This publication is no longer current or has been superseded.
New Zealand’s industrial processes sector totalled 4,601.9 Gg carbon dioxide equivalent (CO2-e) in 2007, contributing 6.1 per cent of total greenhouse gas emissions. Emissions from industrial processes had increased by 1,192.7 Gg CO2-e (35.0 per cent) above the 1990 level of 3,409.2 Gg CO2-e (Figure 4.1.1). This sector is dominated by emissions from the metal production category (CO2 and perfluorocarbons (PFCs)) at 49.2 per cent of industrial process emissions.
Note: The per cent change for other production and the production of halocarbons and SF6 is not occurring (NO) within New Zealand. The per cent change for the consumption of halocarbons and SF6 is not applicable (NA) as within New Zealand there was no production of HFCs in 1990.
The emissions reported in the industrial processes sector are from the chemical transformation of materials from one substance to another. Although fuel is also often combusted in the manufacturing process, emissions arising from combustion are reported in the energy sector. Carbon dioxide emissions related to energy production, for example, refining crude oil and the production of synthetic petrol from natural gas, are also reported within the energy sector.
New Zealand has a relatively small number of plants emitting non-energy related greenhouse gases from industrial processes. However, there are six industrial processes in New Zealand that emit significant quantities of CO2. These are the:
reduction of ironsand in steel production
oxidation of anodes in aluminium production
calcination of limestone for use in cement production
calcination of limestone for lime
production of ammonia for use in the production of urea
production of hydrogen.
Between 2006 and 2007, emissions from the industrial processes sector increased by 368.1 Gg CO2-e (8.7 per cent). The largest increase of 236.5 Gg CO2-e (37.2 per cent) was from the consumption of halocarbons and SF6. This was due to HFCs and PFCs used as replacement refrigerants for CFCs and HCFCs, in refrigeration and air-conditioning equipment.
Between 2006 and 2007, emissions from the mineral products category increased by 146.8 Gg CO2-e (20.6 per cent). This was largely due to one cement company running at full production.
Emissions of CO2 from industrial processes are compiled by the Ministry of Economic Development from information collected through industry surveys. The results are reported in New Zealand Energy Greenhouse Gas Emissions 1990–2007 (Ministry of Economic Development, 2008a).
Most of the activity data for the non-CO2 gases is collated via an industry survey. Between 1990–2007, the only known CH4 emissions from the industrial processes sector came from methanol production. Emissions of HFCs and PFCs are estimated using the IPCC Tier 2 approach. Sulphur hexafluoride emissions from large users are assessed via the Tier 3a approach (IPCC, 2000).
Emission factors and activity data is included in the MS Excel worksheets available for download with this report from the Ministry for the Environment’s website (http://www.mfe.govt.nz/publications/climate/). Due to commercial sensitivity, some activity data has been classified as confidential.
The number of companies in New Zealand producing CO2 from industrial processes is small and the emissions of CO2 supplied by the companies are considered to be accurate to ± 5 per cent (Ministry of Economic Development, 2006). The uncertainty surrounding estimates of non-CO2 emissions is greater than for CO2 emissions and varies depending on the particular gas and category. Uncertainty of non-CO2 emissions is discussed under each category.
For this submission, six of New Zealand’s industrial process companies were visited by members of the national inventory team. This provided an opportunity for the national inventory team to assess the QA/QC procedures employed by the companies and enhance the team’s understanding of processes involved. The visits also provided an opportunity for the visited companies to increase their understanding of the inventory reporting requirements. The increased explanation of the inter-annual variations in aluminium emissions (section 4.4.2) is one result of these meetings.
In 2007, the mineral products category accounted for 860.4 Gg CO2-e (18.7 per cent) of emissions from the industrial processes sector. Emissions in this category have grown 312.8 Gg CO2-e (57.1 per cent) from the 1990 level of 547.5 Gg CO2-e. There are no known emissions of CH4 or N2O from the mineral products category.
This category includes emissions produced from the production of cement and lime, soda ash production and use, asphalt roofing, limestone and dolomite use, road paving with asphalt, and glass production. In 2007, cement production accounted for 687.9 Gg CO2-e (80.0 per cent) of emissions from the mineral products category. In the same year, lime production accounted for 124.3 Gg CO2-e (14.4 per cent) and the use of limestone and soda ash contributed 48.2 Gg CO2-e (5.6 per cent). Only the emissions related to the calcination process for lime and cement production are included in this category. The emissions from the combustion of coal, used to provide heat for the calcination process, are reported in the energy sector.
In 2007, CO2 emissions from cement production were a key category both in the level and trend assessment (Table 1.5.1). There are two cement production companies operating in New Zealand in 2007, Holcim New Zealand Ltd and Golden Bay Cement Ltd. Both companies produce general purpose, portland cement. Holcim New Zealand Ltd also produces general, blended cement. From 1995 to 1998 inclusive, another smaller cement company, Lee Cement Ltd, was also operating.
