Over the time series, the UK operators of aluminium smelters have invested to improve plant performance, and all sites were converted to point feeder technology, leading to large reductions in PFC emissions per unit production as a result. Emissions of carbon are estimated using statistics on the production of aluminium by each type of process and suitable emission factors. The carbon emission factors reflect current practice, and higher emission factors were used for earlier years, due to the production of some aluminium using the Soderberg process. All emissions of PFCs (CF 4 and C2F6) occur during the aluminium smelting process during anode effects. The UK inventory data are directly reported by plant operators, and are emission estimates calculated from the number and duration of anode effects at each facility. Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 279 Operators use (or used) a Tier 2 methodology of a smelter -specific relatio nship between emissions and operating parameters based on default technology -based slope and over - voltage coefficients. This method uses (or used) default factors for the CWPB (Centre Worked Prebaked) plant for three of the plants and default factors for V SS (Vertical Stud Soderberg) for the plant which closed in 2000. One of the operators used the North West American Calculation assuming 3lbs PFC for every minute the cell was “on anode effect”, for the early part of the time series. The time series does no t show any discontinuity as a result of the The UK total primary aluminium production activity data are taken from the UK Minerals Yearbook (British Geological Survey, 2022) in years where complete data on production from operators are not available, 1990-2004 and 2006. In all other years of the time series, we have both the BGS data and also a complete set of operator production estimates. The two datasets are very closely consistent (perhaps as there are only up to three operators in any one year); for example, over the 5 years between 2013 and 2017, both sets of data present UK production of 228 ktonnes aluminium, with very small % differences at the year -specific level. The BGS data are presented rounded to 2 significant figures, and due to this lack of precision but close consistency, the UK inventory method uses the sum of all operator-reported data for 2005 and for 2007 onwards, as these are regarded as the most accurate data to use in each year. Method Activity Data Emission Factors Note that the PFC EFs presented here are essentially back -calculated IEFs for the UK industry, derived from the reported production data and sum of operator-reported emissions. Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 280 4.18.2.1 Aluminium alloy production No emissions of SF6 are reported by any of the aluminium foundries in the Pollution Inventory or SPRI. Emissions from the use of SF6 in the UK aluminium sector are therefore reported as Uncertainties and Time Series Consistency The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. Activity data on UK aluminium production since 2006 is available from both the British Geological Survey (BGS) UK Minerals Yearbook, as well as directly from operators, with the latter data set presented at a greater level of precision. The two datasets show very close consistency over time, with small % differences year to year, which is at least partly due to the rounding in the BGS data. The BGS data are from a long running publication and the compilers of the activity data strive to use consistent methods to produce the activity data; there are also only a small number of UK producers, and complete reporting of their production, direct to the Inventory Agency, has occurred for over a decade. Similarly the methods used by operators to estimate emissions are specific to the technology of their plant, and for PFCs are consistent with the IPCC Tier 2 method across the time series. The consistent access to good quality dat a from the UK industry therefore helps to ensure good time series consistency of the emission estimates across all years, despite the switch to use (more precise) operator activity data from 2007 onwards. There was a large decline in emissions in 2012 as a luminium smelting activities came to an end in March 2012 at one of the largest UK production plants at Lynemouth. In 2010, 2011 and 2014 there was a significant increase in the implied emission factor for PFCs because of process issues during those years, for example an ‘anode crisis’ in 2014. Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Section 1.6. Emissions data taken from the Pollution Inventory are subject to additional QA/QC from the Inventory Agency. Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 281 Source Specific Recalculations There have been no significant recalculations for this sector. Source Specific Planned Improvements Emission factors and activity data will be kept under review. In the UK, SF 6 and an HFC act as cover gases to prevent molten magnesium from burning during the production of magnesium. Sulphur hexafluoride is used as a cover gas to prevent magnesium oxidising when exposed to air, because it is non-flammable and heavier than air. SF6 is non-flammable and non-toxic and is therefore a safe gas to use. In the UK, SF6 has been used as an alternative cover gas to SO2 in magnesium alloy production and sand and die-casting since the early 1990s. Since 2006, EU magnesium producers have looked for alternatives to SF6 in response to bans in the EU F-Gas regulation. Some die casters have gone back to using SO2. Others have used HFC- 134a and a fluoro-ketone (FK 5-1-12) with the trade name Novec 612. The UK magnesium casting industry is very small.
There are three significant manufacturers (one alloy producer, one die-caster and one sand-caster) plus two very small operations (both sand-casters). Alloy production involves the use of primary magnesium ingots, recycled scrap material and second-generation magnesium materials (i.e. material already made into alloys) for the production of different alloys. Both die and sand casters use these magnesium alloys to produce specific components for a wide range of industries. For the casting industry, SF6 is used for casting specific magnesium alloys where other cover gases, such as HFC-134a, are currently considered not suitable. The 2014 EU F-Gas Regulation prohibits the use of SF6 in magnesium die casting, from 1 Jan 2018, the ban is extended to installations using a quantity below 850kg per year. Note that, as mentioned below, most UK magnesium production uses processes other than die casting, so this ban only has a limited impact on this sector. A review of the data sources and methodology used to estimate emissions from F-gases used as cover gases in magnesium foundries was carried out in 2013 (Gluckman, 2013). In all cases UK magnesium companies were able to report consumption but had no actual measured data on emissions. The assumptions about the fraction of SF6 and HFCs that are emitted from the consumption of these F-gases were reviewed through discussion with industry experts and in some cases amended. It is estimated that 95% of SF 6 consumption is emitted but that only 20% of HFC -134a consumption is emitted (as a much greater proportion reacts with the magnesium). These figures are based on expert estimates by Gluckman (2013). For magnesium alloy production, SF6 emissions from 1998 onwards are estimated based on the data reported to the Pollution Inventory (Environment Agency, 20 21), whilst emissions prior to 1998 are estimated based on consultations with the plant operators. From 2004, one of the main industry users of SF 6 as a cover gas has implemented a cover gas system using HFC -134a for some o f its production capacity. There has not been a complete switch to HFC-134a, although the operator is considering this on an ongoing basis depending on suitability for the different alloys produced. In addition to having a significantly lower GWP than SF 6 (and thus reducing emissions on a CO 2 equivalent basis), use of

