The estimates of UK appliance stock, by capacity and design and estimated average gas consumption per appliance per day are all derived from Ecodesign studies (energy efficiency analysis) through the UK Government Market Transformation Programme (Ecodesign Lot 22 and Lot 23, 2011). The estimates of appliance cycle operation times and

UK NID 2025 (Issue 1) Ricardo Page 220 estimated delays to ignition for different appliances are based on expert judgement of UK combustion technology experts (Personal communication, Stewart, 2012). Commercial Gas Catering and other uses Methane emissions from pre -ignition losses of gas appliances used in commercial catering and other uses are based on activity data from ECUK (DESNZ, 2024) which provides a time series of gas use for catering and other uses in the commercial sector to 2023. The method then applies a series of assumptions regarding the operational cycles and delays to ignition, to derive a simple percentage non -combusted estimate for each gas appliance type using references and expert judgements as noted above for domestic appliances. An overview of the time series of gas leak at point of use estimates in the UK, together with overall gas use by economic sector and appliance type is presented in Annex 5.1. Assumptions used to estimate the leakage at point of use for domestic heating and water heating boilers are as • average boiler size in the UK of 30kW; • a burn chamber size, natural gas flow rate taken from a typical combination boiler; • estimated delay to 0.25 seconds for automatic ignition, 2 seconds for manual • an air flow rate based on 25% excess oxygen in the combustion chamber when compared to stoichiometric ratio; • an equation for a mixed reactor (1-ex) that when integrated will provide an estimate of the concentration of un-burnt air/fuel mixture released; and • assumptions relating to the boiler yearly operation and cycling frequency, between heating and water heating applications o On average in the UK domestic properties have heating systems operating for half of the year and on average the heating is on for 5 hours per day. It is also assumed that during each hour that the boiler providing heating cycles on and o All UK domestic properties that have hot water heating systems also have gas o Average water heating is on for 4 hours per day every day of the year. o During each hour that a boiler is heating water, the boiler cycles on and off 5 The number of boilers across the time series is thought to have increased (ca. 22 million in 2008) due to the increasing use of gas central heating for space heating, and the increase in the number of houses. However, it is assumed that pre-ignition gas loss in boilers installed in houses in 1990 were greater than in the current boilers installed, as technology has improved. Therefore, it is assumed that the proportion of gas leaked (i.e. % of the total gas use) from domestic heating and water heating appli ances per annum is steady across the time series, with the rationale that the sum of greater pre -ignition losses from fewer older -technology boilers in the early part of the time series will be roughly equivalent to the sum of lower pre ignition losses per unit from the greater number of newer-technology boilers in recent years. Assumptions used to estimate the leakage at point of use for domestic cooking appliances (manual and automatic ignition) and gas fires are as • gas fires use an estimated 2.5% of total gas used for space heating in the domestic sector, with the remainder used in (automatic ignition) boilers;

UK NID 2025 (Issue 1) Ricardo Page 221 • gas use in cooking hobs is estimated to be 73.6% of the total domestic gas use in cooking, with the remainder in gas ovens. This is based on data of average annual gas oven fuel use in kWh/yr and average domestic gas hob fuel use in kWh/yr, combined with data on UK stock of gas ovens and hobs, taken from a series of 2011 European Commission Eco-design studies (Bio IS / ERA Technology, 2011); • for manual ignition devices, a conservative estimate of the delay prior to ignition of 2 seconds has been assumed (expert judgement), whilst the average operational cycle times for different types of appliance have been estimated at 900 seconds for a domestic hob (expert judgement) and 5400 seconds for a gas fire (EC Eco-design Lot 20 Task 5, gas stove base case, 2011); and • for automatic ignition appliances, a conservative estimate of the delay prior to ignition of 0.25 seconds has been assumed (expert judgement), whilst the average operational cycle times of domestic ovens has been estimated at 900 seconds (expert judgement). Assumptions used to estimate the leakage at point of use for commercial gas appliances (catering and other uses) are as • for commercial catering gas use, a conservative estimate of the delay prior to ignition of 0.5 seconds has been assumed (expert judgement, to reflect a mixture of hobs and oven use), whilst the average operational cycle has been estimated at 900 seconds • for other commercial gas appliances, assumed to be predominantly gas -fired boilers of automatic ignition design, a conservative estimate of the delay prior to ignition of 0.25 seconds has been assumed (expert judgement), whilst the average operational cycle time has been estimated at 1800 seconds (expert judgement). There are minor recalculations throughout the timeseries, reflecting revisions to ECUK data and some minor updates to the leakage data from the distributors. Improvements (completed and planned) An improvement project has been carried out studying the impact of fugitive emissions from post-meter settings such as natural gas fuelled vehicles, appliances in commercial and residential sector and leakage at industrial plants and power stations. The UK is currently pursuing development of an improved methodology or protocol that captures fugitive emissions from significant incidents that the current underlying methods do not currently capture.
Such incidents could include rupture of natural gas do wnstream distribution pipelines and facility level infrastructure failures. Remotely sensed measurement estimates, such as mobile, drone and satellite measurements, could be used to supplement emissions estimates derived from data from regulators and opera tors. Should a new methodology be applied, we would include a methodology statement in the appropriate NID, with an explanation of how we arrived at final emissions figures for such incidents and will, where relevant and possible, undertake recalculation of legacy incidents, to ensure temporal consistency as required by the Transparency, Accuracy, Completeness, Comparability and Consistency (TACCC) principles. The sector estimates are subject to the same Tier 1 QA/QC routines as all other source Checks on data reported by gas network operators are conducted to check consistency across the time-series and also between operators. UK NID 2025 (Issue 1) Ricardo Page 222 As recommended during the September 2014 centralised review of the UK inventory, the UK Inventory Agency has also conducted verification checks on the UK GHGI estimates, by deriving separate emission estimates for methane using the Tier 1 default methods o utlined in both the 1996 GLs and the 2006 GLs. The method in the 1996 GLs uses max and min default factors based on the pipeline length of the transmission and distribution network, whilst the 2006 GLs Tier 1 method uses max and min default factors based o n the total volume of delivered natural gas. The results are summarised below for 1990 and 2013 1990 UK GHGI total (transmission plus distribution) = 378.8 kt CH4 Using IPCC 1996 GLs Tier 1 method, the range for emissions is derived as 155 to 215 Using IPCC 2006 GLs Tier 1 method, the range for emissions is derived as 67 to 105 kt Therefore, compared to both Tier 1 methods, the 1990 UK GHGI estimate is higher than the 2013 UK GHGI total (transmission plus distribution) = 168.5 kt CH4 Using IPCC 1996 GLs Tier 1 method, the range for emissions is derived as 155 to 215 Using IPCC 2006 GLs Tier 1 method, the range for emissions is derived as 95 to 148 kt Therefore, compared to the Tier 1 methods, the 2013 UK GHGI estimate is within the range of values for the 1996 GLs method and higher than the range of values for the 2006 GLs The comparison against the IPCC Tier 1 methods indicates that the UK GHGI estimates are of a similar order of magnitude as the Tier 1 defaults. The 1990 UK GHGI value appears to be high, as it is above the range of values derived from the IPCC Tier 1 methods, whilst the 2013 UK GHGI value is also higher than the range for the 2006 GLs Tier 1 method. However, the UK estimates are derived from a country -specific method and we note that the uncertainty estimates provided in the 2006 GLs for the default EFs pro vided for gas network distribution (which is by far the greatest contributor to overall methane leakage) are cited as -20 % to +500% for factors for developed countries. Therefore, given the large uncertainty range, the UK data are consistent with the IPCC Tier 1 estimates. As far as possible, consistent source data and methods are used across the time series. However, we note the following limitations of the current • The available data on methane leakage from the high pressure gas transmission system is limited. Data are not available for all years of the time series and therefore gap-filling techniques (extrapolation and interpolation) are used; • The calibration of the UK gas leakage model used by all natural gas network operators in based on two in -depth studies of the leakage rates from different constituent elements of the UK gas network – one in 1992, another in 2002. These studies have been used to establish estimated leakage rates in the UK model that are then applied to activity data gathered annually through surveys and from gas network renewal • The derivation of the UK average natural gas composition uses the best available data for every year of the time series, as the factors are critical for the UK GHGI estimates as a whole (not just for the leakage estimates, but also for natural gas combusti on

UK NID 2025 (Issue 1) Ricardo Page 223 estimates). Since 2007 the weighted average has been calculated using actual data available on gas throughout for each LDZ; prior to 2007 these data are not available and the LDZ gas throughput estimates used in the calculation of the UK average gas composition use Local Authority level gas use estimates, aggregated up to LDZs. These earlier data at Local Authority level were regarded as “experimental statistics” by DECC until the 2005 dataset were published as national statistics, and as such are regarded as more uncertain than the more recent data. Uncertainties are presented in Annex 2. Uncertainties in the emission estimates from leakage from the gas transmission and distribution network stem predominantly from the assumptions within the industry model that derives mass leakage estimates based on input data such as network pipe replace ment (plastic replacing old metal pipelines) and activities/incidents at Above Ground Installations; for these sources the methane content of the gas released is known to a high degree of accuracy, but the mass emitted is based on industry calculations. As noted in the section above, the uncertainties for the estimates of gas leakage at point of use are high due to the lack of source data, an IPCC method and the need to use a series of assumptions and expert judgement to estimate the leakage from different gas appliance types. The Inventory Agency considers that the assumptions provide a conservative estimate of gas leakage at point of use across the time series.
UK NID 2025 (Issue 1) Ricardo Page 224 MS 20 Other solid fuel transformation Relevant Categories, source names 1A1ci: Solid smokeless fuel production 1B1bi: Solid smokeless fuel production Coke oven coke, petroleum coke, solid smokeless fuel production, charcoal production Solid smokeless fuels (SSF) are products which are designed to be suitable for use in smoke control areas. These are manufactured by combining products (often with low volatile content, such as anthracite or coke) using binding agents such as waxes and ref orming them into brickettes. Charcoal production and some SSF production involves processes similar to those DUKES (DESNZ, 2024), FAOSTAT Forestry Production and Trade Statistics Emission Inventory Agency mass balance calculations, EIPPCB, 2000, IPCC, An accompanying spreadsheet “Energy_background_data_uk_2025.xlsx” lists all emission information for common activity data sources. Emissions of carbon from SSF production are based on a carbon balance approach. For other pollutants, estimates are either made based on a mass balance approach (for sulphur dioxide) There are a number of SSF production processes used in the UK ranging from processes similar to coking which convert coal into smokeless fuels, to briquetting of anthracite dust and other naturally smokeless fuels. Given the range of processes in use, emission estimates will be very uncertain. It is possible that some emissions from SSF manufacture could arise from the combustion of off -gases produced during SSF manufacturing processes e.g., gases evolved from retorts used to manufacture some fuels, similar to the use of coke oven gas as a fuel in the coke manufacturing process. However, combustion of this type is not identified in the energy statistics and so emissions from SSF manufacture are treated as fugitive and In addition to coal, the manufacture of SSF involves the consumption of small quantities of coke oven coke in some years. This coke oven coke is treated as a fuel rather than a feedstock and the carbon within the coke is assumed emitted and reported under 1A1c. UK NID 2025 (Issue 1) Ricardo Page 225 Activity data for coal use in SSF manufacture are taken from UK energy statistics, DUKES (DESNZ, 2023), combining the sum of fuel used in SSF manufacture. The emission factor is derived from the carbon balance approach which calculates total carbon lost (i .e., emitted) during the SSF manufacturing process, by subtracting the carbon retained in the SSF product from the sum of carbon inputs. The methane emission factor of 0.0802 kt per Mt coke produced is taken from the EIPPCB, Best Available Techniques Reference Document on the Production of Iron & Steel, March 2000 (EIPPCB, 2000) and applied to the SSF production. Emissions from charcoal production are based on UK activity data on charcoal production from FAOSTAT Forestry Production and Trade Statistics (FAO, 2023). These data were available for the UK and the Falkland Islands but not for and other overseas territories or crown dependencies. The methane emission factor is derived from the default emission factors in Note that any fugitive emissions of CO 2 from charcoal production would be considered biogenic, and therefore does not contribute to the GHGI national total. There have been no major changes to estimates for these sources in the 2025 submission. Improvements (completed and planned) The UK is considering reviewing the mass balance methodology for SSF, in particular to better capture the wide range of SSF products with varied feedstocks, and an increasing range of biomass being used for SSF production. This source category is covered by the general QA/QC of the greenhouse gas inventory in The UK believes that the estimates are time -series consistent, although the data reported under sector 1B1b (including coke oven coke manufacture described in MS 4) are a diverse group of sources with highly variable implied emission factors, particularly when aggregated. For example, solid smokeless fuel production sources dominate emissions for 2015–2019 and are mainly responsible for some large inter-annual variation in the CO2 IEF during this period. The IEF variation is driven by fluctuations in the ratio of coal to petroleum coke inputs and by the ratio of inputs to solid smokeless fuel outputs. The activity data and emission factors for these sources can be found in the acco mpanying spreadsheet “Energy_background_data_uk_2025.xlsx” help explain the underlying data for these Due to the nature of the mass balance approach used for SSF manufacture, uncertainty in both the estimated carbon content of input products and the carbon content of SSF delivered to market both contribute to a substantial uncertainty in the difference (i. e., the carbon assumed to be emitted during manufacture). This uncertainty is further increased by the range

UK NID 2025 (Issue 1) Ricardo Page 226 of SSF products, including SSF products which include biomass inputs, introducing an uncertainty on the proportion of the carbon which might be biogenic. Non-CO2 emissions for this category only contribute a small proportion of the total emissions, and therefore do not make a major contribution to overall uncertainty

UK NID 2025 (Issue 1) Ricardo Page 227 Relevant Categories, source names 1A2a: Iron and steel - combustion plant 1A2b: Vehicle manufacture (combustion) 1A2d: Pulp, Paper and Print (combustion) 1A2e: Food & drink, tobacco (combustion) 1A2f: Other industrial combustion 1A2f: Cement production - combustion 1A2f: Mineral products (other): combustion 1A2gviii: Other industrial combustion 1A2gviii: Mechanical Engineering (combustion) 1A4ai: Miscellaneous industrial/commercial combustion 1A4ai: Public sector combustion 1A4ci: Agriculture - stationary combustion Straw, Wood, Landfill gas, Sewage gas, Scrap tyres, Liquid bio -fuels, Municipal solid biomass fraction, Municipal solid non -biomass fraction, Animal Biomass, Non - municipal solid biomass fraction, Non -municipal solid non -biomass fraction, Biogas, Plant Biomass, Waste, Charcoal, Wood – dry, Wood – seasoned, Wood – wet. [Note that this MS fuel used in aviation (Sustainable Aviation Fuel (SAF) - bio based) MS 7 and biofuels used in road transport (Biodiesel, Bio -MTBE, Bioethanol, Hydrotreated Vegetable Oil (HVO), Bio-Methanol) MS 8] This Method Statement (MS) includes information the estimation of GHG emissions from biofuel combustion in stationary sources within the energy sector.
CO2 emissions associated with combustion of material of biogenic origin are estimated and reported as memo items, but not included in the energy sector; these emissions will be reflected in the LULUCF carbon stocks of the country producing the fuel. This is further discussed in section 1.8.2.3. Emissions of other greenhouse gases from biofuel use are estimat ed and included in the national inventory totals, in accordance with IPCC guidance on the treatment of biofuel -derived

UK NID 2025 (Issue 1) Ricardo Page 228 DUKES (DESNZ 2024a) is the key data source for allocation of activity data for biofuel categories in the UK inventory. The mapping between DUKES and NAEI naming conventions DUKES fuel name NAEI fuel name Waste wood Wood (excluding wood used in 1A1ai, and 1A4bi) Wood Wood – dry, Wood – seasoned, Wood – wet Plant biomass Wood (1A1ai only), Straw, Plant biomass Renewable waste Municipal solid biomass fraction (1A1ai only), Non -municipal solid biomass Non-renewable waste Municipal solid non -biomass fraction (1A1ai only), Non -municipal solid non - Liquid biofuels Liquid biofuels Activity DUKES (DESNZ, 2024a), UK and EU ETS (DESNZ, 2024b) Waste Management Information (Environment Agency, 2024), MPA, Power Emission All EFs are predominantly IPCC defaults (IPCC, 2006). An accompanying spreadsheet “Energy_background_data_uk_2025.xlsx” lists all emission factors used in the energy sector, including a full list of references76. 76 This can be found as one of the additional documents to the NID . Note that there can be a delay between the NID being published on the NAEI website after official submission. UK NID 2025 (Issue 1) Ricardo Page 229 The calculation of direct greenhouse gases for the sources covered by this MS The sources of emission factors (EF) and activity data (AD) are summarised under “key data sources” above, with a full list of emission factors set out in “Energy_background_data_uk_2025.xlsx”. The activity data are taken from DUKES, noting the exceptions set out under Assumptions & observations, below. Annex 5.2 describes the energy balance for the UK and how this is used for the inventory, and any deviations from Key assumptions and deviations from the DUKES data are set out below. Plant biomass, animal biomass and biogas Where these categories are aggregated as solid biomass, and data for electricity generation is drawn from DUKES The DUKES categories of Major Power Producers and Autogenerators are summed together to allow reconciliation with data on power stations from other sources, so this does not have an impact on final results Plant biomass From inspection of the data and communication with the RESTATs team, it is known that the fuel categorised as solid biomass, pre-2004, which is consumed in agriculture is plant biomass (straw) so this is all allocated to this category. As this value matches the total heat use of plant biomass in these years, use of plant biomass in all other end use sectors pre 2004 is set to zero. As the agriculture line has been adjusted the TOTAL other line is replaced Animal biomass From inspection of the data and communication with the RESTATs team, it is known that the pre 2015 biogas was appearing in electricity generation, in heat use in agriculture and in transfers. The biogas for electricity generation and heat generation and use pre 2015 from to give a time series that is solely for animal biomass. The animal biomass transfer is known to be biogas injected to the grid and is therefore subtracted from animal biomass in agriculture as well. As the agriculture line has been adjusted the TOTAL other line is replaced with a sum rather

UK NID 2025 (Issue 1) Ricardo Page 230 Waste wood From discussion with the DUKES team this fuel category refers only to wood used for heat production in non - domestic sectors. From inspection of the data, wood use in period 1998 to 2014 is almost exclusively allocated to unclassified industry. For the pre-1998 period, waste wood to the unclassified industry category. heat or electricity generation in period 1990 to 2005. Biogas used for electricity generation pre 2015 is taken rather than major power producers, both because biogas generation plant are typically s mall, and because the data series from 2015 suggests this is the case. Pre 2015 data remove heat supplied via injection to the grid. distributed according to pattern of use in 1998. distributed according to pattern of use in 1998. distributed according to pattern of use in 1998. distributed according to pattern of use in 1998. Additional considerations for more detailed fuel categories and specific inventory sources are • Power bottom -up data from UK and EU ETS, individual operators, and the Environment Agency are used to estimate activity data for power stations. These are balanced with the DUKES electricity generation total and industry totals. Bio -carbon emission factors for straw, and animal biomass, are also based on the operator reported • Scrap the use of scrap tyres within cement and lime kilns, and as part of the power generation sector are included within the cement, lime and power station models. Scrap tyres form part of the renewable and non -renewable waste fuels in DUKES (and t he assumptions for the reconciliation within the non-renewable and renewable waste fractions differ across the time series). Scrap tyre use from the cement, lime and power stations models are imported into the bioenergy model so that these data can be removed from the renewable and non-renewable waste fuel totals to avoid a double count. • Paper / plastic / This is a fuel category reported by the MPA and is modelled as part of the cement mastersheet. Consultation with the RESTATS team has confirmed that

