the UK Offshore Operators’ Association, UKOOA).
The EEMS data provides a detailed inventory of point source emissions estimates, based on operator returns for the years 1995-2021. However, the EEMS data for 1995 to 1997 are not complete, frequently

Other Detailed Methodological Descriptions A3 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 753 exhibiting duplicate entries with identical submissions by operators across years.
Since the 1995 – 1997 data are not considered reliable, the EEMS dataset is only used directly to inform national inventory estimates from 1998 onwards for the following • oil loading (onshore and offshore). [Activity data are not routinely collected via EEMS for sources fugitive releases, direct process activities, oil storage or gas venting.
The emissions from these sources are reported as annual estimates by operators and used directly within the inventory.] These EEMS-derived activity data enable detailed analysis of the oil & gas emissions and related emission factors at the installation level, providing a high degree of data transparency and enabling the Inventory Agency to perform quality checks by source, by site, by year to identify and check/resolve any potential data gaps or outliers.
The EEMS data per installation are only available back to 1998. The UK inventory estimates for the 1990 -1997 period are based on industry surveys and analysis that were submitted to UK Government by the trade association, UKOOA; these data are more aggregated, per source but aggregated across all installations during 1995 to 1997, and aggregated across sources for 1990-1994.
The EEMS data from 1998 onwards help to inform the EFs that are combined with oil and gas sector -wide activity statistics back to 1990 in order to derive time series consistent estimates. Fynes and Sage is a country -specific reference from the mid -1990s, and it includes analysis of solid fuels typically used in the UK economy in that period, deriving mass-based emission factors that are used within the UK GHGI.
In the 1990s, coal used in the UK economy was predominantly mined in the UK, whereas over the time series of the inventory there has been a decline in the share of coal from UK sources and an increase in coal imports from around the world. For recent years, for the more significant emission sources, e.g.
energy indus tries and manufacturing industries, the Inventory Agency uses EFs that are derived from EU ETS data, but for smaller emission sources in the UK that still use solid fuels (such as residential, collieries) the Fynes and Sage data are retained, as there are no EU ETS data for fuels used in these sectors. There is some uncertainty regarding how representative the EFs from Fynes and Sage may be for these smaller combustion sources, but we note that the use of coal-fired technology in sectors such as collieries and residential is predominantly in the UK coal production areas, where local A 3.1.3 Feedstocks and Non-Energy Use (NEU) of fuels The estimation methods are described within individual sections of the NIR, but are summarised here.
The general approach adopted in the UK GHG inventory is to assume that emissions from all non-energy uses of fuels are zero (i.e. the carbon is assumed to be sequestered in products such as plastics and other chemicals), except for cases where emission sources can be identified and emission estimates included in the inventory.
There is one exception to this, for petroleum coke where we have no information on any non -emissive uses at all, and so we adopt the conservative approach of assuming that all petroleum coke use is emissive. Other Detailed Methodological Descriptions A3 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 754 The UK Inventory Agency conducts periodic studies into the fate of fuels reported as non-energy use, in order to assess the levels of stored carbon and carbon emitted for different fuels over the time series.
These detailed studies a re supplemented through annual data gathering and consultation with stakeholders to maintain an accurate representation of the emitted and stored The assumptions and estimates for individual sources are based on a review conducted in 2013- 14 (Ricardo-AEA, 2014b) which included research into UK-specific activities and data sources as well as a review of the National Inventory Reports (NIRs) of other countries. The sections below outline the emission sources from feedstock and NEU of fuels that are included in the UK GHGI, the source data and estimation methods and a summary of the time series for each of the fuel types where there is a stored carbon component in the UK energy balance.
The estimates are all presented in CRF Tables 1.Ab and 1.Ad. Other Detailed Methodological Descriptions A3 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 755 1A1a Scrap tyre combustion in power stations (1994 to 2000 only).
Fossil carbon in MSW combustion in energy from waste plant. 1A1b Other petroleum gas use in refineries (2004, 2006 to 2011, 2013 to 2021 only).
Re-allocated from non-energy use as UK ETS and trade association data indicates that DUKES data on OPG combustion are an under-report. 1A2f Waste solvents, waste-derived fuels containing fossil carbon, in cement kilns.
Scrap tyres and waste plastics etc. combusted in cement kilns.
1A2g Industrial combustion of waste solvents. Emissions of carbon from chemical feedstock via combustion of products such as synthetic rubbers and solvents.
2B8 Energy recovery from process off-gases in the chemical industry. Large quantities of naphtha, butane, propane, ethane, and other petroleum gases are listed in DUKES as used for non-energy applications and these fuels are known to be used extensively as chemical feedstocks.
However, UK ETS and operator data indicate that process off-gases, derived from the chemical feedstocks, are a major fuel for ethylene production processes and other petrochemical sites. Emissions of CO2 are reported in 2B8.
5C Fossil carbon in chemical waste incineration. Fossil carbon in MSW incineration.
Fossil carbon in clinical waste incineration. Fossil carbon in small scale waste burning.
Lubricants 1A1a Waste oil combustion in power stations. 1A2f Waste oil combustion in cement kilns.