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 282 HFC-134a is further advantageous in that a significant fraction of it is destroyed by the high process temperatures (80%) thus reducing the fraction of gas emitted as a fugitive emission. From 2008, emissions of HFCs have been reported in the Pollution Inventory (Environment Agency, 2021), and therefore the reported data are used directly. As part of a study to update the F -gas inventory (Gluckman, 2013), castings operators were re-contacted to provide activity data for recent years (the previous survey was conducted in 2004). The two largest users of SF6 and HFC-134a (that represent 99% of UK emissions from magnesium) are now contacted annually for their activity data (consumption of SF6 and HFC- Emissions of FK 5-1-12 cannot currently be reported via the CRF as there is no space to report this product, it would also be a low priority to include as it is a sparingly used product with a GWP comparable to CO2. It is estimated that the decomposition of 1 tonne of FK 5-1-12 during use as a cover gas generates ~400 tonnes CO2e of PFCs, but as this product is used only at 1 small magnesium site and trialled at one larger site, total emissions in the UK due to the decomposition of FK 5-1-12 have been estimated to be less than 0.001% of the UK national total since 2012 and 0 beforehand. According to the UNFCCC Guidance for reporting, emissions could be “… considered insignificant if the likely level of emissions is below 0.05 per cent of the national total GHG emissions and does not exceed 500 kt CO2 eq.”. Therefore, the UK considers this a low priority to formally estimate and report emissions for. This source is included in the Assessment of completeness in Section 1.8. As far as we know, HFC -134a does not decompose into other potent GHGs; any other products potentially emitted would be offset by our conservative estimate of the proportion of Uncertainties and Time Series Consistency The main area of uncertainty is regarding emissions of SF6 from casting based on discussions with the sector Trade Association for the period prior to 1998. Data from the main magnesium alloy producer is also uncertain for this period. For the period 1998 -2017, the uncertainty of the time -series emissions is estimated to be significantly lower. Data received from the main magnesium alloy producer and the other 4 casting operations are associated with low uncertainty and show good consistency across the SF6 emissions from UK magnesium producers peaked in 2000 at approximately 1,000 kt CO2 equivalent. The use has fallen steadily, particularly from 2006 onwards, being 80 kt CO 2 equivalent in 2020. HFC-134a emissions were zero until 2008 and are 2 kt CO2 equivalent in Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Section 1.6. Emissions data taken from the Pollution Inventory are subject to additional QA/QC from the Inventory Agency. Source Specific Recalculations For information on the magnitude of recalculations to this Source Category, see Section 10. Source Specific Planned Improvements We have recalculated HFC estimates for 2019 and SF6 estimates for 2016-2019 to reflect the more up to date operator data received. Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 283 Lead production in the UK consists of one primary lead production site (now closed) and a small number of secondary lead sites. The p rimary lead site produced zinc, lead and other metals from imported ore concentrates and closed in 2003.
This site produced more zinc than lead, and because it is not possible to split emissions between 2C5 and 2C6 (other than on an arbitrary basis), e missions for this s ite are reported under 2C6 . Further details on this process are given in the following section. The UK also has a number of secondary lead processes, all of which involve the recovery of lead either from automotive batteries or from clean scrap. Emissions of CO2 could, in theory, occur from the use of reductants such as coal, coke oven coke, or natur al gas during secondary lead processes, however none of the se secondary lead processes are known to involve the use of reductants , and therefore we do not believe that there are any process emissions of CO2 from any of the UK’s secondary lead processes. If any use of reductant d id occur, it would be included in UK fuel statistics as an energy use, and thus emissions of CO2 would in any case be included in the UK inventory, but Zinc was produced in the UK until early 2003, using the Imperial Smelting Process (ISP) at a smelter operated by Britannia Zinc at Avonmouth. The site processed imported ore concentrates, and had a capacity to produce approximately 150,000 tonnes of zinc, as well as 65,000 tonnes of lead and small quantities of other metals such as cadmium. The ISP involves the use of a blast furnace to reduce zinc and lead oxides to the metal using coke as a reductant. Limestone could also be added to act as a slag-forming agent. The UK also had two other non-ferrous metal production facilities that would have emitted CO2 • the Capper Pass Tin Smelter at Melton, Humberside (closed in 1991) • IMI Refiners' secondary copper smelter at Walsall (closed in 1997) There is very little data specific to these installations available to the Inventory Agency as their closure pre-dates most of the routine annual emissions reporting regulations in the UK. Both processes used coke oven coke as a reductant that would have led to process emissions of CO2, and since we only have data on the total use of coke oven coke in non -ferrous metal production in UK energy statistics (BEIS, 2022a), we report all emissions from use of this coke oven coke in 2C6. Therefore, the emissions reported in 2C6 will also include emissions fr om these two sites, as well as emissions related to the production of lead at the Britannia Zinc Britannia Zinc reported CO2 emissions in the Pollution Inventory (Environment Agency, 2018) from 1998 until 2002, at which point the site ceased operation. Emissions of CO 2 occurred from the use of coke in the ISP, but also from decarbonisation of any limestone used, and from the other fuels used on site e.g. gas/oil burners u sed on the sinter plant and oil -fired furnaces used in the zinc refinery. No data are available on the quantities of coke and other fuels used, or the quantities of limestone that might have been used. The operator -reported CO2 emissions in the Pollution I nventory are totals only, and do not provide any insight regarding the split of emissions source between coke, other fuels and limestone. The reported emissions are, however, much higher than would be implied by the Tier 1 factors given in the 2006 GLs for the ISP. There is insufficient data to determine whether this is due to a high level

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 284 of fuel combustion emissions on site, or that the process -related emissions at this site were higher than is typical for this type of process. The Digest of UK Energy Sta tistics (BEIS, 2022a), ‘DUKES’, does give a full time -series of data on the consumption of coke oven coke by the non -ferrous metal industry. The consumption shown in this source is zero after 2003, confirming that after the closure of Britannia Zinc, no other non-ferrous metal processes in the UK used coke oven coke. Based on all available information, the Inventory Agency considers that no sites, other than Britannia Zinc, Capper Pass and IMI Refiners have used coke oven coke at any point in the period Because all three sites have been closed for many years, there is no information on the consumption of coke oven coke at each site. Of the three, it is likely that IMI Refiners used relatively small amounts of coke, whereas the Capper Pass smelter was the largest of its kind in the world, and its closure in 1991 coincides with a big reduction in the non -ferrous metal industry's consumption of coke as shown in DUKES. There is insufficient data to split the coke consumption data betw een the three sites, and instead all of the coke use in DUKES is reported in 2C6. This will ensure completeness and reduce the uncertainty in the reported factors for the coke oven coke are derived from the carbon balance approach previously As previously described, limestone may have been used at Britannia Zinc (and possibly in the blast furnaces at Capper Pass as well) but there is no information on which to base emission estimates. Since all of these plants closed more than 10 years ago, there is no scope to access new information to improve this situation, and therefore no emission estimates for these source categories are reported. Further, we note that the UK GHGI already includes emissions from all reported limestone and dolomite activity based on data from the British Geological Survey on UK supply and demand of these materials, and hence there is no gap in the UK GHGI, but possibly a smal l mis-allocation with higher estimates in another sector to counter the possible under-report here.
Uncertainties and Time Series Consistency The use of DUKES data for coke consumption by non-ferrous metal processes ensures time series consistency and completeness, which is important since it is impossible to now determine how much coke oven coke was used in each of the 3 three non -ferrous metal processes that once existed in the UK. Any limestone used in the blast furnaces at Britannia Zinc and Capper Pass cannot be estimated, but emissions data for 2C1 cover all use of limestone and dolomite for blast furnaces and so overall completeness is assured. Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Section 1.6. Source Specific Recalculations No major recalculations have been made to this sector. For further information on recalculations, see Section 10. Source Specific Planned Improvements It is noted that this sector has been identified as a key category in this inventory submission, due to the site closures and resultant sector contribution to the UK inventory trend, and that a tier 1 method is used. The UK has recently reviewed this sector and included some additional sources using the best currently available data. Unfortunately as the only sites in this sector

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 285 have been closed for a number of years it is highly unlikely that new data will be found to Emissions sources Sources included Method Emission Agricultural engines – lubricants Road vehicle engines – lubricants Emissions of CO 2, CH 4 and N 2O arise from lubricant combustion in engines and other machinery. Note that waste lubricants can be recovered and subsequently used as fuels but emissions from this source are included in CRF 1.A. Where the term lubricants is referred to, this correlates to the DUKES definition of lubricating oils (and grease), i.e. “Refined heavy distillates obtained from the vacuum distillation of petroleum residues. Includes liquid and solid hydrocarbons sold by the lubricating oil trade, either alone or blended with fixed oils, metallic soaps and other organic and/or inorganic bodies.” Emissions reported in 2D1 cover all lubricants used by all sectors, with the sole exc eption of lubricants used in mopeds engines. This is deemed to be intentional fuel use and hence is reported in IPCC sector 1A3biv. Detailed activity data on lubricant use by source category are not available in the UK; there is insufficient data to implem ent an IPCC Tier 2 method, and therefore the 2006 IPCC GLs Tier 1 method is applied. DUKES (BEIS, 2022a) includes some limited data breakdown on sector -specific lubricant use (e.g. use by industry, agricultural sector, shipping) in addition to the total lubricant demand time-series. Lubricant consumption in road vehicle engines is estimated using the COPERT method from the EMEP/EEA Emissions Inventory Guidebook (2019). Lubricant use in the remaining sectors uses activity data from DUKES, but the total lubricant use estimated by the inventory diverges from DUKES due to the use of the above method for road engines. While in general we would consider the totals from UK energy statistics to have a higher confidence than bottom-up estimates of demand, in this case we have taken a more conservative approach, reflecting that trends in activities that would demand lubricants do not correlate with the strong decreasing trend presented in DUKES. The consumption estimates are used to calculate CO2 emissions which are reported in IPCC sector 1A3biv for mopeds and 2D1 for all other sectors ,. Whereas the COPERT method directly calculates the quantity of lubricant consumed or burnt in road vehicles, for other sectors we assume that 20% of lubricant is oxidized during use . In all cases we apply a UK - specific carbon emission factor for lubricants, based on analysis of UK waste oil samples. Emissions of CH 4 and N 2O also arise from lubricant combustion in road vehicle engines. However, the exhaust emission factors for these gase s will include the contribution of , and hence the emissions of, CH4 and N2O (and other air pollutants estimated on a vkm -travelled basis) from lubricants are included implicitly in the hot exhaust emissions (IPCC Sector 1A3b) calculated for each vehicle an d fuel type. Treating emissions of these pollutants separately

