This included discussions with representatives of the PV supply sector and PFC supply sector – all those contacted confirmed that all PV cells used in the UK are currently imported or manufactured in the UK using emerging technology that does not require F -gases in the process. It was noted that in the 2006 IPCC guidelines that there was activity data given84 for the UK in 2003. When using this activity data and the default methodology the resulting emission was well below the threshold to be considered significant, so is reported by the UK as ‘NE’ for years before 2014. This source is included in the Assessment of completeness in 4.27.2 Source Specific Planned Improvements Any emergence of volume manufacturing capacity of photovoltaics is kept under review. 4.28.1 Source Category Description PFCs are used as heat transfer fluids (HTFs) in commercial and consumer electronic applications. The various applications of PFC as HTFs use much smaller volumes of liquid PFCs than electronics manufacturing. Some examples of consumer applications include cooling kits for desktop computers and commercial applications include cooling supercomputers, telecommunication, and radar systems, as well as drive units on high - Market analysis by Ricardo (201 6) confirmed that there are no UK emissions from this sector. Discussions were held with the only 2 companies that supply the relevant PFC to the EU market (C 6F14), including one company that manufactures this PFC in the UK. These discussions indicated that there is a small use of PFCs for HTF applications in some EU countries and in non-EU export markets. However, very small quantities (<2 kt CO2e) of PFCs are sold in the UK market for this application, but it is believed that these are sold exclusively for hermetically sealed applications and products that are sold on to be used outside the UK. This source is included in the Assessment of completeness in 4.28.3 Source Specific Planned Improvements Any emergence of volume manufacturing capacity of heat transfer applications using F-gases

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 295 4.29.1 Source Category Description HFCs and HFC blends have been widely used as replacement refrigerants for ozone depleting substances across virtually all refrigeration, air -conditioning and heat pump (RACHP) end - uses. They generally share many of the properties of CFC and HCFC refrigerants, namely low toxicity, zero and/or low flammability and acceptable materials compatibility. Emissions of HFCs can occur at various stages of the refrigeration/air-conditioning product life • During the RACHP equipment manufacturing process; • During on-site installation of equipment • Over the operational lifetime of the RACHP unit; and • At disposal of the RACHP unit. This emission category contains aggregated emission estimates from the end -uses Refrigerated appliances including refrigerators, chest freezers, upright freezers, and fridge freezers. Small, hermetic, stand-alone refrigeration units including retail display cabinets, ice cream cabinets and drinking water coolers. These systems are commonly used in retail food stores but are also found in pubs, restaurants, and other hospitality and catering outlets such as hotels, hospitals, and schools. Each system typically has a cooling capacity in the 0.2 kW to 2 kW range. Refrigeration systems composed of one (or two) compressor(s) and one condenser, assembled into a unit, which is located external to the sales area. The condensing unit is connected by refrigerant pipework to an evaporator located in the retail sales area (e.g. in a chilled retail display). These units are typically installed in small shops, beer cellars and small walk-in cold rooms and have refrigeration capacities ranging from 1 kW to 20 kW. Refrigeration systems that are comprised of racks of compressors installed in a machinery room. These systems are commonly used in supermarket applications, with many refrigerated displays connected to a central system. Each system typically has a cooling capacity in the 30 kW to 150 kW range. Refrigeration systems including industrial process refrigeration and cold storage. Industrial refrigeration systems vary widely in cooling capacity. Many industrial systems are above 1,000 kW. However, the majority that use HFC refrigerants are relatively small, in the 50 Includes small self-contained air-conditioning (including window units) and non-ducted single split air-conditioning. Units are used primarily in commercial applications, but there is some use in the residential sector. System cooling capacities typically range from 3 to 12 kW. The majority of modern systems are reversible – they can operate either as an air-conditioning unit or an air-to-air heat

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 296 Includes non-ducted multi-split, variable refrigerant flow (VRF) non- ducted split, ducted split, and packaged air-conditioning. Units are used in the commercial UK sector. System cooling capacities typically range from 12 to 200 kW. Large water chillers used for commercial comfort air conditioning. Cooling capacity is typically in the range 100 kW to 500 kW. Some are reversible and can operate as air-to-water or water-to-water Residential and small commercial heating only heat pumps providing heat in the form of hot water, including air-source heat pumps (ASHP) (air-to-water systems) and ground-source heat Refrigerated road vehicles (i.e., light commercial vehicles, trucks, trailers) and intermodal containers. Refrigerated general cargo ships, container ships and fishing Air-conditioning systems for passenger cars and light commercial vehicles (up to 3.5 tonnes). Both of these vehicle types are covered under Directive 2006/40/EC (the MAC Directive). Air-conditioning systems for buses/coaches and railcars. The UK estimates activity and emissions in his sector using a comprehensive modelling platform developed by Gluckman Consulting called HFC Outlook which uses a Tier 2a The model makes use of a bottom -up approach with assumptions made about emission factors and stock levels. The model is verified by comparing the predicted HFC consumption for the whole Refrigeration, Air Conditioning and Heat Pumps (RACHP) sector with top-down data for the sales of HFCs in the UK and with predicted emissions made by Bristol University and the UK Met Office based on atmospheric measurements of F -Gas concentrations.
The model takes full account of the impact of the assimilated Regulation (EU) No. 517/2014 (the F-gas Regulation) as assimilated law82, including bans of some higher GWP HFCs for some applications and a general phase down of HFC consumption. The model is reviewed on a For each of the 36 end -use sub-sectors, market data and other country -specific information were considered in the development of assumptions on equipment stocks, market growth, equipment lifetimes, refrigerant market penetrations, charge sizes, manufacturing loss rates, operational loss rates, and disposal loss rates across the 1990-2050 time-series. An extensive literature review was conducted, and key industry stakeholders were contacted. Priority industry stakeholders were selected across all end-uses and initially contacted to fill data gaps and corroborate information found in the literature. Following the development of preliminary assumptions for all end -uses, draft assumptions were then shared with a broader range of stakeholders to solicit additional industry input and vet assumptions. In developing modelling input assumptions by end-use, expert judgment was applied to select appropriate values when more than one estimate was provided by literature and/or stakeholders. In general, more weight was given to estimates that are UK - or region specific and/or more recent. In cases of equal data quality where numerous data points were available, values were selected based on the mid-point of the data range. Where no UK- or EU-specific

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 297 information was available, the 2006 Intergovernmental Panel on Climate Change (IPCC) Guidelines default assumptions were relied on to estimate emissions. The various input assumptions used by the model can be varied on an annual basis. This allows changes in response to market growth or regulatory constraint to be reflected in the bottom-up estimates of HFC emissions made by the model. For example, the 2006 EU F-Gas Regulation82 has led to significant reductions in the levels of leakage from some RACHP sub- sectors and improvements in the level of refrigerant recovery during servicing and at end -of- life. This is reflected in the model by changes to the annual operating emission fa ctors and A key input assumption is the split of different refrigerants used in new and existing equipment in each of the 36 sub -sectors. The accuracy of the input assumptions is checked by comparisons with top-down BRA data for the whole RAC market. The model then generates a detailed speciated split of total emissions. This is available split either by the type of refrigerant used (e.g. a blend such as R -404A) or by the individual HFC components within such blends (e.g. R-404A is a mixture of HFC-143a, HFC-125 and HFC-134a). Industrial Processes (CRT Sector 2) UK NID 2025 (Issue 1) Ricardo Page 298 CRT Sector UK Category Total Stock Refrigeration Domestic Refrigeration 47,489,000 15 0.03 to 1,910,000 15 0.2 to 1 HC-290, HC-600a 1% 1.0% 50% Condensing Units 524,000 15 1.5 to 15 X1500, X600, X150, Refrigeration 63,230 9 to 15 1 to 10 R-452A 2% 17.7% 45% 1,500 R-744, HFC-134a, R-717 2% 15.1% 45% Refrigeration Industrial Systems 42,100 18 to 30 30 to Conditioning 2,942,000 12 0.5 to 8 HFC-32 3% 3.5% 45% Conditioning 295,000 15 2010 to Conditioning (Chillers) 56,200 15 to 21 30 to Hydronic Heat Pumps 259,000 18 3 to 150 R-410A, R-134a, HFC- Conditioning 33,245,000 16 0.4 to Conditioning 138,200 15 4 to 25 HFC-134a, R-410A 2% 12.4% 65% 85 X150 = R454C or R-455A; X600 = R-450A or R-513A; X1500 = R-448A or R-449A

Industrial Processes (CRT Sector 2) UK NID 2025 (Issue 1) Ricardo Page 299

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 300 Speciated emissions are reported for the OTs and CDs under 2F1. Emission estimates from the UK GHGI were scaled by a territory-specific indicator. The indicators for each activity were chosen based on expert judgement and are as • GDP for refrigerated transport and commercial and industrial refrigeration • Number of households for domestic refrigeration and stationary air conditioning for the Falkland Islands and the Crown Dependencies • The proportion of households with air conditioners for stationary air conditioning in Bermuda and the Cayman Islands • Number of vehicles for mobile air conditioning 4.29.3 Uncertainties and Time-Series Consistency The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. 4.29.4 Source Specific QA/QC and Verification In the process of finalising the input assumptions, an analysis was conducted to compare estimated refrigerant consumption (calculated as the amount of refrigerant used to manufacture new equipment produced in the UK plus the amount used to service leaking equipment) with annual refrigerant sales data from the British Refrigeration Association (BRA). Further detail about this comparison is not presented due to the BRA data being confidential Experts from the University of Bristol and the UK Met Office carry out measurement of atmospheric concentration data for all HFCs. These data are combined with meteorological data through a process called “Inversion Technique for Emission Modelling” (InTEM) to create shows a previous comparison of data from InTEM with the ICF model86 estimates and the HFC Outlook model. Version 6.19 Both the ICF and HFC Outlook emissions estimates were higher than those created by InTEM in 2019 and were likely to be conservative over-estimates of HFC were much closer to the InTEM measurements than the ICF model. In 2023 an investigation of these discrepancies was made on behalf of DESNZ. The InTEM modelling methodology was improved in 2020 and the latest 2022 InTEM estimates are generally higher than the previous estimates. The change was related to improving the uncertainty applied to each measurement, a greater emphasis was placed on mat ching the pollution events rather than the baseline values which is much more relevant in the UK framework.
These changes were discussed in detail in the annual report to BEIS (now DESNZ) At the same time, the HFC Outlook model had been updated to version 8.5A (see Section 4.29.5 on Source Specific Recalculations for a description of the changes made). This created lower emission estimates than in version 6.19 and considerably better correlation to the new InTEM estimates.
During the investigation further updates were made to the HFC Outlook 8.5B, in tonnes CO2e. This shows that in the latest HFC Outlook model (which is used to create the GHG Inventory estimates) the emissions estimates are very close to those made through the InTEM atmospheric measurements.
86 The ICF HFC Model was used in the NAEI prior to the development of the HFC Outlook model. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 301 CO2e based on HFC Outlook version 6.19 and InTEM 2019 CO2e, based on HFC Outlook version 8.5B and InTEM 2022

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 302 In the UNFCCC review of the 2019 submission, it was highlighted that the UK trends in emissions presented a steep decline in emissions in recent years, which is a much stronger trend than for other EU Member States subject to the same F-gas regulations. While the model has been updated since this date, and the decline is modelled to be a few years later and less steep, the overall trend remains. This is in part due to the use of conservative emission factors, which means that the UK’s bank model will deplete historically used refrigerants (with typically higher GWPs) more quickly, and therefore the impact of legislation to improve the choice of refrigerants might be reflected earlier in the model than in practice. This is potentially verified by the atmosphe ric measurements and verification of UK emissions estimates provided in Annex 6; which, for recent years, shows a similar declining trend in emissions of some key HFCs used as refrigerants. There are also some UK -specific factors that mean we might expect emissions to be falling faster than other countries in 1. The UK supermarket sector is believed to have had historically high emissions (mainly of HFC-blend R-404A, which has a very high GWP). Since 2014, UK supermarkets have taken significant steps to rectify this situation through improved maintenance of existing systems. These improvements are taken into account in the emissions model. 2. Despite the date of the new equipment ban on refrigerants with a GWP>2500 being in 2020, the UK industry took early action and stopped using R -404A in new equipment several years earlier. For large systems (e.g. in supermarkets and industrial systems) there was little R-404A used in new equipment from around 2016. A key driver was the recognition of the “service ban” which also started in January 2020 and bans the use of virgin refrigerants with a GWP>2500 for the servicing of existing systems. 3. An important difference between the UK and most of the rest of the EU is the widespread retrofitting of R-404A systems, especially in supermarkets. R-404A (with a high GWP) can be retrofitted with several “near drop -in” alternatives. These include HFC blends R-407A and R-407F (with GWPs roughly half that of R -404A) that were used in the period 2012 to 2016 and the more recent HFC / HFO blends R -448A and R-449A (With GWPs roughly a third of R -404A). By carrying out a retrofit, any subsequent leakage emissions will have a much lower global warming impact, because of the considerably reduced GWP. One UK supermarket chain had completely retrofitted their R-404A equipment by 2014 and others did retrofit trials at that time. The old UK model assumes significant further retrofits in the period 2015 to 2019, to ensure that all large R -404A users would be compliant with the 2020 service ban. It is interesting to note that supermarkets in most other EU countries did not adopt retrofits until around 2018. The new UK mod el recognises that many previously planned UK retrofits were delayed for economic reasons – with few being carried out in 2015 and 2016. Most of the large UK supermarket chains started major retrofit programmes in 2017 (driven by the massive price rise that occurred before the 2018 phase-down step, which drove up the price of R -404A by around 1000%). They have combined the retrofits with a careful R -404A recovery and reclaim programme, which allows the retrofits to take place more slowly than originally mod elled, during the period 2017 to 2023. The reclaimed R-404A can continue to be used for maintenance of the remaining R-404A equipment. This slower rate of retrofits does mean that 2015 to 2017 drop in emissions may be lower than predicted by the old model. 4.29.5 Source Specific Recalculations The HFC Outlook model has been through two updates, to create versions 8.5A and 8.5B of The HFC Outlook model was updated in 2022 to support Defra’s work on the upcoming revision of the GB F-Gas Regulation. This major update included the estimation of RACHP energy use and the related indirect CO2 emissions. Steps were taken to begin to address the discrepancy with InTEM data. Key changes (1) increasing the rate of heat pump uptake to align

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 303 better with UK Government forecasts and (2) a change to the leakage deterioration factor for most RACHP equipment. This factor increases leakage from older RACHP equipment after that equipment reaches two thirds of life expectancy. The values used for this factor in Version 6.19 were conservatively high, due to lack of good data. The InTEM estimates provides further justification to use less conservative assumptions. HFC Outlook Version 8.5A has lower estimates of HFC emissions than Version 6.19. During the 2023 investigation of discrepancies between HFC Outlook and InTEM emission estimates (see section x.29.4) the HFC Outlook model was further updated to version 8.5B. Key changes include the in-life leakage and end-of-life emission assumptions for the use of R- 404A in retail and industrial refrigeration have been modified to slightly increase emissions in years before 2014 and to reduce them more quickly after that date. There is a lack of good data on leakage rates and conservative values were pre viously used. The InTEM estimates help justify the use of alternative assumptions. These changes simultaneously improved agreement with InTEM for both HFC-143a and HFC-125 which supports the new assumptions. For information on the magnitude of recalculations, see Section 10. 4.29.6 Source Specific Planned Improvements Emission factors and activity data will be kept under review.
4.30.1 Source Category Description Emissions of HFCs from foams can occur as • During the manufacturing process; • Over the lifetime of the foam; most rigid foams are closed cell foams and the blowing agent is designed to remain in the foam and contributes to its performance. Loss of HFCs is undesirable as it may affect the performance of the foam but is estimated to occur, albeit at a low rate through diffusion; • At disposal of the foam; and • In the waste stream, if the blowing agent is not destroyed following decommissioning Emissions at each point vary significantly according to the type of foam and the type of application. For the bulk of product types, of the HFC used in the product, less than 10% is emitted during manufacture (although emissions may be as high as 40 to 45% for some types of foam), less than 1% per year over the useful lifetime of the product and the remainder on decommissioning and through the waste cycle87. The methodology used to estimate emissions corresponds to the IPCC Tier 2b 'bottom -up' approach. The emission factors from the sector have been summarised below. Emissions are considered separately from the following categories of PU Appliances (F1); PU, PIR Flexibly faced laminate (or boardstock) (F2); PU Discontinuous Panel (F3); PU Continuous Panel (F4); PU, PIR, Phenolic block (F5); 87 Any building insulation that goes into landfill degrades slowly and gives off the remaining gas over many years. This is not well documented and there is little data available on rate of degradation / emission, which is believed to vary depending on the conditions in the landfill. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 304 Phenolic flexibly faced laminate (F6); PU Spray/injected/pipe -in-pipe (F7); Extruded polystyrene (XPS) (F8); Polyethylene Foam (F9); Integral Skin Foam (F10). A full description of the emissions and associated methodology used for this sector is set out in Ricardo (2016), which built upon previous work (AEA, 2010). The emissions for the years 1990 to 2002 were based originally on data from March (1999). However, these and emissions data for more recent years (2003 onward) have been obtained from UK industry experts supported by market information from reputable market sources. The methodology is based on a bottom -up assessment of activity data which requires info rmation on five elements to • Overall dynamics of the thermal insulation market in the UK (including imports and • The market share changes on-going in the sector which determine the demand for • The segregation of the insulation foam sector by manufacturing process and product • The adoption of HFCs as one of the blowing agent options in any chosen process/product combination leading to market penetration assessments against other blowing agent types; and • The formulation levels at which HFCs have been and will be used in the identified The application of the relevant emission factors to this activity data delivers information not only on annual emissions, but also on how banks of blowing agents can develop in products and latterly in waste streams. These banks too will emit steadily, and because of the long - lifetime of many foam applications, the emissions can take place over long periods of time, leading to a number of potential legacy issues. That said, the derived average annual emission rates are relatively low because the products rely for their performance on the retention of the Emission factors are determined based on a combination of country-specific data on the HFCs contained in the foam and the time dependent rate of loss of HFCs. The model has been refined to allow the lifecycle of products to be adjusted in 5 yearly interval s. The outputs also give transparency on the source of emissions both by product type and lifecycle stage. The model provides insight to the manufacturing and trade aspects of each product type in order to determine the amount of product placed on the market in the UK each year. This adds to the existing bank of blowing agent contained in installed products. In parallel, the blowing agent lost from product through annual emission and the decommissioning of product at end- of-life are subtracted from the bank. The waste stream (not to be confused with decommissioning) is considered as a source of emission in its own right on the basis that a bank of blowing agent is established following decommissioning; while this source is mentioned in the 2006 IPCC guidelines , a method for estimating this source is not given. Although this reduces annual emissions when compared with the previous default assumption of full emission on decommissioning, the impact is mitigated by the long lifecycles of most products being conside red. In practice, there is only limited product decommissioning taking place involving HFC -based foams in the period until 2035. Emissions from this source are estimated using a similar approach to product lifetime emissions, i.e. estimated HFCs remaining in the product after decommissioning is added to a bank of gas expected to be in landfill, and a fraction of this is emitted annually. The main difference between this stage and the product lifetime stage is that gas can only escape the bank via emissions, so eventually all of the bank is assumed to be emitted. The species used for foam blowing are given below. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 305 Application HFC-245fa HFC-365mfc HFC-227ea HFC-134a HFC-152a Phenolic (PF) Boardstock Xb Xb Xb a No emissions are occurring for this source in 1990 or in 1995. The bank also includes HFC species not previously reported in the UK GHG inventory (i.e. HFC -365mfc and HFC -245fa), since no GWP was available in the IPCC Second Assessment Report (SAR), but they are included in the 4th Assessment Report (AR4).
b These are potentially used, but not known to be used In the 2015 improvement programme extensive stakeholder consultation was done to determine where parameters of the model should be revised to be most representative of UK parameters and the reason for the deviation. A summary of the factors used in the foams model 4% 0.5% Wider range of products