1A2g Waste oil combustion in unclassified industry (including road-stone coating 1A3biv Lubricant combustion in moped engines 2D1 Lubricant oxidation in aircraft, industrial, road vehicle (except moped), marine shipping and agricultural engines. Bitumen n/a No known UK applications that lead to GHG emissions.
5 I.e. naphtha, Liquid Petroleum Gases (LPG), Refinery Fuel Gas (RFG) / Other Petroleum Gases (OPG), gas oil and Ethane.
Including emissions of carbon from chemical feedstock via combustion of products such as synthetic rubbers

Other Detailed Methodological Descriptions A3 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 756 Based on reported energy use data by specific industries within datasets such as UK ETS and also from direct dialogue with industry representatives, the Inventory Agency re-allocates a small proportion of the reported “NEU” allocation from DUKES, and reports emissions within the UK GHG inventory. This re-allocation generates emissions for the mineral processing sector (1A2f) and other industry (1A2g) and for petcoke use in the domestic sector (1A4b).
There are non-combustion, emissive uses of petcoke in the UK through the use of petcoke-derived anodes in the metal processing industries. Emissions from these uses of petcoke are reported in 2C1 (electrode use in electric arc furnaces) and 2C3 (anode use in aluminium manufacture).
Petroleum coke is also used in the minerals (2A4) and chemicals industries (2B6) leading to further emissions. The remaining consumption of petroleum coke is also assumed to be emissive, with emissions reported under 2D3.
Other Oil 2D2 Carbon released from use of petroleum waxes. Uses of petroleum waxes includes candles, with carbon emitted during use.
n/a Unknown quantities of coal tar pitch are used in the manufacture of anodes for industrial processes. In the UK inventory the emissions from the use of these anodes are allocated only against petroleum coke (also used in anode production).
This is a small mis-allocation of emissions between the two fuels since the carbon emitted is likely to arise from both petroleum coke and the coal tar pitch, but it is due to lack of detailed data, and does not affect the accuracy of Ammonia and methanol production leading to direct release of CO2 from natural gas used to provide the energy for steam reforming and from natural gas feedstock to the reformer. Carbon originating in the natural gas feedstock which is converted into methanol is assumed to be stored.
A 3.1.3.1 Naphtha, Ethane, Gas Oil, Refinery/Other Fuel Gas (RFG/OPG) Propane and Ethane, LPG (given separately as propane & butane in the energy statistics), gas oil, refinery / other fuel gas (RFG/OPG) and naphtha are all consumed in very significant quantities for non - energy uses, primarily as feedstock in chemical manufacturing. In the UK, several major petrochemical production facilities are supplied with Natural Gas Liquid (NGL) feedstock directly from upstream production pipelines, and then utilise NGL fractions such as ethane, propane and butane in their manufacturing processes.
In addition, several integrated refinery / petrochemical complexes in the UK use a proportion of the refinery fuel gas as a fe edstock in petrochemical The NEU allocations presented in DUKES reflect the reported disposals of these commodities as feedstocks to chemical and petrochemical companies. There are several sources of GHG emissions from this stock of “NEU” feeds tock carbon, although a high proportion of carbon is stored into products and not emitted.
One large emission source known to occur in the UK is the use of carbon-containing process off- gases as a fuel within the chemical facilities. Whilst the exact sourc e of the carbon cannot be traced directly to a specific feedstock commodity within the UK sectoral approach, the available information from UK ETS and from consultation with operators enables the Inventory Agency to derive estimates of the GHG emissions across the time series from this emission source.
Other Detailed Methodological Descriptions A3 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 757 The majority of emissions are from installations manufacturing ethylene, but a number of other chemical sites report additional emissions in the UK ETS that can be attributed to the combustion of process off -gases and residues derived from the chemical feedstock. As a result, the UK inventory emissions in 2B8 now include estimates of emissions from use of process off -gases and residues at 5 ethylene manufacturing ins tallations and 17 other chemical manufacturing installations in the UK.
The derivation of a time series of emission estimates from these sources is based as far as possible on reported data by plant operators within trading scheme data and other regulatory reporting mechanisms. For the early part of the time series, data on changes in plant capacity over time is used to derive the best estimates of activity and emissions by extrapolation back from later emission estimates, whilst for later years the complet eness and transparency of operator reporting is greater.
Therefore, whilst the uncertainty for the emission estimates in the early part of the time series is significantly greater than for those in recent years, the Inventory Agency has made best use of the available data to derive the time series estimates of emissions from “NEU” activity. Consultation with a sector trade association has also confirmed that there are no other sector estimates of this activity, or of production data across the time series, that could be used to further improve the time series (Personal Chemical Industries Association, 2014).
Other emissions included within the UK GHG inventory include emissions from the destruction of chemical products, e.g. when wastes are in cinerated or used as fuels.
Although emissions from incineration and combustion of wastes are estimated, we cannot relate the carbon in these wastes back to individual feedstock, so it is not possible to generate reliable UK estimates of the proportion of carbon that is ultimately emitted from each individual fuel. Incineration of wastes derived from chemical feedstocks will be reported in 1A1a (in the case of plastics etc.
in municipal waste incinerated with energy recovery) and in 5C (in the case of chemical, clinical and municipal wastes incinerated without energy recovery). Waste -derived fuels, including waste solvents, waste plastics and scrap tyres are used as fuels in cement kilns and other industrial plants, and emissions reported in 1A2.