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 286 Uncertainties and Time Series Consistency The use of a Tier 1 methodology means that estimates are quite uncertain. Additionally, the divergence in trend in total lubricant consumption presented by energy statistics, and bottom -up estimates of demand reflects uncertainty in activity data for this Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Section 1.6. Source Specific Recalculations Improvements to the road transport model have allowed lubricant use in road vehicle engines to be calculated at a more granular level. The size of the impact of this recalculation is a 0-3% reduction in emissions from 2006 onwards. For further information on recalculations, see Section 10. Source Specific Planned Improvements We are continuing to engage the UK energy statistics team to understand the trends in UK energy statistics for total lubricant demand, and the inventory estimates will be revisited if any major improvements are made to energy statistics. This category includes CO2 emissions from paraffin wax use. DUKES gives total consumption of petroleum waxes for the years 1990-2008 only. For 2009 onwards, petroleum wax consumption is only available as part of the much larger consumption of 'miscellaneous petroleum products' . Activity data for UK consumption of petroleum wax from 2009 onwards are available from the UK energy statistics team (Personal BEIS, 2022c) on the same basis as the earlier data, as they comprise part of other long-term energy data reporting outputs, e.g. to EUROSTAT. Emissions are estimated using the Tier 1 ODU factor of 0.2, and t he IPCC default carbon content of 20 kg C/ GJ (net basis).
Uncertainties and Time Series Consistency Estimates for this sector are uncertain because of the use of a Tier 1 methodology. The time series consistency of the activity data are good, as they are part of a long -running routine energy data compilation and reporting system, by the UK energy statistics team in BEIS, and also for the EFs as a Tier 1 default is used in all years. Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Section 1.6. Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 287 Source Specific Recalculations No major recalculations have been made to this sector. For further information on recalculations, see Section 10. Source Specific Planned Improvements Emission factors and activity data will be kept under review. Emissions of CO2 are estimated from consumption of urea by road vehicles with relevant types of catalytic converters for control of pollutant emissions and are reported under 2D3. Urea has the chemical formula (NH 2)2CO and is injected into the exhaust stream of certain ty pes of diesel vehicles (currently Euro IV, V and VI HGVs and buses) as a 32.5% (by weight) aqueous solution. The catalytic process of converting NOx to nitrogen in the exhaust leads to the release of CO2 from the urea in the tailpipe. Petroleum coke is known to be used by various sectors either as a fuel (e.g. at power stations and in cement kilns), or in various processes (e.g. in brickmaking, titanium dioxide manufacture, aluminium smelting, or electric arc steelmaking). The consumption of petroleum coke for each sector is either available directly from DUKES or estimated, based on ETS and other data. For most years, there is more petroleum coke listed in the UK energy statistics than can be accounted for by these known users . In other years, the known use rs require more petroleum coke than is available in the energy statistics. But since there is excess petroleum coke for most years (20 out of 32) between 1990 and 2021, it is assumed that there are additional, unknown uses of the fuel in those years. The e xcess petroleum coke in the energy statistics is reported as being for non-energy uses but this will include both fuel grade and anode grade coke, so it is possible that the coke could be used as a fuel, or in processes, or both. In the absence of any data, and because the coke appears in DUKES as ‘non-energy use’, it has been assumed that it is used for an unknown process. Such uses could be non - emissive with the carbon stored, but in the UK inventory it is assumed that all carbon in this petroleum coke is emitted and reported in 2D3. The 2006 IPCC Guidelines specify two approaches for estimating CO 2 emissions from urea consumption. This is either from statistics on total urea sales or by estimating urea consumption as a proportion of the amount of fuel consumed. There are no statistics on urea sales in the UK, so the approach based on fuel consumption is used. Not all diesel vehicles use urea, so it is necessary to know the amount of fuel consumed specifically from those vehicles with the relevant exhaust after treatment technology that require urea injection. Urea is used by HGVs and buses in the UK manufactured to Euro IV , V and VI standards. These came into effect from 2006. The EMEP/EEA Emissions Inventory Guidebook (2016) provides the means for estimating urea consumption as a proportion of fuel consumed by these specific types of vehicles. Fuel consumption by Euro IV, V and VI HGVs and buses was estimated using a bottom-up method described in Chapter 3. The estimations involve the use of vehicle km activity and fleet composition data from DfT and g/km fuel consumption factors, with total fuel consumption calculated for road transport by this method normalised to national

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 288 Following figures given in the EMEP/EEA Guidebook for estimating other pollutant emissions, an assumption was made that 75% of Euro V HGVs and buses are equipped with SCR – the catalyst system that uses urea. The same assumption was also applied to Euro IV vehicles, and it is assumed that 100% of Euro VI vehicles are equipped with SCR. Fuel consumption was calculated for these types of vehicles using SCR technology. Following the EMEP/EEA Guidebook, urea consumption is assumed to be 4% of fuel consumption for a Euro IV HGV or bus, 6% for Euro V and 3.5% for Euro VI. Independent assessment in the UK from suppliers of urea and vehicle manufacturers supports these assumptions. These assumptions allowed the time-series for consumption of urea by UK road transport to be estimated. No urea was A constant emission factor of 0.238 kgCO 2/kg urea solution was used, from the EMEP/EEA Guidebook. This is consistent with the factor and emission equation given in the 2006 IPCC Guidelines, assuming urea is used as a 32.5% aqueous solution which is the norm in the UK. The emissive non-energy use of petroleum coke is assumed to result in 100% of the carbon in this fuel being emitted. The 2006 IPCC default factor for petroleum coke has been used in conjunction with calorific values for petroleum coke used in sectors other than electricity generation, taken from UK energy statistics. The relatively high calorific value given for this type of petroleum coke means that the IPCC default factor implies that this petroleum coke is over 90% carbon, which is higher than the carbon content of coke oven coke or anthracite. Uncertainties and Time Series Consistency The main uncertainty on estim ates of emissions from urea consumption comes from the uncertainty in the amount of urea consumed by the categories of vehicles equipped with SCR exhaust after treatment technologies in the UK fleet.
This is linked with uncertainties in the estimates of fuel consumed by these vehicles and uncertainty in the amount of urea consumed per kg of fuel consumed. Uncertainties in the CO2 emission factor from urea consumption are very low because the carbon content of urea is known with high accuracy. The end uses of the petroleum coke reported in 2D3 are unknown and could actually include some use of coke as a fuel and/or some non-energy uses that result in storage of carbon, as well as emissive non-energy uses. The approach taken is conservative since we assume all of the carbon is emitted, but emissions may be wrongly allocated if some of the petroleum coke is actually used as a fuel. The uncertainty in emissions for this source is very high. Because of the use of this source as a balance against energy statistics, the time series is very erratic. There are many years where zero emissions are reported due to the UK Inventory petroleum coke in the UK energy statistics. Source Specific QA/QC and Verification This category is covered by the general QA/QC of the inventory in Section 1.6. Source Specific Recalculations Petroleum coke estimates for this sector have been revised due to a removal of a double count of petroleum coke estimated for residential combustion and some revisions to gap filling for lime sector use of petroleum coke. As the data reported here is a residual of unknown use of petroleum coke, these changes to other sectors have a significant impact on the residual For further information on recalculations, see Section 10. Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 289 Source Specific Planned Improvements Emission factors and activity data will be kept under review. Emissions of SF6 and PFCs from semiconductor manufacturing are combined with emissions from training shoes and electrical insulation in source category 2G2e for reasons of commercial confidentiality. Emissions of NF3 and HFCs from semiconductor manufacture are reported in sector 2E1. This source category (both for pollutants reported in 2E1 and 2G2e) is ICF (2014) determined that the UK does not have volume Flat Panel manufacturing. ICF reached this conclusion after contacting the National Microelectronics Institute (NMI) who represent flat panel display manufacturers in the UK. Further market analysis by Ricardo (2016) confirmed that there are no UK emissions from this sector. This included discussions with representatives of the flat panel supply sector and PFC supply sector – all those contacted confirmed that all flat panel displ ays used in the UK are imported. It was noted that in the 2006 IPCC guidelines that there was activity data given70 for the UK in 2003 -5. When using this activity data and the default methodology the resulting emission was well below the threshold to be considered insignificant, so is reported by the UK as ‘NE’ for years before 2014. This source is included in the Assessment of completeness in Source Specific Planned Improvements Any emergence of volume manufacturing capacity of TFT flat panel display is kept under ICF (2014) determined that the UK does not have volume photovoltaics (PV) man ufacturing. ICF reached this conclusion after contacting the British Photovoltaic Association (BPA) to gather data from PV manufacturing in the UK. The BPA also confirmed that statistics on F - gas use in the PV manufacturing in the UK are not available. Further market analysis by Ricardo (2016) confirmed that there are no UK emissions from this sector. 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 given71 for the UK in 2003. Wh en using this activity data and the default methodology the resulting