Due to commercial sensitivity, individual company estimates have remained confidential and the data has been indexed as shown in Figure 4.2.1. Consequently, only total process emissions are reported and the implied emissions’ factors are not included in the common reporting format tables.
Carbon dioxide is emitted during the production of clinker, an intermediate product of cement production. Clinker is formed when limestone is calcined (heated) within kilns to produce lime and CO2. The emissions from the combustion of fuel to heat the kilns are reported in the energy sector.
Estimates of CO2 emissions from cement production are calculated by the companies using the Cement CO2 Protocol (WBCSD, 2005). The amount of clinker produced by each cement plant is multiplied by a plant-specific emission factor for the clinker. The emission factors are based on the calcium oxide (CaO) and magnesium oxide (MgO) content of the clinker produced. The inclusion of MgO results in the emission factors being slightly higher than the IPCC default of 0.50 t CO2/t cement.
The cement companies supply their emission data to the Ministry of Economic Development during an annual survey. A plant-specific, cement-kiln dust correction factor is included in Holcim New Zealand Ltd’s CO2 emissions calculation. Cement-kiln dust is a mix of calcined and uncalcined raw materials and clinker. Golden Bay Cement Ltd has not included a correction factor as it operates a dry process with no cement-kiln dust lost to the system.
Figure 4.2.1 shows the trends in New Zealand clinker and cement production, imported clinker and the implied emission factor for clinker and for cement for the 1990–2007 time series. In general, the figure shows clinker and cement production increasing over the time series 1990–2007. Relatively, over the same time series, cement production has increased greater than clinker production. The cement-implied emission factor decreased between 2000 and 2004 with increasing amounts of imported clinker. Meanwhile, the implied emission factor for clinker remained relatively unchanged.
A change in national standards for cement production in 1995, permitting mineral additions to cement of up to 5 per cent by weight (CCANZ, 1995), has also resulted in less CO2 emissions per tonne of cement produced. The increase in clinker production from 2006 to 2007 is due to one of New Zealand’s cement companies running at full production in 2007.
Sulphur dioxide is emitted in small quantities from the cement-making process. The amount of SO2 is determined by the sulphur content of the limestone. Seventy-five to 95 per cent of the SO2 will be absorbed by the alkaline clinker product (IPCC, 1996). The emission factor for SO2, used by New Zealand, is calculated using information from a sulphur mass-balance study on one company’s dry kiln process. The mass-balance study enabled the proportion of sulphur originating in the fuel and the sulphur in the raw clinker material as sodium and potassium salts to be determined. The average emission factor was calculated as 0.64 kg SO2/t clinker and was weighted to take into account the relative activity of the two cement companies. This submission continues to use this emission factor as it is still considered to accurately reflect the New Zealand situation.
In 2007, lime production in New Zealand was not a key category. There are four companies (McDonalds Ltd, Taylors Lime Ltd, Websters Hydrated Lime Ltd and Perrys Group Ltd) producing burnt lime in New Zealand. All four companies produce high-calcium lime, and two companies produce hydrated lime.
Emissions from lime production occur when the limestone (CaCO3) is heated within the kilns to produce CaO and CO2. The emissions from the combustion of fuel are reported within the energy sector.
Carbon dioxide and SO2 emission data from lime production are supplied to the Ministry of Economic Development by the lime production companies. Emissions are calculated by multiplying lime activity data by an emission factor (IPCC, 2000). Given the limited data availability before 2002, a single New Zealand-specific emission factor based on the typical levels of impurities in the lime produced in New Zealand was applied for
1990–2002. Since 2002, plant-specific emission factors have been used. In alignment with good practice, a correction factor is applied to the hydraulic lime produced. There has been little change in the implied emission factor varying from 0.72 t CO2/t lime to 0.71 t CO2/t lime from 1990 to 2007.
The SO2 emissions from lime production vary depending on the processing technology and the input materials. An average emission factor for SO2 was calculated as 0.5 kg SO2/t lime. The emission factor was weighted to take SO2 measurements at the various lime plants into account (CRL Energy, 2006). This submission has continued to use the 2005 emission factor.
Limestone and dolomite can be used in pulp and paper processing and mining. However, the majority of limestone quarried in New Zealand is calcinated to produce lime or cement. Emissions from the use of limestone for these activities are reported under the lime and cement categories as specified in the IPCC guidelines (IPCC, 1996). Ground limestone used in the liming of agricultural soils is reported in the land use, land-use change and forestry (LULUCF) sector.
Small amounts of limestone are used in the production of iron and steel by the company, New Zealand Steel Ltd. In the iron production process, the coal is blended with limestone to achieve the required primary concentrate specifications. New Zealand has separated emissions arising from limestone, coke and electrodes used in the iron and steel-making process from the remaining process CO2 emissions, and reported these emissions under the limestone and dolomite use subcategory (2A.3). This data could not be broken down any further (ie, only limestone emissions from iron and steel production). Emissions from limestone/coke/electrode use make up 1–2 per cent of total iron and steel process emissions.