UK NID 2025 (Issue 1) Ricardo Page 231 this is captured in the plant biomass category of DUKES.
This fuel use is imported into the bioenergy model to be removed from the plant biomass category of DUKES, to avoid a • Domestic wood Domestic combustion is modelled based on appliance type, population and age profile, and then normalised to the DUKES totals. Outputs from the Domestic combustion model are combined with the residential wood total from DUKES so that the percentage breakdown by appliance type can be applied. • Charcoal Charcoal is not reported within DUKES, and so the UK inventory estimates production and use based on import, production and export statistics from the FAO. All charcoal use is included in the residential sector, using default emission factors from the The modelling approach to stationary combustion of biofuels has been overhauled for this inventory submission. Whilst ultimately the data sources for greenhouse gas emissions are largely unchanged, re -evaluation of the key data sources has led to a number of improvements, largely to the transparency and granularity of • The fuel category “MSW” has been replaced with four new Municipal solid biomass fraction (1A1ai only), Non -municipal solid biomass fraction, Municipal solid non -biomass fraction (1A1ai only), Non -municipal solid non-biomass fraction. • Formerly, MSW was reported under the power stations and heat generation categories only. This has been replaced with the full sectoral allocation within • The mineral products and unclassified lines in DUKES are adjusted for known use of scrap tyres in cement and lime production and assumptions for biomass fraction of scrap tyres has been aligned with DUKES • The calorific value in DUKES of 10 GJ/t (gross) and 7 GJ/t (net) has been reviewed. This is labelled as renewable in DUKES and as such we have assumed that this was misinterpreted in the current NAEI, as it was considered to be the calorific value for total waste. For the new method, we have replaced the calorific values as follows, based on data from WRATE (Waste and Resources Assessment Tool for the Environment), leading to a significant change in the ratio between the gross and net CV for biogenic waste meaning biogenic CO2 in particular is higher than the previous inventory GCV (GJ/t) NCV (GJ/t) Ratio

UK NID 2025 (Issue 1) Ricardo Page 232 Industrial wood in DUKES is now allocated consistently with the categories and totals in DUKES (i.e. split out across sources, subject to the available granularity in DUKES). Small differences in the overall total are due to differences between DUKES and RESTATS. From 1990 – 1993 the NAEI was applying data from later years, however, the long-term time series this assumption has been removed. No changes to the approach have been made for power stations or residential wood combustion, the only changes in the reported emissions relate to DUKES revisions. Liquid biofuel use in power stations is treated as additional to DUKES - there is no allocation of liquid biofuel use for major power producers in DUKES and after consulting with relevant stakeholders and data providers, we were not able to confirm where t his fuel was being included77. The previous methodology used a combined single “biomass” category, and this fuel allocation was included in the overall reconciliation for any DUKES deviations. This means that at an aggregate level, more fuel has been added into the inventory, however, a direct comparison of liquid biofuel outputs from the two models will not show this difference. Other stationary combustion of liquid biofuels is now all allocated to other industrial combustion. Previously the category “autogenerators” was reported separately. The IPCC category for autogenerators, as defined in the IPCC 2006 Guidelines, is for “ undertakings which generate electricity/heat wholly or partly for their own use, as an activity that supports their primary activity.” In DUKES, the autogenerators category is based on a calculated split of electricity versus heat generation for CHP plant, whi ch does not fit the IPCC definition of autogeneration, as such this category has been reallocated to other industrial combustion. Plant biomass and animal biomass • Plant and animal biomass are no longer combined within the NAEI, and there is no cross allocation with biogas or liquid biofuels. • For power stations, plant biomass estimates are still allocated as straw, and wood, based on point source data from the environmental regulators, plant operators, and the EU and UK ETS. The difference between the NAEI estimates, and DUKES data for total el ectricity production (i.e. major power producers plus autogenerators) is • Animal biomass replaces the category “poultry litter”, this is for transparency as the poultry litter category previously included meat and bonemeal. For years before 2006, the NAEI uses DUKES data directly, as this should be the same as the NAEI since the sites covered are identical between the bottom -up point source data and DUKES. Comparison between the two data sets shows close correlation, and alignment to DUKES means that there is no further reconciliation of the data between categories. Post 2006, bo ttom up estimates from plant operators, ETS and the Environment Agency are used in preference to DUKES and the difference in the fuel allocation between the NAEI bottom-up estimates for power stations, and the DUKES allocation for total electricity generation, is allocated to industry. • For agricultural straw use, a comparison has been made between the RESTATS data and the DUKES time series (for plant biomass in agriculture). There is close agreement between the two data sources for years prior to 2005 and post 2014. Where the two 77 It is possible that historically this was included with solid biomass but no definitive time series was available. UK NID 2025 (Issue 1) Ricardo Page 233 data sets are close, the NAEI uses the DUKES data set, to minimise the need for reallocations between categories. Where there is significant deviation between the two, the RESTATS data is used in preference as this is a much more consistent time series. The difference is allocated to industrial sources.
• Consultation with the RESTATS team on how data from the Mineral Products Association, or from UK ETS, for the cement industry feeds into the data set has confirmed that the line for “Packaging, RDF, profuel, paper and plastic” is included in the DUKES total for plant biomass. In some years this has been aligned with the unclassified industries line and in others the mineral industries line. These categories have now been adjusted, removing the value for these fuels from the plant biomass The overall difference in the time series of biogenic CO 2 emissions from plant biomass is small, these relate to the removal of the double count, and alignment with DUKES directly in the cases where the comparison between bottom-up and top-down data are small. For landfill gas and sewage gas the only change has been to reallocate the estimates that were allocated to heat networks to industrial combustion, as further analysis of the data and consultation with data suppliers did not support the assumption that the se fuels were being generation was previously not accounted for as biogas and is instead picked up in the reconciliation of other biomass. This has been corrected to directly incorporated these. This is a very small change but means that there is no longer any cross allocation of biogas between the biogas and plant and animal biomass categories. • A literature review was carried out as part of the work described above, however, no new emission factors for greenhouse gases were identified. Quantitative information on recalculations is included in Chapter 10. Improvements (completed and planned) The above recalculations were carried out as part of the Greenhouse Gas Inventory Improvement Programme ( GHGIIP) Programme, commissioned by DESNZ. The project report will be published on the NAEI website in the future. Planned/Ongoing: Emission factors and activity data remain under annual review. Defra has commissioned a study to improve the understanding of waste composition which may yield improvements to the CO 2 emission factor. Work is also ongoing to interpret the results of a new burning survey, which will likely impact emissions from wood in the residential sector. Specific QA/QC and validation exercises relevant to these source categories • The Inventory Agency conducts extensive quality checks on the operator-reported UK ETS data emissions, AD, EFs, NCVs. The QC assesses the fuel quality data, time-series consistency of reported data by installation, detailed source -specific UK ETS data against the installation-wide total emissions reported to the EU Transaction Log and UK Compliance Reports, and comparisons between DUKES and EU ETS AD to identify and resolve any potential mis -allocations or under -reports in the DUKES

UK NID 2025 (Issue 1) Ricardo Page 234 dataset. Findings are discussed with the DESNZ energy statistics team and (where necessary) the UK ETS regulators and/or operators. This process has led to many significant improvements in UK GHGI accuracy; • The comparison of the reference/sectoral approach, and mass balance checks between the data in the inventory database and the DUKES totals; • The bioenergy model was developed under the GHGIIP, as part of this the model was developed to be compliant with the DESNZ QA guidance for models, and the model scope and specification, and final report, underwent peer review. • As part of the GHGIIP work programme, extensive consultation with data providers was carried out to check on the understanding and use of the data The energy AD used in these estimates that come from DUKES are subject to the UK Statistics Authority’s Code of Practice for Statistics 78. The UK ETS data, is subject to its own QA process, defined and managed by the competent authority and compliant with UK regulations. DUKES data are typically only updated for the latter 3-5 years of the time series, and there is greater granularity of reporting in the latter part of the time series. Where revisions and step changes to the categorisation of the fuels is evident, and ther e is sufficient fuel to enable it, some extrapolations to earlier years have been used, where possible. Bioenergy use in DUKES is reported in two industry sectors, transport, and other sectors (d omestic, public administration, commercial, agriculture and miscellaneous). It also includes data on transfers of gaseous biofuels to the national gas grid. Electricity generation is further subdivided into major power producers (electricity generation sit es belonging to companies with a portfolio of over 100 MW of generation) and autogenerators (companies who produce electricity, but whose main business is not electricity generation). years - the level of detail provided in more recent years is not present in earlier years. The by sector, pre 2015 all use in the industry sector is allocated to a single sector ‘unclassified’, and a split by industry sector is only included between 2015 and current day. It should be noted that there are some obvious discontinuities in the time series, where it appears that fuel use has been reallocated from one sector to another, but the change has not been applied to current day) but only splits fuels between use for electricity, use for heat (which includes also an additional category – co-firing with fossil fuels – where the type of biomass is not 78 Available from 79 Typical practice in DUKES when changes are implemented is to only implement the change for a few historic years.
UK NID 2025 (Issue 1) Ricardo Page 235 1998 to 2003 2004 to 2014 2015 to Plant biomass No No - included as Animal biomass No No - included as Liquid biofuels No No No No Yes Renewable waste No Yes Yes Yes Yes Landfill gas No Yes Yes Yes Yes Biodegradable energy from waste Yes Yes Non-biodegradable wastes Yes Yes Co-firing with fossil fuels Yes No

UK NID 2025 (Issue 1) Ricardo Page 236 Through inspection of the data, comparisons between the two data sets, and discussions with the DUKES and RESTATS it was possible to create a time series that is considered to represent the most disaggregated and consistent time series available given limitations of the Uncertainties for both activity and emission factors are based on expert judgement. The uncertainty analysis set out in Annex 2 provides details of these uncertainty values. Uncertainties in fuel use statistics are typically low. The detailed consideration of the available activity data has improved the understanding of the data, however it has not been possible to further reduce the uncertainty in the emission factors as these are largely based on IPCC

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 237 4 Industrial Processes and Product Use (IPPU; the Approach 1 and Approach 2 analyses. The uncertainty estimate has been taken from Monte Carlo analysis. Emission trends are presented for 1990 -2023 and 2022-2023. A description of the trends and the main drivers behind these can be found in processes 26.22 -68% -7% 3% 3% A. Mineral industry 5.21 -49% -12% 0% 0% 1. Cement production CO2 (L1) 3% 3.51 -52% -13% 0% 0% CO2 4.2 T2 CS 3. Glass production 5% 0.32 -22% -14% 0% 0% CO2 4.4 T2 CS

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 238 B. Chemical industry CO2, N2O, HFCs production N2O (T1) 10% 0.02 -99% 9% 0% 0% N2O 4.7 T2 CS production N2O (L1, T1) N/A 0.00 -100% N/A N/A 0% N2O 4.8 T2 CS 5. Carbide production N/A 0.00 N/A N/A N/A N/A N/A 4.10 N/A N/A production 10% 0.12 14% -9% 0% 0% CO2 4.11 CS CS 7. Soda ash production 6% 0.10 -56% -15% 0% 0% CO2 4.12 CS CS carbon black production CO2 (L1) 30% C. Metal industry 9% 10.79 -59% 2% 10% -4%

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 239 production 0.00 N/A N/A N/A N/A N/A 4.17 N/A N/A production 0.05 -94% -6% 0% 12% CO2, production 0.00 -99% -17% 0% 0% HFCs, 5. Lead production 0.00 N/A N/A N/A N/A N/A 4.20 N/A N/A 6. Zinc production 0.00 -100% N/A N/A 0% CO2 4.21 CS CS 1. Lubricant use 0.35 -33% 9% 0% 0% CO2 4.22 T1 CS 2. Paraffin wax use 0.02 -51% 0% 0% 0% CO2 4.23 T1 D E. Electronics industry 46% 0.01 -49% -10% 0% 0% semiconductor 0.01 -49% -10% 0% 0% HFCs, 2. TFT flat panel display 0.00 N/A N/A N/A N/A N/A 4.26 N/A N/A

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 240 3. Photovoltaics 0.00 N/A N/A N/A N/A N/A 4.27 N/A N/A 4. Heat transfer fluid 0.00 N/A N/A N/A N/A N/A 4.28 N/A N/A substitutes for ODS(2) HFCs (L2, T2) 9% 6.94 931% -6% -3% 0% 2. Foam blowing agents 0.28 68% -11% 0% 0% HFCs 4.30, 4.31 T2 CS 3. Fire protection 0.14 9309% -34% -16% 0% HFCs, 5. Solvents 0.01 N/A -2% -22% N/A HFCs 4.34 T1a OTH 6. Other applications 0.02 4% -11% 0% 0% HFCs 4.35 CS CS manufacture and use N2O (L2, T2) 63% 1.17 -29% -1% 1% 7% 1. Electrical equipment 0.27 -68% -5% 0% 0% SF6 4.36 T3 CS

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 241 4. Other 0.12 N/A N/A 32% 280% N2O, 4.42 CS CS * CH4 emissions from fletton brick production are reported under 2H in the CRT tables, as not possible to report in 2A4 alongside CO2 emissions from this source. ** N2O emissions from 2B8 are reported under 2B10 in the CRT tables ***N2O emissions from 2C1 are reported under 2C7 in the CRT tables

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 242 The industrial processes and other product use sector (IPCC Sector 2) contributes 6.54% to total greenhouse gas emissions. Emissions from this sector include non -energy related emissions from mineral products, chemical industry and metal production and pro duct use, including emissions of F -gases. Since 1990, this category has seen a 67% decline in emissions, mostly due to changes in the emissions from the chemical production and halocarbon and SF6 production industries. The step-change in emissions between 1998 and equipment at the UK’s only adipic acid production plant (this plant has since closed). UK have been declining since 1990. While this is partly due to the closure of some smaller sites, perhaps with growth in capacity at remaining sites, it is predominantly a reflection of decreasing production of many industrial materials in the UK. A large number of closures in the period 2007 -2009 were due to decreased demand for many products as a result of the general economic situation in the UK and elsewhere, with falling demand for steel, cement, bricks and aluminium, for example, leading to plant closures. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 243 4.2.1 Source Category Description Emissions of CO 2 from fuels burnt in cement kilns are reported under CRT category 1A2f, whilst emissions from calcination of non-fuel feedstocks are reported under category 2A1. Fuel combustion also gives rise to emissions of nitrous oxide, reported under 1A2f. Emissions of methane also occur, both due to fuel combustion but also due to the evaporation of organic components present in the raw materials.
The current GHGI methodolog y for estimating emissions of methane does not allow emissions from fuels and from raw materials to be quantified separately so all emissions are reported under 1A2f. Emission estimates for 2005 onwards are available from the annual UK production of clinker and emission factors provided by the Mineral Products Association (MPA, 2024), formerly the British Cement Association (BCA). These AD and EFs are based on site -specific data generated by UK cement clinker producers for the purposes of reporting to the UK/EU Emission Trading Scheme (ETS), and therefore the methodology is effectively Tier 3. Data from the MPA are cross -checked against the UK/EU ETS data set supplied di rectly by regulators for use in the inventory. The UK/EU ETS data are incomplete for 2005 -2006 as several kilns were reporting within a different trading system, and therefore UK/EU ETS-MPA data comparisons for those two years are not useful. From 2007 onw ards, the scope of the two datasets are the same, and they are closely consistent, particularly from 2008 onwards where there is an average difference of 0.08%. In each year, the inventory estimates are based on the higher of the two figures, i.e. MPA data for 2005-2007, 2010, 2015-2017, 2019 and 2022, and UK/EU ETS for 2008-2009, 2011-2014, 2018,2020-2021. The UK/EU ETS and MPA/BCA data include emissions associated with cement kiln dust. UK/EU ETS and MPA data are available for 2005 onwards only, and are regarded as the best available data to represent the emissions performance of UK cement kilns. Therefore, the

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 244 emission factor value for 2005 has been extrapolated to all earlier years, as it is the most during the economic down -turn of the late 2000s, meaning that emis sion factors for 2007 onwards are less representative of the period before 2005. Period Activity data Emission factor, kt C / kt carbonate Method Use of the 2005 emission factor derived from emissions from all UK cement plant, from the Factor derived from annual, site-specific data compiled from UK/EU ETS data by Mineral Products Association (since higher than UK/EU ETS-based CEF for that year) Factor derived from site-specific UK/EU ETS returns for all UK sites (since higher than 4.2.3 Uncertainties and Time Series Consistency The time-series consistency of the activity data used in the UK GHGI emission calculations is very good across all years, as the Inventory Agency has a complete, consistent dataset from the UK trade association (BCA then MPA) from 2001 onwards, and routine statistical datasets for the earlier years from BGS. Furthermore, since 2005 there is a comprehensive sector-wide dataset for emissions and the EFs applied for carbonisation emissions. Cross -checks with UK/EU ETS data received directly from UK regulators indicate only very small differences. The extrapolation of the EF from 2005 back to 1990 is the best available data to use for the UK cement sector, but does lead to higher uncertainties for the emissions total in the base It is important to note that there is a distinction to be made (i) the data used to estimate emissions in the UK methodology; and (ii) the data that can be released into the public domain for the purposes of reporting the national inventory. The data used to estimate emissions are a complete dataset (of emissions and production) from all UK cement kilns. These data can be provided to a UNFCCC Expert Review team on request. The data reported in the CRT and NID, however, are limited by commercial confidentiality. Statistical publications of cement production since 2001 are routinely made for Great Britain only, i.e. excluding production in Northern Ireland. Throughout the rece nt time series either one or two cement kilns have operated in Northern Ireland. Their emissions and production data are provided to the Inventory Agency and used in the inventory calculations. However, to