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 290 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 Source Specific Planned Improvements Any emergence of volume manufacturing capacity of photovoltaics is kept under review. 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 6H14), including one company that manufactures this PFC in t he 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 belie ved that these are sold exclusively for hermetically sealed applications and products that are sold on to be used outside the U K. This source is included in the Assessment of completeness in Source Specific Planned Improvements Any emergence of volume manufacturing capacity of heat transfer applications using F-gases HFCs and HFC blends have been widely used as replacement refrigerants for ozone depleting substances across virtually all refrigeration and air -conditioning 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 refrigeration equipment manufacturing process; • During on-site installation of equipment • Over the operational lifetime of the refrigeration or air-conditioning unit; and • At disposal of the refrigeration or air-conditioning unit. Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 291 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 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. 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 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 kW to 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 pump. 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 heat pumps 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-

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 292 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 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 emissio n 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 EU F-Gas Regulation (517/2014), including bans of some higher HFCs for some applications and a general phase down of HFC consumption. The model is reviewed on a regular basis. 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 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 Regulation has led to significant reductions in the levels of leakage from some RAC 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 factors and

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 293 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 ass umptions 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 t he individual HFC components within such blends (e.g. R-404A is a mixture of HFC-143a, HFC-125 and HFC-134a). Industrial Processes (CRF Sector 2) UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 294 CRF Sector UK Category Total Stock Refrigeration Domestic Refrigeration 47,181,000 15 0.03 to 1,892,000 15 0.2 to 1 HC-290, HFC-134a 1% 2% 66% Condensing Units 519,000 15 1.5 to 15 X1500, X600, R-744 3% 9% 45% Refrigeration 62,800 9 to 15 1 to 10 R-452A 2% 22% 60% 1,500 R-744, HFC-134a, R-717 2% 20% 55% Refrigeration Industrial Systems 42,100 18 to 30 30 to 3,000 X1500, HFC-134a, R-717 2% 8% 50% Conditioning 2,910,000 12 0.5 to 8 HFC-32 3% 4% 80% Conditioning 288,000 15 2010 to Conditioning (Chillers) 56,000 15 to 21 30 to 1,500 HFC-134a, HFO-1234ze 2% 5% 50% Heat Pumps 199,000 18 3 to 150 R-410A, R-134a, R-407C 2% 3% 60% Conditioning 31,888,000 16 0.4 to Conditioning 136,800 15 4 to 25 HFC-134a, R-410A 2% 13% 65% 72 X600 = R-450A or R-513A; X1500 = R-448A or R-449A

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 295 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 • Population 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 Uncertainties and Time-Series Consistency The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. 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 measur ement 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 comparison of data from InTEM with the ICF model73 estimates and the current HFC Outlook model. Both the ICF and HFC Outlook emissions estimates are higher than those created by InTEM and are likely to be conservative over -estimates of HFC emissio ns. This measurements than the ICF model. 73 The ICF HFC Model was used in the NAEI prior to the development of the HFC Outlook model. Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 296 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 that other EU Member States subject to the same F -gas regulations. While the model has been updated since this date, and the decline is not 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 atmospheric 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 (which both have GWPs roughly half of R-404A) that were used in the period 2012 to 2016 and the more recent HFC / HFO blends R-448A and R-449A (both with lower GWPs again). 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

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 297 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 ba n. It is interesting to note that supermarkets in most other EU countries did not adopt retrofits until around 2018. The new UK model 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 modelled, 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. This will be confirmed during 2022. Source Specific Recalculations No major recalculations have been made to this source for the 2023 submission. For information on the magnitude of recalculations, see Section 10. Source Specific Planned Improvements The bottom-up RACHP modelling is currently under review to take into a) Market changes related to the rapid roll-out of heat pumps. b) Market changes related to the on-going review of the F-Gas Regulation in both the UK c) Improved data from InTEM that can be used to better calibrate the modelled estimates Work is on-going to update the HFC Outlook model in response to these issues. Results from this work are expected to feed into the RACHP modelling in the next inventory. 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 d esigned 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

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 298 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 cycle74. 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); 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 information 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 intervals. 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 74 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 (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 299 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 confu sed 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 considered. 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. 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

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 300 In the 2015 improvement progr amme 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 15 20% 1% Recognises better foam

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 301 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% 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. 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

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 302 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 market 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. Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Section 1.6. Details of verification of emissions are given in Annex 6. 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. Source Specific Planned improvements HFC-245fa and HFC -365mfc are only used in foam blowing applications. The University of Bristol / UK Met Office HFC atmospheric measurements include emissions estimates for both these HFCs. Work is on-going to cross-check the emissions based on the bottom-up modelling methodology with the InTEM estimates based on these atmospheric measurements. Results from this work are expected to feed into the foams modelling in the next inventory. One Component Foams (OCFs) 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, 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 OCFs 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 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

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 303 • 1996: 4,000 kt CO2 equivalent per annum (3100 tonnes of HFC-134a); and • 2000: 1,700 kt CO2 equivalent per annum (1200 tonnes of HFC-134a; 1000 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 emissions occur from 2009 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. Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Section 1.6. Details of verification of emissions are given in Annex 6. Source Specific Recalculations There have been no recalculations to the mass based estimates from this source. Source Specific Planned improvements Emission factors and activity data will be kept under review. 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 electronic and telecommunications equipm ent, 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, CO2 and powder extinguishers. The Fire Safety Advice C entre75 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.” 75

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 304 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 est imates 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 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 consu mption 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 assumed that HFC - 227ea accounts for 100% of HFC consumption in this sector (over the full product lifetime).
The UK has also reported emissions of C4F10 from 1995 to 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

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 305 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 decommissioned 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 1.5-2.976 1.0 % released during recovery (disposal) 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. Uncertainties and Time Series Consistency The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Section 1.6. Details of verification of emissions are given in Annex 6. Source Specific Recalculations For information on the magnitude of recalculations, see Section 10. Source Specific Planned Improvements Emission factors and activity data will be kept under review. 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 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 76 Interpolated between 2000 and 2005

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 306 ‘silly string’ was banned from July 2009, un der 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 ove r ozone destruction led to replacement of CFCs with HFCs. Note that HFC use in MDIs are exempted from the 2014 EU F-gas regulation phase down of HFC consumption. 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 discontinued collecting data for 2013 onwards, so for these years we have projected estimates of HFC 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 ar e 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 2 a 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) prescription 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 propellants. 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. Year MDI Number (thousands) Average Propellant (g per

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 307 Year MDI Number (thousands) Average Propellant (g per 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. Uncertainties and Time Series Consistency Uncertainty data from this study have been used in the uncertaint y analysis presented in Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Section 1.6. Details of verification of emissions are given in Annex 6. Source Specific Recalculations HFC-152a had previously been expected to see an increase in use to replace HFC -134a in non-medical aerosols.
In consultation with the British Aerosol Manufacturers' Association, we found that this has not been the case for the following • 152a is more flammable than 134a • 152a isn't as cheap as using hydrocarbon replacements The BAMA contact expected that the reality has been that ~75% of 134a applications went to hydrocarbons. The remaining ~25% of applications are expected to have changed to HFO- 1234ze, which has low flammability but is more expensive than hydrocarbons.
In future, it's anticipated that the aerosols sector will go towards using compressed air/nitrogen/CO2 for applications that nee d to be non -flammable rather than towards another

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 308 It is now assumed that use of HFC-152a only continues at the level that it was used before the For information on the magnitude of recalculations, see Section 10. 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. 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. 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 us ing 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 solvents 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 ass umptions - 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

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 309 & Schwarz (2003) in years beyond 2002 were projections, EEA (201 9) 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 e mitted over a two -year period, an annual emission factor of 50% 77 was applied in this analysis using the IPCC (2006) equation above. Recovery and recycling are not considered in emission estimates, per the Uncertainties and Time Series Consistency The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inve ntory in Section 1.6. Details of verification of emissions are given in Annex 6. Source Specific Recalculations There have been no major recalculations to emissions from this sector. For information on the magnitude of recalculations, see Section 10. Source Specific Planned Improvements Activity data and emission factors will be kept under review. 77 Note the ICF report (ICF, 2013) states 45%, but the spreadsheet indicates 50% was used. Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 310 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 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 use d 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 isot anks) 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 calculated 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

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 311 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 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

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 312 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 emissio n 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). 4.35.2.4.2 Returned cylinder re-processing All used cylinders have a heel of gas lef t 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 n egligible 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 sold 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 Regulation). The model assumes a 2% heel in small cylinders (approx. 0.25 kg) and a 10% heel in small cans (approx. 30 grams). Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 313 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 p oor 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. The re 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 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. 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 o n 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 Section 1.6. Details of verification of emissions are given in Annex 6. Source Specific Recalculations The input data for quantities of HFC used in new systems has been updated to align with the HFC Outlook model now used for RACHP emissions estimates. In general, this results in lower