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 306 15 20% 1% Recognises better foam 25% 0.75% Annual cell losses greater a Decommissioning and waste factors are not compared here as they are not comparable to the maximum potential end of life emission factors given in the 2006 IPCC guidelines. Dom. Refr-Freezers 15 0.00% 0.25% 2.50% 0.00%

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 307 Other Appliances 15 6.00% 0.25% 5.00% 0.00% PU Reefers-Marine 15 6.00% 0.50% 10.00% 1.00% PU Boardstock 50 6.00% 1.00% 7.50% 2.00% PU Continuous Panel 30 5.00% 0.50% 5.00% 0.75% PU Disc. Panel 30 6.00% 0.50% 5.00% 0.75% PU Spray 50 15-25%a 1.50% 10.00% 2.00% PU Pipe-in-Pipe 30 6.00% 0.25% 2.00% 0.50% PU Block-Pipe 15 45.00% 0.75% 2.50% 1.50% PU Block-Slab 30 15.00% 0.75% 2.50% 1.50% XPS - Board 50 12-25%a 2.50% 7.50% 4.00% PF - Boardstock 50 6.00% 1.00% 7.50% 2.00% PF - Panels 30 10.00% 0.50% 5.00% 0.75% PF - Pipe 15 7.5-45%a 0.75% 2.50% 1.50% PF - Block Slab 30 15.00% 0.75% 2.50% 1.50% a The factor varies depending on the year to reflect the impact of regulation and UK industry practice Speciated emissions for the OTs and CDs are reported under 2F2. Emission estimates from the UK GHGI were scaled using the GDP of each territory. 4.30.3 Uncertainties and Time-Series Consistency There are a number of parameters that feed into the modelled estimate of emissions and hence the uncertainty. Between data on foam manufacturing capacity/utilisation, the blowing agent consumption and the overall tracking of thermal insulation demand through publications such as IAL studies we can have a fairly high level of confidence in the estimate. This is despite some high uncertainties in some of the individual assumptions in the model; manufacturers were cautious in providing comment on the HFC marke t penetration which is the assumption that has greatest cause for uncertainty. Regulatory pressures to label products containing HFCs may help in future to hone the estimates and reduce uncertainties in activity data. The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. 4.30.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Annex 4. Details of verification of emissions are given in Annex 6. 4.30.5 Source Specific Recalculations There have not been any major recalculations to this sector this year. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 308 For information on the magnitude of recalculations, see Section 10. 4.30.6 Source Specific Planned improvements Emission factors and activity data will be kept under review. 4.31.1 Source Category Description One Component Foams (OCF) are used by building tradesmen (and in the DIY home improvement sector, to a lesser extent) to mount doors and windows and to insulate different types of open joints and gaps. When used as an OCF propellant, HFC 134a or 152a is blended with various flammable gases. HFC escapes from the foam on application, leaving small residues, which remain in the hardened foam for up to a year. These products are not manufactured in the UK, although they are imported. The use of HFCs of GWP 150 or greater in OCF has been banned under the EC Regulation on fluorinated greenhouse gases (EC 842/2006) from July 4 th 2008, except for where their use is safety critical. This ban was maintained in the 2014 F-gas regulations (EC 517/2014). The method of calculation is an IPCC Tier 2 method. UK estimates of emissions from this source were based on a European evaluation of emissions from this sector (Harnisch and Schwarz, 2003), subsequently disaggregated by GDP to provide a top-down UK estimate. It has been very difficult to establish the exact size of the UK import market and, therefore, hard to generate an accurate estimate of emissions from the use of this product. Harnisch and Schwarz (2003) estimated EU emissions from OCFs as • 1996: 4,000 kt CO2 equivalent per annum (3,100 tonnes of HFC-134a); and • 2000: 1,700 kt CO2 equivalent per annum (1,200 tonnes of HFC-134a; 1,000 tonnes of Emissions in tonnes of CO2 equivalent have reduced between 1996 and 2000 due to the use of HFCs with lower GWP values, and the manufacture of cans containing less HFC. In 2000, 23 million OCF cans that contained HFCs were sold in Germany while 7 million were sold to the rest of the EU market. Research indicated that Germany accounted for 77% of the total EU emission, and that out of the remaining 23%, the UK accounts for 24%, based on a percentage of total EU GDP (excluding Germany). This is equivalent to 1.68 million cans (AEA, 2008). The estimates of HFCs assume that the ban on F -gas use in one component foams (banned from July 2008 under the F-Gas regulations) has been successful, and this success has been confirmed with the UK Defra F-Gas Regulation team. Therefore, no HFC emissions occur from 4.31.3 Uncertainties and Time-Series Consistency Estimates of the uncertainties associated with time -series data for this sector were made in AEA (2004), based on an understanding of the uncertainties within the sector and from discussion with industry. Uncertainty data from this study have been used in the uncertainty analysis presented in Annex 2. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 309 4.31.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Annex 4. Details of verification of emissions are given in Annex 6.
4.31.5 Source Specific Recalculations There have been no recalculations to the mass based estimates from this source. 4.31.6 Source Specific Planned improvements Emission factors and activity data will be kept under review. 4.32.1 Source Category Description In the UK, manufacturers of fixed suppression systems for firefighting have been using HFCs as an alternative to Halons for many years. HFC-based systems are used for the protection of various high value products such as art works and electronic / telecommunications equipment, and in military applications, records offices, bank vaults and oil production facilities. The main HFC used in UK fixed systems is HFC-227ea. This is used as an alternative to Halon The UK makes no use of HFCs as an alternative to Halon 1211 in hand-held fire extinguishers. There is no suitable HFC used in the UK and the fire industry has switched to a range of not - in-kind technologies including water, water mist, foam spray, CO 2 and powder extinguishers. The Fire Safety Advice Centre 88 confirm “It is not the policy of the fire industry to select fluorinated gases for use in this sector except in special circumstances and none are generally available in the market at present.” The IPCC 2006 GLs state that, because F-gases in fire extinguishers are emitted over a period longer than one year, countries must represent emissions from equipment charged during previous years. As such, the emission estimation equation (Equation 7.17) considers the time dependence of the emissions. Effectively, this requires disaggregating the annual bank estimates into ‘new’ versus ‘existing’ systems and then applying emission factors accordingly (i.e., applying a lifetime loss rate to banks from both new and existing systems, a servicing loss rate to the bank of existing systems, and a disposal loss rate to the bank of existing systems reaching disposal in any given year, based on an assumed average lifetime). Further, additional research was required to ensure that a manufacture loss rate should not be applied by confirming whether there is any production of F-gas fire protection agents in the UK. ICF reviewed available literature to confirm/update key assumptions —notably, EEA (2014, 2016)—and then refined and finalized the estimates based on consultation with ASSURE (European Association for Responsible Use of HFCs in Fire Fighting) and the UK Fire Industry Annual stock estimates for 1997 -2002 were based on data reported by the Fire Industry Confederation and input from industry experts (AEA 2005) and 1995 -6 based on estimates 88

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 310 presented by March (1999). HFCs and PFCs are not believed to be used in the UK for this The equipment stock in years beyond 2007 is estimated based on EEA (2019) estimates for net supply of F-gases in the fire protection sector from 2007 -2012 (metric tonnes) in the EU, 85% of which is HFC -227ea, and scaled to the UK using a time -dependent GDP ratio. This annual net supply was assumed to equal annual UK consumption of fire protection agent in new and existing systems. The methodology and resulting stock estimates were reviewed and approved by ASSURE (2013) and FIA (2013). ASSURE confirmed that the estimates looked reasonable; FIA noted that the estimates looked reasonable for recent years, but that the 2000 estimates are slightly high. Additional information to refine these historical estimates was not available but this is a conservative bias as it will slightly overestimate emissions. The gap for 2003-2006 are filled by using a combination of growth assumptions, assumptions around the phase out of ODS and interpolation. According to FIA (2013) and ASSURE (2013), HFC -227ea accounts for virtually 100% of F - gas consumption in this sector in the UK; consumption of other HFCs (e.g., HFC-23, HFC-125, and HFC-236fa) in the UK are statistically insignificant. Therefore, is it ass umed that HFC - 227ea accounts for 100% of HFC consumption in this sector (over the full product lifetime). The UK has also reported emissions of PFC C 4F10 from 1995 to 2007. The use of PFCs for new fire protection systems was banned under the EU F-Gas Regulation82 from 2007. According to FIA (2013) and ASSURE (2013), the average equipment lifetime of fire protection The emission factors used in the current inventory were reviewed by FIA (2013) and ASSURE (2013); they confirmed that no updates were required. A summary of the emission factors is protection systems create a strong incentive for recovery and recycling, minimising leaks during servicing and decommissioning. Further, ASSURE confirmed that there is no F -gas production in the UK in this sector, which is also supported by De fra (2008). Thus, no manufacturing loss factors are applied. Lifetime emission factors were applied to the entire bank, while servicing emission factors — which decrease over time as more efficient servicing techniques are assumed to be implemented—were applied to the bank of existing systems (not to new or decommissi oned systems). The disposal loss rate is applied to the bank of existing systems assumed to reach disposal; because the equipment lifetime is assumed to be 20 years, the disposal emissions are only reported from 2015—i.e., 20 years following the initial installation of F-gases in 1995. Parameter 1990-2000 2001-2004 2005 onwards % released through fire (lifetime) 1.5 % released through servicing 3.4 1.5-2.989 1.0 % released during recovery (disposal) 89 Interpolated between 2000 and 2005

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 311 Speciated emissions for the OTs and CDs are reported under 2F3. Emission estimates from the UK GHGI were scaled by the relative GDP of each territory. 4.32.3 Uncertainties and Time Series Consistency The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. 4.32.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Annex 4. Details of verification of emissions are given in Annex 6.
4.32.5 Source Specific Recalculations Updates to the EEA GDP proxy dataset caused reductions in HFC emissions. For information on the magnitude of recalculations, see Section 10. 4.32.6 Source Specific Planned Improvements Emission factors and activity data will be kept under review. 4.33.1 Source Category Description Most aerosols use hydrocarbon propellants, with a relatively small proportion of the market favouring other volatile liquids including dimethyl ether (DME) and HFCs. Compressed gases are used in very few aerosols since they suffer from a number of disadvan tages compared with liquefied gas propellants such as HFCs, DME and hydrocarbons. HFCs are used only in a few applications where the use of a more expensive propellant is required to provide a non- flammable material. The most important industrial applications in volume terms are air dusters and pipe freezing products; other applications include specialised lubricants and surface treatments, and specialised insecticides. The use of HFCs for novelty applications, such as ‘silly string’ was banned from July 20 09, under the EC Regulation on fluorinated greenhouse Metered dose inhalers (MDIs) are used to deliver certain pharmaceutical products as an aerosol. For patients with respiratory illnesses, such as asthma and chronic obstructive pulmonary disease (COPD), medication needs to be delivered directly to the lungs. MDIs are one of the preferred means of delivering inhaled medication to patients with these illnesses. MDIs originally used CFC propellants but, as with industrial aerosols, concern over ozone destruction led to replacement of CFCs with HFCs. Note that HFC use in MDIs are exempted from the assimilated Regulation (EU) No. 517/2014 (the F -gas Regulation) as assimilated law82 phase down of HFC consumption, although this exemption will be reviewed in impending the review of this Regulation. The methodology used to estimate emissions corresponds to an IPCC Tier 2a method. Aerosol HFC emission estimates have been derived on the basis of fluid consumption data provided by the British Aerosol Manufacturers’ Association (BAMA) up to 2012. BAMA dis continued collecting data for 2013 onwards, so for these years we have projected estimates of HFC

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 312 consumption using knowledge of the regulatory landscape and industry insight of the market from a contact at BAMA. A 2006 IPCC default approach is used, of assuming that 50% of emissions occur in the year that aerosols are placed on the market, and 50% the following 4.33.2.2 Metered Dose Inhalers (MDIs) The methodology used to estimate emissions corresponds to an IPCC Tier 2a method. The current approach is essentially a “UK consumption model”. The number of MDIs prescribed each year in the UK is derived from the UK National Health Service (NHS) prescript ion data, and a 2006 IPCC default approach applied, i.e. of assuming that 50% of emissions occur in the year of prescription and 50% the following year. HFC emissions have been calculated with estimates of the species and volumes of HFCs used as MDI propel lants. Detailed data from the UK NHS are used for estimates between 1998 and 2018. Estimates for 1990 -1997 are based on extrapolated data from 1998. The NHS data gives good estimates of the number of MDIs of each drug type that have been prescribed. However, the data gives no information about the amount of HFC propellant per number of MDIs used in the UK each year. The majority of MDIs use HFC -134a. A small of MDIs consumed each year in the UK and the estimated charge size. Since 2021 the NHS has encouraged GPs to take account of the high GHG emissions from MDIs and have incentivised (a) the use of non-MDI alternatives (dry powder inhalers) and (b) impact of these efforts. In 2023 the number of MDIs prescribed has fallen by 11% from a peak in 2020 and the average charge size has fallen by 11%. Year MDI Number (thousands) Average Propellant (g per MDI)

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 313 Year MDI Number (thousands) Average Propellant (g per MDI) Speciated emissions for the OTs and CDs are reported under 2F4. Emission estimates from the UK GHGI were scaled by the population of each territory. 4.33.3 Uncertainties and Time Series Consistency Uncertainty data from this study have been used in the uncertainty analysis presented in 4.33.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Annex 4. Details of verification of emissions are given in Annex 6. 4.33.5 Source Specific Recalculations There have not been any major recalculations to this sector this year. For information on the magnitude of recalculations, see Section 10. 4.33.6 Source Specific Planned Improvements The MDI sector is currently under review. The NHS has identified that MDI -related HFC emissions are a significant part of its carbon footprint and are putting policies in place to reduce these emissions. This sector will be closely monitored to measure the impact of NHS policies. Several pharmaceutical companies are developing low GWP alternatives to the current HFC- 134a and HFC-227ea propellants. The first of these are expected to enter the market by 2025 and a significant transition away from current MDIs is expected by around 2030. Activity data and emission factors will be kept under review. 4.34.1 Source Category Description HFCs can be used as solvents in a range of applications such as precision cleaning to replace CFCs, HCFCs or 1,1,1-trichloroethane. HFCs have been developed that are used for precision cleaning in sectors such as aerospace and electronics. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 314 Emissions from solvent applications are considered to be prompt emissions because 100% of the chemical is typically emitted within two years of initial use (IPCC 2006). To calculate HFC emissions from the solvent sector using a Tier 1a method, the 2006 IPCC Guidelines specify that activity data should be the quantity of solvent sold in a given year.
Therefore, obtaining annual sales of so lvents in the UK is required. Using sales data, emissions of HFCs from solvent use in year t are calculated using the following equation, Emissionst = St x EF + St-1 x (1-EF) - Dt-1 Emissionst = emissions in year t, tonnes St = quantity of solvents sold in year t, tonnes St–1 = quantity of solvents sold in year t-1, tonnes EF = emission factor (= fraction of chemical emitted from solvents in the year of Dt–1 = quantity of solvents destroyed in year t-1, tonnes ICF reviewed available literature to confirm/update key assumptions - notably, Harnish & Schwarz (2003), and EEA (2013). Annual sales data of HFCs in the UK solvent sector have not been identified. Therefore, consumption of HFCs in this sector was estimated using the same estimates as in the previous inventory for 2001 and 2002 (i.e., based on Harnish & Schwarz 2003) in addition to historical F-gas supply data in the EU. Because the consumption estimates in Harnish & Schwarz (2003) i n years beyond 2002 were projections, EEA (2019) data on HFC-43-10mee supply data in the EU was used to estimate HFC consumption from 2007 To estimate the amount of HFCs placed on the market in the UK, the EU estimates from EEA (2019) were scaled down using a time-dependent UK to EU GDP ratio from Eurostat (2019). Using GDP as a scaling factor to estimate the UK F-gas supply in the solvent sector was deemed appropriate, given the wide variety of industrial and commercial industries Given the lack of data available on the extent of use of HFC-134a in the UK solvent sector, it is assumed that HFC -43-10mee accounts for 100% of UK F -gas consumption in this According to the 2006 IPCC GLs, the lifetime of all solvents is assumed to be two years. Therefore, any amount not emitted during the first year is assumed to be emitted in the second, final year (IPCC 2006). A lifetime emission factor is applied to the total amount of solvents placed on the market. Because the 2006 IPCC GLs provide that HFCs are emitted over a two -year period, an

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 315 annual emission factor of 50% 90 was applied in this analysis using the IPCC (2006) equation above. Recovery and recycling are not considered in emission estimates, per the 4.34.3 Uncertainties and Time Series Consistency The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. 4.34.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Annex 4. Details of verification of emissions are given in Annex 6. 4.34.5 Source Specific Recalculations A previous issue in how proxies were calculated has been corrected, resulting in a reduction in HFC emissions from 2000 to 2022. For information on the magnitude of recalculations, see Section 10. 4.34.6 Source Specific Planned Improvements Activity data and emission factors will be kept under review. 4.35.1 Source Category Description Emissions sources Sources included Method Emission Key Categories 2F: Product Uses as Substitutes for ODS - HFCs (L2, T2) All relevant emissions from OTs and CDs are included within the UK totals for this sector. Emissions are calculated by scaling emissions from the UK model using GDP as a scaling factor. Completeness No known omissions. A general assessment of completeness for the inventory is 90 Note the ICF report (ICF, 2013) states 45%, but the spreadsheet indicates 50% was used. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 316 Under the 2006 GLs, a new term in the IPCC Tier 2a method emissions equation for the Refrigeration and Air Conditioning sector includes emissions from the management of refrigerant containers used to service existing refrigeration/air-conditioning equipment, including refrigerant cylinders used by professional service technicians and small cans used by Do-It-Yourselfers (DIYers). No Tier 1 methodology is provided for this source. Emissions from refrigerant containers occur when refrigerant is transferred from bulk containers (e.g. 20 -tonne isotanks) to smaller capacity containers, typically ranging from approximately 300-500 grams (small cans) to 60 - 70 kg (cylinders). Emissions also occur at time of cylinder reprocessing (for reusable cylinders) or cylinder disposal (for non -returnable cylinders) if the refrigerant “heel” is not fully recovered. IPCC 2006 GLs require that emissions from each type of refrigerant container be calcul ated separately for refrigerant sold in small cans and in cylinders, including both disposables and reusables. The IPCC 2006 GLs default disposal emissions factors are 20% for small cans and 2% for disposable cylinders. Although the GLs do not specify a default emission rate for losses during the transfer of refrigerant into smaller containers, they do specify a default loss rate of 0.5% during the charging of refrigeration/air-conditioning equipment. ICF (2014) provides a review of available literature to develop key assumptions on stock and emission factors—notably, Enviros Consulting Limited (2008), Defra (2008), and BRA (2010). ICF also contacted the five largest refrigerant Fillers & Packers in the UK that reported sales data to BRA in order to confirm/refine the estimates. Further work was carried out and is reported in Ricardo (2016) to refine a refrigerant containers model that is now used for the UK 4.35.2.1 Package Sizes and Types Refrigerants are used by four different types of end users who each use different sizes of a) Original equipment manufacturers that manufacture pre -charged RACHP equipment. They purchase the majority of refrigerant in large volumes e.g. 20 tonne iso-containers b) RACHP system installers that charge new systems after construction at an end user site. For larger sized systems (e.g. supermarket refrigeration systems or air - conditioning water chillers) the majority of refrigerant is supplied in large cylinders (e.g. 60 kg). For small systems (e.g. split air -conditioning) small cylinders (e.g. 15 kg) may c) RACHP maintenance companies that carry out regular maintenance of equipment.
The majority of refrigerant used for maintenance is supplied in small cylinders. d) DIY activities for mobile air-conditioning – refrigerant is supplied in small cans (e.g. 0.3 to 0.5 kg) for use in the DIY market. All large package sizes (e.g. 20 tonne iso-containers, 1 tonne drums, and 60 kg cylinders) have been sold as re-usable containers since before 1990. A small proportion of smaller cylinders (e.g. 15 kg) were sold as non -returnable containers from 1990 to 2008. From 2008 the supply of non -returnable cylinders was banned under the The majority of small cans for mobile air-conditioning were sold as non-returnable containers from 1990 to 2008. From 2008 the supply of non-returnable small cans was banned under the