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 245 release the complete UK clinker production statistics would be disclosive for the sites in are presented from 2001 onwards. This is the reason for the step-change upwards in IEF over the time series between 2000 and 2001. The underlying calculations do not exhibit any such A large drop in clinker production after 1990 can be explained by a sharp drop in construction activity. This initial drop and a less pronounced downward trend in production over the period 1994-2007 may, in part, also be due to increased use of slag cemen t, production of which is likely to have risen sharply over the same period; the Inventory Agency estimates that capacity for slag cement production increased from 0.75 Mtonnes in 1990 to 2 Mtonnes by 2007. A sharp decrease in clinker production between 2007 and 2009 is linked to the recession, which caused a decline in construction and therefore demand for cement. A number of kilns were closed or mothballed during those years, and none have subsequently been re -opened. However, there has been a slow and un even increase in clinker production since 2009, and production in Great Britain in 2016 was at the highest level since 2008, before falling back are for the whole of the UK. The CO2 emission factors are therefore a mixture of those based entirely on UK data (for 1990 -2000) and those that mix UK emissions and GB activity data (2001 onwards), but are shown to give an indication of the trend in the factor over time. CO2 emitted (kt) CO2 emission factor, (t / a Figures in italics exclude production in Northern Ireland The UK -specific emission factor for cement clinker production is constant for 1990 -2000 because no year-specific data are available, and a UK factor from the UK/EU ETS reporting period is extrapolated back to UK production data.
Factors presented above for the period 2005 onwards are all higher than the factor for 1990 -2000, because of the change in the activity data from UK to GB in 2001, as explained above. Since the later activity data exclude a smal l number of sites in Northern Ireland, the activity dat a are lower, and the implied emission factors for CO2 are therefore higher. The emission factors in the period 2001 onwards

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 246 do vary from year to year, from a minimum value of 0.546 t CO 2 / t in 2006 and a maximum value of 0.575 t CO2 / t in 2007. The reason for the large increase in the IEF compared with the other years is not known, although the inconsistency between the activity data (excluding Northern Ireland) and emissions (including Northern Ireland) may be at least partially 4.2.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Annex 4. Emissions reported to the Inventory Agency by the Mineral Products Association are cross checked with plant specific data reported in the UK/EU ETS to ensure complete coverage of all emissions. 4.2.5 Source Specific Recalculations No recalculations have been made to emissions from this category. 4.2.6 Source Specific Planned Improvements Emission factors and activity data will be kept under review. 4.3.1 Source Category Description Lime (CaO) is manufactured by the calcination of limestone (CaCO 3) and dolomite (CaMg(CO3)2) in kilns fired mainly by coal, coke or gas, though some wastes and other fossil fuels are also used. The calcination results in the evolution of carbon dioxide. However, it is necessary to distinguish between merchant lime processes where the purpose is to produce lime for use off -site and where carbon dioxide is an unwanted by -product emitted to atmosphere, and those captive lime processes where lime is produced so that both the carbon dioxide and lime can be used on-site in the process. In these latter processes, which include sugar refining, none of the carbon dioxide is emitted to atmosphere, apart from the exception listed in the next section. Emissions from lime kilns used in the manufacture of sodium carbonate are, in line with IPCC Guidelines, reported in 2B7. The UK method uses EU and UK ETS data to determine emissions from 2005 onwards, Pollution Inventory (PI) data from 1994 to 2004 and British Geological Survey (BGS) data from 1990 to 1993. The EU/UK ETS data consist of CO 2 emission estimates (including emissions associated with lime kiln dust) and activity data. The activity data takes various forms e.g. feedstock or product, depending upon site, and so it is not possible to generate UK activity data simply by summing the activity data in EU/UK ETS. Therefore, the emissions data have been adopted, with the lime activity data then being back-calculated using a default emission factor of 121.5 t carbon/kt limestone or dolomite. This emission factor is derived by assuming that 85% of UK lime production is from l imestone and the remaining 15% is from dolomite (based on a recommendation from the EU’s UNFCCC review). For limestone, an emission factor of 120 t carbon/kt limestone is then assumed, based on the stoichiometry of the chemical reaction, and for dolomite, a corresponding emission factor of 130 t carbon/kt dolomite is used. EU/UK ETS returns do provide some indication of site-specific activity data although this is a mixture of data on carbonate inputs and lime outputs. Nevertheless, it would be possible to generate an approximate time -series of lime production for merchant lime producers from EU/UK ETS returns for the period from 2008 onwards and while these cannot be published due to the confidential nature of the data, the figures could be provided on

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 247 request to a UNFCCC Expert Review Team. There are no suitable data in EU/UK ETS for captive lime processes so we are unable to provide any similar lime production estimates for Prior to 2005 there are no UK/EU ETS data at all, and data are incomplete for 2005 -2007 because of UK exemptions from the EU ETS for some sites in those years. Therefore, between 1994 and 2004, CO 2 emission estimates for lime production are based on emissions data published for each site in the Pollution Inventory (PI), and these data are also used for those sites that were exempt from EU ETS before 2008. The PI data are mostly for total CO 2 i.e. include emissions from both decarbonisation and fuel combustion on a site, but estimates of the CO2 from decarbonisation only are made using EU ETS data and PI data for 2006 -2008, both of which give fuel combustion emissions separately from decarbonisation. For the period 1994-1997, there is less reporting of CO 2 in the PI and so site -specific CO2 emissions are estimated based on other site-specific data such as emissions data for particulate matter from those sites in the relevant years. The PI data are assumed to cover the same scope as the later EU ETS data i.e. to include emissions from lime kiln dust as well as lime product. There are no PI data for the period 1990 -1993 so BGS activity data are the only data available to calculate emissions. As emissions estimates based on BGS data are consistently lower than emissions from PI and UK/EU ETS sources for the period from 1994 onwards, it is assumed that BGS data for 1990-1993 would also underestimate emissions and the Inventory Agency has therefore applied a ‘correction’ factor of 1.08 to the BGS data for those years. The methods used for each part of the time series are summarised below.
Period Activity data Emission factor, 1990-1993 BGS x 1.08 121.5 AD x EF 1994-1997 (back-calculated) 121.5 PI CO2 + estimates extrapolated from later PI data on basis of other data such as emissions 1998-2004 (back-calculated) 121.5 PI CO2 2005-2007 (back-calculated) 121.5 EU ETS & PI CO2 2008-2020 (back-calculated) 121.5 EU ETS 2021-2023 (back-calculated) 121.5 UK ETS The calculated emissions and activity data exclude carbonates calcined in the chemical industry since this is all used in the Solvay process, for which emissions are reported in 2B7. The EU/UK ETS data for UK sugar producers do not include any emissions from calcination, and consultation with the industry in the past confirmed that the industry considers there to be no CO2 emissions from this source - all of the lime used in the carbonatation process (whereby lime and carbon dioxide are used to remove impurities in sugar solutions) is considered to be converted back to calcium carbonate at the end of the process, meaning no net emission in CO2. However, the UNFCCC centralised review of the 2013 submission of the UK GHG Inventory recommended that CO 2 emission estimates were needed and that it should be assumed that some unreacted lime was present in waste sludges at the end of the carbonatation process. Emission estimates are therefore included using a default percentage (24%) of unreacted lime as adv ised by the Expert Review Team (ERT). This ERT default is based on data from other countries since UK-specific data indicate zero emissions. Due to the

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 248 confidentiality of the lime production data at the sugar production sites, further details of the methodology are not presented here, but can be provided to a UNFCCC Expert Review Team. The calcium carbonate produced by the sugar industry is marketed as a soil liming agent and is assumed to be wholly used by UK agriculture. Emissions associated with this usage are included in the estimates for agriculture as described in Section 5. 4.3.3 Uncertainties and Time Series Consistency Uncertainty in the emission estimates for merchant lime plants is low for recent years but higher for earlier years in the time series. EU and UK ETS provide a full dataset for UK facilities from 2008 onwards, and the uncertainties associated with these verified data are low. UK/EU ETS data for 2005 -2007 provide partial coverage of the sector and are used in conjunction with other data sources to derive inventory estimates, and hence these estimates are also regarded as subject to low uncertainty. Uncertain ty is higher for the estimates before 2005, because of the need for assumptions to be made in deriving the estimates (for example, assumptions regarding the split between combustion and process emissions in the PI data used between 1994 and 2004). Estimates for the years 1990 to 1993 are the most uncertain, because no reported CO2 emissions data are available, and emissions have therefore to be based on the BGS data that are known to be inaccurate for later years. An adjustment is made to the BGS data to tr y to deal with the expected underestimating of activity by BGS, but a comparison of BGS and other data for later years indicates that the BGS underestimates are not consistent and so the scale of any underestimation in 1990-1993 is difficult to predict with The estimates for lime kilns used in sugar production are highly uncertain since UK/EU ETS data for those sites suggest no CO 2 is emitted. In addition, a study for the European Commission on UK/EU ETS emission allowances for the lime sector (Ecofys, 2009b) states that it can be assumed that “there are no process -dependent CO2 emissions released from the limestone that is used”. The UK producer has also indicated that they consider the conversion of lime back to calcium carbonate as being complete (Personal 4.3.4 Source-specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Annex 4. Cross comparison of the BGS data with the UK/EU ETS data as a means of verification has indicated a potential under report in the BGS data. This has led to a change in the methodology to ensure completeness of the inventory reporting. 4.3.5 Source Specific Recalculations No recalculations have been made to emissions from this category. 4.3.6 Source Specific Planned Improvements Emission factors and activity data will be kept under review. In response to the ERT recommendation (2017 ARR, item I.14) to collect lime production data to enable the UK to derive and report a production -based IEF, the UK Inventory Agency has consulted wi th the Office of National Statistics (ONS) to seek any data that are available from the industry on production of lime, via the Prodcom surveys and database. The Inventory Agency research has found that there is no complete, consistent time series of annual production data from UK producers from ONS. This is due to the nature of the periodic surveys conducted by ONS, the combination of production data from several mineral sectors (e.g. cement with lime aggregated) and the commercial sensitivity of reported production data. The Inventory Agency notes that the UK/EU ETS emissions reporting is known to cover all existing UK lime works

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 249 and therefore is complete and accurate for recent years, and that to gather any further activity data from the industry is not practicable given the competing priorities for inventory improvement resources. As discussed in Section 4.3.2, it would be possible to provide an ERT with an approximate timeseries of lime production estimates for 2008 onwards for merchant lime sites only, which could then be used to generate an approximate IEF for those 4.4.1 Source Category Description Emissions from glass manufacture include emissions of carbon dioxide resulting from the use of limestone, dolomite and soda ash as sources of CaO, MgO and Na2O respectively in soda- lime and other glasses. Emissions from fuels used in glass furnaces are reported in 1A2g. The UK had 23 large sites making glass at the end of 2023, producing container glass (12 sites), flat glass (4 sites), continuous filament glass fibre (1 site), glass wool (4 sites), and stone wool (2 sites). A fifth site producing flat glass by the float process closed in November 2013. There is also a small site producing ceramic fibres.
Ballotini are produced at three sites, but production is small - output was less than 1% of UK glass production in 2022. Special and non-lead domestic glasses are no longer manufactured in the UK, and production of lead glass is only on a very small scale. The last producer of frits closed in 2014. It is assumed that limestone and dolomite are used in the production of container, flat, and special glass, and in glass and stone wool. Any use of carbonates in frits and lead glass is assumed to be trivial because of the small-scale production of these in the UK (together, both sectors account for about 0.1% of UK glass production). UK/EU ETS data for the sole UK site making ce ramic fibres indicate that this process does not involve the use of the three carbonate minerals. The ballotini processes are not covered by UK/EU ETS but are based almost exclusively on the use of recycled glass (cullet) and so carbonates are not used in significant quantities. Since the production of ballotini is a trivial fraction of UK glass production and the use of carbonates for ballotini is also trivial, emissions are not estimated. Due to the very small number of sites involved, and the confidential nature of the UK/EU ETS data used to generate the emissions data, reporting the stone wool sector separately would be problematic. The UK therefore combines the data with emissions for ot her glass industry Process emissions of N2O are not estimated for glass production because suitable methods or data have not been found. Operators of UK plants regulated under the Environmental Permitting Regulations (EPR) 2016 (England and Wales) and The Pollution Prevention and Control (PPC) Regulations for Scotland and Northern Ireland do not report any emissions data to the regulators and so any releases of N2O from these sites (including N2O from combustion of fuels) must be below the reporting threshold of 10 tonnes and therefore any process emissions will be very low for the UK as a whole. Emissions from the use of carbonates in glass production are calculated using data from two • A detailed, site by site survey of raw material usage in the glass industry, carried out in 2006 (GTS, 2008). This report covered the flat, container, and fibre sectors; • Data reporting under the UK/EU Emissions Trading System (UK/EU ETS) from 2008

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 250 In the case of the survey of raw material usage, data are available on the quantities of each type of carbonate used by each sub -sector of the industry during 2006. Emissions must be estimated, and this is done based on the stoichiometric relationship between carbon and the related carbonate, and assumes all of the carbon is released to atmosphere i.e. The UK/EU ETS data are for CO2 emissions, disaggregated by the source of the emission e.g. use of natural gas, use of limestone etc. The data have to be analysed so that emissions can be separated into those that occur due to use of fuels, and those that are due to use of the three carbonates. Data are available for the period 2008-2023 for all sites manufacturing flat glass, container glass, continuous filament glass fibre, glass wool and stone wool. Carbonate use is back-calculated using the stoichiometric relationships given above. Since ETS data are available on a site -by-site basis, the emissions data and the derived activity data can be agglomerated to give estimates for each sub-sector of the glass industry. The two data sources can be used to derive estimates of carbonate use / CO 2 emissions for each sub-sector of the glass industry as 2008-2023: flat, container, glass fibre, glass wool, stone wool; 2006: flat, container, glass fibre/glass wool (combined in the survey). These data indicate some changes over time in rates of carbonate use for flat, container and glass wool, and partial UK/EU ETS data for 2005-2007 also support this. Therefore the 2006 survey, rather than the later UK/EU ETS data, is assumed to be more reli able as a guide to the rates of carbonate usage in the three sectors in the years 1990 -2005 and usage for that period is therefore extrapolated from the 2006 figures on the basis of production in each sub- sector in each year. For stone wool, data are only available from the UK/EU ETS for 2008 - 2023, so the average consumption rate calculated for those years is then applied to the period 1990-2007 using stone wool production estimates for each year. The data indicate that some glass industry sub-sectors in the UK do not use all three carbonate minerals, or only use small quantities of some. Neither of the two data sources contains information on special or domestic glasses because the only UK sites producing either type of glass closed before the end of 2006. Therefore, carbonate usage for both types of glass have been assumed to be equal to the average rate for container, flat and glass wool in 2006, as given in the raw material usage Glass production data are available on an annual basis for container glass only (British Glass, 2023), and a full time-series of production for other types of glass has therefore to be estimated based on the partial time series of production data covering a limited years (e.g. data for late 1990s from EIPPCB, 2000; flat glass data for 2003 onwards from British Glass). These are then extrapolated to other years on the basis of estimated plant capacity. In the case of flat and container glass, the glass production data used to estimate carbonate usage are corrected for the amount of cullet used in each year, so the estimates do take into account changes over time in recycling rates and use of cullet. This is not possible for other types of glass, and so the ca lculation of carbonate usage for these glass types is based on total production.
Therefore, the estimates for glass wool, special glasses and domestic glass implicitly assume that the rate of recycling in these sectors remains constant over the time series. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 251 for CO2 emissions from carbonate use Glass wool 104 302 Yes Yes Yes Ceramic fibres 14 14 No No No The UK/EU ETS data also includes extremely small CO2 emissions (<1 tonne) occurring due to use of barium or potassium carbonate by the glass sector, and somewhat larger though still relatively trivial emissions from other process sources. The largest of these is emissions that occur when waste wool at one site is recycled through the process, and it is assumed that the carbon results from oxidation of organic coatings that were applied to the wool as part of the finishing process. Waste generated during cutting of the wool following the coating process is 4.4.3 Uncertainties and Time Series Consistency For the years 2008-2023, the methodology is based on the use of highly accurate emissions data reported under the EU and UK ETS for all significant UK glass producers. The emission estimates for 2006 are based on activity data given in a detailed industry study. These emission estimates should be assumed to be slightly more uncertain than the EU and UK ETS data of 2008 -2023 since the source gives carbonate usage figures only, and emissions have to be calculated assuming that these figures refer to pure carbonates and that all carbon in the minerals is released to atmosphere. While the emissions data are therefore conservative, the uncertainty is still considered to be low since fairly pure carbonate minerals For the remaining years in the time -series, the methodology relies upon the extrapolation of highly accurate activity/emissions data for one year to all other years based on glass production. The glass production data are, however, a mixture of actual production data from the glass industry, and Ricardo estimates, which are far more uncertain. The emission estimates for 2A3 are therefore subject to far greater uncertainty for the earlier part of the time-

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 252 series than for recent years, because of the greater reliance on extrapolation, and the lower quality of the glass production estimates for these years. 4.4.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Annex 4. 4.4.5 Source Specific Recalculations There have been no significant recalculations. 4.4.6 Source Specific Planned Improvements Emission factors and activity data will be kept under review. 4.5.1 Source Category Description The UK has a large number of sites involved in the production of heavy clay goods such as bricks, roofing tiles, and similar items. These sites range from the smallest operations where bricks are hand-made, to bigger sites where bricks are manufactured on a large scale, using automatic production methods. The brick industry can also be divided into fletton and non - fletton types. Fletton bricks are manufactured using the Lower Oxford Clay found in South - East England. This clay has an exceptionally high content of carbonaceous material which acts as an additional fuel when the bricks are fired, but also produces a characteristic appearance in the finished bricks. Non -fletton bricks are made from other clays and shales and these have much lower carbon contents. For all bricks, firing leads to emissions of CO 2 from the carbonaceous material in the clay. Limestone, dolomite, and barium carbonate can also be used in brickmaking, leading to further releases of CO 2 during firing. Finally, many brick manufacturers add crushed coke ("colourant") to some bricks to change the final appearance of the bricks. Coke oven coke is known to have been used in this manner, and it is assumed that petroleum coke is as well. Colourant is added at rates of up to 15% of the raw material weight. A high proportion of the carbon in the colourant is known not to be oxidised during firing and remains in the for Emissions Trading Scheme (ETS) reporting use of carbonates, the UK inventory estimates include carbon emissions from the use of colourants in bricks here as well, in the absence of anywhere more appropriate to report them. Also included are emission estimates fo r the use of clays to produce ceramics other than The 2006 GLs draws attention to other sources of CO 2 emissions from use of soda ash and other carbonates. These other uses include Flue Gas Desulphurisation (FGD), magnesia production, and use of soda ash in soaps & detergents, and other applications. The UK inventory includes CO2 emissions that occur during the manufacture of soda ash and from the use of soda ash by the glass sector and detailed descriptions of those source categories are provided in Sections 4.12 & 4.4 respectively. The inventory also includes emission estimates for the use of soda ash in applications other than glass production, and these emissions are reported in 2A4b. These estimates are based on a review (Passant et al, 2019) which found that soda ash is used in the UK for a wide range of applications but that most is used for one of three purposes – manufacture of glass, manufacture of chemicals (including sodium bicarbonate) and manufacture of detergents and soaps. Not all uses of soda ash are likely to result in CO 2 emissions and so this review also considered the potential for