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 314 emissions estimates, reflecting that HFC Outlook’s estimates were lower than the prior ICF model in the historic time-series. For information on the magnitude of recalculations, see Section 10. Source Specific Planned Improvements Activity data and emission factors will be kept under review. 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. Consequent ly, it has gradually replaced equipment using older technologies, namely oil filled and air blast equipment. Recently, alternatives such as fluoronitrile-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 78, 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 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 20 21).
Since the introduction of the EU F -Gas Regulation in 2006, 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 o f the SF6 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. Uncertainties and Time Series Consistency The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Section 1.6. Details of verification of emissions are given in Annex 6. 78

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 315 Source Specific Recalculations Data for 2019 and 2020 have been revised due to data that was not available in time for the last submission now being available. There are some smaller changes to earlier years relating improved estimates for one operator. For information on the magnitude of recalculations, see Section 10. Source Specific Planned Improvements Activity data and emission factors will be kept under review. 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, 2021). Data supplied • Measurements of SF6 emitted from AWACS systems for 2016-2020 • 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 The estimates for 2014-2020 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. 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. The uncertainty analysis in Annex 2 provides estimates of uncertainty according to IPCC source category and fuel type. Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Section 1.6. Details of verification of emissions are given in Annex 6. Source Specific Recalculations There have been no major recalculations to emissions from this sector. For information on the magnitude of recalculations, see Section 10. Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 316 Source Specific Planned Improvements Activity data and emission factors will be kept under review. 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 factor 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 accelerators 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): 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 SF6 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 ind ustrial 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 each accelerator. The Tier 1 est imation 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 ac celerator by process

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 317 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 cha rge 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 acceler ators 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 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. 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 Nucl ear 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 onl y operational particle accelerator ceased usage of SF 6 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. Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 318 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Section 1.6. Details of verification of emissions are given in Annex 6. Source Specific Recalculations There have been no major recalculations to emissions from this sector. For information on the magnitude of recalculations, see Section 10. Source Specific Planned Improvements Activity data and emission factors will be kept under review. 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 2G2e, 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. 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 plas ma 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

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 319 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 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

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 320 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 further activity data have been identified during consultations with relevant UK and EU trade bodies, although, UK industry have contributed to determining suitable est imates 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 200179; and, • Mixed assessments of how the sector will grow after 2003. In addition to the 200 4 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. In the absence of data on the degree of this contraction, we have conservatively assumed that the sector has remained constant in size On our understanding that the primary use of PFCs in this sector is to generate a fluorine plasma, we have assumed that there is an increase in other input gases in 2005 -10 to offset the reduction in CF4 and C2F6 and maintain a constant level of total fluorine in input gases used 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 chambers who se 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 79 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 (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 321 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) (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 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. 80 As defined at the beginning of Section 4.39.2.1

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 322 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 almost81 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 reviews82 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) an d/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 NIR, and (3) emission and removal estimates are accurate and time-series consistency 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 • 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 81 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. 82

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 323 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 g ather 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, Invent -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 any 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.). 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. Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 324 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 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. Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the g reenhouse gas inventory in Section 1.6. Details of verification of emissions are given in Annex 6. Source Specific Recalculations There have been no major recalculations to emissions from this sector. For information on the magnitude of recalculations, see Section 10. Source Specific Planned Improvements Activity data and emission factors will be kept under review. We note that the ERT has specifically requested that the UK improves estimates for semiconductor manufacture, and there is an in progress study investigating this topic. This category includes emissions from N2O used as an anaesthetic. 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

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 325 N2O/bed/year83. 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 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 w ell 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. Source Specific QA/QC and Verification This source category is cove red 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. Source Specific Recalculations There are no major recalculations to this source for this submission. For information on the magnitude of recalculations, see Section 10. 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. 83

Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 326 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, 2022). 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 substances is only a single canister; • An N2O cartridge has a volume of 10ml and is compressed to 60 bar; and, Uncertainties and Time Series Consistency The UK method for cream consumption relies upon the ass umption 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 s old 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 gapfilled by interpolation of the surrounding years. Prior to 2012, no data is avai lable. 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 Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the greenhouse gas inventory in Source Specific Recalculations There are no major recalcu lations to this source for this submission. For information on the magnitude of recalculations, see Section 10. Industrial Processes (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 327 Source Specific Planned Improvements 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 regulate d 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 permitted processes 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 reportin g 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 NO X and N2O). This process has been in operation since the 1940s. 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 reporting 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 emiss ions of NOx, 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 (CRF Sector 2) 4 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 328 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 emissio ns would be smaller than those from the three sites currently included. Source Specific QA/QC and Verification This source category is covered by the general QA/QC of the inventory in Section 1.6 and the source emissions data from plant operators is subject to the QA/QC procedures of the PI. Source Specific Recalculations There are recalculations in the year 1990 to 1998 for this source due to correcting a discrepancy in the calculations. The size of this change is an increase of 10-16%. Source Specific Planned Improvements The estimates will be kept under review, and additional sites added if appropriate. 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 CRF category 1A2d. Other emissions of GHGs from UK paper and pulp processes will be minor and are not estimated. 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 NIR 2023 (Issue 1) Ricardo Energy & Environment Page 329 3F: Field Burning of Agricultural Residues Gases Reported CO2, CH4, N2O, NOx, CO, NMVOC, SO2 3A: Enteric Fermentation - CH4 (L2, T2) 3A1: Enteric fermentation from Cattle - CH4 (L1, T1) 3A2: Enteric fermentation from Sheep - CH4 (L1, T1) 3B1: Manure management from Cattle - CH4 (L1, T1) 3B2: Manure Management - N2O (L1) 3D: Agricultural soils - N2O (L1, T1, L2, T2) Completeness A general assessment of completeness for the inventory is since last submission Revision to fertiliser N estimates applied to cropland in GB, based on re-analysis of British Survey of Fertiliser Practice (BSFP) data and access to import-export fertiliser data; improvement to analysis to derive timing of fertiliser application by type, improving disaggregation of fertiliser use across different months, better-reflecting climatic conditions and emissions arising; revision of mitigation uptake for fertiliser placement to cropping, now derived from BSFP data per fertiliser type, and for uptake of urease inhibitors since first-reported in 2009; revision to estimates of the use of ammonium sulphate and diammonium phosphate. Method improvement to better-reflect available data resolution for crop yield estimates across crop sub-categories, including for malting / non-malting barley, spring and winter-sown oats and oil seed rape, impacting emissions from crop residues. Updates to dairy cow concentrate use in GB; revisions to poultry N excretion rates using higher precision values from Updates to manure storage and application practices, using new 2021 NI Nutrient Management Survey data; revisions to proportion of cattle managed on slurry vs FYM systems for

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 330 Wales and Scotland, to estimates of manure stored under different storage types and estimates of land application activity data all based on reviews of available AD; revised data on proportion of dairy cow collecting yards that are washed down as a mitigation method, previously assumed to be zero but now based on analysis of farm management survey data; update to use latest AD on manure processed via Anaerobic Digestion including an increase in poultry litter in NI diverted to AD since 2016. Updates to nitrous oxide EFs for histosols used as cropland and improved grassland from Tier 1 to Tier 2 using values developed by the James Hutton Institute. Minor changes to the assumed area of histosols based on re-analysis of the The agriculture inventory uncertainty analysis has now been fully updated to properly reflect the method developments across all source categories, including all cattle methods. In the agriculture sector, the United Kingdom reports emissions from the following iii. agricultural soils direct and indirect , nitrous oxide (N2O), including synthetic fertiliser, manures and digestates applied to soils, urine and dung deposition during grazing, vi. emissions of other pollutants, including NMVOCs, NOx and PM (Tables 3B and 3D). Emissions from fuel use on UK farms are reported in the Energy sector. Emissions from rice 5.1.1.1 Agriculture Emissions in the UK Trends and drivers decrease of 18.0% between 1990 and 2021.
Emissions of CH4 were the largest contributor to the total emissions in 2021 (65.1%) followed Key events and other 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; ➢ 2001 UK foot and mouth crisis. Large numbers of livestock culled to mitigate the spread of foot and mouth disease, leading to a large one-off decline in livestock numbers; ➢ Other livestock diseases have also contributed to this trend; ➢ Annual fertiliser application rates and associated emissions are strongly affected in the UK 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 ➢ Changes in organic fertilisers and manure management over time. UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 331 5.1.1.2 Agriculture National System, Stakeholders and Management of The UK agriculture inventory of GHGs and ammonia (NH3) is managed by the UK Department of Environment, Food and Rural Affairs (Defra), which is the UK Government department with policy responsibility for farming, food standards and air quality emissions. The inventory is used as a reporting mechanism for UK and sub -national emissions as well as to underpin emission projections and policy scenario analysis; as such it is developed and managed via a