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 317 4.35.2.2 Sources of emission from refrigerant containers The refrigerant containers emissions model takes into account 4 sources of HFC a) During package filling at a specialist company that transfers refrigerant from bulk storage into the package sizes described above. b) During the re -processing of re -usable packages, at the specialist packer -filler c) From non-returnable cylinders in the waste stream (only until 2008 when they were d) From the use of cylinders in the field by installers and maintenance companies. All emissions are assumed to occur when cylinders are connected or disconnected to other equipment. There are small losses each time a cylinder is filled, used in the field or reprocessed. The emissions are on a “per event” basis. For example, each time a cylinder is filled there is a small emission – the filling emission is the same for filling a large 60 kg cylinder as for filling a small 15 kg cylinder. There are no emissions from cylinders in storage. 4.35.2.3 Number of cylinders filled, used and reprocessed Annual estimates of cylinder use were developed using data on the sales of refrigerant into the UK market consistent with the UK RACHP model. The split of cylinder sizes for each application type was estimated through discussions with packer -fillers as summarised in the 1 these were banned in 2008, so after this date it is assumed that small cylinders are used instead Emission factors for each type of emission have been assessed in discussion with industry Emissions during cylinder filling are very low. Packer-fillers use sophisticated automatic filling equipment and have taken steps to minimise losses of refrigerant when a cylinder is connected or disconnected to filling equipment, including use of “gas drawback” systems to suck gas out of connecting pipework before they disconnect a cylinder after it has been filled. Packer-fillers estimate that the loss per charging operation is under 1 gram of gas in the most sophisticated facilities. Prior to 2006 it is likely that the e mission rates were higher. An emissions factor of 10 grams per charging operation has been used in the period 1990 to 2000, tapering to 2 grams after 2008 (a conservatively high estimate). Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 318 4.35.2.4.2 Returned cylinder re-processing All used cylinders have a heel of gas left in them. This is usually a small amount (e.g. well under 5% of full cylinder quantity) although in a few cases partially filled cylinders are returned with over 50% of the original quantity. Packer -fillers treat returned cylinders with great care, partly for environmental reasons and also because of the potential value of the returned gas. Packer-fillers use one of two methods to re-process returned a) They “de -heel” each cylinder by transferring any remaining refrigerant into a large storage drum. When this drum is full it is tested for quality and then added to the main refrigerant bulk tank for use in filling new cylinders b) They “top -fill” a cylinder with the appropriate refrigerant, filling to the required total Packer-fillers indicate negligible losses from these processes (e.g. for top fill there is no emission other than that for cylinder filling). Conservatively the model uses 10 grams per de - heeling operation in the period 1990 to 2000, tapering to 2 grams after 2008. 4.35.2.4.3 Non-returnable cylinders Any heel left in a non-returnable cylinder will be emitted e.g. from a landfill site or a waste metal reprocessing site. There is no data on the average heel size for non -returnable cylinders or small cans. Only a small proportion of UK refrigerant was sol d in non-returnable packages in the period 1990 to 2008 and none after that date (due to the ban in the 2006 EU F -Gas Regulation82). The model assumes a 2% heel in small cylinders (approx. 0.25 kg) and a 10% heel in small cans (approx. 30 grams). 4.35.2.4.4 Cylinder use in the field There are losses each time a cylinder is connected / disconnected to RACHP equipment during field installation or maintenance. The loss will depend on the care taken by the technician carrying out the filling operation. Refrigerant is lost from the connection hoses when a cylinder is disconnected. Technicians are trained how to use cylinders correctly (it is part of the mandatory F-Gas handling training specified in the 2006 EU F-Gas Regulation and part of the training specified by the EU Ozone Regulation). With best practice the losses are estimated to be in the range of 0.5 to 3 grams of refrigerant per filling event, assuming only refrigerant vapour is emitted. However, with poor practice some liquid refrigerant could be emitted – this could result in an emission of 50 to 100 grams per event. Discussion with experts has established that an average loss of 10 grams per event is reasonable for properly trained technicians (allowing for one in ten filling events to be poor practice). Prior to the introduction of mandatory training loss rates were higher – the model assumes 40 grams per filling event prior to 2001, tapering to 10 grams in 2008. Some cylinders are used multiple times in the field e.g.
a 15 kg cylinder could be used to add, say 5 kg to plant A, 1 kg to plant B etc. There is no detailed data available on average cylinder use patterns. Based on discussion with experts the model assumes 5 filling events per cylinder. A high proportion of the emissions are from cylinder use in the field. There is a drop of field emissions in the period 2000 to 2008 due to the introduction of better training. There is a drop in filling / disposal emissions in 2008 due to the ban on non-returnable cylinders and cans. 4.35.2.5 Refrigerant handling by other organisations In addition to the Fillers & Packers, Koura Global (formerly known as Mexichem), an organisation involved in HFC manufacture, processing and bulk transportation in the UK provides estimates of the HFCs and PFCs emitted as a result of refrigerant handling separately from emissions associated with halocarbon manufacturing. It’s likely that there is some overlap in scope with the modelled approach to total UK emissions due to the transportation of refrigerants. However, we know that some of the activities being

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 319 conducted – like the refinement of HFC -134a to medical grade – are not considered in the transport of refrigerants model, so we include both to ensure completeness. 4.35.3 Uncertainties and Time Series Consistency As discussed above, emissions in the field dominate the total. From 2009 the emissions from filling and disposal of cylinders are well under 10% of the total. There is a high confidence in the estimates for filling and disposal post-2009. Prior to 2008 the filling and disposal estimates have a lower confidence because of uncertainties regarding the quantity of refrigerant left in non-returnable cylinders/cans on disposal. There are significant uncertainties regarding cylinder use in the field. In particular there is no data on the proportion of “poor practice” filling events or on the average number of filling events per cylinder. The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. This source category is covered by the general QA/QC of the greenhouse gas inventory in Annex 4. Details of verification of emissions are given in Annex 6. 4.35.5 Source Specific Recalculations There have not been any major recalculations to this sector this year. For information on the magnitude of recalculations, see Section 10. 4.35.6 Source Specific Planned Improvements Activity data and emission factors will be kept under review. 4.36.1 Source Category Description Sulphur hexafluoride has been used in high and medium voltage switch gear and transformers since the mid -1960s. The physical properties of the gas make it highly effective as an arc - quenching medium and as an insulator. Consequently, it has gradually repla ced equipment using older technologies, namely oil filled and air blast equipment. Recently, alternatives such as fluoro-nitrile based blends are being commercially deployed as much lower GWP alternatives to SF 6 for many types of electrical insulation, including retro filling of SF6-based systems in some cases. As far as the UK inventory team are aware, these alternatives are yet to be proven for the highest voltage applications, but progress continues to be made towards those. In December 2021 National Grid announced a pilot project to deploy an alternative product at a substation 91, and if successful this might play a significant role in the operator’s target to reduce SF6 emissions by 50% by 2030. A review of the data sources and methodology used to estimate emissions from electrical switchgear was carried out in 2013. Data is reported by the key UK users of Gas Insulated Switchgear (GIS), including National Grid and the UK electricity distribution companies via the electricity industry Regulator, Ofgem. Data was also obtained from ENA (Electrical Networks 91

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 320 Association) and data for power stations that use relatively small amounts of SF6 for switchgear from the environmental regulators’ inventories (EA, NRW, SEPA and NIEA; all 2021). Since the introduction of the EU F -Gas Regulation in 2006 82, the UK electricity industry has made significant efforts to monitor and reduce consumption of SF6. The operator-reported annual data are used to estimate the size of the SF 6 bank in GIS and emissions for 2013 onwards. Estimates for 2008-12 are based on reporting from the National Grid and each of the distribution companies. Emissions from earlier years were estimated by extrapolating the data backwards, using the previously r eported bank size in 1995 and 2000 and previously reported leakage rates. 4.36.3 Uncertainties and Time Series Consistency The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. 4.36.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Annex 4. Details of verification of emissions are given in Annex 6. 4.36.5 Source Specific Recalculations Recalculation due to revisions to Ofgem data from operators. For information on the magnitude of recalculations, see Section 10. 4.36.6 Source Specific Planned Improvements Activity data and emission factors will be kept under review. 4.37.1 Source Category Description Military applications include Airborne Warning and Control System (AWACS), which are military reconnaissance planes. In AWACS, the SF6 is used as an insulating gas in the radar Estimates for this source are based on data supplied by the MoD Defence Equipment & Support Secretariat (MoD, 2022). Data supplied • Measurements of SF6 emitted from AWACS systems for 2016-2022 • Estimates of SF6 emitted from AWACS systems based on logistic throughput for 2014 • The number of AWACS active in the UK fleet for 1990-2021 • Confirmation that the fleet was sold in 2021, but that emissions continued in 2022 as part of training provided as part of selling the fleet The estimates for 2014-2022 have been used directly in the NAEI for those years.
For years where measurements data are not available, an implied emission factor for SF6 emissions per active AWACS has been determined using the data based on measurements and applied to the time-series of active AWACS. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 321 4.37.3 Uncertainties and Time Series Consistency Uncertainties for this source for recent years are low given the data received from the MoD on actual SF6 data. Time-series consistency for earlier years is achieved by using MoD data on the number of active AWACS for each year since 1990 as a proxy for emissions in years where actual SF6 data are available. Where data are available there are fluctuations in the levels of emissions as reported by the MoD, where emissions fall in 2022 reflecting that lower levels of emissions occurred for the final year that the systems remained in the UK before falling to zero The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. 4.37.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Annex 4. Details of verification of emissions are given in Annex 6. 4.37.5 Source Specific Recalculations Estimates for 2021 and 2022 were updated to more recent data provided the MoD, this includes a 31% reduction in 2022 compared to the previous estimate reflecting that lower levels of emissions occurred for the final year that the systems remained in the UK. For information on the magnitude of recalculations, see Section 10. 4.37.6 Source Specific Planned Improvements Activity data and emission factors will be kept under review. 4.38.1 Source Category Description Particle accelerators are used for research purposes (at universities and research institutions), for industrial applications (in cross -linking polymers for cable insulation and for rubber parts and hoses), and in medical (radiotherapy) applications. Estimates of emissions in the UK are confined to those from research and university particle The emissions from industrial particle accelerators are a result of leakage during operation and repair. Research and industrial high voltage systems usually need to be opened more frequently than industrial low voltage accelerators. Hence the emission fac tor of low voltage industrial accelerators is comparably lower. In the case of radiotherapy applications, industrially pre-set particle accelerators with hollow conductors filled with SF 6 are used. The emissions of SF 6 are planned releases. Radiotherapy ac celerators are typically opened two times a year when being serviced and the SF 6 contained is not captured but completely SF6 emissions from research and university accelerators are estimated using an IPCC Tier 2 method – an accelerator -level emission -factor approach. This required information on the individual charge of the various research and university accelerators operating in the UK. This information is used in the following equation along with default emission factors (IPCC 2006):

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 322 Total emissions = University and research particle accelerator Emission Factor x Σ Individual Accelerator Charges SF6 university and research particle accelerator Emission Factor = 0.07 kg SF 6 per kg SF6 charge, the average annual university and research particle accelerator emission rate as a fraction of the total charge. Individual Accelerator Charges = SF 6 contained within each university and research The SF 6 emissions from medical and industrial accelerators are estimated using a Tier 1 method – country-level method. Given the scale of the number of medical and industrial particle accelerators, it was not feasible to collect individual charge information of e ach accelerator. The Tier 1 estimation method consists of the following equation, which relies on default Emissions = (number of particle accelerators that use SF6 by process description in the country) x (SF6 charge factor, kg) x (SF6 applicable particle emission factor) Number of particle accelerators by type in the country = the total number of particle accelerators by type (industrial high voltage, industrial low voltage and radiotherapy) SF6 charge factor = the average SF 6 charge in a particle accelerator by process SF6 particle accelerator Emission Factor = the average annual SF 6 particle accelerator emission rate as a fraction of the total charge by process description. These factors are Process Description SF6 Charge Factor, kg Emission Factor, kg/kgSF6 Industrial Particle Accelerators – Industrial Particle Accelerators – Medical (Radiotherapy) 0.5 2.0 For the Particle Accelerators sector, ICF (ICF 2014) contacted the Science and Technology Facilities Council (STFC) and the Cockcroft Institute to gather activity data for the Tier 1 and Tier 2 methods. STFC and the Cockcroft Institute were able to provide ICF with the charge information, years of operation and status of usage of SF 6 in the research and university particle accelerators in the UK. It is assumed that the charges of the accelerators are constant for all the years. For one facility whose charge was unavailable, a default charge in Tier 1 was The Cockcroft Institute also provided an approximate estimate of the number of low voltage industrial accelerators in the UK for 2012—approximately 100 (Cockcroft Institute 2013). The total number of medical accelerators for 2012 was estimated from a list of accelerators compiled by a member of STFC, estimated at 50 (STFC, 2013). Due to the large number of medical and industrial accelerators, collecting accelerator -specific charge data was not feasible. Therefore, a Tier 1 approach was used to estimate emissions. To confirm the number of accelerators, ICF also solicited information from the National Physical Laboratory and the

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 323 Institute of Engineering and Technology, but without success. In the absence of specific information on the number or percent of medical particle accelerators that use SF 6, ICF conservatively assumed that 100% of UK medical particle accelerators use and emit SF 6.
To estimate SF6 emissions for years 1990-2011 and 2013 onwards, emissions have been scaled from the 2012 estimate based on historical UK GDP growth rates. 4.38.3 Uncertainties and Time Series Consistency Emissions of research and university particle accelerators are very high for the period 1990 - 1992. This is because of the operation of the Nuclear Structure Facility that held 135 tonnes of SF6 charge. After its closure in 1992 (assumed to be at the end of 1992), the emissions of research and university particle accelerators and medical and industrial accelerators are comparable. In 2004, the only operational particle accelerator ceased usage of SF6 and, hence, the emissions are considered to be zero. Three other particle accelerators began operation in 2010, 2011, and 2012, respectively, leading to non-zero but small SF6 emissions For the medical and industrial particle accelerators, the emissions rise as they were estimated The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. 4.38.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Annex 4. Details of verification of emissions are given in Annex 6. 4.38.5 Source Specific Recalculations There have been no major recalculations to emissions from this sector. For information on the magnitude of recalculations, see Section 10. 4.38.6 Source Specific Planned Improvements Activity data and emission factors will be kept under review. 4.39.1 Source Category Description Emissions of PFCs and SF6 from the production of semiconductors, and PFCs and SF 6 from sporting goods (training shoes) have been combined in order to preserve the confidentiality of estimates of emissions of SF6 and PFCs used in training shoes. Emissions from the use of SF6 as a tracer gas are also reported under 2G2eii, and the methodology described in this section The semiconductors industry uses PFCs • Cleaning of chambers used for chemical vapour deposition (CVD) processes; • Vapour phase soldering and vapour phase blanketing; • Leak testing of hermetically sealed components; and • Cooling liquids, e.g. in supercomputers or radar systems. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 324 In addition, SF6 is used in etching processes for polysilicon and nitrite surfaces, and there is some usage of CHF3 (also referred to as HFC-23), NF3 and some other fluorine compounds. In the semiconductor manufacturing process, the fluorinated gases (PFCs, SF 6, HFCs and NF3) are mainly used as a source of highly reactive fluorine ions that are used in plasma etching and plasma cleaning. The stable fluorinated molecules are converted into a plasma (via high voltage electrical breakdown) and the majority of fluorine ions react with other materials to create stable molecules that are not GHGs. Hence emissions of the F-Gases are only a small proportion of consumption. The UK uses of SF6 as a tracer in scientific research. A sports goods manufacturer selling shoes in the UK used SF 6 as a cushioning material in a range of training shoes from 1990 to 2003. Prior to 1990, the manufacturer used perfluoroethane (a PFC) for cushioning. SF 6 is well suited to this application because it is chemically and biologically inert and its high molecular weight means it cannot easily diffuse across membranes. This means the gas is not released until the training shoe is destroyed at The manufacturer committed itself to eliminating SF6 from its training shoes by 30 June 2003 – a goal which was achieved. It had originally planned to replace all SF 6 applications with nitrogen-filled cushioning, but technical difficulties mean it had to switch temporarily to perfluoropropane (a PFC) in some high -performance applications. The use of F gases in footwear was banned in 2006 by the F-gas Regulation and discussions with the manufacturer have confirmed that they are no longer using PFCs or SF6. Cushioning units typically outlast the lifetime of the training shoe because the rate of diffusion of SF6 is so slow. In the UK, training shoes are generally sent to landfill at the end of their useful lives, where any SF6 or PFC will eventually leak to the atmosphere. 4.39.2.1 Semiconductor For the semiconductor manufacture sector, the methodology adopted follows the T2a approach described in Volume 3 chapter 6 of the 2019 refinement to the 2006 IPCC guidelines The 2019 refinement Tier 2a method is represented by equations 6.5-6.9 as 𝐸𝐴𝐵𝐶𝐹4,𝑖 = 𝐶𝑖 ∗ (1 − 𝑈𝑖) ∗ (1 − 𝜂) ∗ 𝐴𝐵𝐶𝐹4,𝑖 Ci = consumption of input gas 𝑖 (kg); 𝑈𝑖 = use rate of gas 𝑖 (fraction destroyed or transformed in process) (fraction); 𝐷𝑖 or 𝐷𝑘 = Overall reduction of mass of gas 𝑖 or 𝑘 emissions; 𝐵𝑃𝐸𝑘 = Emissions of by-product 𝑘 generated from the conversion of all input gases