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 253 emissions. Emissions also occur from the subsequent use of sodium bicarbonate and these emissions are reported in 2A4d. Limestone was used in FGD systems for abatement of SO2 emissions at various UK coal-fired power stations and emissions are reported under 2A4.
The power stations at Drax and Ratcliffe were the first to get FGD (in 1994), followed by West Burton A in 2004, Eggborough and Cottam in 2005, then Ferrybridge C, Fid dlers Ferry, and Rugeley B in 2008/2009. The Ferrybridge C and Rugeley B stations were both closed during 2016, Eggborough closed in September 2018, Cottam in September 2019, and Fiddlers Ferry in March 2020, while the last coal-fired units at Drax closed in March 2021 (FGD was no longer required for the remaining biomass units). West Burton A closed in March 2023 so the sole remaining coal station with FGD at the end of 2023 was Ratcliffe, which subsequently closed in September 2024. Various small, predominantly waste and/or biomass -fired stations also report CO 2 emissions from limestone scrubbing in the ETS. In all of these processes, limestone reacts with the SO 2 present in flue gases, being converted to gypsum, with CO2 being evolved. Uskmouth B has a dry lime-injection system, so there is no potential for CO2 emissions at this site, and in any case this site was mothballed in 2017. Seawater scrubbing systems were used at Aberthaw (closed March 2020), Kilroot (closed September 2023) and Longannet (closed March 2016). However, CO2 emission estimates are not included in the GHGI for this type of FGD there is no estimation method for this process. Some MSW incinerators are believed to use the dry lime injection process to remove SO2 as with Uskmouth B, there will be no CO2 emissions from this type of FGD technology. Magnesia production in the UK is thought to be limited to a single plant that closed in 2005. This site produced magnesia from seawater, with magnesium salts in the seawater precipitated as magnesium hydroxide, followed by conversion to magnesia in kilns. No process emissions of CO2 occurred at this site. CO2 emissions from production of bricks and tiles are based on data reported in the UK and EU ETS. ETS provides site by site emissions, with data in most cases broken down by source (e.g., from clays, fuels, colourants etc.). The ETS data from the producers o f bricks and tiles are representative of the sector from 2008 onwards, when all significant manufacturing sites were included in ETS. The ETS dataset is documented and reported at a level of resolution such that the Inventory Agency can readily apportion t he emissions data between fuel combustion and non -fuel sources (i.e., process emissions). However, it is more difficult to divide the non -fuel data into sub -types such as emissions from clays, colourants, or 'pure' carbonates like limestone, dolomite, and barium carbonate since some of the information on the source of the CO2 is presented as aggregated data and not resolved per specific material input to the process. The information presented by UK operators confirms that the emissions from the colourant (coke oven or petroleum coke) are included within the aggregated process The ETS data are calculated by each brick and tile producer using site -specific activity data, and industry -wide emission factors, compiled by the industry trade association (British Ceramic Confederation, 2014). These include factors for simple carbonates based on the stoichiometric relationship of carbon to the carbonate, as well as measured emission factors for different types of clay e.g., Keuper Marl, Weald Clay, and Lower Oxford Clay. A high proportion of the carbon in the colourant is known not to be oxidised during firing and remains (British Ceramic Confederation, 2013). Consultation with the brick industry indicates that the ETS data for 2008 -2012 covered 93% of sector production. A single further site joined ETS in 2013, bringing coverage to 95%. The remaining 5% of production is at small sites that are outside the scope of ETS. The ETS

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 254 emissions data for 2008 onwards are therefore increased using these figures to reflect non - reporting brickworks, assuming that emission rates at non-reporting sites will be the same as on average at reporting sites. With the exception of the large site that joined in 2013, the non- reporting sites over the period since 2008 are much smaller producers and it is not known how representative the industry factors will be for these atypical sites. In the absence of better data, it is assumed that emission rates are the same. ETS data are incomplete before 2008, and therefore are not used to derive a national total. Instead, annual brick production data are used, available in Government Statistics (Monthly Statistics of Building Materials and Components, July 2023, available fr om to extrapolate back from the ETS data. These data are for total numbers of bricks produced, and it is necessary to consider what proportion of these bricks are of the fletton type, since this type of brick is associated with higher process emissions. Fletton bricks have had a declining share of the UK brick market for many years and are no longer used in the construction of new buildings. Information on the market share is however Ove Arup (1990) puts it at 25%, Blythe (1995) states it is 20%, and by 2011, following the announcement that the last but one fletton brickworks was being closed, local media reports all stated that fletton bricks now accounted for less than 10% of the UK market. The inventory method therefore assumes a 25% share in 1990, falling to 20% in 1995, then falling to 10% by 2010. ETS data for the fletton works suggest production has fallen further since 2010 and so is used to estimate the trend for fletton bricks since 2010. Using these data and assumptions, it is possible to then generate estimates of the numbers of fletton bricks and non-fletton bricks produced each year.
For the period from 2015 onwards, it is estimated that, on average, 5% of UK bricks produced were emission estimates for 2008-2013, and then the estimates of non-fletton bricks produced can be used to generate emission estimates for the period 1990-2007 using this emission factor. In the case of fletton bricks, the PI provides additional data to supplement the information in the ETS for 2008 onwards. Total CO 2 emissions are reported for the Stewartby and Saxon/Kings Dyke sites for each year between 1998 and 2007. The later ETS data at these sites is used to separate the PI data for 1998 -2007 into a fuel component and a process component. This gives a time series of process emission estimates back to 1998, and this is further extrapolated back to 1990 on the basis of the estimates of fletton brick production. operating and the data available for emission estimates over the time series. Years Number of sites and fuels Availability of data 8 fletton works operating in 1990; only 5 still in operation by 1993. Those in 1993 burnt coal, or a mixture of coal and natural gas. Unknown number of No emissions data available, annual production (numbers) of all bricks available and fletton and non -fletton brick production estimated from this. Emission estimates require use of emission factors generated from later PI and ETS Two of the 5 fletton works in operation since 1993 close in 1998/1999. Both used only coal as a fuel so by the end of 1999, 3 works Stewartby (Saxon/Kings Dyke), both in the same area in England, now burn natural gas Annual emissions of CO 2 and methane available in the Pollution Inventory for each fletton site until 2004, when emissions for the two gas -burning sites, which are located about 1.5 km apart start to be reported as combined totals. Reported emissions have to be split between ener gy- and process-related emissions. Estimates for non-fletton bricks have to be generated using emission factors from later ETS

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 255 Years Number of sites and fuels Availability of data only. Approximately 100 non -fletton Annual production (numbers) of all bricks fletton and non-fletton brick production estimated. 2008 Closure of coal -burning fletton works at end of 2008, leaving only the 2 gas- 63 non -fletton brickworks report in Annual emissions of CO 2 and methane available in the Pollution Inventory for Stewartby, and for Saxon/Kings ETS data for the same two fletton brickmaking units, and also for non -fletton brickworks. These data are detailed, allowing fuel -related and process -related emissions to be separated. Emission estimates can be based directly on Saxon works closed in 2011, leaving only the Kings Dyke fletton brickworks brickworks, with 49 reporting in ETS by 2011. In 2013, final large site joins ETS, with total of 46 non -fletton sites Annual emission of CO 2 and methane available in the Pollution Inventory for the Saxon/Kings Dyke works. ETS data for all significant fletton and non-fletton works for all years except for one site that joins ETS in 2013. Emission estimates can be based directly on ETS data. Other types of ceramics are manufactured in the UK, including wall and floor tiles, refractories, sanitary ware, household ceramics etc. No suitable national data on the levels of production for these types of ceramic goods have been found. However, the UK Minerals Yearbook (BGS, 2023) gives production, imports, and exports for 4 types of clay (ball clay, china clay, fireclay, other clays & shales), and these data can be used to estimate total UK demand for each type of clay. These figures can then be compared with ETS data for clays used in brick production, and then the difference can be assumed to be clay usage for non-brick manufacture. ETS data only extend back to 2005 but clay usage for bricks in 1990 -2004 can be estimated by extrapolating back from 20 05 using the brick production data. Significant quantities of clays and shales are used in the manufacture of cement clinker, and emissions from this usage will already be reported in 2A1. BGS reports separate figures for this usage, so clay usage in other ceramics can then be calculated using the following ClayOther ceramics = ClayTotal (from BGS) - ClayBricks (from ETS) - ClayCement (from BGS) There are likely to be other, possibly non-emissive uses of clay, for instance some china clay may be used in paper production. But we assume these other uses are either trivial or emissive. The calculations suggest that, on average over the 1990 -2023 period, about two thirds of UK clay consumption is used for bricks, and the remaining third is used for the manufacture of other ceramics, cement clinker or other uses. The trends in the total clay and brick clay estimates are fairly similar in the 1990 -2014 p eriod, so that this pattern of approximately two thirds bricks to one third other uses is broadly true for all years within that period. But this pattern has changed since 2015, and the total clay figures for 2015, 2018 & 2019 are only slightly higher than the estimates for brick clay, suggesting that hardly any clay was used in those years for other uses. BGS data for clays used for cement confirm that consumption by this sector reduced by about 90% after 2014. It is therefore assumed likely that UK production of other ceramics has declined significantly in the last five years. BGS data are never available for the latest year in each inventory submission, and therefore we have to assume the same total clay consumption in the latest year as the year prior.
T he figures for the latest year will be revised in the next submission once BGS data for the year become

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 256 No emission factors are available specifically for clays used in other ceramics, therefore we apply the emission factors used by brickworks to estimate their emissions in the ETS dataset. Separate factors are available for ball clay and fire clay, whereas emissions from china clay and ‘other clays and shales’ are estimated using the generic ‘other clay’ factor also used for ETS reporting by brick producers. A few non -brick ceramic processes do report in ETS and so the emissions data for these sites are used directly. For non-glass use of soda ash, consultation with the only UK producer of soda ash identified application has been assumed to be emissive i.e., leading to emissions of CO2. The UK emission estimates are based on UK demand estimates supplied by the sole UK producer for soda ash, who estimated consumption in 1990 and 2019 (Tata Chemicals Europe, 2019). Consumption in 1991-2018 was then estimated by the Inventory Agency, with one of three methods being used to estimate consumption in each • For most sectors, the overall demand for soda ash/sodium bicarbonate was similar in 1990 and 2019, so intervening years were estimated on the basis of a linear change. • For the chemical sector, a linear change would not be realistic since consumption would have been dominated by a small number of sites, many of which are now closed. Therefore, the processes operating each year were identified, and annual consumption then estimated based on the likely consumption at each site. The overall consumption figures then reflected the closure of key sites and the commissioning of new o Closure of the tripolyphosphate works in 1999 o Closure of the Ultramarine Blue works in 2008 o Closure of the sodium chromate works in 2009 o Commissioning of the sodium percarbonate works in 2000 and closure in 2014 • A breakdown of the sodium bicarbonate market is only available for 2019 (for 1990 we have only the total market). Therefore, we have estimated the market split for sodium bicarbonate by extrapolation back from the 2019 figures. However, one of the key markets is flue gas treatment and we consider it unlikely that this market existed until fairly recently. This type of flue gas treatment is likely being used in recently commissioned Energy from Waste (EfW) plants, and since many have been built since 2010, we assume that consumption for flue gas treatment was zero up until 2009. Figures for 2019 were extrapolated to 2020 onwards assuming no change in demand. We expect that some uses such as detergents might have been affected by the pandemic and demand in sectors could have also increased or decreased for other reasons. However, w e believe that any year-on-year changes will be relatively small because of the nature of these uses. Future submissions may be able to incorporate new data if soda ash suppliers can Soda chemicals Used in production of various chemicals or chemical

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 257 Soda detergents Used as a builder to emulsify oil; to reduce the deposit of dirt during cleaning; to provide alkalinity, and to soften laundry Soda other Fertilizers, production of bentonites, organic and inorganic colourings, enamelling, petroleum industry, fats, glue and Used in poultry & cattle feeds 0% Sodium bicarbonate used where a milder detergent is required. Used in hard surface cleaners where its limited water-solubility is advantageous. Used for treatment of acidic flue gases. 100% Sodium food Used as a raising agent for a wide range of bakery and Sodium bicarbonate can be used in foam blowing, soda blasting, explosion suppressants and fire extinguishing. Sold to distributors (so end use is unknown) 75% a Rather than being emissive, conversion of soda ash to sodium bicarbonate requires CO 2 so the process consumes some of the CO 2 generated in the production of soda ash. This consumption of CO 2 to convert from soda ash to sodium bicarbonate is taken into account in the emissions reported in 2B7. Emissions were then estimated assuming that uses were emissive or non-emissive as shown industry, except those for named chemical processes, where the assumption was based on the chemical reactions taking place. For emissive processes, it is assumed that all of the carbon in the soda ash was converted to CO2 which was then emitted. So, an emission factor of 0.4151 ktonne CO2 / ktonne soda ash consumed was used for emissive applications. In the case of sodium bicarbonate use, the activity data used in the UK inventory are expressed as soda ash converted to bicarbonate. The conversion from soda ash requires reaction with So, it follows that for any emissive uses of sodium bicarbonate, an emission factor of 0.8302 kt CO2 / kt soda ash is appropriate i.e., double that of soda ash used for other applications. Further detailed discussion of the methodology is included in the report by Passant et al Emissions from Flue Gas Desulphurisation (FGD) are either calculated using an emission factor of 69 t carbon/kt gypsum produced or based on UK/EU ETS emissions data. The factor is based on the stoichiometric relationship between gypsum and carbon dioxide formed in the FGD plant. Data on gypsum produced in FGD plant are available from the UK Minerals Yearbook (British Geological Survey, 2016 and earlier versions), but these data are not always consistent with site-specific emissions data available from ETS, and so a composite series of emissions data is used with BGS activity data, and the emission factor used for 1994 -2004, and ETS emissions data for 2005 -2023.
Four small biomass -fired power stations were no longer in ETS after 2012, and so we have obtained CO2 emissions data for the scrubbing

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 258 systems at these sites from the operator. Emissions at these non -ETS sites have averaged about 2% of the total emission in recent years. applications in the inventory for 1990 -2023. The provided activity data correspond to the 1990 170.4 10.8 0.0 59.2 5.7 3.8 1995 179.1 11.2 0.0 59.0 5.9 3.9 2000 146.5 11.6 0.0 58.8 6.1 4.1 2005 146.5 12.0 0.0 58.6 6.3 4.2 2008 146.5 12.2 0.0 58.5 6.5 4.3 2009 109.6 12.3 0.0 58.5 6.5 4.3 2010 78.0 12.4 2.8 58.4 6.6 4.4 2015 67.9 12.8 17.1 58.3 6.8 4.5 2020 67.9 13.1 28.5 58.1 6.9 4.6 2021 67.9 13.1 28.5 58.1 6.9 4.6 2022 67.9 13.1 28.5 58.1 6.9 4.6 2023 67.9 13.1 28.5 58.1 6.9 4.6 Non-Energy chemical feedstock, soda ash Soda chemicals Bread baking, sodium bicarbonate Sodium food Flue gas treatment, sodium bicarbonate Sodium flue gas treatment Other emissive applications of soda ash Soda other Unknown applications, sodium bicarbonate Sodium distributors Other emissive applications, sodium bicarbonate Sodium miscellaneous 4.5.3 Uncertainties and Time Series Consistency The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. In the case of FGD plant there is a change in methodology between 2004 and 2005. However, BGS and UK/EU ETS-based emission estimates for 2005 are very close, and for 2006 -2014

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 259 are within 6% of each other (with the UK/EU ETS numbers usually higher). No data are available from BGS for 2015-2023 and so no comparison can be made with the UK/EU ETS Emission estimates for soda ash are relatively uncertain, for a number of • The time-series of estimates rely on estimates for UK demand in 1990 and 2019 only and a linear interpolation is generally used to estimate demand in the years in - between. The UK manufacturer was unable to provide further data, so alternative sources would probably need to be identified in order to refine the time-series. • No data could be obtained for 2020 onwards, so we assumed the same consumption as in 2019. In reality some uses such as detergents might have been affected by the Covid pandemic and demand in sectors could have also increased or decreased for other reasons, such as population change. However, we believe that any year-on-year changes will be relatively small because of the nature of many of the sectors that use soda ash and sodium bicarbonate, and so assuming no change in usage is unlikely to introduce large errors providing this is only done over a very short period. Future submissions will be able to incorporate new data if soda ash suppliers can provide this, alternatively it will be necessary to obtain alternative data to allow a better long-period timeseries (for example, estimates of consumption of bread and other baked products could be considered as a means to extrapolate forward the estimates for bicarbonate • Estimates are also sensitive to assumptions regarding the operation of certain chemical processes. However, since these plant closed in the years from 1999 to 2014, this uncertainty does not affect the estimates for recent years. • While it is certain that some uses of soda ash are emissive (e.g., glass and certain chemical processes), for other uses it is less so. Soda ash seems to be used for a wide range of minor applications, including both emissive and non -emissive ones. In the absence of any detailed breakdown of individual uses, we assume 50% emissive. Estimates for bricks are considered to be highly reliable for the period 2008 onwards where ETS data are available for almost all sites. For earlier years, the emission estimates rely upon extrapolation of the 2008 emissions data using brick production est imates and this will introduce uncertainty within the earlier part of the time series. Emission estimates for methane from fletton brickworks are, similarly, based on reported data in later years and extrapolation using brick production for the early part of the time -series, so the uncertainty will again be greatest in the earlier part of the time series. Emission estimates for other ceramics are derived using the difference between total UK consumption of clays, and consumption of clays by the brick and cement sectors. Emission factors specifically for other ceramic processes do not exist, therefore we use factors developed by the UK brick industry for the purpose of reporting to ETS. Emission estimates for other ceramics are more uncertain than those for bricks because of this. The figures for 1990-2004 are also more uncertain than later figures, because t he estimates for clay usage for brickmaking are more uncertain. 4.5.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Annex 4. 4.5.5 Source Specific Recalculations The methodology for extrapolating bricks activity data for 1990-97 has been refined to use an average of several years’ reported data instead of only 1998 data. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 260 4.5.6 Source Specific Planned Improvements Emission factors and activity data for bricks, ceramics, soda ash use and FGD will be kept under review. We will continue to seek updated data on soda ash consumption from the We are aware that one sodium bicarbonate site has recently started using captured CO2 from combustion as a feedstock for the process, and it is on the improvement programme to consider how best to estimate and report this process. 4.6.1 Source Category Description Ammonia is typically produced using the Haber process, which starts with the steam reforming of natural gas to make hydrogen. The simplified reactions The hydrogen is then reacted with nitrogen to form ammonia.
If the by -products CO and CO 2 are not captured and used, then these are emitted to atmosphere. Ammonia plants can be integrated with methanol manufacture for greater efficiency, since the carbon oxides can be used to manufacture Over the time period covered by the UK greenhouse gas inventory, ammonia has been manufactured at four locations in the UK. CO 2 emissions are reported from three of those at the remaining site (Hull), the ammonia is produced with hydrogen supplied as a by - product from another chemical process operated on a neighbouring site. At one of the remaining three sites where CO2 is reported, some carbon from the steam reformer was, until 2001, exported for use in the manufacture of methanol. At least one ammonia plant sold CO2 to the food industry and nuclear industry. Because this CO2 was ultimately emitted to atmosphere, it is included in the emissions reported here. This is considered more reliable than trying to identify carbon emissions at the point of final use since CO2 will also be emitted from other processes within those sectors, for example from fermentation. Potential applications for exported CO2 might include (but are not limited to): • use in carbonating drinks (emitted on consumption of the drinks, which is not reported • use as a cover gas for the brewing industry (emitted during brewing or consumption of drinks, not reported elsewhere in the inventory); • use as a refrigerant (emitted from leakage during the manufacture, use and disposal of the product, not reported elsewhere in the inventory, although it is modelled as part of wider refrigerant modelling); • use as a feedstock for other chemical industries (emitted on oxidation of those chemicals, this is accounted for in the case of methanol; we do not currently hold data on the extent to which other chemical processes might use this feedstock); or • by slaughterhouses to render animals unconscious (emitted during use, and not reported elsewhere in the inventory). Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 261 It is also worth noting there is cross-border activity for some CO2-containing products, such as soft drinks. So, it is expected that some of the CO2 is emitted outside the UK, and some CO2 will be emitted in the UK which ultimately derives from by-product CO2 generated outside the UK. For simplicity, we assume that by-product CO2 generated in the UK is emitted in UK and that net imports of CO2 in products is zero. Methane emissions from the steam reforming processes and the associated ammonia production facilities are reported partly under 2B1 and partly under 2B10, with the latter including methane emissions from other chemical manufacturing sites as well. Nitrous oxide emissions from natural gas combustion are also estimated. UK ammonia manufacturers do not report any emissions of this pollutant and so any additional process emissions are assumed to be negligible or not occurring. CF Fertilisers UK Ltd permanently closed its Ince manufacturing facility in 2022 and its ammonia plant at the Billingham Complex in 2023. This resulted in significant reduction in production of ammonia for 2023. Urea production was occurring in the UK at one site as recently as 1986, but this facility closed soon after. No other urea production facilities have been commissioned in the UK, and throughout the records from UK environment regulation and permitting of production plant (whereby individual plants operate under agreed permits, which in England was implemented from 1993 onwards) there is no mention of urea production in any EPR/PPC permits. The main company that currently manufactures ammonia in the UK has three urea production facilities (one in each of France, Germany and Netherlands) that they use to supply the UK market. Therefore, the Inventory Agency is confident that there has been no production of urea in the UK since 1990, and the UK ammonia produc tion estimates throughout the time series need not take any account of urea production. Ammonia production processes require natural gas both as a feedstock and as a fuel to produce heat required by the steam reforming stage of the ammonia process. The emissions from both feedstock and fuel use of natural gas are both reported under 2B1, in line with the requirements of the 2006 Guidelines. Emissions of CO2 from both fuel and feedstock use of natural gas are calculated by combining reported data on CO2 produced, emitted and sold by the various ammonia processes. Where data are not available, they have been calculated from other data such as plant capacity or total natural gas consumption. The ammonia plant utilising hydrogen by-product from chemical manufacture does not need to be included as there are no process emissions of CO2. production and emissions etc. by the sector. Plant Feedstock Carbon emissions Notes Billingham Natural gas Yes Some production of methanol Severnside Natural gas Yes Closed in 2007 Ince Natural gas Yes Closed in 2022