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 332 network of stakeholders in order to identify new / emerging data, to keep pace with UK regulation, farm practices, mitigation actions, scientific and policy research. Defra funds the compilation and reporting of the agriculture GHG and ammonia (NH3) inventory via a multi -year contract, currently held by a consortium led by Rothamsted Research (to August 2023) . The outputs are incorporated into the wider UK GHG inventory via the National Atmospheric Emissions Inventory database, whic h 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 . The Rothamsted Research consortium sector experts are the inventory compilers for the Agriculture sector, whilst the DESNZ-contracted Ricardo consortium is the UK Inventory Agency 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 and can be summarised as ➢ January - 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 and Devolved Administration (DA) science and policy leads). Identification of new data and/or methodological improvement options, 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 – 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. ➢ June – Access data, consult stakeholders (e.g. AIC, Defra, devolved Governments 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 impacts also on air quality pollutant emissions, e.g. ammonia, consult with the Defra-led Air Quality Inventory Steering Group whic h comprises AQ modellers, air quality researchers. Engage with the UNFCCC review process as required. ➢ 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 ➢ January – March (n+2): Finalise the UK agriculture inventory submission, i.e. update the UK inventory central estimates and uncertainty analysis and then start again with In the 2023 submission cycle, t he Rothamsted team has considered an inventory method improvement to disaggregate the activity and emissions across the livestock manure management systems (MMS), aiming to develop a method that will more accurately represent the emissions and the fate of materials across different manure management in storage, in housing and at the point of spreading, for slurry and manure materials. UK sector experts prepared a draft paper for submission to international peer reviewers from Ireland, Denmark and Fr ance. Peer reviewer feedback on the proposed method indicated that the rationale and objective of the proposed improvement is sound and should be explored further, noting that further work is needed to address data and evidence gaps before the UK can move to implementation. We will seek to progress this item during the 2024 submission cycle,

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 333 subject to resource availability and identification of relevant evidence to populate the proposed The UK has developed a new model to estimate the emissions from cropland which has been approved and used in the 2023 submission. Whilst the implemented calculation method has not been revised, the inventory team recognised that the previous MS Excel models were reaching the end of their useful life. In some cases, methodologies to fill data gaps across the time series, for example where fertiliser survey data were very limited for specific country - crop-fertiliser combinations, were not considered statistically reliable.
The team has made • Rebuilt the methodology in a coded model in R and taken the opportunity to work back through the full time series of electronic versions and hard copies of the British Survey of Fertiliser Practice, implementing a systematic tiered approach to gap -filling where survey data were insufficient for a specific country/crop/fertiliser type. • The level of disaggregation of per crop type has been revised to reflect the limited data • Fertiliser activity data available from the UK surveys ha s now been supplemented by information from import statistics, in particular to deliver more accurate estimates of fertiliser types that are not manufactured in the UK and hence must be imported; this approach has enabled the team to over-write previous as sumptions regarding the share of the UK market for these fertilisers and use the import data as more accurate totals for the UK farming sector. • More strict checks in cross-sector activity data, including LULUCF, Waste sectors. 5.1.1.3 Uncertainty Analysis in the Agriculture Sector The identification of inventory improvement priorities, as then managed via the stakeholders and mechanisms described above, is informed by the assessment of inventory uncertainty. In the 2023 submission, the UK agriculture uncertainty an alysis has been extensively revised The agriculture inventory uncertainties have been calculated using an Approach 2 method as described by the IPCC, i.e. a Monte Carlo simulation based on probability distribution functions for all key model i nput parameters (IPCC, 2006). Model runs of the UK agriculture inventory are computationally intensive and so a preliminary 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 were computed, suitable distributions were fitted to the outputs and fed forward to the wider inventory calculations. As an assurance check, the central tendencies from the uncertainty analysi s were compared with those produced from the deterministic inventory runs and these were In the 2023 submission, all of the uncertainty parameters per source category have been fully updated to reflect the higher tier UK methods. Where th is has led to substantial revisions in the uncertainty ranges per source category – pollutant compared to the 2022 submission, this is noted in the relevant NIR source category sections. In some cases (e.g. dairy cattle – enteric methane) the uncertainty in the underlying parameters has been updated but remains under review and will be updated as appropriate in the next inventory cycle. The UK Greenhouse Gas Inventory Model for the Agriculture This section provides an overview of the UK GHGI model f or agriculture; for more details on the model, please see Annex 3 Section A3.3.7. UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 334 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 and air quality pollutant emissions for the agriculture sector , focusing on methane (CH4), nitrous oxide (N2O) and ammonia (NH3). 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 f uture 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 invento ry improvements are documented in the relevant source category sections below. 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 generating 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 • 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 MS 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 confidentiality restrictions placed on the mapping of inventory input and output datasets. 5.1.2.2 Activity data handling When there are data gaps for one year in livestock numbers or crop areas, holding level data for the previous year are used. 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). General sector characteristics Activity data that apply to more than one source category (i) farm types (Section 5.1.3.2); (ii) livestock types and numbers ( Section 5.1.3.3); (iii) crop types and crop areas (Section 5.1.3.4); (iv) fertiliser types and application rates ( Section 5.1.3.6).
These are described in this section and are referred to in the relevant sections throughout this chapter. The data relevant to calculation of emissions from crop residues are described in Section 5.1.3.5. The

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 335 emission factors used to estimate N2O emissions from synthetic fertiliser applications to soils are determined via an empirical model that relies on environm ental factors and is described Year-specific activity data and EFs are provided in supplementary tables. 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 nitrogen leaching following application of fertilisers, managed manures and excreta r eturns. 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 the 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 topsoil measurements of pH (≥ 7), which is used in calculations of ammonia emissions from manufactured fertilisers. Long-term annual and monthly average rainfall and air temperatures were obtained from the Met Office. Met Office UKCP09 baseline average datasets are for the period 1981 to 2010 (Jenkins et al., 2008). The UKCP09 data are available at 5 by 5 km resolution and summarised to the reference 10 by 10 km grid cell s used in the agriculture inventory model . Daily time - series of measured rainfall derived from the UK synoptic network for the MORECS model (Hough and Jones, 1997) were obtained from the Met Office across the 1981 to 2010 time series at 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 nitrogen application to land (used in calculations of ammonia emissions from manufactured 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 10 by 10 km 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 livestock) of the various types of agricultural production. Ten robust farm types (RFT) are applied at Devolved Administration level (England, 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. 5.1.3.3 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, 2022a) 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 (BCMS, 202 2) are used to provide further deta il of all cattle across England, Wales and Scotland, based on analysis of cattle movement records. UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 336 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 Defra AC0114 GHG platform project for GHGI data management (Defra, in prep.). All livestock are associated w ith a holding, which is located within a 10 by 10 km grid 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 su bsequent 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) 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). More details of individual sector structure are given below. 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 are derived from the CTS (BCMS, 2022) 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 not included because of the difficulties of differentiating them from the beef sector. This ensures complete reporting of total emissions from UK agriculture, with all bulls accounted for in the beef sector. Dual purpose animals are assigned as dairy 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 years prior to the introdu ction 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. Breakdown of dairy cow breed types for 1990 was derived from Dairy Facts and Figures, 1992 (Milk Marketing Board), with the breeds being associated with 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 data. 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, 202 2) 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

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 337 Sheep are disaggregated into three production systems (hill, upland and lowland) associated with different livestock parameters and management practic es, and three types (ewe, lamb and ram) using data from the June Agricultural Survey (Defra, 2022a), 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 by Wheeler et al. (2012) and the occasional surveys of the Breeding Structure of the British Sheep Industry (Pollott, 1998; Pollott and Stone, 2006; Pollott, 2012; and Pollott and Boon, 2021). The ewe category includes replacement breeding sheep and cull ewe s, 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 analys is 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 June Agricultural Survey count of lambs is raised by between 1% (Scotland) and 5% (England) 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, 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 against historical records o f 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 analyses 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 (Pollott, 1998; Pollot and Stone, 2006; Pollot, 2012; 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 Olsen (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 (including barren sows for fattening); (5) fattening swine 20-80 kg; (6) fattening swine <20 kg. Data are obtained from the JAS (Defra, 2022a) for England, Wales, Scotland and Northern Ireland, and where JAS categories do not match the inventory categories, consistent data translation rules are applied from the Defra AC0114 project (Defra, in prep). 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, 2022a) for En gland, Wales, Scotland and Northern Ireland, 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 t he agricultural census (holding level) data and have been recreated by scaling these at a holding-level with the 1995 census to national totals.
UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 338 5.1.3.3.6 Goats, deer, and horses The number of goats, deer and horses are derived from JAS holding level data (Defra, 2022a), and for horses not kept on agricultural holdings, from the British Equestrian Trade Association national survey (BETA, 2019). Missing data for some years were gap -filled by extrapolation, using data from adjacent years. 5.1.3.4 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 the supplementary material. Grassland is classed as (i) improved temporary (sown within the last 5 years), (ii) improved permanent (not sown with the last 5 years), and (iii) 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, 2022a). 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 area that is renewed annually are between 3.7 (Wales) and 14.7% (England) for temporary grass, and between 2.0 (England) and 4.0% (Scotland) for permanent grass (BSFP, 2022). As part of the quality control (QC) process, t he grassland areas are verified using 2 different data