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 325 𝐵𝑘,𝑖 = Emission factor for by-product 𝑘 generated from input gas 𝑖 (kg of by-product gas 𝑘 created per kg of gas 𝑖 consumed); 𝐸𝐴𝐵𝐶𝐹4,𝑖 = Emissions of CF4 from hydrocarbon-fuel-based combustion emissions control systems when direct reaction with hydrocarbon fuel and fluorinated species 𝑖 is not certified not to occur by the emissions control OEM or electronics manufacturer (only for 𝑖 = NF3 used in remote clean process or F2) (kg); 𝜂 = Ratio of emissions control systems certified not to form CF4 within emissions control systems to the total number of emissions control systems in the facility (site- 𝐴𝐵𝐶𝐹4,𝑖 = Mass fraction of 𝑖 in process exhaust gas that is converted into CF4 by direct reaction with hydrocarbon fuel and F2 gas in a combustion emissions control system; 𝑎𝑖 = Estimate of the fraction of gas 𝑖 emitted from process tools equipped with suitable emissions control technologies (site-specific fraction); 𝑑𝑖 = Destruction Removal Efficiency (DRE) for gas 𝑖 (fraction); and, 𝑈𝑇 = Average uptime factor of all emissions control systems (site-specific fraction).
The 2019 refinement also sets out equations for determining 𝑎𝑖, and 𝑈𝑇, but as the UK does not hold data that would be required to make these calculations but does have input from stakeholders on suitable assumptions for the equivalent to (𝑎𝑖 ∗ 𝑈𝑇), these equations are not Estimates of PFC used for the UK semiconductor industry in 2001 were provided by UK Microelectronics Environmental Advisory Committee, based on 2001 purchases of PFCs as reported by individual companies in the UK semiconductors industry. No suitable furthe r activity data have been identified during consultations with relevant UK and EU trade bodies, although, UK industry have contributed to determining suitable estimates of the trends, including trends in total semiconductor industry trends, the relative use of different PFCs, and the installation of abatement technology (AEAT, 2004). Specific trends which stakeholders have indicated • A 3% growth rate in input gas per unit production required between 1990 and 1996; • A -8% growth rate in CF4 and C2F6 demand per unit production between 2005 and 2010 as part of a global semiconductor industry drive to reduce PFC emissions; • The output of the sector has grown 15% per year between 1990 and 2000; • The output of the sector contracted by 39% in 200192; and, • Mixed assessments of how the sector will grow after 2003. In addition to the 2004 study, more recent engagement with the UK trade association TechWorks, who represent all UK semiconductor manufacturers, has indicated that it is likely that the sector has contracted in recent years, and in 2023 a survey of operators was facilitated by TechWorks, which provided consumption of each F -gas for 2016 -2021 (Gluckman Consulting, 2023). Not all semiconductor manufacturers engaged in the survey, but we estimate that those that did would represent 80% of F-gas use in the UK, and therefore activity data are uplifted to account for this. 92 This reflects our understanding of the semiconductor industry over this period where there was a closure of several operators in the UK, particularly those linked to ‘silicon Glen’. ‘Silicon Glen’ was the name given to a region in Scotland where the UK semiconductor industry was focussed, and after strong growth throughout the 90s, but many of these businesses closed in quick succession in the early 2000s in part triggered by the bursting of the dotcom bubble. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 326 When the uplifted 2023 data were compared with estimates previously extrapolated based on the qualitative information from stakeholders, we found very similar total CO 2e emissions estimates, although there were some significant differences in which specific substances were The uplifted 2023 survey data are used as the activity data for 2016-2021. Estimates for 2002- 2015 are estimated by linear interpolation, and for 2022 onwards, activity is assumed to be The NF3 consumption has been divided into NF3 remote clean and all other NF3 consumption (i.e., for in -situ chamber clean and etch processes). NF 3 remote clean refers to a cleaning method for chemical vapour deposition chambers in which the film cleaning -agents formed from NF3 (F-atoms) are produced in a plasma upstream (remote) from the chamber being cleaned. In situ chamber cleans are chemical vapour deposition chamber cleaning processes, which may use NF 3 or other F-gases to generate F -atoms in the chamb ers whose walls are being cleaned. NF3 may also be used to etch patterns (i.e., circuits) on semiconductors. The use of NF3 remote clean is assumed to start in 2003 and growing increasingly over time. As no data on the UK’s use of NF3 remote clean processes was made available from NMI, the US semiconductor market was used as a proxy to estimate the use of NF 3 in remote clean processes relative to all other processes. Specifically, the share of NF3 remote clean versus other uses was estimated based on industry reported NF3 usage data from US semiconductor manufacturers for the years 2009 and 2010 (US EPA, 2011). This US data was readily available and is believed to be a good proxy for the UK given that semiconductor processes do not typically vary by world region. The ratio of NF3 remote to other uses was interpolated for years between 2003 and 2010, assuming zero before 4.39.2.1.2 Emission factors and other default factors A summary of the model parameters used from the 2019 refinement to the 2006 IPCC 6.17 and page 21 of Volume 3, chapter 6. semiconductor manufacture sector (kg per kg input gas) headings are the input gas, 𝒊) (1 − 𝑈𝑖) 0.73 0.55 0.4 0.13 0.47 0.02 0.18 0.55 𝐵𝐶𝐹4,𝑖 NA 0.19 0.2 0.099 0.082 0.034 0.067 0.12 𝐵𝐶2𝐹6,𝑖 0.043 NA 0.000018 0.02 0.045 NA 0.014 0.095 𝐵𝐶3𝐹8,𝑖 NA NA NA NA NA NA NA NA 𝐵𝐶𝐻𝐹3,𝑖 0.04 0.002 0.000012 0.022 NA NA 0.0068 0.0014 𝐴𝐵𝐶𝐹4,𝑖 NA NA NA NA NA 0.093 NA NA 93 As defined at the beginning of Section 4.39.2.1

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 327 headings are the input gas, 𝒊) 𝑑𝑖 0.89 0.95 0.99 0.98 0.98 0.95 0.95 0.95 The degree of abatement utilisation (equivalent to 𝑎𝑖 ∗ 𝑈𝑇 as defined at the beginning of Section 4.39.2.1) has been estimated using information from stakeholders collected during the 2003 study (AEAT, 2003), • Abatement was not used in UK operations until 2003; • It is expected that all fabrication plants opened after 2003 will have abatement installed; • Semiconductor fabrication plants have a lifetime of 25 years. This allows us to model the turnover of semiconductor fabrication plants, and therefore the rate at which modern plants with higher degrees of abatement substitute legacy unabated plants. We are continuing to engage the UK semiconductors industry to understand how successful the sector were in having abatement installed in post-2003 plants, and in the meantime have made the conservative assumption that abatement is only applied to half of production at new fabrication plants.
This means that we estimate that in 2002 𝑎𝑖 ∗ 𝑈𝑇 = 0, and this increases over almost94 25 years to 𝑎𝑖 ∗ 𝑈𝑇 = 0.5 Due to the toxicity of NF3, it is assumed that all use of NF3 is abated, i.e. 𝑎𝑁𝐹3 ∗ 𝑈𝑇 = 1. 4.39.2.1.3 Justification for using a 2019 refinement to the 2006 IPCC guidelines methodology The conclusions and recommendations from the 18 th meeting of greenhouse gas inventory lead reviews95 states in paragraph 12a “…The LRs also noted that for categories and subcategories covered by the 2006 IPCC Guidelines, the ERT should review whether (1) the methodologies, emission factors (EFs) and/or assumptions taken from the 2019 Refinement or a country -specific approach based on or consistent with the 2019 Refinement are well documented, (2) the Party demonstrated that they better represent the national circumstances and justified their use in its NID, and (3) emission and removal estimates are accurate and time-series consi stency has been maintained in accordance with the 2006 IPCC The UK believes that these are addressed in this case, (1) The methodology adopted is documented in the preceding sections (2) The 2019 refinement utilises more recent studies and understanding of emissions from this source and the methodology presented accounts for more features; we argue that means that the methodology should be better representative of UK emissions. The UK trade association TechWorks, who represent all UK semiconductor manufacturers, were engaged during the development of the UK implementation of the 2019 refinement approach, and there were not any more UK-specific parameters identified. (3) The methodology has been applied to the entirety of the time -series estimated, and activity data have been reviewed with stakeholder support to ensure that they are consistent and representative of UK trends. 4.39.2.2 Use of SF6 as a tracer gas in scientific SF6 is used in a number of applications in the UK 94 Because we model the sector to have contracted in 2001, we assume that there were not any new plants installed between then and 2003, meaning that it took less time for the oldest legacy plants to be replaced than might otherwise be expected. 95

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 328 • Tracer gas to certify fume hoods; and • UK studies of greenhouse gas emissions ICF investigated the use of tracer gas to certify fume hoods. The use of SF6 as a tracer gas to certify fume hoods is a practice established by ASHRAE in the test procedure ASHRAE-110, “Method of Testing Performance of Laboratory Fume Hoods” (ASHRAE, 1995). SF6 is emitted in the fume hood and the concentration of the gas is measured after some time has passed. This is to ensure that the gases created under the fumes, toxic or otherwise, are properly ventilated. The amount of gas used per test is dependent on the tester. All of the SF6 used in tracer tests is lost in the atmosphere and so the emissions are treated as prompt emissions—i.e., each test results in direct emissions of SF 6 (IPCC 2006). SF6 is also used for tracer testing of nuclear power plant control room emergency ventilation systems Due to data limitations, SF6 emissions were estimated using a slightly modified Equation 8.23 of Volume 3 of the 2006 GLs. The SF 6 emission is calculated on a per-use basis as opposed to the amount purchased/sold as provided in the equation. This modified method relies on the number of tracer tests conducted annually as the activity data, which when multiplied by the emissions per test as the emission factor, gives the total SF6 emissions from this sector. This method is represented in the following Total emissions = emissions per test x number of tests Additional emissions may also occur from bottling, leakage, and piping; however, such emissions cannot be estimated without activity data and are believed to be de minimis. In order to apply the method above, ICF had to gather information on the number of tracer tests conducted annually (activity data) and the emissions per test (emission factor). ICF first identified various companies that performed fume hood tracer testing. ICF contacted the three largest companies that perform tracer tests in the UK (Crowthorne, Dale Flow, and Invent-UK) and obtained the company-specific emissions per test and the total number of tests performed in 2012 (Crowthorne 2013, Dale Flow 2013, Inv ent-UK 2013). For the prior years, the total numbers of tests have been estimated by scaling the number of tests performed in 2012 to the UK’s historical GDP growth rate. The amount of emissions per test for prior years was held constant unless a company specified that the volume had increased after a certain period. The value of the emissions per test differed among companies and ranged from 0.033 to 0.046 kg ICF also verified when these companies came into existence. Other, smaller companies were identified but were not contacted as —according to qualitative information from Dale Flow (2013)—the bulk of the market is covered by the three major companies, and an y additional research was not expected to result in significant changes to the emission estimates, which only account for a very small share of total F-gas emissions. ICF also contacted Sellafield Ltd, a nuclear decommissioning company, which uses SF 6 to conduct tracer tests, and included their company specific emission factor and total number of Finally, ICF contacted the UK Nuclear Regulation Agency to confirm if there is any use of SF6 in the tracer testing of nuclear power plant control room emergency ventilation systems in the UK. ICF was unable to obtain information because the inquiry did not fall within the remit of the Office of Nuclear Regulation/Health and Safety Executive. However, ICF experts believe that such use was replaced many years ago. SF6 is used as a tracer gas in UK studies of greenhouse gas emissions from ruminant livestock.
It is currently the only viable way to measure emissions of methane from ruminant livestock individuals at pasture (Defra, per. comm.). Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 329 A small charge of SF6 is stored in a permeation tube, which is then introduced to the rumen of the animal. The gas emissions are vacuum sampled from eructation via a tube near the animal’s muzzle connected to an evacuated flask. The total CH 4 emissions are inferred from the differential concentrations of SF6 and CH4 between the flask and atmosphere. More details of the work can be found at This research project ended in 2014, so emissions from this source do not occur in 2015 onwards. 4.39.2.3 Use and disposal of training Estimates of emissions from sports-shoes were based on a bottom-up Tier 2 estimate, using activity data supplied in confidence by the manufacturer. A full description of the emissions and associated methodology used is contained in AEA 4.39.3 Uncertainties and Time-Series Consistency Estimates of emissions in some categories of this sector are based on very limited and uncertain data and are therefore uncertain. More information on uncertainty data used in the uncertainty analysis is presented in Annex 2. 4.39.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Annex 4. Details of verification of emissions are given in Annex 6. 4.39.5 Source Specific Recalculations There have been no major recalculations to emissions from this sector. For information on the magnitude of recalculations, see Section 10. 4.39.6 Source Specific Planned Improvements Activity data and emission factors will be kept under review. 4.40.1 Source Category Description This category includes emissions from N2O used as an anaesthetic. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 330 Emissions have been calculated using the outcomes of a study by NHS England (2013). This report calculates the total N2O emissions based on the number of bed -days in NHS England 2011 – 2012, multiplied by the EU GHG inventory derived emission factor of 10.3 kg N2O/bed/year96. This provides an estimated total N 2O emission of 1,641,147 kg per annum, arising from the use of anaesthetic at NHS England facilities. This is not the recommended methodology given in the 2006 IPCC guidelines, but as we have been unable to obtain the data required to follow the default methodology (sales of N 2O for anaesthetic use) this was considered the best approach to a country specific estimate for this source. Suppliers of N 2O for anaesthesia were contacted, but they declined to provide data. provided in the Carbon Footprint report. This has then been applied to the total population for the England, Wales, Scotland and Northern Ireland to provide a complete time -series of 4.40.3 Uncertainties and Time Series Consistency As the duration of a patient’s hospital stay can vary considerably, the use of bed -days as an indicator of N2O should be considered to have a high degree of uncertainty. The methodology doesn’t take into account N2O used in non-NHS hospital environments (for example dental and veterinary practices or private hospitals), however total emissions from these sources are estimated to be much smaller than the uncertainty in the conservative NHS estimate. The time series estimate does not consider trends in the uptake of alternative anaesthetics or alternative approaches to applying N2O as an anaesthetic, as some methods can reduce the consumption of N 2O. Though using population as an indicator of trend should well reflect demand for anaesthetics, it would not take into account changing practices. We also make the assumption that the rest of the UK consumes anaesthetic in the same way as England. 4.40.4 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in In the case of Gibraltar, we have actual data on N2O imports for anaesthetic use for one year. When compared to the population of Gibraltar this yields an IEF of 0.015 kg per capita. In addition to providing robust data upon which to base Gibraltar emission estimates (using population data to generate a time-series), this improves our confidence that the UK estimate is of the correct order of magnitude. 4.40.5 Source Specific Recalculations There are no major recalculations to this source for this submission. For information on the magnitude of recalculations, see Section 10. 4.40.6 Source Specific Planned Improvements The inventory team will continue to search for data relating to the sales of N2O for anaesthetic use and will make improvements to the methodology when this information is available. 96

Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 331 4.41.1 Source Category Description Very little UK data are available on the use of N2O in cream products, therefore the approach adopted has been based on the method used in the Danish GHG Inventory (Hjelgaard, 2015). • 1% of cream consumption is in the form of whipped cream sprays; • N2O consumption in those sprays is equal to 5% of the mass of the cream; and UK cream consumption data are available from Government (DEFRA) statistics (Defra, 2024). Activity data on the number of adults using new psychoactive substances in the UK is available from 2012 in the Home Office Drug Misuse tables, which is now maintained by ONS (Office of National Statistics, 2021b), whilst frequency of use is available only for financial year 2017/8. • The average frequency of use for 2017/18 is appropriate for other years of the time - • Each recorded use of new psychoactive substance amounts to 5 canisters; • An N2O cartridge contains 7.5g of N2O and, 4.41.2 Uncertainties and Time Series Consistency The UK method for cream consumption relies upon the assumption that UK consumption of whipped cream sprays is similar to that in Denmark i.e. 1% of total cream consumption.
Overall cream consumption in Denmark and the UK are similar on a per -capita basis, but the market share of whipped cream sprays in the UK is not known, and so the 1% assumption is the most significant source of uncertainty for the UK estimates. The assumption regarding the 5% usage of N2O relative to cream content is expected to be reasonable – there is no reason to think that the products sold in Denmark and the UK will differ significantly in design. UK cream consumption data are available for the full time-series from 1990 onwards. The UK method for recreational use of N2O relies on the assumptions that the canister volume and pressure are similar to those used in the whipped cream industry in the absence of more Activity data on the number of adults who use new psychoactive substances is available on an annual basis since 2012 with some gaps. In these cases, the number of adults is gap-filled by interpolation of the surrounding years. Prior to 2012, no data is ava ilable. In these years, the Inventory Agency believes that the level of emissions will not exceed the value of 2012 and therefore are insufficient to demand estimates are made, and therefore are recorded as “Not 4.41.3 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in 4.41.4 Source Specific Recalculations There are no major recalculations to this source for this submission. For information on the magnitude of recalculations, see Section 10. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 332 4.41.5 Source Specific Planned Improvements 4.42.1 Source Category Description This category reports N 2O emissions from the chemical industry that are not captured elsewhere. All chemical sites reporting significant N 2O emissions are included where that emission is believed to be from a chemical process, rather than combustion. Other sites do report N2O emissions, but those are small, and there is no evidence that they are from chemical processes. As such, the estimates reported in 2G4 are thought to be complete. Emissions from nitric and adipic acid are not included here, as these are reported in 2B2 and 2B3. The UK has a large chemicals sector and all manufacturing sites are regulated and required to report emissions of N2O (as well as other pollutants). From 1998, when reporting was first required, until 2001 there was no threshold for reporting N 2O, but since 2002, reporting is required only when emissions exceed 10 tonnes. Across the time-series, N2O emissions have been reported in at least one year for about 30 sites permitted by the EPR which could include chemical manufacturing. For most of those sites, N2O is reported for only one or two years out of the time -series and we think it is likely that the reported N 2O is an error (operators do occasionally confuse N2O and NOx on their reporting submissions) and in a few other cases it is likely that the N2O occurs from the substantial combustion processes that constitute part of the reporting installation. In four cases however N 2O is reported in multiple years, from processes which are either known to emit the gas, or thought to be the most likely • A process to manufacture nitrous oxide, and to transfer it into gas cylinders for sale. This process was commissioned in 2004; • A process manufacturing industrial gases, which probably also supplied nitrous oxide in cylinders and which closed in 2008; • A process manufacturing pharmaceutical products. This process has been in operation since at least the early 90s; and, • A catalyst manufacturing process which involves dissolving metals in nitric acid, leading to emissions of oxides of nitrogen (including both NOx and N2O). This process has been Emission estimates are based on the data reported by the process operators to the Environment Agency for inclusion in the Pollution Inventory (PI). A gap in the reported data for the first site listed above (for 2004) is filled by assuming that operation started half-way through the year and that emissions were 50% of the level reported in 2005. The second plant only reports N2O back to 2002, but reports NOx in 2002 as well, and also in 1997-2001. Emissions of N2O in the years 1997-2001 are therefore assumed to follow the same trend as for NOx back to 1997 and to be at 1997 levels prior to that. Emissions for the third site for 1990 -2005 are assumed to be the same as 2006, i.e. the earliest year where nitrous oxide emissions are reported, and for 2013 onwards, emissions have been below the repo rting threshold, so we have conservatively assumed that emissions were at the reporting threshold. Emissions for the fourth site for the years 1990-1997 i.e. before reporting of N2O was required, are assumed to follow the same trend as emissions of NO x, which is reported back to 1995, and to be the same as in 1995 before that. Using this approach suggests that emissions from this plant were about 2 times higher in 1990 than in 1998, when data are first reported. Industrial Processes (CRT Sector 2) 4 UK NID 2025 (Issue 1) Ricardo Page 333 4.42.3 Uncertainties and Time Series Consistency Gaps in the PI data for the three sites is the most significant source of uncertainty in the estimates. It is possible that other sites that report N 2O emit the gas from chemical manufacturing processes but if this were the case, these emissions would be smaller than those from the three sites currently included. 4.42.4 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 PI. 4.42.5 Source Specific Recalculations There are no major recalculations to this source for this submission. For information on the magnitude of recalculations, see Section 10.
4.42.6 Source Specific Planned Improvements The estimates will be kept under review, and additional sites added if appropriate. 4.43.1 Source Category Description The UK paper industry is mainly confined to the production of pulp from recycled material and the production of papers using imported virgin pulp, recycled pulp or a combination of the two. Production of virgin pulp is limited to a few processes producing mechanical or neutral sulphite semi-chemical pulp. Emissions from UK paper processes consist largely of emissions from the associated combustion processes and these are reported under CRT category 1A2d. Other emissions of GHGs from UK paper and pulp processes will be minor and are not estimated. 4.44.1 Source Category Description Food and drink processes will use fuels and emissions from this fuel use are reported in 1A2e. No process emissions of GHGs have been identified, however. UK NID 2025 (Issue 1) Ricardo Page 334 3F: Field Burning of Agricultural Residues Gases Reported CO2, CH4, N2O, NOx, CO, NMVOC, SO2 3A: Enteric Fermentation - CH4 (L2, T1, T3) 3A1: Enteric fermentation from Cattle - CH4 (L1, T3) 3A2: Enteric fermentation from Sheep - CH4 (L1, T3) 3B1: Manure management from Cattle - CH4 (L1, T3) 3B2: Manure Management - N2O (L1) 3D: Agricultural soils - N2O (L1, T1, L2, T2, T3) Completeness A general assessment of completeness for the inventory is EFs revised for N2O from liquid/slurry from dairy cattle in tanks with a natural crust cover or cover, and NH3 EF from housing for poultry (affects N balance approach and N2O emissions). Review and use of new country-specific activity data that reflect the uptake of mitigation practices on manure management, storage and application of organic N materials Small revisions to activity data, including fleece growth, milk yield, slaughter weights, amounts of digestate from manure and non-manure, protein content of grazed grass, fertiliser data, urease inhibitors rates, grass areas and grass protein Further details are found in relevant sections. In the agriculture sector, the UK reports emissions from the following enteric direct and indirect (N2O). These categories include synthetic fertiliser, manures and digestates applied to soils, urine and dung deposition during grazing, sewage sludge, mineralisation, crop