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 262 CO2 emitted (kt) CO2 emission factor, (t / t NH3) (all UK production + Majority of ammonia production facilities were closed by 2023. Therefore, no data is provided here. where there are no CO2 emissions). Due to the limited market for ammonia production in the UK, to present detailed technology - specific data on production and emissions would be disclosive. Full details of the installation- specific production, fuel use and emissions will be provided upon request to a UNFCCC Expert of ammonia (which is partly based on operator data and partly on Inventory Agency estimates based on plant capacity), total estimated 2B1 CO 2 emissions and ammonia IEF on a production basis, as presented in the CRT. The operator of the Ince and Billingham UK ammonia plants has provided information on reasons underlying the year on year variation in emission factors. Firstly, plants are typically shut down for routine maintenance every two years, and start -up and shut-down procedures increase the emission factors overall.
Secondly, plant production rates are varied by the operator during times of high gas prices or low demand, which reduce efficiency and increase emission factors. In addition to these operational variab les, each plant will have a different intrinsic efficiency, which will in part reflect the age of the plant and the technology used. The IPCC 2006 Guidelines suggests a Tier 1 default emission factor of 1.694 tonnes CO 2 / tonne NH3 for a ‘modern’ European plant, but a higher Tier 1 default of 2.104 tonnes CO 2 /

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 263 tonne NH3 for a ‘typical’ plant i.e. based on a mix of modern and old plant. The overall UK IEF the UK plant where there are no CO2 emissions; Aggregate UK factors for the three sites with CO2 emissions show an average of 1.51 tonnes CO 2 / tonne NH3 for production across the whole 1990-2023 time-series, and averages for individual years would mainly be within the range suggested by the two IPCC defaults, the exceptions being 1990-1993 & 1998 when the factors were marginally below 1.694 tonnes CO 2 / tonne NH3, and 2002 when the emission factor was slightly higher than 2.1 tonnes CO 2 / tonne NH3. [Note that fully detailed data are to an ERT.] All of the UK plants have been in operation since befor e 1990; the fact that the average UK factor lies between the 2006 IPCC Guideline defaults for modern plant and mixed modern/old plant indicates that the performance of the UK ammonia plants is broadly typical of European ammonia production facilities. Methane and nitrous oxide emissions from natural gas burnt at ammonia plant to produce heat are estimated by applying IPCC default factors for industrial combustion of natural gas (1 kg methane / TJ & and 0.1 kg N2O / TJ), and these emissions are reported in 2B1. It is assumed that there are additional emissions of methane from the ammonia process itself, for example from fugitive leaks. Therefore, in the UK inventory, methane emissions from ammonia production also include estimates provided from plant oper ator reports to the UK regulators; these emissions are reported, together with process emissions from other chemical sites, in 2B10a. These operator -reported emissions may include estimates of methane from fuel combustion and hence there is potential for a small double-count in emissions reported across 2B1 and 2B10a. Because it is not at all certain that the methane reported by the operator would include methane from fuel combustion, we have retained the estimates in both 2B1 and 2B10a on the basis that a potential double-count is preferable to a potential gap, particularly since we believe that the latter is more likely were we to remove one of the estimates. 4.6.3 Uncertainties and Time Series Consistency The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. The uncertainty associated with this source is low, since the carbon content of natural gas is well known and plant specific data are received from the A consistent time series of activity data has been reported from the manufacturers of ammonia, and this results in good time series consistency of emissions. 4.6.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Annex 4 and the source emissions data from plant operators is subject to the QA/QC procedures of the Environment Agency’s Pollution Inventory. 4.6.5 Source Specific Recalculations There have been no significant recalculations to this category. 4.6.6 Source Specific Planned Improvements Emission factors and activity data will be kept under review. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 264 4.7.1 Source Category Description Emissions sources Sources included Method Emission 2B2: Nitric Acid Production T3, T2 CS Key Categories 2B2: Nitric acid production - N2O (T1) Completeness No known omissions. A general assessment of completeness for the inventory is No major improvements to the data and methods. Further information on the abatement technology applied at UK installations has been added below. Nitric acid is produced by the catalytic oxidation of Nitrous oxide is also formed by oxidation of Nitrous oxide is emitted from the process, as well as a small percentage of the NOx that cannot be recovered for conversion into nitric acid. At the end of 2021, nitric acid was being manufactured at 2 UK sites with a total of 4 production plants. At one site, the nitric acid production plant has had NO x/N2O abatement fitted to all units since commissioning (pre - 1990), whilst at the other UK production site, all three production lines have had nitrous oxide abatement retrospectively fitted during 2011 Quarter 1. This has led to a notable reduction in the UK IEF for nitrous oxide emissions from nitric acid production in the UK between 2010 and Across the 1990 -2023 time-series the availability of emissions and production data for UK nitric acid plant is inconsistent, and so a range of methodologies have had to be used to provide estimates and derive emission factors. Where possible, emission estimates are based on site-specific data provided by process operators. Site -specific production estimates are largely based on production capacity reported directly by the plant operators. This approach may overestimate actual production. No data are availab le for three sites operating between 1990 and 1993, and production at these sites is calculated based on the difference between estimates of total production and the sum of production at the other sites.
Emission estimates for N2O are derived for each nitric acid site using one of the

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 265 a) Emissions data provided by the process operators directly or via the Pollution Inventory (1998 onwards for plant in England, 2001 onwards for plant in N Ireland); b) Site-specific emission factors derived from reported emissions data for the same site for another year (1990 -1997 for some plant in England, 1994 -1997 for other plant in England, 1990-2000 for plant in N Ireland); and c) A default emission factor of 7 kt N 2O /Mt 100% acid produced in cases where no emissions data are available for the site (some sites in England, Scotland, 1990-1993). This default factor is the default factor provided in the 2006 IPCC Guidelines (IPCC, 2006) for medium pressure plant. production and N 2O emissions for the UK inventory and the methods used by operators to derive the emissions data they report to regulators and the inventory team. The emissions monitoring at the two sites still in operation was originally based on periodic (at least quarterly, if not more frequent) sampling, but from 2010 onwards has been continuous, using on -line infra-red monitoring systems. The continuous monitors at both sites are certified to MCERTS, installed and maintained to EN14181, and subject to UK ETS Permit. M CERTS (Monitoring Certification Scheme) was set up by the Environment Agency to ensure good quality environmental measurements. The scheme is based on international standards and provides for the product certification of instruments, the competency certification of personnel and the accreditation of laboratories. The European Standard EN14181 covers quality assurance for automated measuring systems. The details of monitoring at the closed sites are not known, but it is assumed to have been the same as the sites that remain in operation i.e. periodic prior to 2010. The closed sites were shut before the fitting of continuous monitoring devices was required for UK/EU ETS reporting purposes; the N2O monitoring systems at these sites comply with the requirements of UK/EU ETS reporting, and are subject to low uncertainty (5 -10%). Therefore, the emissions data reported by operators are associated with low uncertainty, and are representative of the technology and abatement in the UK installations. a One site closed at end of January 2008 which submitted emissions data for that month based on emission factors having used monitoring to quantify emissions the previous year. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 266 Year Number of sites Production (Mt 100% The larger of the two remaining UK plants fitted control equipment to reduce N 2O emissions in early 2011, and this has decreased NO x emissions from that plant as well, leading to the large decreases in the aggregate EFs for both pollutants in 2011 compared with the previous year. A large increase in N 2O emissions between 1998 and 1999 resulted from a change in the NOx abatement system at one plant from NSCR to SCR. NSCR reduces emissions of N2O as well as NOx, whereas SCR only abates NOx and can actually increase N2O emissions. Since 2011 all of the UK nitric acid production facilities are fitted with EnviNOx SCR abatement (Alexander, 2019) which includes heating of the tail gases from the production vessels, followed by NOx and N2O destruction in a catalyst bed using ammonia gas and hydrocarbon inputs to mitigate the NO x and N2O. The technology is described in a reference document (Groves and Sasonow, 2010)80. The UK installations apply the technology in process variant 2 design, which achieves N2O mitigation performance of around 99.5%, and this is the reason for the very low IEF of the UK nitric acid production sector since 2011. The N 2O emissions from all UK plant are monitored (since 2009 for all plant) using Continuous Emission Monitoring systems, and the annual operator submissions to the Environment Agency (the environmental regulatory agency for both UK nitic acid facilities) are subject to quality checks by the Site Inspectors to validate that the annual data reported to the PI and used in the UK 4.7.3 Uncertainties and Time Series Consistency The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. Emissions from nitric acid production are estimated based on a combination of emission factors and reported emissions data. The methodology used to estimate N 2O for this sector does vary through the time-series depending upon the availability of data. The calculated N2O

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 267 EF for UK nitric acid production facilities varies quite significantly across the time series, which is a reflection of nitric acid production patterns across UK sites that utilise different process conditions. Successive closures have changed the average N2O EF, as plants with generally above-average emission rates cease production. Abatement of N 2O using catalytic decomposition technology at the remaining UK production plants has also played a part in reducing the UK emission factors over time. The changes in EF may also partially reflect the lack of availability of a consistent time-series of emissions data. Emission estimates for recent years have been based partially (1998-2008) or wholly (2009-2021) on continuous monitoring, and therefore will be subje ct to low uncertainty. The monitoring systems used at the 2 sites currently in operation are subject to an uncertainty of 5-10%. The nitric acid plant emissions data reported by operators since 1998 are considered to be complete and accurate, since they are subject to internal QA/QC checks by the plant operators and the Environment Agency before being reported in the Pollution Inventory. 4.7.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Annex 4. 4.7.5 Source Specific Recalculations There have been no significant recalculations to this category. 4.7.6 Source Specific Planned Improvements Emission factors and activity data will be kept under review.
4.8.1 Source Category Description Adipic acid is manufactured in a multi-stage process from cyclohexane via oxidation with nitric acid. Nitrous oxide is produced as a breakdown product from the nitric acid. There was only one company manufacturing adipic acid in the UK, but this closed in early 2009. Production data are not provided in the NID because of commercial confidentiality. Production data and emission estimates have been provided by the process operator (Invista, 2010). The emission estimates are based on the use of plant -specific emission factors for unabated flue gases, which were determined through a series of measurements on the plant, combined with plant production data and data on the proportion of flue gases that are unabated. In 1998 an N2O abatement system was fitted to the plant. The abatement system was a thermal oxidation unit and was reported by the operators to be 99.99% efficient at N2O destruction. The abatement unit was not available 100% of the time, and typically achieved 90-95% availability during adipic acid production. A small nitric acid plant was associated with the adipic acid plant, and both the adipic and nitric acid plants emitted NOx. From 1994 until the plant’s closure in 2009, the NO x emission from the nitric acid production is reported under 2B2, but prior to 1994 it is included under adipic acid production because separate emissions data for the different processes on that site were not available for those years. Therefore, the N 2O emissions from nitric acid production and adipic acid production were reported together for 1990 – 1994 under category 2B3 (adipic acid production). This discrepancy in reporting will cause a variation in the reported

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 268 effective emission factor for these years for 2B2 and 2B3 but overall emission estimates are 4.8.3 Uncertainties and Time Series Consistency The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. Emissions data for N2O from adipic acid production are provided by the process operator, but can be cross -checked against emissions reported in the Pollution Inventory. The level of uncertainty associated with reported emissions is not known, but the data are considered to be reliable as they are subject to QA/QC checks by the operator, and the related Pollution Inventory data are also checked by the regulator. A higher uncertainty is assumed for 1990 than for later years. Emissions no longer occur from this source since the plant has closed. Fluctuations in the N2O EF from this plant are apparent since the installation of the abatement plant. Following direct consultation with the plant operators, it has been determined that the variability of emissions is due to the varying level of availability of the abatement plant. A small change in the availability of the abatement system can have a very significant impact upon overall plant emissions and hence upon the annual IEF calculated. 4.8.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Annex 4. During summer 2005, consultation between Defra, AEA, plant operators and the UK Meteorological Office was conducted to discuss factors affecting emissions from the adipic acid plant, plant design, abatement design, abatement efficiency and ava ilability, emission measurement techniques, historic stack emission datasets and data to support periodic fluctuations in reported emissions. The meeting prompted exchange of d etailed plant emissions data and recalculation of back-trajectory emission models. 4.8.5 Source Specific Recalculations There have been no significant recalculations in this category. 4.8.6 Source Specific Planned Improvements Emission factors and activity data will be kept under review. Caprolactam was made at one site in the UK in the early 1970s. The site was destroyed in a serious explosion in 1974, and no other production sites have been built since. Glyoxal and glyoxylic acid have not been produced on an industrial scale in the UK at any time. A literature search of documents from the last 25 years on chemical production in Europe as well as consultation with the Chemical Industries Association has confirmed that these sources should This source category includes silicon carbide and calcium carbide. Neither chemical is known to have been manufactured on an industrial scale in the UK since the 1960s, when calcium carbide plants at Kenfig and Runcorn closed. As above for 2B4, literature searches and

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 269 consultations with UK chemical industry representatives have confirmed that this source should be reported as not occurring in the UK. 4.11.1 Source Category Description Titanium dioxide has been produced in the UK by two i) from ilmenite, using the sulphate process; and ii) from rutile, using the chloride process. Only the chloride process leads to process emissions of greenhouse gases. In 1990, there were two sites each using the chloride and the sulphate process, but the two sulphate processes closed in 1997 and 2009, so all titanium dioxide in the UK is now produced using the chloride process at the two sites at Stallingborough and Greatham. The chloride process involves the chlorination of rutile ore in a reducing atmosphere to produce titanium tetrachloride (TiCl 4), followed by oxidation of the TiCl 4 to titanium dioxide. The reducing atmosphere is produced by combustion of petroleum coke or coke oven coke. The 2006 GLs recommend the use of either a Tier 1 method involving a default emission factor and national activity data, or a Tier 2 method using installation-specific data on reducing agent usage. For the UK, neither of these methods are feasible options due to limited data; there are no UK activity data (i.e. annual production statistics) for any individual chemical product, and the only site -specific data for the UK plant is in the form of CO 2 emissions data. These emissions data are available from two r egulatory reporting sources, however the scope of reporting has varied over the utilities.
However, for three years (2006-2008), the process operators were required to report thermal CO2 and chemical CO2 separately, so the latter could be assumed to cover emissions from coke use only; • From the ETS, detailed data covering fuel use for energy production in site boilers during phase II (2008-2012), extended to cover fuels burnt in furnaces, driers etc. as well as use of reducing agents (coke) for phase III (2013 onwards). From these data it is possible to obtain the emissions from the chemical process for some 2006-2008 (using the PI data for chemical CO 2 emissions), and 2013 onwards (from the detailed ETS data). The fuel/process split in emissions for these years can be calculated, and the PI provides total CO2 emissions at each site back to 1998. Prior to 1998, there is no data on either emissions or production, and therefore it is assumed that emissions in 1990 - 1997 are at the same level as in later years (the production capacity at all UK sites producing TiO2 by the chloride route is the same for all years). In order to avoid a potential double -count in emissions in the UK GHGI, it is necessary to ensure that the reductant used in the processes is not included as a fuel and emissions reported in 1.A. The method adopted by the inventory team addresses this issu e by back - calculating the coke oven coke/petroleum coke used as a reductant from the emissions data using UK carbon emission factors for the feedstock, and discounting this amount from the