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 339 For the estimate of emissions from mi neralisation, the land use change areas have been significantly updated (see the LULUCF chapter for further details). Previously they were based on decadal matrices derived from the Countryside Survey data. In the 2022 submission these historic estimates were updated to use annual matrices derived from a land use tracking data assimilation process bringing together earth observation / remote sensing and national datasets. Areas of bioenergy crops in England (miscanthus and short rotation coppice) have been included in the cropland management calculations for the first time. UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 340 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 o verestimates cereal crop residues when primary yields are as high as those in the UK. Activity data on residue management available since 2004 from the British Survey of Fertiliser Practice (BSFP, 2022) enables limited disaggregation by country, crop and farm type. Residues from grassland are calculated using a UK -specific semi-empirical nitrogen mass - balance model which captures the effect of level of nitrogen fertilisation, soil water stress and cutting frequency on dry matter production, nitrogen off -take and nitrogen leaching. The structure 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, 2022). Primary crop yields are taken from national statistics, except for some minor crops that that are taken from the main farm management guides (Nix, 2020; Mowbray, 2020). Regional yields of major cereals in England became available from 1999 and these are used in preference to the national values for England (Defra, 2022a; Defra, 2022d). Farm practice data in Northern Ireland (NI) is supplied by the lead NI government agricultural statistician (DAERA, 2022). Details of values used for this year’s inventory are in the Annex section A3.3. 5.1.3.6 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, 2022) and the Farm Business Survey (FBS) for Northern Ireland (DAE RA, 2022) on application rates to crop type and the relative use of different fertiliser types. The data from before 2004 is 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. Less data exists 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. As part of the quality compared to IFA data (<6%), the other data have good agreement with our estimates.
UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 341 overall N application rate to crops overall N application rate to grass

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 342 contribution to total fertiliser use ammonium nitrate contribution to total fertiliser use The data sources, application and deposition of animal manures are des cribed in Chapters 5.3 and 5.4. In addition, other organic sources are also applied in the a) Sewage sludge (liquid or as sludge cake) b) Digestate from the anaerobic digestion of livestock manure

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 343 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 materials being applied to land, the characteristics of those materials (e.g. N content, total ammoniacal nitrogen (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 th e proportion to which specific mitigation measures Emissions of N2O are calculated Where Q is the quantity of organic material applied (m3), TN is the total nitrogen 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 (to reflect differences in practices if such data become available) are considered. Indirect N 2O emissions from volatilised and leached N are calculated according to IPCC 2006 Guidelines, using default IPCC N2O emission factors EF4 and EF5 and applying UK-specific values for FRACleach. 5.1.3.8 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 3). The U K has implemented a detailed N -flow model for synthetic fertiliser application and livestock excretion through the manure management chain (based on Webb and Misselbrook, 2004), at each manure management stage, followed by the application to soil accountin g for all N losses (via NH 3, N 2O, NO, N 2 and N leaching) and transformations (immobilisation, mineralisation). A flow diagram illustrating for the latest year the N inputs and main outputs is shown below. In response to ERT review comments the UK has also provided a supplementary file to accompany the NIR with further details of the N flows through the

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 344 grassland, arable, other soils, to emissions and losses

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 345 The UK has now appended the Emission Factors used for the 1990-2021 inventory in a supplementary file in excel format. 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) 3A2: Enteric fermentation from Sheep - CH4 (L1, T1) Completeness No known omissions. A general assessment of completeness for the inventory is 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 shee p), and some non-ruminant animals (e.g. swine and horses) produce methane, although ruminants are the largest source per unit of feed intake. 5.3.1.1 Source category significance, trends and drivers Between 1990 and 2021, total emissions of enteric methane decreased by 15%. Total enteric methane emissions in 2021 were 841 kt CH4. UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 346 Enteric methane emissions are estimated from the intake and diet characteristics for The flow diagram illustrates the highest Tier method used for estimating dry matter intake and N content in the diet from ruminant livestock. For non -ruminants, calculations for N 2O and manure CH4 start from Box 2.1 using Country Specific N contents and default VS; enteric CH4 is estimated using IPCC default methodology. Enteric methane 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 (Defra, in prep. ): 𝐶𝐻4_𝑒𝑛𝑡𝑒𝑟𝑖𝑐_𝑑𝑐 = (15.8185 × 𝐷𝑀𝐼) + 88.6002 CH4_enteric_dc is the enteric methane 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 characterisat ion of production, management and feed by dairy cow category for each month. Further details are given in 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

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 347 on industry data84 regarding yields for specific breeds ( 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 national Devolved Administration (DA), and finally UK statistics on average milk yield. 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 and 20, 23 and 25 months for NI, respectively, giving respective age at first calving of 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 time in age of 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 book ( Redman, 2022) 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 pr otein 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 methane 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 dry matt er intake 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 (Defra, in prep.) 𝐶𝐻4_𝑒𝑛𝑡𝑒𝑟𝑖𝑐_𝑜𝑐 = (17.5653 × 𝐷𝑀𝐼) + 45.8688 CH4_enteric_oc is the enteric methane emission per other cattle, g d -1; DMI is feed dry matter intake, kg d -1; and standard error values for th e slope and intercept are 2.4112 and As for dairy cows, dry matter intake for other cattle categories is determined using UK-specific energy balance equations, derived for non -lactating cattle from AFRC (1993) combined with cattle category- and system-specific production and diet characteristics at a monthly resolution as described for dairy cows (and further detail given in Annex 3.3). UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 348 The AFRC (1993) recommendations on the energy allowances for cattle are used to estimate the metabolisable energy (ME) needs of cattle (based on l iveweight, growth rate, gestation and lactation). The ME coupled with activity data from a Defra FBS module ( Parsons 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 collected at national level (Defra, 2022b), 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 thr oughout 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 methane 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 materia l) are from the FBS (Parsons and Williams, 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, Williams, 2015) and other farm practices surveys (Defra, 2022c) 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 is 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 housin g 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 (NH3) and nitrous oxide (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 dry matter intake specific 𝐶𝐻4_𝑒𝑛𝑡𝑒𝑟𝑖𝑐_𝑠ℎ𝑒𝑒𝑝 = (12.3894 × 𝐷𝑀𝐼) + 5.1595 CH4_enteric_sheep is the enteric methane 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,