UK NID 2025 (Issue 1) Ricardo Page 335 Emissions of other pollutants reported include NMVOCs, NOx and PM (Tables 3B and 3D). 5.1.1 Agriculture Emissions in the UK Trends and drivers decrease of 17.9% between 1990 and 2023 and a decrease of 1.5% between 2022 and 2023. Emissions of CH 4 were the largest contributor to total emissions in 2023 (66%) followed by Key events and drivers of UK agriculture emission trends include the ➢ Long term trends are primarily impacted upon by the key underlying activity data such as livestock numbers and crop production across the UK; ➢ The 2001 UK foot and mouth crisis led to the culling of large numbers of livestock (6.5 M animals) to mitigate the spread of the disease, resulting in a significant short-term decline ➢ Other livestock diseases, such as bird flu, with several outbreaks in 2021, 2022, and 2024 resulting in culling of large bird populations. ➢ Annual fertiliser application rates and associated emissions are strongly affected across the time series by periods of poor weather, most commonly when the UK experiences very wet autumn/winter weather, inhibiting the sowing of winter crops and lowering the fertiliser application overall. This explains the lower agricultural soil emission of nitrous oxide from inorganic fertiliser application in years 2020, 2013, 2001 and 1993. In all cases the fertiliser rates declined and then recovered the following year. ➢ In recent years, higher energy prices have increased the price of fertiliser production, leading to higher costs of inorganic fertilisers to farmers. The UK inventory trends reflect that there has been a consequent shift by some farmers to use more urea -based inputs and less inorganic fertiliser use due to these higher costs of inorganic fertilisers. ➢ Changes in organic fertilisers, for example an increase in the production of digestate from anaerobic digestion plants. Also, changes in manure management, particularly due to the implementation of Firm and funded Policies. ➢ Differences in data collation and management at regional level

UK NID 2025 (Issue 1) Ricardo Page 336 in 2023. Total emissions 41.2 MtCO2e. 5.1.2 Agriculture National System, Stakeholders and The UK agriculture inventory of GHGs and ammonia is managed by the UK Department of Environment, Food and Rural Affairs (Defra), which is the UK Government department with

UK NID 2025 (Issue 1) Ricardo Page 337 policy responsibility for farming, food standards and air quality (AQ) emissions. The inventory is used as a reporting mechanism for UK, England and devolved administrations’ emissions, as well as to underpin emission projections and policy scenario analys is. As such, it is developed and managed via a network of stakeholders to identify new / emerging data, to keep pace with UK, England and devolved administration regulations, farm practices, mitigation actions, scientific and policy research. Defra funds the compilation and reporting of the agriculture GHG and ammonia inventory via a multi-year contract, managed by Rothamsted and subsequently ADAS (from August 2023). The outputs are incorporated into the wider UK GHG inventory via the National Atmospheric Emissions Inventory (NAEI) database, which is managed by the UK Department of Energy Security and Net Zero (DESNZ). DESNZ is the UK’s Single National Entity for GHG submissions to the UNFCCC, and the agriculture consortium sector experts and in ventory compilers for the Agriculture sector, whilst the DESNZ -contracted Ricardo consortium is the Inventory Agency overall and compiles the GHGI for other sectors. The process for inventory review, identification of new data and method improvements, prioritisation and implementation, compilation and reporting involves a range of stakeholders. This can be summarised as ➢ January to Post submission review by the Inventory Agency team; inputs from latest UN and other reviews; engagement with research and industry contacts (e.g. academic researchers, Agricultural Industries Confederation (AIC), Defra policy leads).
Identification of new data and/or methodological improvement o ptions, prioritising key source categories, sources of high uncertainty and sources where mitigation actions are planned or implemented and not currently represented in the inventory; ➢ April to May : Consult with the National Inventory Steering Committee (NISC), advisory and executive stakeholders, i.e. across industry and Government; distil down to highest priority improvement actions for implementation in the next inventory cycle. Specify data ➢ June to October : Access data, consult stakeholders (e.g. AIC, Defra, devolved administrations of Scotland, Wales and N Ireland) develop new methodologies, where necessary consult with peer reviewers (UK, international) to test and refine the new methods; consider cross-sectoral impacts (where appropriate) and communicate to other inventory teams (e.g. waste, bioenergy, LULUCF). Where there are also impacts on AQ pollutant emissions, e.g. ammonia, consult with the Defra-led Air Quality Inventory Steering Group which comprises AQ modellers and researchers. Engage with the UNFCCC review ➢ November to Prepare documents to share with the NISC (Advisory panel) in late November as part of the pre-submission review process for the UK inventory; present the new data / methods and impacts on level and trend of emissions; outline uncertainties, next steps. The NISC Executive then meets to consider the improvement and sign it off or indicate that further work is needed prior to acceptance within the UK submission. ➢ January to Finalise the UK agriculture inventory submission, i.e. update the UK inventory central estimates and uncertainty analysis and then start again with the post - 5.1.3 The UK Greenhouse Gas Inventory Model for the Agriculture This section provides an overview of the UK GHGI model for agriculture; for more details on the model, please see Annex 5.1 Section A 5.1.3.9. UK NID 2025 (Issue 1) Ricardo Page 338 The UK Government funded a major programme between 2011 and 2017 to substantially improve the calculation methodology, emission factors and sector representation in the estimate of GHG emissions for the agriculture sector. This culminated in the development of a sector-specific model with a fully revised structure to enable representation of the key underlying driving variables of the GHG emissions, including soils, climate, livestock and cropping characteristics and farm management practices including the uptake of specific mitigation methods. The model also includes detailed representation of uncertainties, allowing full uncertainty analyses to highlight areas for future improvement. The UK inventory undergoes continuous improvement to reflect developments in source data and scientific understanding, for example when inventory guidance is updated to improve methods, new EFs or to add new emission sources. The inventory improvements are documented in the relevant The agriculture sector model is written in C#, calling on a SQL server database, using stored queries. The coded model covers the major sources of the agriculture sector with a separate module for each source, drawing on source -specific input tables and ge nerating source - specific output tables, including • manure management CH4 and N2O emissions from Dairy, Beef, Sheep, Swine, Poultry, • direct and indirect N 2O emissions from synthetic N fertiliser, organic N (e.g., animal manure, sewage sludge and digestate) applied to grassland and arable crops, and crop • N2O emissions from urine and dung N deposited on pasture from Dairy, Beef, Sheep, Swine, Poultry, Goats, Horses and Deer. N2O emissions from mineralisation and histosols and CO 2 emissions from liming and application of urea to soils and NMVOC emissions from rough grazing are estimated using simpler Excel spreadsheet models. Data are collated and calculations performed by year (from 1990) and by country (England, Wales, Scotland and Northern Ireland) at a 10 x 10 km grid cell resolution, the results being aggregated across the four countries to derive UK totals. The choice of grid size reflects uncertainty in agricultural holdings that are variously geo -referenced by parish, holding office or field centroids, but is principally justified by the confidential ity restrictions placed on the mapping of inventory input and output datasets. 5.1.3.2 Activity data handling When there are data gaps for one historic year in livestock numbers or crop areas, holding level data for an adjacent year are used. If no data are available for the current submission, an extrapolation using the time series trend, or the same data from the previous submission may be used, this would be described under the relevant sector. Scaling factors are applied where necessary to ensure that the sum of all holding level data equates with the official statistics for national totals, for a given category. For example, if the sum of all holding level data (of a given category) is 100, and the official statistic reported national total is 101, a scaling factor of 1.01 would be applied to all holding values (to ensure the holding level data matches national totals). 5.1.4 General sector characteristics Activity data that apply to more than one source category (i) farm types (Section 5.1.4.2); (ii) livestock types and numbers ( Section 5.1.4.3); (iii) crop types and crop areas ( Section 5.1.4.4); (iv) fertiliser types and application rates (Section 5.1.4.6). These are described in this section and are referred to in the relevant sections throughout this chapter. The data relevant

UK NID 2025 (Issue 1) Ricardo Page 339 to the calculation of emissions from crop residues are described in Section 5.1.4.5. The emission factors used to estimate N2O emissions from synthetic fertiliser applications to soils are determined via an empirical model that relies on environmental factors and is described in Year-specific activity data and EFs are provided in the Annex document and supplementary tables as Excel files, Supplementary file EFs UK inventory agriculture_1990 - A full uncertainty analysis is conducted using Monte Carlo simulation based on probability distribution functions for all key model input parameters and variables. This is not run annually because of resource implications (long model run times) and there i s little change in results between years. The Monte Carlo approach is therefore run approximately every 5 years, or when significant methodological changes are introduced to the model.
For the years in between we assume the uncertainty to be similar to pre vious years and simply offset the uncertainty distribution to align with the revised expected value. This was the case for the 1990-2023 inventory for which no significant methodological changes occurred. Further details of the uncertainty analysis for this submission are in ANNEX 2 Soil properties, notably field capacity, plant available water and percent clay and organic carbon content are used as input to inventory calculations of grass growth and N leaching following application of fertilisers, managed manures and excreta returns. The improved inventory uses the RB209 (MAFF, 2000) soils classification, based on soil texture and depth to rock, with seven soil types (light sandy, shallow, medium, deep clay, deep fertile silty, organic, peaty). For each country, soil scientists from t he James Hutton Institute (Scotland), National Soils Resources Institute University (England and Wales) and the Agri -Food and Biosciences Institute (Northern Ireland) applied the RB209 soil typology to national digital soils datasets. The resulting United Kingdom map of RB209 soil types was spatially intersected with the reference 10 by 10 km grid to provide a statistical summary of the percent of the agricultural land area located on each of the RB209 soil types. The same national digital soils datasets were also used to calculate the percent of the soil area within each grid cell (excluding peaty soils) that is alkaline, based on top-soil measurements of pH (≥ 7), which is used in calculations of ammonia emissions from synthetic fertilisers. Long-term annual and monthly average rainfall and air temperatures were obtained under project license from the Met Office. Met Office UKCP09 baseline average datasets are for the period 1981 to 2010 (Jenkins et al., 2008). The data were made available at a 5 by 5 km resolution and summarised to the reference 10 by 10 km grid cell. Daily time -series of measured rainfall derived from the UK synoptic network for the MORECS model (Hough and Jones, 1997) were obtained under project licence from the Met Office. Time series for the period 1981 to 2010 were made available at a 40 by 40 km resolution. The probabilities of more than 5 mm of rainfall falling in 24 hours within 1 to 6 days (or more) of a N application to land (used in calculations of ammonia emissions from synthetic fertilisers), occurring with equal probability on each day of the year, were calculated for each of the MORECS grid squares. The resulting probabilities were correlated with annual rainfall and downscaled to the reference Farm types may be associated with specific structures and practices (from survey data stratified by Farm Type) which can be used to provide better representation in the emission calculations. The classification of agricultural holdings by Farm Type as used in the UK inventory is based on the method described in the EC typology book (EC typology handbook). It is based on the type of farming and economic size, determined on the basis of Standard Output (SO) coefficients and structural information (area of crops and number of heads of

UK NID 2025 (Issue 1) Ricardo Page 340 livestock) of the various types of agricultural production. Ten robust farm types (RFT) are applied at England and devolved administration level (Wales, Scotland and Northern Ireland): (1) cereals; (2) general cropping; (3) horticulture; (4) specialist pig ; (5) specialist poultry; (6) dairy; (7) grazing livestock (LFA); (8) grazing livestock (lowland); (9) mixed; (10) other. 5.1.4.3 Livestock types and numbers There are eight livestock categories in the UK dairy cattle, beef cattle, sheep, swine, poultry, goats, deer and horses. The June Agricultural Survey (JAS) data (Defra, 2024a) provide a number of sub-categories within the major livestock categories (dairy and beef cattle, sheep, swine, poultry), which are used as the basis for subsequent emission calculations. Since 2005, Cattle Tracing Scheme (CTS) data from the British Cattle Movement Service (Jon Ellerbeck (2023) of APHA and BCMS, 2024) are us ed to provide further detail of all cattle across England, Wales and Scotland, based on analysis of cattle movement records. In the case of Northern Ireland, the data are provided by DAERA (DAERA, 2024). Actual subcategories included in the JAS vary across years and countries, so standard methods for category aggregation (or occasionally disaggregation) have been developed to provide a consistent set of livestock categories across all countries and years, in accordance with the approaches set out in the individual livestock sector methodologies derived in Defra AC0114 GHG platform project for GHGI data management (Defra, in prep.). All livestock are associated with a holding, located within a 10 by 10 km gr id cell, and with a Farm Type. For animals which are present for less than 1 year (e.g. broilers, finishing swine, lambs) the survey data are assumed to represent the number of animal places and all subsequent calculations are performed on an animal place basis (e.g. N excretion calculations will account for the number of crop cycles within a year for broilers). Note that for animals which are present for less than 1 year (e.g. broilers, finishing pigs) and as the survey data represents a screenshot of one day in the year, the value corresponds to a statistical estimate of the average number of ‘occupied’ places – and estimates of excretion, emissions per animal etc need to treat it accordingly. This can be conducive of errors in these particular livestock sectors. More details of individual sector structure are given below, also in the Annex JAS pre-processing and RFT calculation (1990-2023). For the purposes of inventory calculations, dairy cattle are disaggregated into three production/breed types (large, medium, small), associated with different average milk yields for each year (high, medium, low) and into four sub-categories by age and physiological status (dairy calf < 1 year, dairy replacement > 1 year not in calf, dairy replacement in calf, dairy cow). Data have been derived from the CTS (BCMS, 2024) at a monthly resolution for England, Wales and Scotland since 2005.
Each animal is categorised by breed, gender, age and parity (if relevant) and associated with a holding. Breed is associated with a role (dairy, beef, dual purpose). All dairy females are included in the dairy sector; bulls used in the dairy sector and replacements for adult bulls are included with all other bulls in the beef sector. This is because of the difficulties of differentiating bulls between the sectors and thus ensures complete reporting of total emissions from UK agriculture. Dual purpose animals are assigned as da iry or beef according to the majority cattle type on the specific holding. Each breed type is associated to one of the inventory categories of large, medium or small. For the years prior to the introduction of the CTS in England, Scotland and Wales (1990-2004), and for Northern Ireland for the entire timeseries, annual data were derived from the JAS at holding level. Monthly cattle numbers for these years are assumed to be equal to the annual JAS total. Dairy industry data were used to characterise the proportion of dairy cattle associated with each production system for pre -CTS years, i.e. 1990 to 2004 for England, Wales and Northern Ireland. Breakdown of dairy cow bree d types for 1990 was derived from Dairy Facts and Figures, 1992 (Milk Marketing Board), with the breeds being associated with

UK NID 2025 (Issue 1) Ricardo Page 341 the inventory production system categories. Data for 1991 to 2005 were interpolated between Dairy Facts and Figures for 1990 and CTS data for 2006 onwards. Straw use is a fixed quantity per head based on survey data97. Beef cattle are disaggregated into 15 age bands, four breed types (continental, lowland native, upland native and all dairy males) and six sub-categories by role, associated with different live weights, growth rates and management practices. The roles include heifers for breeding, beef females for slaughter, bulls for breeding, cereal fed bulls for slaughter, steers for slaughter and beef cows. Data from the CTS (BCMS, 2024) are used to populate the inventory categories at a monthly resolution for England, Scotland and Wales from 2005 onwards. Prior to this date, JAS data are used with monthly population scalars applied as derived from the period 2005 to 2009 when both CTS and JAS data were available. For Northern Ireland, JAS data are used for the entire time series. Straw use is a fixed quantity per head based on survey data. Sheep are disaggregated into three production systems (hill, upland and lowland) associated with different livestock parameters and management practices, and three types (ewe, lamb and ram) using data from the JAS (Defra, 2024a), the December Agricultural Survey (1993 to 2010), a specific survey on the disposal of lambs and their slaughter age from the United Kingdom sheep flock (Wheeler et al. ; 2012) and the occasional surveys of the Breeding Structure of the British Sheep Industry (Maniatis and Pollott, 1 998; Pollott and Stone, 2006; Pollott, 2012; and Pollott and Boon, 2021). The ewe category includes replacement breeding sheep and cull ewes, as well as the ewes and ewe lambs that were successfully lambed in the survey year. The lamb category includes slaughtered lambs and those retained for breeding. The proportions of replacement ewes that are first mated as ewe -lambs is based on an analysis of an extended time -series from the December Agricultural Census (1993 to 2010), that was verified against the latest Breeding Structure of the British Sheep Industry survey (Pollott and Boon, 2021). The JAS count of lambs is raised in England, Wales and N Ireland by 5%; and Scotland by 1%.to account for the fraction of early spring lambs that are born, reared and marketed before the survey takes place (Pollott and Stone, 2006; Wheeler et al., 2012; Pollott and Boon, 2021). Animal numbers are split between hill, upland and lowland systems (associated with breed and management practices), based on holding location with respect to the Less Favoured Areas (LFA) weighted by survey data from Wheeler et al. (2012), and verified aga inst historical records of payments made under the Hill Livestock Compensatory Scheme (Agricultural Notebook, 2003). For each system, the proportions of lambs finished at grass, finished as stores, or used for breeding replacements, are derived from analys es of the survey data collected by Wheeler et al. (2012), and verified against the occasional surveys of the Breeding Structure of the British Sheep Industry (Maniatis and Pollott, 1998; Pollot and Stone, 2006; Pollot, 2012; and Pollot and Boon, 2021). Bedding straw use in housing is calculated from how much urine an individual sheep produces, and the quantity of straw that is required to absorb the urine, based on absorbance measurements reported by Misselbrook and Powell (2005) and Olson (1940). Six categories of swine are (1) sows (including sows in pig, sows being suckled and dry sows being kept for further breeding); (2) gilts (including gilts in pig and gilts not yet in pig); (3) boars for service; (4) fattening swine >80 kg (includi ng barren sows for fattening); (5) 97

UK NID 2025 (Issue 1) Ricardo Page 342 fattening swine 20-80 kg; (6) fattening swine <20 kg. Data are obtained from the JAS (Defra, 2024a) for England, Wales, Scotland and Northern Ireland, and where JAS categories do not match the inventory categories, consistent data translation rules are app lied from the Defra AC0114 project (Defra, in prep). The JAS has not collected information on all fattening pig sizes since 2009, estimates of the proportions are based on earlier census returns in every year since. The format of the census also changed in the 2024 submission with a new explicit Eight categories of poultry are (1) growing pullets; (2) laying hens; (3) breeding flock; (4) broilers; (5) turkeys; (6) ducks; (7) geese; (8) all other poultry (exc. turkeys, ducks and geese).
Data are obtained from the JAS (Defra, 2024a) for En gland and the DAs, and where JAS categories do not match the inventory categories, consistent data translation rules are applied from the Defra AC0114 project (Defra, in prep.). Data for England & Wales in 1996 were missing from the agricultural census (ho lding level) data and have been recreated by scaling these at a holding-level with the 1995 census to national totals. 5.1.4.3.6 Goats, deer, and horses The number of goats, deer and horses are derived from JAS holding level data (Defra, 2024a), and for horses not kept on agricultural holdings, from the British Equestrian Trade Association national survey (BETA, 2019). This dataset has not been updated sin ce 2015 due to lack of access, so we report UK population of professional horses as 87,112 and domestic horses as 608, 242 (derived from reported percentages). Missing data for some years were gap-filled by extrapolation, using data from adjacent years. 5.1.4.4 Crop types and crop areas Data are required by crop type, end purpose, location, rates, timing and type of fertiliser or manures applied, crop yields, residue management practices, residue N concentrations and Forty-eight annual and perennial crops (and composite crop groups) are categorised in the UK inventory. Cereals comprise oats, wheat, barley and other minor cereals (with disaggregation for spring and winter types and end uses (e.g. milling vs feed wheat) where possible); other crops include field beans and peas; potatoes, sugar beet, oilseed rape, maize (for silage), root crops, leafy forage and other fodder crops; vegetables and other horticultural crops, soft and top fruit, miscanthus coppice, willow, vine grapes, linseed and flax. Full details of crops are in Grassland is classed as improved temporary (sown within the last 5 years), improved permanent (not sown with the last 5 years), and unimproved (Unimproved Sole Right Rough Grazing and Unimproved Common Grazing). Areas are estimated using a new categorisation of holding level records from the JAS (Defra, 2024a). Improved grass area is disaggregated between representative farm types, defined by enterprise share of standard output. Values for the proportion of both temporary and permanent improved grassland ar ea that is renewed annually are 16.6%, 5.4% and 12.1%, for England, Wales and Scotland, respectively for temporary grass, and 3.1%, 2.7% and 2.5% for England, Wales and Scotland, respectively for permanent grass (BSFP, 2024). The grassland areas are verifi ed using two different data