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 270 4.11.3 Uncertainties and Time Series Consistency The country-specific method used is regarded as the best available method for the UK, given the lack of any production activity data. The use of site-specific EU/UK ETS and PI data, even if not relating to input materials as required by the Tier 2 method i n the GLs, ensures that emissions data are quite certain for the period from 1998 onwards. Estimates for 1990 -1997 are more uncertain due to the need to extrapolate 1998 data backwards in the absence of any specific information on production, materials usage or emissions in those years. 4.11.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Annex 4. 4.11.5 Source Specific Recalculations There have been no significant recalculations in this category. 4.11.6 Source Specific Planned Improvements Emission factors and activity data will be kept under review. 4.12.1 Source Category Description Soda ash has been produced in the UK using the Solvay process at two sites operating since the start of the time period covered by the inventory. The Solvay process involves the conversion of limestone (calcium carbonate) and brine (sodium chloride) to soda ash (sodium carbonate) and calcium chloride. The initial stage in the process is the calcination of limestone in a kiln to produce lime and CO2 gas, both of which are used in the process. Coke oven coke is used to fire the lime kilns and CO2 from the coke is included in the gases used in the soda ash plant. In theory, if limestone and brine are converted completely to soda ash and calcium chloride, then that part of the soda ash process is carbon-neutral and the CO2 emitted should be equal just to those emissions occurring from the coke. In practice, the process is not 100% efficient so emissions of CO2 are actually higher than would just be due to the coke use. Soda ash production at one of the two UK sites (Winnington) ceased in February 2014, although the site is still being used to make sodium bicarbonate from sodium carbonate solution & CO 2, which we assume is sourced from the neighbouring Lostock plant. The sodium bicarbonate process will consume CO2 some of which is subsequently emitted since some uses of sodium bicarbonate are emissive. However, these emissions from sodium bicarbonate usage are reported elsewhere. UK/EU ETS data suggest that the sodium bicarbonate process does emit some CO2 – presumably unreacted CO2 that passes through the process and, since this CO2 probably originates with the soda ash process at Lostock, it is included in the emission Emissions from soda ash (sodium carbonate, Na2CO3) used in the manufacture of soda-lime glasses is reported under source category 2A3 and emissions from other uses of soda ash and sodium bicarbonate are reported in 1B2d and 2A4d. The 2006 GLs suggest that emissions should be based "on an overall balance of CO2 around the whole chemical process”. In the UK, soda ash has been produced at two sites and both began to report under the UK/EU ETS in 2013, although one is now closed. The UK/EU ETS emissions data for the two sites is calculated using a carbon balance approach with inputs in

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 271 coke and limestone balanced against soda ash and waste products. The 2013 -2021 EU and UK ETS data therefore meets the requirements for the method suggested in the GLs. Prior to 2013, no data for the UK plant were reported in UK/EU ETS, but CO2 emissions have been reported in the PI from 1998 onwards. Comparison of the PI and UK/EU ETS data for 2013-2020 shows that UK/EU ETS data were 34% higher than emissions in the PI in 2013 and, on average, 60% higher in the years from 2014 -2020. The reason for this is not known, but since the PI data for 1998 -2013 are fairly consistent, it is assumed that there is a systematic underestimate in the PI data across the entire time-series (possibly they represent CO2 releases from just part of the process, rather than the whole-process balance used in the UK/EU ETS).
We have assumed that the level of underestimation in 1998-2012 is at the same level as in 2013 and we have therefore used the PI data for 1998 -2012 but m ultiplied by a factor of 1.34 to give estimates of emissions in those years. The difference in 2014-2020 was consistently higher and so a more conservative approach would be to use a factor based on data for all years after 201 3 (1.65). However, the Winnington plant was closed in early 2014 and so the years from 2014 onwards are atypical compared with the 1990-2013 period of full operation of both processes. For 1990-1997, no data of any type are available, but since the same two sites have been in operation in the UK across the entire time -series, emissions in 1990-1997 are assumed to be at the same level as in later years. A Carbon Capture & Utilisation (CCU) system has been installed at a CHP plant in Winnington sodium bicarbonate production facility. The steam and power produced from the plant are used onsite or by other industrial businesses in the area, whilst the captur ed CO2 from the combustion process is used onsite for the production of Sodium Bicarbonate (CHP case study, Winnington CHP with CCU Technology). The inventory uses the submissions of the facility to the ETS to account for the carbon emissions from the site , and accounts for the capture against the process emission (i.e. emissions are not deducted from the combustion emissions allocated to 1A2c, instead they are deducted from 2B7). 4.12.3 Uncertainties and Time Series Consistency The method used is regarded as the best available given the lack of any production activity data, or a time-series of coke consumption. The use of site-specific EU and UK ETS data for 2013-2022 should ensure that the emission estimates for those years are quite certain and this would avoid any double counting with regards to the utilisation of the CO 2 generated as part of the Solvay process. The poor agreement between the PI and UK/EU ETS data in 2013- 2020 means that the emission estimates for 1998 -2012, based on PI data, are far more uncertain. The difference between UK/EU ETS and PI data is even grea ter (in percentage terms) in 2014 -2020 than in 2013, however both sites only operated fully throughout 2013, Winnington having closed in February 2014. We have therefore treated the 2013 UK/EU ETS/PI ratio of 1.34 (based on both plants operating throughout the year) as a more reliable guide to the potential underestimation in the PI data in earlier years. Estimates for 1990-1997 are more uncertain still due to the need to extrapolate 1998 data backwards in the absence of any specific information on producti on, materials usage or emissions in those years. The accounting for CCU against the process emission has a significant impact on the implied emission factor for recent years. 4.12.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Annex 4. 4.12.5 Source Specific Recalculations No recalculations have been made to emissions from this category. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 272 4.12.6 Source Specific Planned Improvements Emission factors and activity data will be kept under review. 4.13.1 Source Category Description This category includes emissions from the following 2B8a Methanol, 2B8b Ethylene, 2B8c Ethylene Dichloride, 2B8d Ethylene Oxide, 2B8e Acrylonitrile, 2B8f Carbon Black and 2B8g Other. The UK has a large petrochemical industry, with manufacture of all the chemicals explicitly mentioned in the 2006 IPCC Guidelines for at least part of the period 1990 -2023, although a series of site closures in recent years has reduced the number of products Methanol was manufactured in the UK until 2001 in a process which was integrated with ammonia production. Ethylene was produced at five sites in 1990, although the closure of the two works in 1993 and 2010 reduced this to three at the end of 2021. The UK ethylene crackers use either naphtha or natural gas liquids as feedstocks, and off -gases from the ethylene crackers are used as fuels on -site. Ethylene dichloride (EDC) has been produced at 4 sites over the period covered by the GHGI, although only 1 is still in operation, and only 2 of those processes used the oxychlorination route that causes process emissions of CO 2. Ethylene oxide (EO) was produced at a single UK plant between 1990 and closure in January 2010. There is also a single site producing acrylonitrile (ACN): this has operated since 1990 and is still in operation. Two sites produced carbon black, until their closure at the very start, and in the middle of 2009 respectively. Most of the production was of furnace black. A number of other chemical sites also emit CO2 due to the use of off-gases as fuels. Emissions of CO2 at these sites are very small relative to the emissions from ethylene production. All emissions of CO 2 from use of off -gases as fuels is reported under 2B8g, including the emissions from ethylene production. Many chemical processes emit small quantities of methane, either as a result of fugitive releases from equipment, or as a component of tail gases released from vents. The inventory includes separate emissions data for production of ethylene, methanol, ACN, EO, and carbon black. Emissions of methane from other chemical processes are reported under 2B10. Details of the methodologies used for petrochemical and related processes are shown in Ethylene 2B8g 2B8a Site specific emissions data from UK/EU ETS (CO 2 only), PI and from process operators. Where no emissions data are available, these are estimated by extrapolation from data available for later years, taking into account changes in plant capacity. Methanol 2B8b 2B8b See below for CO2 methodology. Emission estimates for methane are based on operator-reported data from the PI.
Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 273 2B8c - Emissions estimated using IPCC Tier 1 emission factor for process CO2 assuming production is 500,000 tonnes per yeara. Ethylene Oxide 2B8d 2B8d CO2 emission estimates for 1995 -2009 from the PI, emissions in 1990-1994 assumed same as in 1995. CH 4 estimates for 2004 - 2009 from the PI. No emissions data are available for 1990 -2003, so the Tier 1 IPCC default is used, combined with estimates of EO production at the plant derived from the CO 2 emitted, and assuming a CO2 emission factor of 0.663 t CO2 / t EO (IPCC default for oxygen process, default catalyst sensitivity). Acrylonitrile 2B8g 2B8e CO2 emission estimates for 2008-2022 from UK/EU ETS. No data on emissions for earlier years, but the capacity of the plant is thought to have been unchanged since 1990, so the average emission for the 5 -year period 2008 -2012 is used for 1990 -2007. The operator reports methane emissions to be below the 10 tonne threshold for reporting in the PI, so an emission of 5 tonnes/annum Carbon black 2B8f 2B8f CO2 emissions are reported in the PI for 1998 -2009 for one site, and 2003-2008 for the other (this site closed at the start of 2009, so emissions in 2009 are assumed zero). The PI emissions are assumed to be from process sources, and emissions in earlier years are assumed to be the same as in the earliest year for which data exist. Emission estimates for methane are also based on PI data for later years, but no data are available for the period 1990 - 2003, and so the IPCC Tier 1 default is used instead. 2B8gii 2B10b Emissions data for other petrochemical processes are taken from UK/EU ETS (CO2 only), and the PI (English/Welsh sites) or SPRI (Scottish sites). For those years where operator -reported emissions data are not available, then emissions are assumed to be the same as for later years where data are available. There are no petrochemical p rocesses located in Northern Ireland which a – production is not known but capacity of two plant in 1987 was 500,000 tonnes and one subsequently closed so 500,000 tonnes is considered a conservative estimate. Methanol production, like ammonia, requires hydrocarbon fuels both as a source of raw materials and as a fuel. The UK methanol process used natural gas. Whereas in ammonia processes, natural gas is reformed to produce hydrogen for the process and carbon di oxide as a waste by -product, in the methanol process reforming of natural gas generates carbon dioxide for the process with hydrogen as the waste product. The UK’s only methanol plant was integrated with one of the ammonia plants, so that carbon dioxide pr oduced by the ammonia plant could be exported and used to synthesise methanol. This CO 2, and additional CO 2 produced in the methanol plant’s own reforming process is assumed stored. The plant closed in 2001 and there is limited information on emissions and none at all on natural gas consumption at the plant. The nominal capacity of the plant was 500 ktonnes but analysis of European production data for the 1997-2001 period indicate that the UK plant production fell sharply between 1997 and 1998 as new capacity came on stream elsewhere in Europe, and the plant was closed as uneconomic in 2001. For the period 1990-1996, it has been assumed that the UK plant was running at 98% of capacity, as in 1997. The various estimates of production have then been combined with the IPCC Tier 1 emission factor for methanol using conventional steam reforming of natural gas with integrated ammonia plant (1.02 t CO 2 / t methanol) to give the emission reported in 2B8b. The production estimates are also used to

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 274 calculate the CO2 stored, and finally, both emitted CO2 and stored CO2 are also converted into estimates of natural gas consumed so that we can ensure there is no double-counting of that The methodology for CO 2 emissions from 2B8g was developed through an inventory improvement research project in 2013-14 (Ricardo-AEA, 2014b), with a review conducted of available data on industrial use of process off -gases and waste residues as fuels, including consultation with operators of several of the installations that were known to use process off- gases as a fuel. The research included a review of data within the UK/EU ETS. In addition, installation-specific (but anonymised) data from the chemical industry Climate Change Agreement (CCA) data reported for 2008 and 2010 were also reviewed. CCA data was used primarily to quality check the number of sites in the chemicals sector that reported the use of waste-derived fuels, and this dataset confirmed that there were a very small number of sites reporting waste-derived fuel use. It is not possible with the current data available to distinguish between feedstock-derived off-gases that are used directly as a fuel and those used in other process-related activities that result in emis sions, such as flaring, and therefore the total emissions reported for those sites are allocated to 2B8g. 4.13.3 Uncertainties and Time Series Consistency For the use of waste residues and process off -gases as fuel in the chemical industry, the emissions estimates are somewhat uncertain as the level of completeness of the data over the whole time-series is hard to verify; the 2014 inventory improvement study , however, has confirmed that the inventory covers all high-emitting sites in the UK that have been in operation in recent years, and therefore the overall uncertainty on the UK inventory estimates, at least for the period covered by UK/EU ETS data, is not regarded as significant.
Energy and environmental experts within the UK trade association for the chemical sector, the Chemical Industries Association, also confirmed that they were not aware of any other sites in the UK that used process off -gases, over and above the sites included in the UK GHGI (Personal communication, Chemical Industries Association, 2014). These are dominated by the four ethylene production sites and a handful of other sites producing organic chemicals, typically Emission estimates for other sources are mostly based on a mixture of PI and/or UK/EU ETS data with estimates for earlier years then based on the assumption that emissions are as in later years. Tier 1 IPCC default emission factors are used for the minor s ources 2B8c (for CO2), 2B8d and 2B8f (both CH4, part of time-series only). No UK-wide activity data (production data) are available with which to generate a better time series for any of the sub-sectors within 2B8, so the earlier part of the time-series for all of the chemical industry sectors is particularly uncertain. UK/EU ETS-based emissions are considered the most reliable basis for estimates in the GHGI and the uncertainty is estimated to be +- 5%. PI data are more uncertain, because it is not clear what methods are used and the emission sources (combustion, process, other) are not transparent. Uncertainty for GHGI estimates based on the PI data is estimated to be

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 275 +- 15%. Emissions data for methane are likely to be more uncertain than those for CO2 since the former are often fugitive in nature, or minor components in stack emissions (thus requiring stack monitoring to quantify). 4.13.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Annex 4. 4.13.5 Source Specific Recalculations No recalculations have been made to emissions from this category. 4.13.6 Source Specific Planned Improvements It is noted that this sector has been identified as a key category, and that not all of the estimates within this sector use a tier 2 or higher approach. The UK has recently reviewed this sector and included some additional sources using what is believed to be the best currently available data. The UK will review this position should further information come to light. 4.14.1 Source Category Description Emissions arise from the UK manufacture of HFCs, PFCs and HCFC -22. HFC-23 is a by - product of HCFC -22 manufacture. There are two single manufacturers of HFCs and PFCs respectively in the UK, and two companies were operating HCFC-22 plants. Both HCFC plants closed in 2008/9; one reopened in 2013 and was shut down again in 2016. HFC production There is no UK production of SF6. A full description of the emission model and associated methodology used for this sector is contained in AEA (2008). Within the model, manufacturing emissions from UK production of HFCs, PFCs and HFC-23 (by-product of HCFC-22 manufacture) are estimated from reported data from the respective manufacturers. Manufacturers have reported both production and emissions data, but only for certain years, and for a different range of years for different manufacturers. Therefore, the emissions model is based on implie d emission factors, and production estimates are used to calculate emissions in those years for which reported data are not available. Two of the three manufacturers were members of the UK greenhouse gas Emissions Trading Scheme. As a requirement of partic ipation in the scheme, their reported emissions were verified annually via external and independent auditors. For PFC production, emissions are now reported to the Environment Agency’s Pollution Inventory, and these emissions are directly used within the G HG inventory. The operator of the HFC and (now closed) HCFC-22 plant provides speciated emissions data directly to the Inventory Agency, based on vent analysis and flowmeter readings, or on weighbridge differences. The other HCFC-22 plant, which closed in 2008, also reported to the Pollution Inventory and these emissions were used within the GHG inventory. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 276 4.14.3 Uncertainties and Time-Series Consistency The uncertainty analysis in Annex 2, provides estimates of uncertainty according to IPCC source category and fuel type. The uncertainty estimate for emissions from HFC manufacture has been revised for this submission, based on information from the plant operator. There is a significant decrease in HFC emissions in 1998/1999. This step-change in emissions is due to the installation of thermal oxidiser pollution abatement equipment at one of the UK manufacturing sites. Fugitive HFC emissions from both an HCFC -22 plan t and HFC manufacturing plant (run by the same operator) are treated using the same thermal oxidiser unit. Emissions also decrease in 2004, reflecting the installation of a thermal oxidiser at the second of the UK’s HCFC-22 manufacturing sites. This was installed in late 2003, and became fully operational in 2004. HFC-23 emissions decreased in 2009 and 2010 following the closure of both HCFC-22 manufacturing sites. A small emission of HFC-23 remains, which arises from the production of HFC -125, most likely due to impurities in the feedstock. HCFC -22 manufacture restarted in 2013 and was shut down in 2016. A significant increase in PFC emissions from the production of halocarbons is observed from 1992 to 1996 (with the trend changing after 1996). The increase in emissions was due to increasing production levels at the single UK manufacturing plant during thi s period. Since 1996, the level of emissions has changed each year which broadly reflects the demand (and hence production levels) for PFCs. In 2004 and 2005, emissions reported by the company increased compared with the preceding 3 years of fairly stable emission levels 2001 -2003. Emissions declined sharply in 2007-2009, before increasing again in 2010 and 2011 and then 4.14.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Annex 4, and details of verification of emissions are given in Annex 6 .
Data reported via the Pollution Inventory are also further checked by the Environment Agency. 4.14.5 Source Specific Recalculations There have been no significant recalculations in this category. 4.14.6 Source Specific Planned Improvements There are currently no planned improvements for this sector, however data sources will be 4.15.1 Source Category Description The UK has a large chemical manufacturing sector and emissions of methane are reported elsewhere in 2B for emissions from specific chemical processes, but also reported in 2B10 in the case of emissions from other, general petrochemical processes. Methane emissions from ammonia production sites are included in 2B10, rather than being reported separately in 2B1. Site-specific emissions data for chemical processes located in England and Wales are available in the Pollution Inventory (Environment Agency, 202 4) and Welsh Emission Inventory (NRW, 202 4) respectively. Reporting generally started in 1994 or 1995, and few