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 349 Is calculated using a modified version of the ARFC (1993) energy requirements t o 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 and lamb has separate growth-curves, access to housing and handling yards, and different acc ess to forage, concentrate and conserved feeds that determine its feed intake. 5.3.2.3.2 Sheep live weights (LW) The inventory uses country- and system-specific values for the live weights of the adult ewe and lamb, and for the rate of weight gain. The annual aver age weight of ewes and slaughter weight of lambs are calculated separately for each country based on average carcase weights and a fixed killing -out percentage of 42 and 45% respectively, derived from national slaughterhouse statistics85. 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 an 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 manufactured fertiliser N applied to pasture. Ewe and rams are fed a supplement of conserved silage and hay for 120 days ove r-winter, and store lambs are fed 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 a fter lambing. The metabolisable energy and crude protein 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 da ys, 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 days, varying with country and system (Wheeler et al., 2012). Lambs intended for breeding replacement, and all ewes and rams are present all year. Enteric emissions for swine, goats, horses and deer are estimated using IPCC (2006) Tier 1 methodology by combining the Tier 1 default E F with the 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 85 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 NIR 2023 (Issue 1) Ricardo Energy & Environment Page 350 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. 5.3.2.5 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 emission factors were applied to animal numbers. For CDs, UK implied emission factors were applied. Uncertainties and time-series consistency The uncertainty analysis in Annex 2 provides estimates of uncertainty per IPCC source 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 Enteric emissions from cattle and sheep are derived using Tier 3 methods in the UK inventory. In the 2023 submission uncertainty analysis the Inventory Agency has reviewed and updated all of the uncertainty parameters for these source categories. The uncertainty parameters for the ME requirement and enteric methane VS DMI relationship have been revised to be more representative of UK circumstances and the Tier 3 method, applying parameters that reflect the statistical relationships evident from UK field experiment results. However, the resultant uncertainties related to dairy cattle enteric fermentation methane emissions are noted to be somewhat l ower than those derived for other country Tier 3 approaches.
Our sector expert view is that whilst the updated uncertainty estimates are an improvement on the previous approach, for the next submission we must review the component of uncertainty that is re lated to the derivation of the DMI estimates. We are confident that the analysis of the relationship between DMI and methane emissions is well characterised and accurately reflected in the updated uncertainty calculations. Compared to previous inventory uncertainty analysis, the results reflect where methods have been improved. The beef sector method is unchanged, and the uncertainties are not significantly revised. Where changes have been made to methods, data and assumptions and hence to uncertainty para meters, there are increases in the uncertainty ranges evident Emissions are calculated from animal population data and appropriate emission factors. The animal population data are collected in the June Agricultural Census (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 provided. Control measures introduced in response to the Bovine Spongiform Encephalopathy (BSE, also known as "mad cow disease”) outbreak in the UK introduced an incons istency 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 period were interpolated using the linear trend of increasing lives weight with time for the years immediately prior to and following this period. Source-specific QA/QC and verification This source category is covered by the general QA/QC procedures, which are discussed in

UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 351 Details of the data flows and QAQC across the agriculture inventory model and methods are described within Annex A3.3. Some of the data validation checks are also presented within the supplementary MS Excel file that accompanies the NIR and within the NIR (sections 3.1.3.4 and 3.1.3.5). 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; in 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. The implied emission factors for dairy, other cattle and sheep (124, 55 and 5 kg/head/year, respectively) were different to IPCC 2006 default values (109, 57, 8 kg/head/year). Source-specific planned improvements Revise the parameters for the energy balance equations for non -lactating cattle based on recent and ongoing research (AFBI). Explore Northern Ireland CTS data access, to bring the cattle method for NI into line with other parts of the UK. Revise housing assumptions. Simplify the allocation of ewes to hill-upland-lowland sectors. Agriculture (CRF Sector 3) 5 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 352 Source-specific recalculations Details of and justifications for recalculations to activity data and to emission factors are given in the tables below. 2022 submission 2023 submission Units Comment/Justification 1990 2020 1990 2020 3.A.1 Enteric fermentation – Dairy cattle 278.37 229.36 279.44 229.05 kt Very small correction to coded model dairy DMI vs CH4 relationship (affects all years); Replaced slaughter weight timeseries (affects 2008 to 2020); Updated 2019 and 2020 milk yield to match UK/NI stats and replaced unweighted Scotland milk yield data with weighted milk yield data from 2013-2020 which also has a very small effect on other DAs due to weighting/correction factors applied against UK milk yield; Concentrate use updated for 2020 for E,W,S which has slight effect on emissions from 2011 due to values being 3.A.1 Enteric fermentation – Non-Dairy 476.30 415.85 476.49 416.09 kt Very small correction to coded model dairy DMI vs CH4 relationship (affects all years); Replaced slaughter weight timeseries

Agriculture (CRF Sector 3) 5 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 353 2022 submission 2023 submission Units Comment/Justification 1990 2020 1990 2020 3.A.1 Enteric fermentation – Dairy Cattle 97.73 123.81 98.11 123.64 kg/hd/year Reason for change as above 3.A.1 Enteric fermentation – Non-Dairy Cattle 51.34 54.89 51.36 54.92 kg/hd/year Reason for change as above

Agriculture (CRF Sector 3) 5 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 354 Source included Method Emission Emissions sources 3B11: Dairy Cattle Wastes 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 methane nor nitrous oxide emissions for this source are currently reported in the GHGI. A general assessment of completeness for the inventory is Updates to manure storage and application practices Aside from method improvements, the UK has also included a detailed livestock MMS nitrogen flow dataset for the latest inventory year. This is in response to ERT findings from the Centralised Review of the 2022 UK GHGI submission and can be found in the supplementary MS Excel file that accompanies Methane is produced from the decomposition of manure under anaerobic conditions. Agriculture (CRF Sector 3) 5 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 355 5.4.1.1 Source category significance, trends and drivers Total methane emissions from manure management in 2021 were 153.2 kt CH4. Emissions in 2021 were 7.7% lower than in 1990. For nitrous oxide , total emissions from manure management in 2021 were 9.4 kt N 2O. Emissions in 2021 were 17.2% lower than in 1990.
5.4.2.1 Methane emissions from animal manures and manure-based digestates The emission factors for manure management are calculated following IPCC Tier 2 methodology for cattle, sheep, swine and poultry, accord ing 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 dry matter intake 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 matter intake, kg d -1. In the case of sheep, VS excretion also accounts for varying energy content of urine, varying with feed protein level. UK-specific data on the methane producing potential (Bo) of cattle excreta were not significantly different from IPCC (2006) default values (Defra 2014a), so the default values are retained. For swine and poultry, IPCC (2006) default values for VS and Bo are used. applied, with the exception of liqu id/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 b ased 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 MCFs assumed for the different systems. There are no UK activity data for the practice of composting of manure within MMS and hence no methane nor nitrous oxide 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; methane emissions would be lower, as MCFs 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 nitrous oxide 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 omission. 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/hd/d, is according to the IPCC 2019 refinement to the 2006 guidelines, 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

Agriculture (CRF Sector 3) 5 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 356 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. 5.4.2.2 Nitrous Oxide emissions from Animal Waste Management Systems Animals are assumed not to give rise to nitrous oxide 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 Manure 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 IPCC (2006), the following AWMS are reported in the Agricultural • All animal manures, slurries and digestates applied to soils; and The methodology is summarised in the flow diagram below. Note that the DMI, diet N content Emissions trends and methodologies Total nitrous oxide emissions from manure management in 2021 were 9.44 kt N2O. Emissions in 2021 were 18.1% lower than in 1990. Agriculture (CRF Sector 3) 5 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 357 5.4.2.2.1 Livestock N excretion Nitrous oxide emis sions 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 managed according to the different AWMS, and a combination of default and country -specific emission factors 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 (based 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. 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 dry matter intake, 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). For sheep, based upon a na tional 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 lamb from the housing calculations 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 assume that no lambs are housed during the finishing period. Other assumptions regarding handling shee p 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. Kate Phillips). 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 United Kingdom surveyed slaughter ages (after Wheeler et al., 2012) have proven that lamb are present on average for only 237 days. The N excretion value of around 4 kg N per lamb is therefore for a 237-day period, and not for a complete year (365 days). In the case of sheep weighted 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 per lamb produced (see important note on N excretion above); around 11 kg N yr-1 per ram; and around 9 kg N yr-1 per ewe. Average N excretion values for neighbouring countries reported in their NIR 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 (France). 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

Agriculture (CRF Sector 3) 5 UK NIR 2023 (Issue 1) Ricardo Energy & Environment Page 358 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 either the same or lower than the UK inventory values of 17.3 g N day-1 for all lamb, both finished and replacements; 30.9 g N day-1 for ram; and 23.8 g N day-1 for all ewes. These reported data support the UK CS values. For other livestock types, country-specific values for N excretion were derived from the report of Defra project WT0715NVZ (Cottrill and Smith, 2007), with interpretation by Cottrill and Smith poultry, 70% of excreta is assumed to rapidly become ammoniacal N with 30% remaining as organic N. For goats, horses and deer, the respective excretal proportions are assumed to be 60 and 40%. In the case of swine and poultry, in this submission the N excretion values were revised using data from Defra WT1568 (2016b) to interpolate for years from Defra WT0715NVZ (2004). For poultry also included a revision to proportional uplift in N excretion for outdoor laying hens. Values were also updated for goats (from 20.6 to 8.4 kg/y) and deer (from 13 to 29.3 kg/y) according to IPCC 2019 refinement to the 2006 guidelines. 5.4.2.2.2 Direct nitrous oxide emissions from MMS The conversion of excreted N into nitrous oxide 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 is used and for po ultry manure where a UK -specific EF of 0.5 is used, as derived from UK UK data relating to direct N2O emissions from manure management were reviewed as part of Defra project AC0114. There were a limited number of studies, the mean EF for which are 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 value 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 default given by the 2006 IPCC Guidelines which is therefore applied in the UK inventory.