UK NID 2025 (Issue 1) Ricardo Page 343 For the estimate of emissions from mineralisation , the land use change areas have been significantly updated. Previously they were based on decadal matrices derived from the Countryside Survey data. In this submission, minor changes to soil N mineralisation were carried out in all DAs from 2010 onwards from updates to deforestation areas from 1990 onwards as well as minor changes to organic soil areas. Calculations of N inputs from the biomass in crop residues include UK-specific data on above ground biomass, management methods and the N concentrations in such biomass (Williams and Goglio, 2017). Nitrogen inputs from cereal crop and oilseed rape residues are estimated in the UK inventory using an approach based on the Harvest index parameterised using mostly UK (and some European) data. The IPCC Tier 1 method considerably overestimates cereal crop residues when primary yields are as high as those in the U K. Activity data on residue management available since 2004 from the British Survey of Fertiliser Practice (BSFP, 2024) enable limited disaggregation by country, crop and farm type. Residues from grassland are calculated using a UK -specific semi-empirical N mass-balance model which captures the effect of level of N fertilisation, soil water stress and cutting frequency on dry matter (DM) production, N off -take and N leaching. The stru cture of the model is informed by existing grassland N -balance (Scholefield et al, 1991; and Ritjema, ICW, 1980) and nitrate leaching models (SLIM: Addiscott and Whitmore, 1991; and Anthony et al., 1996) and calibrated against national field trials. Areas of crop residues that were harvested or burned came initially from national level surveys from 1990 to 1993 (when straw burning was made illegal in the UK) and then from the BSFP field level data from 2004 to the latest year (BSFP, 2024). Primary crop yields are taken from national statistics, except for some minor crops that that are taken from the main farm management guides (Nix, 2024; Mowbray, 2020). Regional yields of major cereals in England became available from 1999 and these are used in prefe rence to the national values for England (Defra, 2024a; Defra, 2024d). Farm practice data in Northern Ireland (NI) are supplied by the lead NI government agricultural statistician (DAERA, 2024). UK NID 2025 (Issue 1) Ricardo Page 344 Details of values used are in the Annexes. 5.1.4.6 Inorganic fertiliser types and application rates Six N fertiliser types are considered in the UK greenhouse gas 1) ammonium nitrate, 2) urea, 3) urea ammonium nitrate, 4) ammonium sulphate/diammonium sulphate (considered together), 5) calcium ammonium nitrate, and 6) all other N fertilisers. The inventory uses data from the BSFP for England, Wales and Scotland (BSFP, 2024) and the Farm Business Survey (FBS) for Northern Ireland (DAERA, 2024) on application rates to crop type and the relative use of different fertiliser types. The data from befo re 2004 are sourced from paper reports of the BSFP (1990 to 2003). From 2004, field level data are available from BSFP enabling N applications for most crops (or crop groups) to be disaggregated to the levels of country, region and Farm Type. Fewer data exist for minor crops which are disaggregated at the country level. For grassland, emissions are calculated for improved temporary and permanent grassland; it is assumed that no N is applied, and no renewal takes place in sole rights or commons rough grazing land.
Field average fertiliser N application rate for improved temporary and permanent grassland are calculated separately, by Farm Type, using additional information sourced from these surveys on the proportion of the grass area receiving fertiliser N. Fertiliser use has decreased in the timeseries due to the energy and input price crisis, less for data for comparison. The proportion of urea from the total fertiliser applied significantly In both cases, the BSFP data is re -analysed. In the first 2 figures, the inventory data was produced by re -analysing the BSFP values, creating new statistical weights for the survey strata (by farm type and size) and using June Agricultural Survey (JAS) information that is specific to the agricultural reporting year, as well as using our Inventory standardised definition of a farm type. In the last 2 figures, the IFASTAT data (that also originated from BSFP) is used as it has data -disaggregation not explicit in the BSFP, specifically by fertiliser type to derive

UK NID 2025 (Issue 1) Ricardo Page 345 overall N application rate to crops overall N application rate to grass

UK NID 2025 (Issue 1) Ricardo Page 346 contribution to total fertiliser use ammonium nitrate contribution to total fertiliser use

UK NID 2025 (Issue 1) Ricardo Page 347 The data sources, application and deposition of animal manures are described in Chapters 5.3 and 5.4. In addition, other organic N additions are also applied in the a) Sewage sludge (liquid or as sludge cake) b) Digestates from the anaerobic digestion of livestock manure c) Digestates from the anaerobic digestion of energy crops, food waste and other organic d) Composted green waste applied to land (emissions from which are currently NE as no Emissions are estimated based on the quantities of the different organic N additions being applied to land, the characteristics of those N additions (e.g. N content, total ammoniacal N (TAN) content), the land use to which they are being applied (arable or grassland), the appropriate emission factor for each greenhouse gas or air quality pollutant (see Chapters 5.4 and 5.5) and a reduction factor for the proportion to which specific mitigation measures are Emissions of N2O are calculated Where Q is the quantity of organic material applied (m 3), TN is the total N content of the material (kg m -3); EFN2O is the emission factor applied (as % of the TN applied). Month of application (to account for seasonal differences in practices and emission factors if such data become available) and Robust Farm Type (RFT, to reflect differences in practices if such data become available) are considered. Indirect N2O emissions from volatilised and leached N are calculated according to IPCC 2006 Guidelines, using default IPCC N 2O emission factors EF4 and EF5 and applying UK-specific values for FRACleach. 5.1.4.8 Animal waste manure systems The split of manures into different management systems is based on data from several reference Smith (2012); Smith and Williams (2016); Parsons and Williams (2015); DAERA personal communication, 2019 (see details in Annex 5.1). UK NID 2025 (Issue 1) Ricardo Page 348 The UK Emission Factors used for the 1990-2023 inventory are in a supplementary file in 5.3.1 Source category description Source included Method Emission Emissions sources 3A1: Dairy Cows Enteric Key Categories 3A: Enteric Fermentation - CH4 (L2, T2) 3A1: Enteric fermentation from Cattle - CH4 (L1, T1, T2) 3A2: Enteric fermentation from Sheep - CH4 (L1, T1) Completeness No known omissions. A general assessment of completeness for the inventory is Updates to activity i) revised the rate of fleece growth; ii) revised milk yield values; iii) revised slaughter weights Methane is produced in herbivores as a by -product of enteric fermentation. Enteric fermentation is a digestive process whereby carbohydrates are broken down by micro - organisms into simple molecules. Both ruminant animals (e.g. cattle and sheep), and some non-ruminant animals (e.g. swine and horses) produce CH4, although ruminants are the largest source per unit of feed intake. UK NID 2025 (Issue 1) Ricardo Page 349 Source category significance, trends and drivers Between 1990 and 2023, total UK emissions of enteric CH 4 decreased by 16.8% and compared with 2022, emissions were 2% lower in 2023. Total enteric CH 4 emissions in 2023 Enteric CH4 emissions are estimated from the intake and diet characteristics for ruminants. The steps are described in Schematic diagram 1. Schematic diagram 1: highest Tier method used for estimating dry matter intake (DMI) and N content in the diet from ruminant livestock. For non -ruminants, calculations for N 2O and manure CH 4 start from Box A using Country Specific N contents and default VS; enteric CH4 is estimated using IPCC default methodology. ME is metabolisable energy, VS is volatile solids and LWG is liveweight gain. Enteric CH4 emissions for dairy cows are estimated using a UK-specific relationship between daily enteric emission and feed dry matter intake, as developed under Defra -funded projects AC0115 (Defra, 2014a) and AC0114 (Compton et al., 2022): 𝐶𝐻4_𝑒𝑛𝑡𝑒𝑟𝑖𝑐_𝑑𝑐 = (15.8185 × 𝐷𝑀𝐼) + 88.6002 CH4_enteric_dc is the enteric CH4 emission per dairy cow, g d-1; DMI is feed dry matter intake, kg d-1; and standard error values for the slope and intercept are 0.8338 and 14.5782, respectively. Calculations are performed at a monthly resolution, with characterisation of production, management and feed by dairy cow category for each month. Further details are given in

UK NID 2025 (Issue 1) Ricardo Page 350 Dry matter intake by dairy cows is determined using UK-specific energy balance equations as published in Feed into Milk (Thomas, 2004), based on metabolisable energy (ME). The daily ME intake by the animal is assumed to correspond with the requirement for live weight gain, activity, milk and gestation. Average milk yield per cow is derived from national statistics provided by each country and this is disaggregated to breed type (large, medium, small) based on industry data regarding yields for specific bree ds ( Breed-specific data are available back to 1999 and extrapolated back to 1990 based on the trend from 1999-2014.
All are then normalised against the devolved administration (DA) data, and finally UK statistics on A standard growth curve is defined for dairy cattle, based on that given by Coffey et al., (2006), and is used to define live weights for each age category, with annual data for mature cow weight by proxy breed type being obtained from UK slaughter statistics as analysed by SRUC. Calf birth weight is related to mature cow weight (AFRC, 1993). Average age at conception for first calving is defined as 19, 20 and 18 months for large, medium and small breed proxies for GB, respectively. For NI it is defined as 20, 23 and 25 months, respectively. Respective age at first calving is 28, 29 and 27 months for GB and 29, 32 and 34 for NI, for which relevant live weights can be derived. There is no evidence from industry data of any consistent trend over Standard dietary components have been defined and associated with the outdoor grazing and indoor housing periods for each production system. Cattle are assumed to be fed concentrates at an average level as reported annually in Nix Farm Management Pocket bo ok (Redman, 2025) for GB cattle, and Ferris (2021) for NI cattle, with the remainder of the diet derived from forage (at grazing or fed as conserved silage). Forage diet components include grazed grass (with and without clover), grass silage, maize silage and whole crop silage. Increasing use of forage maize, with associated higher energy and lower crude protein content, is reflected in 5.3.2.1.4 Housing and grazing period Dairy cattle are managed according to four year -round housing, winter housed and summer part-housed (overnight), winter housed and summer grazing, extended grazing. The proportion of the national herd associated with each management regime is based on a survey reported by March et al. (2014) for GB cattle and Ferris (2021) for NI cattle and industry expert judgement on trends since 1990, assuming no year-round housing. Enteric CH4 emissions from other cattle, including dairy sector replacements and calves, and all beef sector cattle, are estimated using the same approach as for dairy cows but with different relationships between enteric emission and DMI for lactating and non-lactating cattle. For lactating cattle (i.e. beef suckler cows) the same equation as for dairy cows (presented above in 5.3.2.1) is used. For all non -lactating cattle, the relationship as developed under Defra-funded projects AC0115 (Defra, 2014a) and AC0114 (Compton et al., 2022) 𝐶𝐻4_𝑒𝑛𝑡𝑒𝑟𝑖𝑐_𝑜𝑐 = (17.5653 × 𝐷𝑀𝐼) + 45.8688 CH4_enteric_oc is the enteric CH4 emission per other cattle, g d-1; DMI is feed DMI, kg d-1; and standard error values for the slope and intercept are 2.4112 and 16.1505, respectively. As for dairy cows, DMI for other cattle categories is determined using UK -specific energy balance equations, derived for non -lactating cattle from AFRC (1993) combined with cattle

UK NID 2025 (Issue 1) Ricardo Page 351 category- and system-specific production and diet characteristics at a monthly resolution as described for dairy cows (and further detail given in Annex 5.1.3). The AFRC (1993) recommendations on the energy allowances for cattle are used to estimate the metabolisable energy (ME) needs of cattle (based on liveweight, growth rate, gestation and lactation). The ME coupled with activity data from a Defra FBS module (P arsons and Williams, 2015) is used to derive diets, characterised by composition of ME (MJ/d), gross energy (GE) and crude protein (CP) in each diet. DMI (kg/d), GE and CP intakes are derived from the ME needs (MJ/d) and the ME density in feed (MJ/[kg DMI]). 5.3.2.2.2 Cattle live weights (LW) Cattle live weights are based on a Michaelis -Menten type growth model (López et al., 2000). The model requires mature LW, calf LW and two fitted parameters. Mature LW data are obtained from the established time series of slaughter weights that are collecte d at national level (Defra, 2024b), and supplemented with a very large sample of data from which separate populations are derived of the breed types and age bands used in the model (Wall and Pritchard, 2017). Calf weights are calculated from an established equation in AFRC (1993). Parameters were fitted from a variety of industry and literature sources, as summarised in The fractions of cattle lactating and/or gestating are derived from industry performance data and an analysis of the CTS dataset. The fractions of cattle lactating and/or gestating are applied uniformly over the population throughout the year. The ME needs for maintenance, growth, lactation and gestation are calculated for every age band and cattle type to estimate the DM intake and intakes of CP and GE, which are used to calculate enteric CH4 emissions, volatile solids (VS) excretion and N excretion. There are 11 standard diets assumed for cattle, three corresponding to different types of grass and two corresponding to suckled calves at grazing with mixed nutrition from milk and grass. Data for feeds used (by material) are from the FBS (Parsons and Wil liams, 2015) and nutritional properties of each material in the diets are derived mainly from the Feed Composition Tables (MAFF, 1992), with some from Ewing (1998). Diet data for dairy replacements and calves follows the same approach as for dairy cows with data derived from 5.3.2.2.4 Housing and grazing period Data from a FBS module (Parsons and Williams, 2015) and other farm practices surveys (Defra, 2024c) were used to derive the grazing season lengths across the UK at DA level and with England split into three parts. These applied to cattle roles and ages, although age bands were more highly aggregated than the CTS-based age bands. Farm practices survey data are used to quantify the housing systems and manure management regimes used as (1) Housed all year; (2) Housed in the winter, out in the summer; (3) Outside all year; (4) Housed all year + yards; (5) Housed winter, out summer + yards. The housing management regimes were used to define cattle locations by month, i.e. grazing, in resting areas and in feeding yards.
Each of these has its own emission factors for ammonia and N2O. The same approach to estimating enteric emissions for cattle is taken with sheep, but using a UK-measurement derived relationship between enteric emission and DMI specific to sheep 𝐶𝐻4_𝑒𝑛𝑡𝑒𝑟𝑖𝑐_𝑠ℎ𝑒𝑒𝑝 = (12.3894 × 𝐷𝑀𝐼) + 5.1595

UK NID 2025 (Issue 1) Ricardo Page 352 CH4_enteric_sheep is the enteric CH 4 emission per sheep, g d -1; DMI is feed dry matter intake, kg d -1; and standard error values for the slope and intercept are 1.483 and 0.8301, Feed intake is calculated using a modified version of the AFRC (1993) energy requirements to meet the metabolisable energy needs of the animal. It is applied to a description of the live - weight gain of the animal from birth to slaughter. Each type of ewe a nd lamb has separate growth-curves, access to housing and handling yards, and different access to forage, concentrate and conserved feeds that determine its feed intake. The energy requirement is a function of the animal’s live -weight, stage of pregnancy, growth rate and production of milk. Application of the model is dependent on estimates of live -weight at slaughter, derived from national slaughterhouse statistics and of age at slaughter, derived from a national survey of lamb slaughter age (Wheeler et al., 2009). 5.3.2.3.2 Sheep live weights (LW) The inventory uses country- and system-specific values for the LW of the adult ewe and lamb, and for the rate of weight gain. The annual average weight of ewes and slaughter weight of lambs are calculated separately for each country based on average carcas e weights and a fixed killing-out percentage of 42 and 45% respectively, derived from national slaughterhouse statistics98. The relative ewe weights for the hill, upland and lowland systems within each country are estimated based on an analysis of breed lists and expected mature weights and are centred on the country average. Fresh grass is the most important feed, with a metabolisable energy content of 11.1 MJ kg -1 DMI and a crude protein content that varies spatially in response to the clover content and level of synthetic N fertiliser applied to pasture. Ewes and rams are fed a supplement of conserved silage and hay for 120 days over -winter, and store lambs are fe d silage, hay and roots for 100 days. The metabolisable energy contents are 10.6 MJ kg-1 dm for silage, 9.4 MJ kg-1 DMI for hay, and 9.2 MJ kg-1 DMI for roots. The crude protein contents are 130 g kg-1 DMI for silage, 111 g kg -1 DMI for hay, and 192 g kg -1 DMI for roots. Lambs are provided with an average creep feed ration of c. 0.150 kg day-1 DMI for 42 days prior to weaning, and ewes are provided with a concentrate ration of c. 0.130 kg day -1 DMI in the 56 days before and after lambing. The crude protein and metabolisable energy content of concentrate are 160 g kg -1 DMI and 12.5 MJ kg-1 DMI for the ewe and 180 g kg-1 DMI and 12.6 MJ kg-1 DMI for the lamb. 5.3.2.3.4 Housing and grazing periods The pregnant ewe and ewe lamb is housed for 42 days prior to lambing. The fraction of ewes housed varies with system from 40% (hill) to 75% (lowland) (Roderick, 2001). Straw is added to excreta in housing at a rate of 0.60 kg FW day -1. All ewes occupy handling yards for an overall average of 5 days, for essential welfare tasks. Feed and manure management is assumed to be the same as during housing. Lambs finished at grass are slaughtered at between 133 and 172 days, and store lambs at between 276 and 331 da ys, varying with country and system (Wheeler et al., 2012). Lambs intended for breeding replacement, and all ewes and rams are present all year. 98 Rural and Environment Science and Analytical Services (Annual), Economic Report on Scottish Agriculture, Scottish Government Directorate for Environment and Forestry ( agriculture/), Department of Agriculture, Environment and Rural Affairs (Annual) Output Value of Farm Products ( Hybu Cig Cymru (Meat Promotion Wales) Welsh Monthly Slaughterings ( Defra Latest Cattle, Sheep and Pig Slaughter Statistics (

UK NID 2025 (Issue 1) Ricardo Page 353 Enteric emissions for swine are estimated using IPCC (2006) Tier 1 methodology, with a Tier 1 default EF and UK-specific activity data on animal numbers from the JAS (Defra, 2024a). Enteric emissions for goats, horses and deer are estimated using IPCC (2006) Tier 1 methodology, with a Tier 1 default EF and UK -specific activity data on animal numbers. The EF for goats of 9 kg/head/y, is according to the IPCC 2019 refinement to the 2006 guidelines for high production systems, as this is regarded as the most representative of UK farming practices in the expert judgement of the UK Inventory Agency. Whilst the UK GHG Platform research has not led to the derivation of a UK-specific EF, we note that the UK evidence was used to derive a value consistent with the value presented in the 2019 Refinement, and hence in our expert judgement to use the 2019 Refinement EF is the most representative EF option available to best reflect UK circumstances; we consider that applying that EF minimises the uncertainty in the UK Inventory for this source. 5.3.2.6 Overseas Territories and Crown Dependencies Emission estimates were compiled using animal numbers sourced from the territories directly and can be found in Annex 3.6. In the case of OTs, IPCC default EFs were applied to animal numbers. For CDs, UK implied EFs were applied. 5.3.3 Uncertainties and time-series consistency The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC The estimates of uncertainties in emissions were calculated using Approach 2 (Monte Carlo simulation) described by the IPCC using the new Tier 3 models derived for the UK greenhouse gas inventory. Model runs are computationally intensive and so a prelimina ry analysis was undertaken to determine the number of samples needed.
This analysis showed that 2500 samples were sufficient to estimate the 95% confidence interval with 95% confidence. Once samples have been computed suitable distributions are fitted to the outputs and fed forward to the wider inventory calculations. Emissions are calculated from animal population data and appropriate EF. The animal population data are collected in the JAC, published annually by the devolved administrations (i.e. England, Wales, Scotland and Northern Ireland). These are long running publications and the compilers of the activity data strive to use consistent methods to produce the activity data. The time-series consistency of these activity data is very good due to the continuity in data Control measures introduced in response to the bovine spongiform encephalopathy (BSE) outbreak in the UK introduced an inconsistency in the slaughter weight statistics and the derived dairy cow live weights for the years 1997 to 2005. To correct for the artefacts introduced by these control measures in the data time -series, data for this p eriod were interpolated using the linear trend of increasing lives weight with time for the years immediately prior to and following this period. 5.3.4 Source-specific QA/QC and verification This source category is covered by the general QA/QC procedures, which are discussed in Details of the QAQC across the agriculture inventory model and methods are described within Annex A5.1.3 Some of the data validation checks are also presented within the supplementary MS Excel file that accompanies the NID and within the NID (sections 5.1.4.4 and 5.1.4.5). UK NID 2025 (Issue 1) Ricardo Page 354 Specific to the Enteric Fermentation source category, the UK sector experts conduct the following QC activities on the cattle • In Cattle Tracing Scheme (CTS) data processing, QC is conducted to identify cattle that are mixed breeds (dairy/beef) and to review the holding level information across the time series to ascertain the type of farm and likely cattle type; additional QC identifies any new breeds and flags those to sector experts to assign them to dairy or beef sector. • Completeness and time series consistency checks against other herd statistics (e.g. from Defra JAS/C data) are conducted at the DA / livestock type level. In the annex, we describe the flow for the CTS data processing. 5.3.5 Source-specific recalculations In this submission provisional average milk yields have been updated to match the most recent published statistics, resulting in small changes to the average milk yield of dairy cows for the Small updates to the slaughter weight activity data have been made for the years 2016, 2017, The rate of fleece growth for growing lambs was revised from a yearly value to a function of live-weight applied daily, derived from measurements of clean fleece and animal weights for UK breeds presented in Saul et al. (1993; n=27). This resulted in a net increase in the feed energy intake and protein retention to support fleece growth for lamb finished off grass and present for around six months in a year. Changes in activity data and to emission factors due to these recalculations to are given in

Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 355 2024 submission 2025 submission Units Comment/Justification 1990 2022 1990 2022 3.A.1.a Enteric fermentation – Dairy cattle 279.44 227.96 279.44 228.00 kt Replaced slaughter weight timeseries (from 2016); Updated milk yield (2021 and 2022) to match 3.A.1.b Enteric fermentation – Non-Dairy cattle 476.49 416.11 476.49 416.11 kt Replaced slaughter weight timeseries (growth curve for followers/calves based on cow mature weight) 3.A.2 Enteric fermentation – Sheep 209.25 169.27 209.66 169.70 kt Revisions to annualised rate of fleece growth and protein retention in growing lambs (affects all years) 2024 submission 2025 submission Units Comment/Justification 1990 2022 1990 2022 3.A.1.a Enteric fermentation – Dairy Cattle 98.11 123.34 98.11 123.36 kg/hd/year Replaced slaughter weight timeseries (from 2016); Updated milk yield (2021 and 2022) to match 3.A.1.b Enteric fermentation – Non-Dairy Cattle 51.36 54.55 51.36 54.55 kg/hd/year Replaced slaughter weight timeseries (growth curve for followers/calves based on cow mature weight) 3.A.2 Enteric fermentation – Sheep 4.60 5.01 4.61 5.02 kg/hd/year Revisions to annualised rate of fleece growth and protein retention in growing lambs (affects all years)

Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 356 5.3.6 Implied emission factors The implied emission factors for CH4 emissions from enteric fermentation for dairy, non-dairy cattle and sheep (123.3, 55.5, 5.0 kg/head/yr, respectively) were different to IPCC 2006 default values (109, 57, 8 kg/head/yr) due to the application of country specific data. 5.3.7 Source-specific planned improvements There are a number of methodological improvements that the UK Inventory Agency will consider for future submissions, dependent on the availability of evidence from research and statistics agencies, • Revise the parameters included in the energy balance equations for non-lactating cattle based on recent and ongoing research from the Agri-Food and Biosciences Institute • Explore Northern Ireland CTS data access, to bring the cattle method for NI into line • Revise livestock housing assumptions. • Simplify the allocation of ewes to hill-upland-lowland sectors. • Consider cattle age at death from CTS data – improve estimate of emissions, • Data on concentrates for cattle followers – similarly effect on enteric CH 4 emissions (but will affect other losses)

Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 357 5.4.1 Source category description Source included Method Emission Key Categories 3B1: Manure management from Cattle - CH4 (L1, T1) 3B2: Manure Management - N2O (L1) Completeness There are no UK activity data for the practice of composting of manure within MMS and hence no CH4 nor N2O emissions for this source are currently reported in the GHGI. A general assessment of completeness for the inventory is included in Changes in Implementation of 2019 EF for liquid/slurry from dairy cattle with a natural crust cover or cover.
Revision of the housing ammonia (NH 3) EF for pullets, breeding flock, ducks & geese and other poultry (changes in NH3 affect the N balance Changes in manure management have been introduced due to the implementation of Firm and Funded In Northern Ireland, activity data have been revised for slurry storage in above ground tanks, from 2020 all new above ground slurry stores are required to be fitted with a cover. Also, Low Emission Slurry Spreading

Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 358 Equipment (LESSE) (including incorporation) must be used i) for digestate applications from 2020, ii) for slurry spread by contractors from 2021 and, iii) on all large cattle and pig farms from 2022. In Wales, application of organic manure (slurry, digestate and poultry manure) to bare soil or stubble must be incorporated within 24 hours, unless LESSE has been used (applied from 2022). In Scotland, from 2023 all liquid digestate, slurry applied by contractors or on large cattle and pig farms should be applied using LESSE. Updates to activity data : i) amount of dairy, beef, pig and poultry manure anaerobically digested affecting amounts in storage and spread to land; ii) milk yield; iii) slaughter weights; iv) from 1992 for the amount of poultry litter incinerated; v) amount of non-manure digestate applied to land from 1997 of sewage sludge; vi) revised the rate of sheep fleece growth; vii) revised values of protein content of grazed grass. Methane is produced from the decomposition of manure under anaerobic conditions during its storage and treatment. This applies mainly for liquid systems, whilst for solid systems and deposition of excreta during grazing, conditions are less anaerobic, so less CH4 is expected to be emitted. The main factors affecting emissions are the quantity of manure and temperature during storage. Nitrous oxide is also produced from manure as a result of nitrification and denitrification occurring during its storage and treatment. The main factors affecting emissions are the quantity/quality of the manure (C, N content), duration of the storage and type of treatment. Indirect emissions from manure also occur, through volatilisation of N (as NH 3 or In the UK, livestock manure is mainly managed as liquid slurry or solid manure (Farmyard Manure, FYM), and as urine and dung deposited to pasture. Manures based digestate are also managed and have increased in importance in the last few years. Source category significance, trends and drivers Total UK CH4 emissions from manure management in 2023 were 147.7 kt CH 4. Emissions in 2023 were 11% lower than in 1990 and 2.5% lower than 2022. 5.4.2.1 Methane emissions from animal manures and manure-based digestates The EFs for manure management are calculated following IPCC Tier 2 methodology for cattle, sheep, swine and poultry, according to IPCC (2006) Equation 10.23. For cattle and sheep, country-specific values for volatile solids (VS) excretion are derived by animal sub-category and production system using the UK-specific ME balance equations (as described in Section 5.1) and an estimate of GE intake (based on estimated DMI and feed energy content) according to a variation of IPCC (2006) Equation 10.24: 𝑉𝑆𝑒𝑥 = (𝐺𝐸𝑖 × (1 − (𝑀𝑒𝑟𝑒𝑞 𝐺𝐸𝑖⁄ ))) × ((1 − 𝐴𝑆𝐻) (𝐺𝐸𝑖 𝐷𝑀𝐼⁄ )⁄ ) VSex is the volatile solids excretion, kg d-1; GEi is the gross energy intake, MJ d-1; ASH is the ash content of the manure as a fraction of the dry matter feed intake; DMI is the dry

Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 359 UK-specific data on the CH 4 producing potential (Bo) of cattle excreta were not significantly different from IPCC (2006) default values (Defra 2014a), so the default values were retained. In the case of sheep, VS excretion also accounts for varying energy content of urine, varying with feed protein level. VS values are calculated using the AFRC (1993) energy balance model and calculated enteric methane emissions (Crompton et al., 2017). The range of calculated volatile solids excretion is 33 to 67 kg hd -1 for lambs, 129 to 161 kg hd -1 for rams and 128 to 155 kg hd -1 for ewes. Default methane conversion factor (MCF) for excreta are applied, at grazing of 1% and for manure managed as ‘solid st orage’ of 2%, expressed as a fraction of the default maximum methane producing capacity (0.19 m 3 CH4 kg-1) of the excreted volatile solids. The effective methane conversion factor (MCF), expressed as a fraction of the gross energy intake, is in the range 4.4 to 5.0% for lambs and 4.8 to 5.3% for ewes, in comparison to IPCC (2006) default values of 4.5% and 6.5% respectively. For swine, IPCC (2006) default values for VS and Bo are used. Manure is split into 3 management systems, slurry, FYM and outdoor systems. Animals are on fully slatted floor, part slatted floor, solid floor with bedding or outdoors. For poultry, IPCC (2006) default values for VS and Bo are used. applied, with the exception of liquid/slurry systems with a natural crust cover, where no reduction in the MCF value is assumed in accordance with recent literature evidence (e.g. Petersen et al., 2013). Country -specific MCF values are used for the anaerobic digestion of livestock manures based on the values used in the German inventory. These data are combined with country -specific data for the proportion of manure from each livestock type managed according to the different animal waste management systems (AWMS). The EFs are conversion factors assumed for the different systems. There are no UK activity data for the practice of composting of manure within Manure Management Systems (MMS) and hence no CH 4 nor N 2O emissions for this source are currently reported in the GHGI. The composting of manures is a very minor activity in the UK and, as noted in recent UNFCCC reviews, the omission of this activity is not expected to lead to an under-report in UK emissions.
The separate reporting of manure being composted would be expected to lead to lower overall emissions from manure management ; CH4 emissions would be lower, as CH 4 conversion factors for composting are lower than for most other manure management systems (in particular, lower than for solid storage and liquid systems). In the view of recent ERTs, the actual difference in N 2O emissions would depend on the management system that is diverting manure to composting, but any underestimation would likely be small and the impact on overall emissions negligible. The UK will retain this completeness issue on our inventory improvement log, seeking activity data to address this For goats, deer and horses , IPCC (2006) Tier 1 default emission factors were used (IPCC Tables 10.15). For broilers the VS excretion value of 0.02 kg/head/d, is applied according to the IPCC 2019 refinement to the 2006 guidelines. This value is regarded as the most representative of UK farming practices in the expert judgement of the UK Inventory Agency. Whilst the UK GHG Platform research has not led to the derivation of a UK -specific EF, we note that the UK evidence was used to d erive a value consistent with the value presented in the 2019 Refinement, and hence in our expert judgement to use the 2019 Refinement EF is the most representative EF option available to best reflect UK circumstances; we consider that applying that EF minimises the uncertainty in the UK Inventory for this source. Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 360 5.4.2.2 Nitrous oxide emissions from Animal Waste Management Systems Animals are assumed not to give rise to N2O emissions directly, but emissions will arise from N excreted by livestock. Emissions from manures during storage are calculated for different animal waste management systems (AWMS) defined by IPCC. Emissions from the following AWMS are reported under the M anure Management IPCC category (it is assumed that uncovered anaerobic lagoons are not present in the UK): • Solid storage/deep litter/poultry manure; Following IPCC methodology (2006), the following AWMS are reported in the Agricultural Soils • All animal manures, slurries and digestates applied to soils; and In this submission, we have introduced an EF for N2O emissions from slurry tanks with natural crust cover or cover for dairy cows’ slurry. The IPCC 2019 Refinement value of 0.5% has been mitigation actions to control ammonia emissions which then impact upon the Nitrogen balance Schematic diagram 2: Manure management systems in the UK agriculture inventory. [Box B contains all the manure management systems relevant for the UK.] [DMI: dry matter intake; activity data; Cattle Tracing Scheme]

Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 361 Emissions trends and methodologies For N2O, total emissions from manure management in 2023 were 9.4 kt N 2O. Emissions in 2023 were 19.6% lower than in 1990 and 2.5% lower than in 2022. 5.4.2.2.1 Livestock N excretion Nitrous oxide emissions from manure management are estimated following IPCC (2006) (equation 10.25) for each livestock category and subcategory, using country-specific data for N excretion by the different livestock types and for the proportion of manure m anaged according to the different AWMS, and a combination of default and country -specific EFs for the different AWMS. The UK has implemented a detailed N-flow model describing the flow of N from livestock excretion through the manure management chain (base d on Webb and Misselbrook, 2004), accounting for all N losses (via NH 3, N2O, NO, N 2 and N leaching) and transformations (immobilisation, mineralisation) at each manure management stage (i.e., housing and yarding, storage, land spreading, grazing). For cattle and sheep, N excretion is estimated as the balance of N intake and N retained in live weight gain, milk, wool and developing foetus, specific to livestock sub -category, production system and diet. N intake is estimated from the calculation of DMI, based on energy requirement and feed characteristics (Section 5.1), and the crude protein content of the feed. For cattle, N excreta are partitioned to urine N and dung N, based on literature equations relating N excreta to N intake (Reed et al., 2015). The urine N is assumed to rapidly convert to ammoniacal N whereas the dung N remains as organic N. These different N forms have important implications for subsequent N losses and transformations through the manure management chain (Webb and Misselbrook, 2004). In this submission, N 2O emissions from slurry tanks with a cover are calculated following IPCC 2019 guidelines. For sheep, based upon a national survey by Roderick (2001) of 2,649 flocks managed by members of the National Sheep Association, the inventory calculations assume that 75% of ewes associated with lowland systems, 60% with upland systems, and 40% with hill systems are housed in the last weeks of pregnancy. Also, that housed breeding ewes are housed for 42 days prior to lambing, and that neither the ewe nor new-born lamb are housed post lambing. The effect of excluding new -born lambs from the housing calculat ions is a negligible (< 1%) reduction in the quantity of managed manure. Data from 2 other surveys by Lima et al. (2018) (England and Wales) and Bohan (2017) (Ireland) were used to support the assumption that no lambs are housed during the finishing period. Other assumptions regarding handling of sheep manure for short period in housing or yards are based on smaller surveys (Defra 2004; Dauven and Crabb, 1998; Webb et al., 2001) and communications from sheep experts ( Pers.
For sheep, the partition of excreta N between urine and dung is dynamic and from these 85% of urine N is TAN, and 15% of dung N is TAN, estimated from separate regression equations for excreta and urine N on the dietary protein content taken from the meta-analysis published The N excretion values for lambs appear low in comparison to published values for other countries, as these are often presented on the assumption that a lamb is present for a complete year (365 days) before slaughter. Statistical analyses of UK -surveyed slaughter ages (after Wheeler et al., 2012) have proven that lambs are present on average for only 237 days. The N excretion value of around 4 kg N/lamb is therefore for a 237 -day period, and not for a complete year (365 days). In the case of sheep, the weig hted average N excretion rate from all sheep categories is 7.5 kg N yr-1 (2019). We report N excretion values of around 4 kg N/lamb

Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 362 produced (see important note on N excretion above); around 11 kg N yr-1 per ram; and around Average N excretion values for neighbouring countries reported in their NIDs (previously NIRs) in 2019 are for all sheep 7.8 kg N yr -1 (Germany) and 6.6 kg N yr -1 (Denmark); and for ewes they range from 6.5 kg N yr -1 for upland ewes (Ireland) to 12.9 kg N yr -1 for lactating ewes Decandia et al. (2011) reported published N excretion rates data from sheep. The total N excretion rate averaged 13.9 g N day -1 for growing sheep (n 52); 16.7 g N day -1 for rams (n 20); 15.5 g N day-1 for dry ewe (n 21); and 40.4 g N day-1 for lactating ewe (n 26). The values for the dry and lactating ewe can be weighted by the UK surveyed average number of days from birth of lamb until weaning (around 120 days) to give an average yearly value of 23.7 g N day-1 per ewe. These average literature values are e ither the same or lower than the UK inventory values of 17.3 g N day-1 for all lambs, both finished and replacements; 30.9 g N day- 1 for rams; and 23.8 g N day-1 for all ewes. These reported data support the UK CS values. Schematic diagram 3: N inputs in the UK inventory to calculate N emissions For other livestock types, country-specific values for N excretion were derived from the Defra project WT0715NVZ report (Cottrill and Smith, 2007), with interpretation by Cottrill and Smith

Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 363 For swine and poultry, 70% of excreta are assumed to rapidly become ammoniacal N with 30% remaining as organic N. For goats, horses and deer, the respective excretal proportions are The revised N excretion values for swine were interpolated using data from Defra WT0715NVZ (for 2004): for sows, maiden gilts, boars, fatteners >110 kg, fatteners 80-110 kg, fatteners 50- 80 kg, fatteners 20-50 kg and weaners (<20 kg): 20.5, 15.5, 25, 17.6, 17.6, 12.7, 12.7, 4.0 kg N hd-1 y-1, respectively. Data reported by Defra WT1568 (for 2016) for the same categories 21.1, 11.7, 18.9, 13.2, 13.2, 9.6, 9.6, 4.0 kg N hd -1 y-1, respectively. For 1990, values were assumed to be 15% greater than those of 2004, except for gilts where the value was kept In the case of poultry, the N excretion values were revised by interpolating data from Defra WT0715NVZ (for 2004) laying hens – cages, laying hens - barn, perchery, laying hens - free-range, broilers, pullets, breeding hens, turkeys (m), turkeys (f), ducks (and geese), oth er 0.75, 0.75, 0.84, 0.51, 0.34, 1.08, 2.10, 1.40, 1.60 and 1.60 kg N hd-1 y-1 respectively. Values from Defra WT1568 (were used for 2016), for the same 0.66, 0.66, 0.83, 0.28, 0.36, 1.14, 2.10, 1.47, 1.20 and 1.20 kg N hd-1 y-1, respectively. For poultry a proportional uplift in N excretion for outdoor laying hens is included. N excretion values are for goats (from 20.6 to 8.4 kg/y) and deer (from 13 to 29.3 kg/y) according to IPCC 2019 refinement of the 2006 guidelines. 5.4.2.2.2 Direct N2O emissions The conversion of excreted N into N 2O emissions is determined by the type of manure For manure types with bedding addition, the N content of the added bedding is included in the for cattle, pig, sheep, goat, deer and horse deep litter systems where a UK-specific EF of 2.0% of total nitrogen excreted is used and for poultry manure wh ere a UK-specific EF of 0.5 % of total nitrogen excreted is used, as derived from UK measurements (Misselbrook, 2017, UK data relating to direct N2O emissions from manure management were reviewed as part of Defra project AC0114 (Smith and Williams, 2011). There were a limited number of studies, the emission sources. The UK CS values for cattle and pig FYM are greater than the default values given in the 2006 IPCC Guidelines (but much closer to the IPCC 2000 Good Practice Guidance value of 2%), and this higher val ue is also supported by other UK studies not included in the literature review (Moral et al., 2012; Defra project AC0112 – unpublished). The values are not significantly different, so a value of 2% is applied to both cattle and pig FYM. The mean measured EF for broiler litter is also greater than the default 2006 IPCC Guidelines value and therefore a CS value of 0.5% is applied to poultry manure management.
UK measurements of emissions from pig slurry storage were very low (apparently negative) and support the zero - emission factor default given by the 2006 IPCC Guidelines which is therefore applied in the A review of the literature on livestock housing and manure management practices ( Smith and Williams, 2013), updated with survey data on manure spreading practices from the BSFP (BSFP, 2024), and data from DAERA statistics for NI (DAERA, 2024) was used as the basis for developing the 1990 to 2023 time series of livestock housing and manure management practices for England and each DA (Wales, Scotland and Northern Ireland) from which a weighted average was derived for the UK. Underlying data sources include routine and ad-hoc

Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 364 surveys such as the Defra Farm Practices Surveys (Defra, 2024c) and published manure management surveys (Smith et al., 2000, 2001a, 2001b). The proportions of cattle manure management practices were based on a UK data synthesis by Smith and Williams (2016). The housing period for beef animals was derived from Parsons Within the sheep sector, all (100%) manure from the ewe housing period is assumed to be managed as solid farmyard manure with additions of straw bedding. All (100%) manure from the housing period is assumed to be stored for a period of several months as a field heap on grass before spreading to land. It is assumed that 75% of ewes associated with lowland systems, 60% with upland systems, and 40% with hill systems are housed in the last weeks of pregnancy and that these breeding ewes are housed for 42 days p rior to lambing, and that neither the ewe nor new-born lamb(s) are housed post-lambing (Roderick, 2001). Management for other activities (e.g. shearing) were obtained from various sources (Defra, 2004; Webb et For swine and other minor livestock, bedding N at housing is included in the calculations before Poultry manure going to incineration in power stations is associated with N2O emissions during A 5.1.13. The amount of poultry litter incinerated in each year is obtained directly from MRE UK99; the amounts exported from Northern Ireland to be incinerated in Scotland and England going for incineration are deducted prior to calculations of emissions from land spreading. Manure types going to incineration are assumed to be broiler and turkey litter and the reported quantities incinerat ed are converted to a proportion of the total manure for these poultry categories based on estimated manure outputs per bird. 5.4.2.2.3 Indirect N2O emissions For estimation of indirect N 2O emissions from manure management, country -specific values for FracGASM and FracLEACH are used. FracGASM is derived directly as output from the UK N-flow model for each livestock x AWMS combination, as the sum of the NH3-N and NO-N emissions (further details can be found in the UK Informative Inventory Report). A country-specific value of 2.4% of manure N for FracLEACH is used, based on Nicholson et al. (2017) and applied only to solid manure heaps stored in fields. For manure heaps stored on concrete pads, the leachate is assumed to be collected and is subsequently included in the N content of liquid/slurry managed manure. Indirect emissions from manure management due to volatilisation and leaching are then calculated according to IPCC (2006) equations 10.27 and 10.29, respectively, applying the IPCC 2019 refinement to the 2006 Guidelines default value (‘wet climate’) for EF4 (1.4%) and the IPCC 2006 Guidelines default value for EF5 (0.75%), as these are regarded as the most representative for UK conditions. 5.4.3 Uncertainties and time-series consistency The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC The estimates of uncertainties in emissions were calculated using Approach 2 (Monte Carlo simulation) described by the IPCC using the new Tier 3 models derived for the UK greenhouse

Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 365 gas inventory. The uncertainties in the estimates of livestock data were provided by the Emissions are calculated from livestock population data and appropriate emission factors. The livestock population data are collected in the JAC, published annually by the devolved administrations (i.e. England, Wales, Scotland and Northern Ireland). These are long running publications and the compilers of the activity data strive to use consistent methods to produce the activity data. The time -series consistency of these activity data is very good due to the 5.4.4 Source-specific QA/QC and verification This source category is covered by the general QA/QC procedures, which are discussed in 5.4.5 Source-specific recalculations In this submission, there have been updates to the activity data for the amount of dairy, beef, pig and poultry manure anaerobically digested and therefore entering storage and spread to land. The amount of manure digested (Sam Tomlinson (UKCEH), from the National Non-Food Crops Centre (NNFCC) database) has significantly increased in later years for England and Wales, decreased in Scotland, and changed very little for Northern Ireland. As a result, changes in emissions are seen in the dairy and beef sectors from c. 2008, and in the poultry and pig sectors from 1991 and 2005, respectively. We have also implemented changes to the inventory methods to reflect the impact of firm & funded mitigation policies, mostly regarding emissions from slurry stores and from spreading. In Northern Ireland, for slurry storage in above ground tanks, from 2020 all new above ground slurry stores are required to be fitted with a cover (DAERA Nutrients Action Programme 2019- 2022). Previous data were provided from the same data source for the year 2020, which were very similar, so the values have been averaged and used for the year 2021, with uptake of covers being interpolated from zero in 2009 (expert opinion Tom Misselbrook) to 11.4% in 2021 and beyond.
The policy applies to new stores which are assumed to be built at a rate of 5% per year (based on the assumption that the lifetime of above ground tanks is 20 years), therefore uptake of covers is increased at this rate from 2021. Also, Low Emission Slurry Spreading Equipment (LESSE) (including incorporation) must be used i) for digestate applications from 2020, ii) for slurry spread by contractors from 2021 and, iii) on all large cattle and pig farms from 2022. LESSE (including incorporation) must be i) for digestate applications from 2020, ii) for slurry spread by contractors from 2021 and, iii) on all large cattle and pig farms from 2022. The inventory method has been updated in this submission to reflect the impact of this policy, to apply additional country-specific data that has become available. In Wales, application of organic manure (slurry, digestate and poultry manure) to bare soil or stubble (amounts based on BSFP data) must be incorporated within 24 hours, unless LESSE has been used. A proportion of slurry (60%) and poultry manure (80%) are estimated to be applied to bare soil/stubble so the uptake of LESSE and incorporation has been adjusted accordingly. No further uptake of spreading mitigation has been applied to digestate because 100% is already assumed to be applied using LESSE. The policy was introduced in April 2021 so would only apply to winter sown crops in 2021, therefore the mitigation uptake associated with the policy was implemented in 2022 for inventory purposes, i.e. the first full year to which In Scotland, from 2023 all liquid digestate, slurry applied by contractors or on large cattle and pig farms should be applied using LESSE. Livestock numbers used in the inventory (June

Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 366 census) to calculate the proportion of beef and pig farms to which the policy applies. The minimum compliance is determined by the proportion of large farms which was higher than the percentage of slurry spread by contractors. The actual level of complianc e depends on the proportion of slurry spread by contractors on ‘small’ and ‘large’ farms, which is an unknown and may result in a conservative approach based on the minimum compliance implemented as a three-year trailing average. Country-specific data are available and used in the inventory method for dairy farms in 2023. Provisional average milk yields have been updated to match the most recent published statistics, resulting in small changes to the average milk yield of dairy cows for the years 2021 and 2022. Small updates to the slaughter weight activity data have been m ade for the years The above changes affect both CH4 and N2O emissions from manure management systems. Specifically for N2O, following a review of the N2O factors used to estimate N2O emissions from manure management, the IPCC 2019 Refinement default values for storage of slurry from dairy cows have been adopted. For liquid/slurry without a natural crust cover the default value of 0% is applied, and when a natural crust cover or cover is present the default value of 0.5% is A revision has been introduced of the housing ammonia (NH 3) EF for pullets, breeding flock, ducks & geese and other poultry from 14.1 to 13.5 % TAN to incorporate the updated NH3 EF for broilers (AFBI Ammonia report 2023 June; Elizabeth Ball). The new broiler EF was incorporated into the broiler housing EF dataset last year. The new EF for pullets, breeding flock, ducks & geese and other poultry, which are a weighted average of the broiler and turkey housing EFs, has been updated for the current year. Chang es to NH3 emissions affect the N balance approach of the UK inventory and therefore N2O emissions. Updates to the activity data for the amount of non-manure digestate applied to land from 1997 of sewage sludge applied to land have been implemented for the whole timeseries. The rate of fleece growth for growing lambs was revised from a yearly value to a function of live-weight applied daily, derived from measurements of clean fleece and animal weights for UK breeds presented in Saul et al. (1993; n=27). This resulted in a small decrease in nitrogen Changes in activity data and emission factors due to these recalculations to are given in the

Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 367 2024 submission 2025 submission 3.B.1.a Manure Methane 63.90 70.36 63.90 70.29 kt Replaced slaughter weight timeseries (from 2016); Updated milk yield (2021 and 2022) to match published stats; Updated amount of manure destined for anaerobic digestion 3.B.1.b Manure Methane 59.09 52.23 59.25 52.29 kt Replaced slaughter weight timeseries (growth curve for followers/calves based on cow mature weight) (from 2016); Updated amount of manure destined for anaerobic digestion (from 1991); Correction to management regime and location activity data (small changes in whole timeseries) 3.B.2 Manure Methane 5.19 4.32 5.19 4.33 kt Small change in model parameters 3.B.3 Manure Methane 35.00 20.81 35.00 20.70 kt Updated amount of manure sent to anaerobic digestion 3.B.4 Manure Methane 2.19 3.32 2.19 3.41 kt Updated quantities of litter going to anaerobic digestion and 3.B.1.a Manure Nitrous Oxide 1.17 0.98 1.48 1.36 kt Small changes in N excretion associated with changes to milk yield (2021 and 2022) and updating slaughter weight timeseries (from 2016); Adoption of 0.5% EF for crusted/covered stored dairy cow slurry (affects whole 3.B.1.b Manure Nitrous Oxide 5.16 4.28 5.17 4.29 kt Small changes in N excretion associated with updating slaughter weight timeseries (growth curve for followers/calves based on cow mature weight) (from 2016); Correction to management regime and location activity data 3.B.5 Manure Indirect N2O Emissions 2.241 1.788 2.238 1.787 kt As direct manure management above plus changes in ammonia emission, e.g. revision of storage mitigation regulations in Northern Ireland, contribute to changes in indirect nitrous oxide emissions from the re-

Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 368 deposition of NH3 and NOx nitrogen.
Changes in N excretion or manure management result in changes in the quantity of nitrate leached and the indirect nitrous oxide 2024 submission 2025 submission Units Comment/Justification 1990 2022 1990 2022 3.B.1.a Manure Methane emissions 22.44 38.07 22.44 38.03 kg/hd/year Replaced slaughter weight timeseries (from 2016); Updated milk yield (2021 and 2022) to match published stats; Updated amount of manure destined for anaerobic digestion 3.B.1.b Manure Methane emissions 6.37 6.85 6.39 6.85 kg/hd/year Replaced slaughter weight timeseries (growth curve for followers/calves based on cow mature weight) (from 2016); Updated amount of manure destined for anaerobic digestion (from 1991); Correction to management regime and location activity data (small changes in whole timeseries) 3.B.2 Manure Methane emissions 0.1141 0.1277 0.1142 0.1279 kg/hd/year Small change in model parameters 3.B.3 Manure Methane emissions 4.64 4.03 4.64 4.01 kg/hd/year Updated amount of manure destined for anaerobic digestion 3.B.4 Manure Methane emissions 0.0158 0.0180 0.0158 0.0185 kg/hd/year Updated quantities of litter going to anaerobic digestion and 3.B.1.a Manure Nitrous Oxide 0.41 0.53 0.52 0.74 kg/hd/year Small changes in N excretion associated with changes to milk yield (2021 and 2022) and updating slaughter weight timeseries (from 2016); Adoption of 0.5% EF for crusted/covered stored dairy cow slurry (affects whole 3.B.1.b Manure Nitrous Oxide 0.556 0.562 0.558 0.563 kg/hd/year Small changes in N excretion associated with updating slaughter weight timeseries (growth curve for followers/calves based on cow mature weight) (from 2016); Correction to management regime and location activity data (small changes in whole timeseries)

Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 369 3.B.2 Manure Nitrous Oxide 0.002 0.003 0.002 0.003 kg/hd/year Negligible change in model parameters resulting in

Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 370 5.4.6 Implied emission factors The CH4 implied EFs from manure management for major categories such as dairy and non - dairy cattle in the UK inventory (38, 6.9 kg/head/yr, respectively) are higher than the IPCC default values (21 and 6 kg/head/yr, respectively). Values for sheep and swine (0.13 and 4.0 kg/head/yr, respectively) are lower than IPCC (0.19 and 6 kg/head/yr, respectively). In the case of N2O, the implied EFs from manure management for dairy and other cattle in the UK inventory are 0.74, 0.56 kg N2O/head/yr. Values for sheep and swine are 0.003 and 0.163 5.4.7 Source-specific planned improvements There are a number of methodological improvements that the UK Inventory Agency will consider for future submissions, dependent on the availability of evidence from research and statistics agencies, • Development of partial EF for N 2O and CH 4 emissions for the different manure management stages, i.e. separate EF for housing and storage, that also enable accounting of the impacts of duration and conditions of manure storage. • Sourcing data on the time spent by manures in housing versus storage, per livestock type and manure management system and to fully account for ambient temperature and oxic/anoxic conditions in each stage of the manure management system. • Emission factors and activity data will continue to be reviewed including the use of more detailed emission factors and activity data to improve emission estimates and allow estimation of the effect of future mitigation policies. • Slurry tanks-covers and crusting – effect on N2O, NH3 and CH4 emissions • Full representation of anaerobic digestion – represent CS management • Compost-AD required, amounts – improve AD data • For swine and poultry improve current values of N excretion rates • For swine and poultry consideration of empty places – ensure no double counting of • Consideration of immobilisation from bedding in poultry – potential reduction in

Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 371 5.5.1 Source category description Source included Method Emission Factors Emissions sources 3D1: Direct N2O Emissions from 3D2: Indirect N2O Emissions from Key Categories 3D: Agricultural soils - N2O (L1, T1, L2, T2, T3) Completeness A general assessment of completeness for the inventory is Emissions from the composting and subsequent land application of livestock manures are currently Not Estimated due to a lack of activity data. Updates to activity i) For Northern Ireland 2022 N fertiliser data were replaced for surveyed use data provided by DAERA; ii) for Northern Ireland and Scotland revisions to cereal and oilseed rape 2022 yields; iii) average use of urease inhibitors of all surveyed years replaced by 3-year rolling average for urea ammonium nitrate; iv) adjustment of effective efficient area for permanent grass; v) revised rate of sheep fleece growth; vi) revised protein content of grazed grass (for Emissions of N 2O from agricultural soils occur due to an increase in available N promoting nitrification and denitrification in soil. These happen due to the application of N amendments or due to management practices that stimulate mineralisation of organic N, including land use change or cultivation of organic soils. Emissions are influenced by environmental conditions including ambient temperature, soil moisture conditions, the addition of other nutrients such as organic fertilisers. The latter include livestock manures , excreta deposition from grazing animals, digestate, sewage sludge, compost. UK emissions of N2O from agricultural soils are estimated using IPCC (2006) Tier 1, 2 (IPCC Equations 11.1, 11.2) and T3 methodology, implementing UK -specific EF and parameters where available. The T3 corresponds to the emissions estimates via an empirical model developed from CS emissions data. (i) The use of inorganic fertiliser (ii) Application of livestock manures to land (iii) Application of sewage sludge and other organic N additions materials to land (iv) Urine and dung deposited by grazing animals on pasture, range and paddock (v) Crop residues returned to soils

Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 372 (vii) Cultivation of histosols (organic soils) Indirect N2O emissions are estimated from 2 (viii) Atmospheric deposition of agricultural NOx and NH3 (from (i), (ii), (iii) and (iv)) (ix) Leaching and run-off of agricultural nitrate (from (i), (ii), (iii), (iv), (v) and (vi)). Further details on activity data and EF are given in Annex 5.1.3.
Source category significance, trends and drivers The total emissions of N 2O in 2023 from UK agricultural soils (3D) were 37.6 kt. Emissions have decreased by 24.4% since 1990 and 1.5% between 2022 and 2023. Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 373 production of N2O from agriculture Sources leading to N 2O emissions include slurry, farmyard manure (FYM), sewage sludge, digestates, fertiliser, and dung and urine depositions to grazed lands. Detailed information on some of the individual experiments that provided the data for the analysis can be found in reports (Smith and Williams, 2011; AC0116) and journal articles (e.g. Bell et al., 2016a; Bell et al., 2016b; Bell et al., 2015; Sylvester -Bradley et al., 2015). Following the guidelines of the IPCC (2006) for the derivation of N 2O EFs, all the data from the experiments were collected over a 12 -month period. The static chamber methodology was used for emission measurement, which is consistent with the Global Research Alliance guidelines (de Klein and Harvey, 2012; Charteris et al., 2020). Data were collated by N -source: surface-spread and broadcast slurry, FYM, dung and urine, and ammonium -based and urea-based fertilisers. In all experiments, a control treatment which received no organic or inorganic fertiliser was included. In all cases, as well as the emissions and the N application rates, data on the soil characteristics, total rainfall (RainYr, mm) and the average daily temperature for the 365 days associated with the experimental period were collated. The analysis was carried out by using Restricted maximum likelihood ( REML) regression using Genstat 17 th Edition Release 17.1 VSN International Ltd., Oxford. With the exception of the fertiliser N category ‘Other N to grassland’, the EFs for fertiliser application, FYM, broadcast slurry and grazing were lower than the IPCC default value of 1%. Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 374 Direct N2O emissions from fertiliser N applications are calculated using values of EF1 derived from UK -specific measurements (Topp et al., in prep ). Direct N 2O emission is related to fertiliser type, application rate and average annual rainfall, with the relationship for urea-based fertilisers as in equation 1. For all other fertiliser types, the calculation involves fertiliser rate applied and average annual rainfall (equation 2) (see small changes in parameters compared Ln(𝐶𝑢𝑚𝑁2𝑂 + 1.63) = 0.8404(±0.06846) + 0.001518(±0.0001077) ∗ 𝑁𝑅𝑎𝑡𝑒 (eq.1) Ln(𝐶𝑢𝑚𝑁2𝑂 + 1.63) = 0.5700(±0.1107) − 0.0001942(±0.0001968) ∗ 𝑁𝑅𝑎𝑡𝑒 + 0.3962(±0.1326) ∗ 𝑅𝑎𝑖𝑛𝑌𝑟 + 0.003284(±0.0002291) ∗ 𝑁𝑅𝑎𝑡𝑒 ∗ 𝑅𝑎𝑖𝑛𝑌𝑟 (eq.2) CumN2O = cumulative annual N2O-N emission (g ha-1) Nrate = rate at which fertiliser N is applied (kg ha-1) RainYr = annual average rainfall (m) limited to 0 to 1.3 m. EF are derived as shown in equation 3. ((𝐶𝑢𝑚𝑁2𝑂 𝑎𝑡 𝑠𝑝𝑒𝑐𝑖𝑓𝑖𝑒𝑑 𝑁𝑅𝑎𝑡𝑒 – 𝐶𝑢𝑚𝑁2𝑂 𝑎𝑡 𝑧𝑒𝑟𝑜 𝑁𝑅𝑎𝑡𝑒) / 𝑁𝑅𝑎𝑡𝑒 (eq.3) The correction multipliers to the total N 2O losses due to the bias for the log transformation 1.011 and 1.02 for urea and ammonium nitrate application, respectively. The activity data for annual fertiliser applications are primarily obtained from the British Survey of Fertiliser Practice (BSFP) which provides sampled data from a stratified survey of farm types across Great Britain. These data are analysed and upscaled to generate UK -wide fertiliser application data by fertiliser type and crop type. In addition, the BSFP data provide temporal information that enables analysis of the timing of fertilisers by type across the year; this added detail enables the UK method to reflect the different climatic conditions that prevail at the time of fertiliser application, which impacts upon the emissions. For a couple of fertiliser types that are not produced in the UK, the activity data are obtained from fertiliser import data. I n the case of NI, as the BSFP does not cover data for fertiliser applications, we use data from DAERA’s Survey of Fertiliser Delivered (SFD). As a data validation step, the UK inventory team also consults with the farming industry, such as the Agricultural Industries Confederation (AIC), to compare the inventory fertiliser activity data against other statistics that are gathered from suppliers. If the inventory data deviate from the industry statistics, the Inventory Agency will explore the reasons for these differences with the fertiliser suppliers to seek any potential improvement in total fertiliser application per 5.5.2.2 Application of livestock manures to land Emissions are calculated following the IPCC methodology (2006, equation 11.1) using country- specific EFs. Proportions of managed manure N applied to GB cropland are derived from Smith (2012). Assumptions regarding proportions of manures spread to land for Northern Ireland were made based on data provided directly by DAERA (DAERA, 2021). The values assumed (see following paragraphs) are constant throughout the time series with the exception of poultry The nature of manure management differs between farm types, with more manure retained on farms with grazing livestock than on pig and poultry farms and also more is spread on grassland for those farm types than to arable crops. In general, slurries are less likely to be

Agriculture (CRT Sector 3) 5 UK NID 2025 (Issue 1) Ricardo Page 375 transported long distances than solid manures. The fate of manure is estimated by considering spatial disaggregation as in the BSFP. On broiler and turkey farms a proportion of the excreted N is deducted to allow for that amount going to biomass power stat ions and the remainder is assumed to be applied to land in the neighbourhood. In the case of dairy cattle, the UK inventory assumes for England, Wales and Scotland that 24% of slurry and 40% of FYM is spread to cropland. For Northern Ireland, 9.5% of slurry is spread to cropland and 25.5% of FYM is spread to cropland.