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 277 data exist for the years prior to 1994. Site specific emissions data for processes in Scotland have been obtained from the Scottish Pollutant Release Inventory (SEPA, 2024). All of the data available are in the form of emission estimates generated by the process operators and based on measurements or calculated based on process chemistry. Emission factors and activity data are not available, but emission factors are estimated using the best available ‘surrogate’ activity data that are available across the time series; this approach then enables estimates of emissions to be made for the years prior to operator -reported emission estimates (typically pre-1994). For most commodities, the extrapolation is linked to changes in the level of output from the chemicals manufacturing sector as measured by the 'index of output' figures published by the Office for National Statistics (2024). 4.15.3 Uncertainties and Time Series Consistency The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. Estimates for 1994 onwards are mostly based on data reported by process operators through the regulatory agency data management and checking systems that govern UK industrial emissions data within the PI, WEI, SPRI and NIPI. The dataset is evidently incomplete in some years, due to the variations through time in the reporting thresholds for different pollutants. The Inventory Agency has used good practice techniques to address these reporting inconsistencies, and therefore the completeness of the data is good through the time series. Unfortunately, UK production data are not readily available for chemicals and other products from the sites reported under 2B8. This inhibits the Inventory Agency’s ability to conduct data validation tests on the reported emissions data against a reliable time -series of production estimates. Emission estimates for the period prior to 1994 are also more uncertain due to the need for extrapolation of emissions data for 1994 or some other year backwards, using general indicators of chemical industry output. 4.15.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Annex 4. Emissions data taken from the Pollution Inventory are subject to additional QA/QC by the Environment Agency before being used in the inventory. 4.15.5 Source Specific Recalculations There have been no significant recalculations in this category. 4.15.6 Source Specific Planned Improvements Minor revisions to emission estimates may be required periodically in order to deal with changes in the data available e.g. revisions to emissions reported to UK regulators. The Inventory Agency will continue to review the available operator -reported data and seek to derive a consistent time series of emissions. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 278 4.16.1 Source Category Description Emissions sources Sources included Method Emission Basic oxygen furnaces - dolomite Following for indirect gases Rolling Mills (Hot & Cold Rolling) Iron and steel production may be divided into integrated steelworks, electric arc steelworks, downstream processes such as continuous casting, and iron & steel foundries. Integrated steelworks convert iron ores into steel using the three processes of sintering, pig iron production in blast furnaces and conversion of pig iron to steel in basic oxygen furnaces. For the purposes of the inventory, emissions from integrated steelworks are estimated for these three processes, as well as other minor processes such as slag processing. Sintering agglomerates the raw materials for the production of pig iron by mixing these materials with fine coke (coke breeze) and placing it on a travelling grate where it is ignited. The heat produced fuses the raw materials together into a porous material called sinter. Blast furnaces are used to reduce the iron oxides in ore to iron. They are continuously charged with a mixture of sinter, fluxing agents such as limestone, and reducing agents such as coke. Hot air is blown into the lower part of the furnace and reacts with the coke, producing carbon monoxide, which reduces the iron ore to iron. Gas leaving the top of the furnace has a high heat value because of the residual CO content, and is used as a fuel in the steelworks. Molten iron and liquid slag are withdrawn from the base of the furnace. The most significant greenhouse gas emissions to occur directly from the blast furnace process are the combustion gases from the 'hot stoves' used to heat the blast air. These generally use blast furnace gas (BFG), together with co ke oven gas and/or natural gas as fuels. Emissions are reported in CRT category 2C1. Gases emitted from the top of the blast furnace are collected and emissions occur when this BFG is subsequently used as fuel. Pig iron has a high carbon content derived from the coke used in the blast furnace. A substantial proportion of this must be removed to make steel and this is done in the basic oxygen furnace. Molten pig iron is charged to the furnace and oxygen is blown t hrough the metal to oxidise carbon and other contaminants.
As a result, carbon monoxide and carbon dioxide are emitted from the furnace and are collected for use as a fuel. As with blast furnace gases, some losses occur and these losses are reported with blast furnace gas losses in 2C1. Limestone and dolomite are used in steelmaking, typically being added to sinter where they are calcined, releasing CO2 which is emitted. Some of the limestone or dolomite used may be added directly to blast furnaces without being sintered first, which would mean that the CO 2 released would be emitted from the blast furnace stage of steelmaking rather than the sintering stage. However, this distinction is not important for GHG reporting and the practice is ignored

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 279 for the GHGI with all additions and, therefore, emissions being reported as from sintering. Dolomite is also an important addition as a fluxing agent in basic oxygen furnaces and CO 2 evolved from the dolomite is reported as a separate category under 2C1. Electric arc furnaces produce steel from ferrous scrap using electricity to generate the high temperatures necessary to melt the scrap. Carbon dioxide emissions occur due to the breakdown of the graphite electrodes used in the furnace. The UK had 2 integrated steelworks (at Port Talbot & Scunthorpe) in operation at the end of 2023, following the closure of the Teesside works in September 2015. The heavy end operations of the Port Talbot Steelworks were shut in 2024, including the coke ov ens, sinter plant, blast furnaces and basic oxygen furnace steelmaking. As the emissions reported here cover the 2023 operations, the latest closures do not affect the currently reported methodology. In 1990, five sites had been in operation, with the steelworks at Ravenscraig in Scotland closing in 1992, followed by the closure of Llanwern in Wales in 2001. Teesside was mothballed between January 2010 and April 2012 due to the loss in demand for its steel products. Electric steel is manufactured in 4 large steelworks, in Rotherham, Sheffield and Tremorfa. Other large electric arc steelworks once operated in Sheerness, and Newport. The methodology for estimating CO2 emissions from fuel combustion, fuel transformation, and related processes at integrated steelworks is based on a detailed carbon balance (this methodology is described in more detail within the section on CRT sector 1A2a). Carbon emissions from integrated steelworks are reported under 1A1c, 1B1b, 1A2a, 2A3 and 2C1, depending upon the emission source. Emissions from sintering (from use of both coke breeze and limestone & dolomite), flaring of blast furnace gas and basic ox ygen furnace gas, use of dolomite in oxygen furnaces, and from arc furnaces are all reported under 2C1. Flared losses of blast furnace gas (including basic oxygen furnace gas) are given in DUKES and carbon factors are derived using the carbon balance described previously. Usage of limestone and dolomite for steel production is available from the Iron & Steel Statistics Bureau (2023). The carbon content of limestone and dolomite used at steelworks is available from operators via the UK/EU ETS data. Separate values are available for the years 2007-2023. These data show close consistency across the time series and therefore the 2007 value has been extrapolated back to 1990. The carbon emissions from electric arc furnaces cover electrode emissions, as well as CO 2 emissions from the addition of scrap metal, alloys, carbonate minerals and other additives. The methodology also takes account of carbon stored in by -products, such as steel, slag, scales etc., produced during the steelmaking process. Electric arc furnace operators including Liberty Steel and Marcegaglia (previously operated by Outokumpu) have provided additional information regarding the fuels used, process inputs (e.g. other carbon sources, reductants, electrodes, wastes, slags, carbo nates) that underpin the carbon emissions data for their electric arc furnaces as reported via the UK/EU ETS. [A UK GHG Inventory research paper was drafted in 2021 to summarise research in the sector and describe the development of the inventory methodology; that report (Passant and Gorji, 2021) is commercial in confidence but can be shared with an Expert Review Team on request.] The comparison between the operators and UK/EU ETS data allows for calculation of a more detailed timeseries of emission factors for those individual sites. Further analysis was then required for the purpose of gap-filling for the periods where no or limited data were available due to the changes in the reporting procedures in different UK/EU ETS phases. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 280 There are a number of electric arc furnace plants that have been closed over the years, and therefore further gap -filling exercise was required to estimate emissions from such plants. Based on the revision of the operations of such plants, the emission factors obtained from the first phase of the currently operational plants were deemed suitable for estimating their emissions. This method therefore allowed to account for emissions from the plants that have stopped production over the timeseries.
The Inventory Agency has developed a time series consistent method by applying IPCC good practice methods to address data gaps, as • Identification of (22) EAF sites operating in the UK across the time series; this includes several EAFs that operated only prior to the start of the EU ETS in 2005 and for which there are very scarce data on activity and emissions; • Analysis of the ISSB production statistics on EAF steel production since 1990, including annual UK-wide statistics and also regional production data; • Analysis of the Regulator Inventory data, to identify all available emissions data, including for smaller EAF sites that are evidently omitted from the ISSB statistics; • Use of UK/EU ETS emissions data and ISSB regional production data to derive a time series of IEFs for production for the larger (8) EAF sites that report within UK/EU ETS; • Development of a hybrid approach to apply operator emissions data per installation where available and to gap -fill for the remaining UK production using the IEF across the sector from the UK/EU ETS reporting, with the 2005 data back-cast to earlier years. Emissions from the use of coke oven coke in foundries and other iron & steel industry processes are included in category 1A2a but any other process emissions from foundries of methods used for emissions reported under 2C1. Source Category Method Activity Data Emission Factors UK-specific factor from carbon UK-specific based on reported Sintering – carbonates AD x EF ISSB UK-specific from UK/EU ETS Iron & steel - flaring AD x EF DESNZ energy UK-specific factor from carbon Electric arc furnaces AD x EF ISSB UK-specific factor Ladle arc furnaces AD x EF ISSB UK-specific factors 4.16.3 Uncertainties and Time Series Consistency The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 281 Much of the activity data used to estimate emissions from this source category come from the Iron and Steel Statistics Bureau and from DUKES. Time -series consistency of these activity data is very good due to the continuity in data in these publications. 4.16.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Annex 4. The UK inventory carbon balance method uses the best available industry data across the time series, including UK/EU ETS data from integrated steelworks from 2005 onwards. The comparison in recent years between the UK GHGI method and the UK/EU ETS data for individual installations indicates that the GHGI method is somewhat conservative, as the GHGI data are generally slightly higher than installation data. The Inventory Agency will continue to keep the method and input data under review to ensure that the carbon balance model delivers estimates that are as accurate as possible for the UK. 4.16.5 Source Specific Recalculations Due to a methodology update to further utilise the ETS data, a more complete timeseries of operator data has been developed. The result of this is an increase in total emissions across the timeseries, specifically an increase of 18kt in 1990 and an increas e of 8kt in 2019. For further information on recalculations, see Section 10. 4.16.6 Source Specific planned Improvements It is noted that this sector has been identified as a key category, and that not all of the estimates within this sector use a tier 2 or higher approach. The UK uses what is believed to be the best currently available data, and that tier 1 methods are only used for very limited parts of this sector. The UK will review this position should further information come to light. Emission factors and activity data will be kept under review. Where appropriate, fuel characterisation data from verified EU/UK ETS data sets will be considered in future GHGI The term ferroalloy covers a wide range of products, manufactured by various means, only some of which lead to industrial process emissions of greenhouse gases. Potential sources of • Use of reductants such as coke oven coke; • Consumption of carbon electrodes in furnaces used for melting raw materials; • Decarbonisation of limestone or dolomite used as a fluxing agents; • Decarbonisation of any carbonate ores used. The UK has been a minor producer of ferroalloys. The previous version of the BREF note (Best Available Techniques Reference document) for the non -ferrous metals industry, produced by the European IPPC Bureau81 estimated UK production in 1993 as 55 ktonnes out of a European total production of 2,620 ktonnes while the updated version of that document, published in 2017, does not identify any production of ferroalloys at all in the UK in the period Other than the estimate for 1993 given in the BREF note, the Inventory Agency has not found any data on UK production of ferroalloys. The absence of the UK as a European producer in 81 downloadable from

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 282 the recent update of the BREF note suggests that UK production is either zero or insignificant; through consultation with trade associations and industry statistics experts (ISSB) the Inventory Agency has only been able to identify a few small-scale manufacturers of specialist ferroalloys such as ferro-molybdenum and ferro-vanadium. The production data for 1993 lists 45,000 tonnes of ferromanganese production in a blast furnace (where emissions would arise from use of reductants), and 10,000 tonnes of other ferroalloys in electric furnaces. The ferroalloy producers identified as in operation in recent years either carry out exothermic processes only (for ferro -molybdenum alloys) or use electric induction furnaces for melting. None of the processes report any CO2 emissions in the Pollution Inventory, or are included in the UK/EU ETS; the Inventory Agency has not identified any process currently in operation that would cause any industrial process emissions of direct GHGs.
The estimated production of 45,000 tonnes of ferromanganese in 1993 would use coke oven coke or coal as a reductant, and therefore the emissions are already included in the inventory as all UK consumption of these fuels is assumed to lead to emissions of CO2. Any emissions associated with ferroalloy production would therefore already be included in 1A2a or 1A2b for coal, or 1A2g or 2C6 for coke oven coke. Given the lack of a time-series of production data, or information on the type or quantities of any reductant used in the ferromanganese prod uction, the Inventory Agency has not made any re-allocation of emissions from 1A or 2C6 to 2C2. There is no evidence of any current use of electric arc furnaces, or the use of limestone or dolomite fluxes or carbonate ores. Therefore, UK emissions from ferroalloys are i) Included Elsewhere in the case of any emissions from use of reductants; ii) Not Occurring in the case of emissions from other sources. 4.18.1 Source Category Description Aluminium was produced by the electrolytic reduction of alumina at two UK sites at the end of 2011, although the larger of these two sites subsequently closed in early 2012, leaving just one small smelter operating in the UK. A third site had closed during 2009, and a fourth closed in mid-2000. The operational site and the recently closed processes all use or used the pre - baked anode process, whereas the plant closed in 2000 used the Soderberg Cell process. This distinction is important because of large differences in emission rates for some pollutants. Both process types make use of carbon anodes and these anodes are consumed as the process proceeds, resulting in emissions of CO2. The PFC species tetrafluoromethane (CF4) and hexafluoroethane (C2F6) are formed if the alumina content of the electrolyte falls too low. Computerised control of alumina addition to the cells is a feature of modern plant and has helped to reduce PFC emissions from aluminium production. Emissions of methane are not estimated as there is no methodology available and emissions are considered to be negligible. The smelter design has a large effect on the rate of PFC emissions, and point feeder prebake technology is regarded as the best option for feeding aluminium oxide into the electrolytic cells, allowing addition at controlled intervals, resulting in fewer anode effects. Over the time series, the UK operators of aluminium smelters have invested to improve plant performance, and all sites were converted to point feeder technology, leading to large reductions in PFC emissions per unit production as a result. Emissions of carbon are estimated using statistics on the production of aluminium by each type of process and suitable emission factors. The carbon emission factors reflect current practice, and higher emission factors were used for earlier years, due to t he production of some aluminium using the Soderberg process. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 283 All emissions of PFCs (CF 4 and C2F6) occur during the aluminium smelting process during anode effects. The UK inventory data are directly reported by plant operators and are emission estimates calculated from the number and duration of anode effects at each facility. Operators use (or used) a Tier 2 methodology of a smelter -specific relationship between emissions and operating parameters based on default technology -based slope and over - voltage coefficients. This method uses (or used) default factors for the CWPB (Centre Worked Prebaked) plant for three of the plants and default factors for VSS (Vertical Stud Soderberg) for the plant which closed in 2000. One of the operators used the North West American Calculation assuming 3lbs PFC for every minute the cell was “on ano de effect”, for the early part of the time series. The time series does not show any discontinuity as a result of the The UK total primary aluminium production activity data are taken from the UK Minerals Yearbook (British Geological Survey, 2024) in years where complete data on production from operators are not available, 1990-2004 and 2006. In all other years of the time series, we have both the BGS data and also a complete set of operator production estimates. The two datasets are very closely consistent. The BGS data are presented rounded to 2 significant figures, and due to this lack of precision but close consistency, the UK inventory method uses the sum of all operator-reported data for 2005 and for 2007 onwards, as these are regarded as the most accurate data to use in each year. Method Activity Data Emission Factors Technology-specific default EFs Derived from operator reported Note that the PFC EFs presented here are essentially back -calculated IEFs for the UK industry, derived from the reported production data and sum of operator-reported emissions. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 284 4.18.2.1 Aluminium alloy production No emissions of SF6 are reported by any of the aluminium foundries in the Pollution Inventory or SPRI. Emissions from the use of SF6 in the UK aluminium sector are therefore reported as 4.18.3 Uncertainties and Time Series Consistency The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. Activity data on UK aluminium production since 2006 is available from both the British Geological Survey (BGS) UK Minerals Yearbook, as well as directly from operators, with the latter data set presented at a greater level of precision. The two datasets sh ow very close consistency over time, with small % differences year to year, which is at least partly due to the rounding in the BGS data. The BGS data are from a long running publication and the compilers of the activity data strive to use consistent methods to produce the activity data; there are also only a small number of UK producers, and complete reporting of their production, direct to the Inventory Agency, has occurred for over a decade.
Similarly, the methods used by operators to estimate emissions are specific to the technology of their plant, and for PFCs are consistent with the IPCC Tier 2 method across the time series. The consistent access to good quality data from the UK industry therefore helps to ensure good time series consistency of the emission estimates across all years, despite the switch to use (more precise) operator activity data from 2007 onwards. There was a large decline in emissions in 2012 as aluminium smelting activities came to an end in March 2012 at one of the largest UK production plants at Lynemouth. In 2010, 2011 and 2014 there was a significant increase in the implied emission factor for PFCs because of process issues during those years, for example an ‘anode crisis’ in 2014. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 285 4.18.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Annex 4. Emissions data taken from the Pollution Inventory are subject to additional QA/QC 4.18.5 Source Specific Recalculations There have been no significant recalculations for this sector. 4.18.6 Source Specific Planned Improvements Emission factors and activity data will be kept under review. 4.19.1 Source Category Description In the UK, SF 6 and an HFC act as cover gases to prevent molten magnesium from burning during the production of magnesium. Sulphur hexafluoride is used as a cover gas to prevent magnesium oxidising when exposed to air, because it is non-flammable and heavier than air. SF6 is non-flammable and non-toxic and is therefore a safe gas to use. In the UK, SF6 has been used as an alternative cover gas to SO2 in magnesium alloy production and sand and die-casting since the early 1990s. Since 2006, EU magnesium producers have looked for alternatives to SF6 in response to bans in the EU F-Gas regulation82. Some die casters have gone back to using SO 2. Others have used HFC-134a and a fluoro-ketone (FK 5-1-12) with the trade name Novec 612. The UK magnesium casting industry is very small. There are three significant manufacturers (one alloy producer, one die-caster and one sand-caster) plus two very small operations (both sand-casters). Alloy production involves the use of primary magnesium ingots, recycled scrap material and second-generation magnesium materials (i.e. material already made into alloys) for the production of different alloys. Both die and sand casters use these magnesium alloys to produce specific components for a wide range of industries. For the casting industry, SF6 is used for casting specific magnesium alloys where other cover gases, such as HFC-134a, are currently considered not suitable. The assimilated Regulation (EU) No. 517/2014 (the F -gas Regulation) as assimilated law prohibits the use of SF 6 in magnesium die casting, from 1 Jan 2018, the ban is extended to installations using a quantity below 850kg per year. Note that, as mentioned below, most UK magnesium production uses processes other than die casting, so this ban only has a limited A review of the data sources and methodology used to estimate emissions from F-gases used as cover gases in magnesium foundries was carried out in 2013 (Gluckman, 2013). In all cases UK magnesium companies were able to report consumption but had no actual measured data on emissions. The assumptions about the fraction of SF6 and HFCs that are emitted from the consumption of these F-gases were reviewed through discussion with industry experts and in some cases amended. It is estimated that 95% of SF 6 consumption is emitted but that only 82 Which was transposed into UK law via the Withdrawal Agreement Bill (2019)

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 286 20% of HFC -134a consumption is emitted (as a much greater proportion reacts with the magnesium). These figures are based on expert estimates by Gluckman (2013). For magnesium alloy production, SF6 emissions from 1998 onwards are estimated based on the data reported to the Pollution Inventory (Environment Agency, 2021), whilst emissions prior to 1998 are estimated based on consultations with the plant operators. From 2004, one of the main industry users of SF 6 as a cover gas has implemented a cover gas system using HFC -134a for some of its production capacity. There has been no use of SF6 by this company since 2022. In addition to having a significantly lower GWP than SF6 (and thus reducing emissions on a CO2 equivalent basis), use of HFC-134a is further advantageous in that a significant fraction of it is destroyed by the high process temperatures (80%) thus reducing the fraction of gas emitted as a fugitive emission. From 2008, emissions of HFCs have been reported in the Pollution Inventory (Environment Agency, 2021), and therefore the reported data are used directly. As part of a study to update the F -gas inventory (Gluckman, 2013), castings operators were re-contacted to provide activity data for recent years (the previous survey was conducted in 2004). The two largest users of SF6 and HFC-134a (that represent 99% of UK emissions from magnesium) are now contacted annually for their activity data (consumption of SF6 and HFC- Emissions of FK 5-1-12 cannot currently be reported via the CRT as there is no space to report this product, it would also be a low priority to include as it is a sparingly used product with a GWP comparable to CO2. It is estimated that the decomposition of 1 tonne of FK 5-1-12 during use as a cover gas generates ~400 tonnes CO2e of PFCs, but as this product is used only at 1 small magnesium site and trialled at one larger site, total emissions in the UK due to the decomposition of FK 5-1-12 have been estimated to be less than 0.001% of the UK national total since 2012 and 0 beforehand.
According to the UNFCCC Guidance for reporting, emissions could be “… considered insignificant if the likely level of emissions is below 0.05 per cent of the national total GHG emissions and does not exceed 500 kt CO2 eq.”. Therefore, the UK considers this a low priority to formally estimate and report emissions for. This source is included in the Assessment of completeness in Section 1.7. As far as we know, HFC -134a does not decompose into other potent GHGs; any other products potentially emitted would be offset by our conservative estimate of the proportion of 4.19.3 Uncertainties and Time Series Consistency The main area of uncertainty is regarding emissions of SF6 from casting based on discussions with the sector Trade Association for the period prior to 1998. Data from the main magnesium alloy producer is also uncertain for this period. For the period 1998 -2023, the uncertainty of the time -series emissions is estimated to be significantly lower. Data received from the main magnesium alloy producer and the other 4 casting operations are associated with low uncertainty and show good consistency across the 4.19.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Annex 4. Emissions data taken from the Pollution Inventory are subject to additional QA/QC

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 287 4.19.5 Source Specific Recalculations No significant recalculations have been made to estimates for this sector for the 202 5 For information on the magnitude of recalculations to this Source Category, see Section 10. 4.19.6 Source Specific Planned Improvements We have recalculated HFC estimates for 2019 and SF6 estimates for 2016-2019 to reflect the more up to date operator data received. Lead production in the UK consists of one primary lead production site (now closed) and a small number of secondary lead sites. The primary lead site produced zinc, lead and other metals from imported ore concentrates and closed in 2003. This site produced more zinc than lead, and because it is not possible to split emissions between 2C5 and 2C6 (other than on an arbitrary basis), emissions for this site are reported under 2C6. Further details on this process are given in the following section. The UK also has a number of secondary lead processes, all of which involve the recovery of lead either from automotive batteries or from clean scrap. Emissions of CO2 could, in theory, occur from the use of reductants such as coal, coke oven coke, or natural gas during secondary lead processes, however none of these secondary lead processes are known to involve the use of reductants, and therefore we do not believe that there are any process emissions of CO2 from any of the UK’s secondary lead processes. If any use of reductant did occur, it would be included in UK fuel statistics as an energy use, and thus emissions of CO2 would in any case be included in the UK inventory, but 4.21.1 Source Category Description Zinc was produced in the UK until early 2003, using the Imperial Smelting Process (ISP) at a smelter operated by Britannia Zinc at Avonmouth. The site processed imported ore concentrates, and had a capacity to produce approximately 150,000 tonnes of zinc, as well as 65,000 tonnes of lead and small quantities of other metals such as cadmium. The ISP involves the use of a blast furnace to reduce zinc and lead oxides to the metal using coke as a reductant. Limestone could also be added to act as a slag-forming agent. The UK also had two other non-ferrous metal production facilities that would have emitted CO2 • the Capper Pass Tin Smelter at Melton, Humberside (closed in 1991) • IMI Refiners' secondary copper smelter at Walsall (closed in 1997) There is very little data specific to these installations available to the Inventory Agency as their closure pre-dates most of the routine annual emissions reporting regulations in the UK. Both processes used coke oven coke as a reductant that would have l ed to process emissions of CO2, and since we only have data on the total use of coke oven coke in non -ferrous metal production in UK energy statistics (DESNZ, 2024a), we report all emissions from use of this coke oven coke in 2C6. Therefore, the emissions reported in 2C6 will also include emissions from these two sites, as well as emissions related to the production of lead at the Britannia

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 288 Britannia Zinc reported CO2 emissions in the Pollution Inventory (Environment Agency, 2018) from 1998 until 2002, at which point the site ceased operation. Emissions of CO 2 occurred from the use of coke in the ISP, but also from decarbonisation of any limestone used, and from the other fuels used on site e.g. gas/oil burners used on the sinter plant and oil -fired furnaces used in the zinc refinery. No data are available on t he quantities of coke and other fuels used, or the quantities of limestone that migh t have been used. The operator -reported CO2 emissions in the Pollution Inventory are totals only, and do not provide any insight regarding the split of emissions source between coke, other fuels and limestone. The reported emissions are, however, much higher than would be implied by the Tier 1 factors given in the 2006 GLs for the ISP. There is insufficient data to determine whether this is due to a high level of fuel combustion emissions on site, or that the process -related emissions at this site were higher than is typical for this type of process. The Digest of UK Energy Statistics (DESNZ, 2024a), ‘DUKES’, does give a full time-series of data on the consumption of coke oven coke by the non -ferrous metal industry.
The consumption shown in this source is zero after 2003, confirming that after the clos ure of Britannia Zinc, no other non-ferrous metal processes in the UK used coke oven coke. Based on all available information, the Inventory Agency considers that no sites, other than Britannia Zinc, Capper Pass and IMI Refiners have used coke oven coke at any point in the period Because all three sites have been closed for many years, there is no information on the consumption of coke oven coke at each site. Of the three, it is likely that IMI Refiners used relatively small amounts of coke, whereas the Capper Pass smelter was the largest of its kind in the world, and its closure in 1991 coincides with a big reduction in the non -ferrous metal industry's consumption of coke as shown in DUKES. There is insufficient data to split the coke consumption data between the three sites, and i nstead all of the coke use in DUKES is reported in 2C6. This will ensure completeness and reduce the uncertainty in the reported factors for the coke oven coke ar e derived from the carbon balance approach previously As previously described, limestone may have been used at Britannia Zinc (and possibly in the blast furnaces at Capper Pass as well) but there is no information on which to base emission estimates. Since all of these plants closed more than 10 years ago, there is no scope to access new information to improve this situation, and therefore no emission estimates for these source categories are reported. Further, we note that the UK GHGI already includes emissions from all reported limestone and dolomite activit y based on data from the British Geological Survey on UK supply and demand of these materials, and hence there is no gap in the UK GHGI, but possibly a small mis -allocation with higher estimates in another sector to counter the possible under-report here. 4.21.3 Uncertainties and Time Series Consistency The use of DUKES data for coke consumption by non-ferrous metal processes ensures time series consistency and completeness, which is important since it is impossible to now determine how much coke oven coke was used in each of the 3 three non -ferrous metal processes that once existed in the UK. Any limestone used in the blast furnaces at Britannia Zinc and Capper Pass cannot be estimated, but emissions data for 2C1 cover all use of limestone and dolomite for blast furnaces and so overall completeness is assured. 4.21.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Annex 4. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 289 4.21.5 Source Specific Recalculations No major recalculations have been made to this sector. For further information on recalculations, see Section 10. 4.21.6 Source Specific Planned Improvements It is noted that this sector has been identified as a key category in this inventory submission, due to the site closures and resultant sector contribution to the UK inventory trend, and that a tier 1 method is used. The UK has recently reviewed this sector and included some additional sources using the best currently available data. Unfortunately, as the only sites in this sector have been closed for a number of years it is highly unlikely that new data will be found to 4.22.1 Source Category Description Emissions sources Sources included Method Emission Agricultural engines – lubricants Road vehicle engines – lubricants Emissions of CO 2, CH 4 and N 2O arise from lubricant combustion in engines and other machinery. Note that waste lubricants can be recovered and subsequently used as fuels but emissions from this source are included in CRT 1.A. Where the term lubricants is referred to, this correlates t o the DUKES definition of lubricating oils (and grease), i.e. “Refined heavy distillates obtained from the vacuum distillation of petroleum residues. Includes liquid and solid hydrocarbons sold by the lubricating oil trade, either alone or blended with fixed oils, metallic soaps and other organic and/or inorganic bodies.” Emissions reported in 2D1 cover all lubricants used by all sectors, with the sole exception of lubricants used in mopeds engines. This is deemed to be intentional fuel use and hence is reported in IPCC sector 1A3biv. Detailed activity data on lubricant use by source category are not available in the UK; there is insufficient data to implement an IPCC Tier 2 method, and therefore the 2006 IPCC GLs Tier 1 method is applied. DUKES (DESNZ, 2024a) includes some limited data breakdown on sector-specific lubricant use (e.g. use by industry, agricultural sector, shipping) in addition to the total lubricant demand time-series. Lubricant consumption in road vehicle engines is estimated using the COPERT method from the EMEP/EEA Emissions Inventory Guidebook (2019). Lubricant use in the remaining sectors uses activity data from DUKES, but the total lubricant use estimated by the inventory diverges from DUKES due to the use of the above method for road engines. While in general we would consider the totals from UK energy statistics to have a higher confidence than bottom-up estimates of demand, in this case we have taken a more conservative approach, reflecting that trends in activities that would demand lubricants do not correlate with the strong decreasing trend presented in DUKES. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 290 The consumption estimates are used to calculate CO2 emissions which are reported in IPCC sector 1A3biv for mopeds and 2D1 for all other sectors, whereas the COPERT method directly calculates the quantity of lubricant consumed or burnt in road vehicles, for other sectors we assume that 20% of lubricant is oxidized during use. In all cases we apply a UK-specific carbon emission factor for lubricants, based on analysis of UK waste oil samples. Emissions of CH 4 and N 2O also arise from lubricant combustion in road vehicle engines.
However, the exhaust emission factors for these gases will include the contribution of, and hence the emissions of, CH4 and N2O (and other air pollutants estimated on a vkm -travelled basis) from lubricants are included implicitly in the hot exhaust emissions (IPCC Sector 1A3b) calculated for each vehicle and fuel type. Treating emissions of these pollutants separately 4.22.3 Uncertainties and Time Series Consistency The use of a Tier 1 methodology means that estimates are quite uncertain. Additionally, the divergence in trend in total lubricant consumption presented by energy statistics, and bottom -up estimates of demand reflects uncertainty in activity data for this 4.22.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Annex 4. 4.22.5 Source Specific Recalculations No major recalculations have been made to this sector. For further information on recalculations, see Section 10. 4.22.6 Source Specific Planned Improvements We are continuing to engage the UK energy statistics team to understand the trends in UK energy statistics for total lubricant demand, and the inventory estimates will be revisited if any major improvements are made to energy statistics. 4.23.1 Source Category Description This category includes CO2 emissions from paraffin wax use. DUKES gives total consumption of petroleum waxes for the years 1990 -2008 only. For 2009 onwards, petroleum wax consumption is only available as part of the much larger consumption of 'miscellaneous petroleum products'. Activity data for UK consumption of p etroleum wax from 2009 onwards are available from the UK energy statistics team (Personal DESNZ, 2024b) on the same basis as the earlier data, as they comprise part of other long-term energy data reporting outputs, e.g. to EUROSTAT. Emissions are estimated using the Tier 1 ODU (Oxidation During Use) factor of 0.2, and the IPCC default carbon content of 20 kg C/ GJ (net basis). Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 291 4.23.3 Uncertainties and Time Series Consistency Estimates for this sector are uncertain because of the use of a Tier 1 methodology. The time series consistency of the activity data are good, as they are part of a long -running routine energy data compilation and reporting system, by the UK energy statist ics team in DESNZ, and also for the EFs as a Tier 1 default is used in all years. 4.23.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Annex 4. 4.23.5 Source Specific Recalculations No major recalculations have been made to this sector. For further information on recalculations, see Section 10. 4.23.6 Source Specific Planned Improvements Emission factors and activity data will be kept under review. 4.24.1 Source Category Description Emissions of CO2 are estimated from consumption of urea by road vehicles with relevant types of catalytic converters for control of pollutant emissions and are reported under 2D3a. Urea has the chemical formula (NH2)2CO and is injected into the exhaust stream of certain types of diesel vehicles (currently Euro IV, V and VI HGVs and buses) as a 32.5% (by weight) aqueous solution. The catalytic process of converting NOx to nitrogen in the exhaust leads to the release of CO2 from the urea in the tailpipe. Petroleum coke is known to be used by various sectors either as a fuel (e.g. at power stations and in cement kilns), or in various processes (e.g. in brickmaking, titanium dioxide manufacture, aluminium smelting, or electric arc steelmaking). The consumption of petroleum coke for each sector is either available directly from DUKES or estimated, based on ETS and other data. For most years, there is more petroleum coke listed in the UK energy statistics than can be accounted for by these known users. In other years, the known users require more petroleum coke than is available in the energy statistics. But since there is excess petroleum coke for most years (25 out of 34) between 1990 and 2023, it is assumed that there are additional, unknown uses of the fuel in those years. The excess petroleum coke in the energy statistics is reported as being for non-energy uses but this will include both fuel grade and anode grade coke, so it is possible that the coke could be used as a fuel, or in processes, or both. In the absence of any data, and because the coke appears in DUKES as ‘non-energy use’, it has been assumed that it is used for an unknown process. Such uses could be non - emissive with the carbon stored, but in the UK inventory it is assumed that all carbon in t his petroleum coke is emitted and reported in 2D3d. The 2006 IPCC Guidelines specify two approaches for estimating CO 2 emissions from urea consumption. This is either from statistics on total urea sales or by estimating urea consumption as a proportion of the amount of fuel consumed. There are no statistics on urea sales in the UK, so the approach based on fuel consumptio n is used. Not all diesel vehicles

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 292 use urea, so it is necessary to know the amount of fuel consumed specifically from those vehicles with the relevant exhaust after treatment technology that require urea injection. Urea is used by HGVs and buses in the UK manufactured to Euro IV, V and VI standards. These came into effect from 2006. The EMEP/EEA Emissions Inventory Guidebook (2023) provides the means for estimating urea consumption as a proportion of fuel consumed by these specific types of vehicles. Fuel consumption by Euro IV, V and VI HGVs and buses was estimated using a bottom-up method described in Chapter 3.
The estimations involve the use of vehicle km activity and fleet composition data from DfT and g/km fuel consumption factors, with total fuel consumption calculated for road transport by this method normalised to national Following figures given in the EMEP/EEA Guidebook for estimating other pollutant emissions, an assumption was made that 75% of Euro V HGVs and buses are equipped with SCR – the catalyst system that uses urea. The same assumption was also applied to Euro IV vehicles, and it is assumed that 100% of Euro VI vehicles are equipped with SCR. Fuel consumption was calculated for these types of vehicles using SCR technology. Following the EMEP/EEA Guidebook, urea consumption is assumed to be 4% of fuel consumption for a Euro IV HGV or bus, 6% for Euro V and 3.5% for Euro VI. Independent assessment in the UK from suppliers of urea and vehicle manufacturers supports these assumptions. These assumptions allowed the time-series for consumption of urea by UK road transpor t to be estimated. No urea was A constant emission factor of 0.238 kgCO 2/kg urea solution was used, from the EMEP/EEA Guidebook. This is consistent with the factor and emission equation given in the 2006 IPCC Guidelines, assuming urea is used as a 32.5% aqueous solution which is the norm in the UK. The emissive non-energy use of petroleum coke is assumed to result in 100% of the carbon in this fuel being emitted. The 2006 IPCC default factor for petroleum coke has been used in conjunction with calorific values for petroleum coke used in sectors other than electricity generation, taken from UK energy statistics. The relatively high calorific value given for this type of petroleum coke means that the IPCC default factor implies that this petroleum coke is over 90% carbon, which is higher than the carbon content of coke oven coke or anthracite. 4.24.3 Uncertainties and Time Series Consistency The main uncertainty on estimates of emissions from urea consumption comes from the uncertainty in the amount of urea consumed by the categories of vehicles equipped with SCR exhaust after treatment technologies in the UK fleet. This is linked with uncerta inties in the estimates of fuel consumed by these vehicles and uncertainty in the amount of urea consumed per kg of fuel consumed. Uncertainties in the CO2 emission factor from urea consumption are very low because the carbon content of urea is known with high accuracy. The end uses of the petroleum coke reported in 2D3d are unknown and could actually include some use of coke as a fuel and/or some non-energy uses that result in storage of carbon, as well as emissive non-energy uses. The approach taken is conservative sinc e we assume all of the carbon is emitted, but emissions may be wrongly allocated if some of the petroleum coke is actually used as a fuel. The uncertainty in emissions for this source is very high. Because of the use of this source as a balance against ene rgy statistics, the time series is very erratic. There are many years where zero emissions are reported due to the UK Inventory petroleum coke in the UK energy statistics. 4.24.4 Source Specific QA/QC and Verification This category is covered by the general QA/QC of the inventory in Annex 4. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 293 4.24.5 Source Specific Recalculations As the estimate of these other non -energy uses of petroleum coke are a residual, they are sensitive to revisions to estimates of petroleum coke in other sectors. There have been significant revisions to estimates of petroleum coke used in electric arc furnaces as discussed in Section 4.15.5, and in some years revisions in petroleum coke burning at refineries which mean that the petroleum coke allocated to 2D3d are generally higher than the previous submission, and some of these increases are very large relative changes compared to Revisions to urea use estimates are much more modest (<3% in all years), and linked to revisions to revisions to road transport estimates. For further information on recalculations, see Section 10. 4.24.6 Source Specific Planned Improvements Emission factors and activity data will be kept under review. Emissions of SF6 and PFCs from semiconductor manufacturing are combined with emissions from training shoes and electrical insulation in source category 2G2e for reasons of commercial confidentiality. Emissions of NF3 and HFCs from semiconductor manufacture are reported in sector 2E1. This source category (both for pollutants reported in 2E1 and 2G2e) is ICF (2014) determined that the UK does not have volume Flat Panel manufacturing. ICF reached this conclusion after contacting the National Microelectronics Institute (NMI) who represent flat panel display manufacturers in the UK. Further market analysis by Ricardo (2016) confirmed that there are no UK emissions from this sector. This included discussions with representatives of the flat panel supply sector and PFC supply sector – all those contacted confirmed that all flat panel di splays used in the UK are imported. It was noted that in the 2006 IPCC guidelines that there was activity data given83 for the UK in 2003 -5. When using this activity data and the default methodology the resulting emission was well below the threshold to be considered insignificant, so is reported by the UK as ‘NE’ for years before 2014. This source is included in the Assessment of completeness in 4.26.2 Source Specific Planned Improvements Any emergence of volume manufacturing capacity of TFT flat panel display is kept under

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 294 ICF (2014) determined that the UK does not have volume photovoltaics (PV) manufacturing. ICF reached this conclusion after contacting the British Photovoltaic Association (BPA) to gather data from PV manufacturing in the UK. The BPA also confirmed that sta tistics on F- gas use in the PV manufacturing in the UK are not available. Further market analysis by Ricardo (2016) confirmed that there are no UK emissions from this sector.