There is no soda ash production in New Zealand. A survey of the industrial processes sector estimated CO2 emissions resulting from the use of soda ash in glass production in 2005 (CRL Energy, 2006). The glass manufacturer provided information on the amount of imported soda ash used in 2005. The manufacturer also provided approximate proportions of recycled glass over the previous 10 years to enable CO2 emissions from soda ash to be estimated from 1996 to 2005. This is because the amount of soda ash used is in fixed proportion to the production of new (rather than recycled) glass. Linear extrapolation was used to estimate activity data from 1990 to 1995. Updated activity data for subsequent years was provided by the glass manufacturer through an external consultant. The IPCC default emission factor of 415 kg CO2 per tonne of soda ash was applied to the soda ash activity data to calculate the CO2 emissions.
There is one company manufacturing asphalt roofing in New Zealand, Bitumen Supply Ltd. Default IPCC (1996) emission factors of 0.05 kg NMVOC per tonne of product and 0.0095 kg CO/t product respectively were used to calculate NMVOC and CO emissions. A survey of indirect greenhouse gases was last conducted for the 2005 calendar year. In the absence of updated data, activity data for 2005 has been used for 2006 and 2007.
There are three main bitumen production companies operating within New Zealand. Data on bitumen production and emission rates are provided by these companies. Estimates of national consumption of bitumen for road paving are confirmed by the New Zealand Bitumen Contractors’ Association.
In New Zealand solvents are rarely added to asphalt. This means that asphalt paving is not considered a significant source of emissions. New Zealand uses a wet “cut-back” bitumen method rather than bitumen emulsions that are common in other countries.
The revised 1996 IPCC guidelines (IPCC, 1996) make no reference to cut-back bitumen but do provide default emission factors for the low rates of SO2, NOx, CO and NMVOC emissions that arise from an asphalt plant. The IPCC recommended, default road-surface emissions factor of 320 kg of NMVOC per tonne of asphalt paved is not considered applicable to New Zealand. There is no possibility of this level of NMVOC emissions because the bitumen content of asphalt in New Zealand is only 6 per cent.
For the 2004 inventory submission, the New Zealand Bitumen Contractors’ Association provided a method (Box 4.1) for calculating total NMVOC emissions from the use of solvents in the roading industry. The industrial processes survey for the 2005 calendar year (CRL Energy, 2006) showed that the fraction by weight of bitumen used to produce chip-seal has been changing over recent years as methods of laying bitumen have improved. From 1990 to 2001, the fraction by weight of bitumen used to produce chip-seal was 0.80. From 2002 to 2003, it was 0.65 and, from 2004, the fraction was 0.60. The emissions of NMVOCs were updated to reflect this changing fraction.
In the absence of updated data, activity data for 2005 was extrapolated for 2006 and 2007.
NMVOC emitted = A x B x C x D
A = The amount of bitumen used for road paving
B = The fraction by weight of bitumen used to produce chip-seal (0.80)
C = Solvent added to the bitumen as a fraction of the chip-seal (0.04)
D = The fraction of solvent emitted (0.75)
There is one major glass manufacturer in New Zealand, O-I New Zealand. The IPCC guidelines (IPCC, 1996) state that NMVOCs may be emitted from the manufacture of glass and suggest a default emissions factor of 4.5 kg NMVOC per tonne of glass output. It has been assumed that the IPCC default emission factor for NMVOC was based on total glass production that includes recycled glass input. NOx and CO emissions are assumed to be associated with fuel use and are reported under the energy sector. Estimates of CO2 from soda ash use were obtained from the industrial processes survey for the 2007 calendar year (CRL Energy, 2008).
Uncertainties in CO2 emissions are assessed as ±5 per cent (section 4.1.2). Uncertainties in non-CO2 emissions (Table 4.2.1) have been assessed by a contractor from the questionnaires and correspondence with industry sources (CRL Energy, 2006).
|Product||Uncertainty in activity data||Uncertainty in emission factors|
|Asphalt roofing||±30% (+50% for 1990–2000)||±40%|
|Road paving with asphalt||±10%||±15% (chip-seal fraction and solvent emission fraction) to ±25% (solvent dilution).|
|Glass||0%|| NMVOC: ±50%
SO2: : ±10%
In 2007, CO2 emissions from cement production were a key category (level assessment). In the preparation of this inventory, the data for these emissions underwent IPCC Tier 1 quality checks.
New Zealand provided CO2 estimates for limestone, coke and electrode use for the first time in the 2008 submission. The emissions were separated from the industrial process emissions (excluding fuel combustion emissions reported in the energy section) from steel and iron production. In this submission, New Zealand has instead, separated emissions from limestone, coke and electrode use from total iron and steel emissions (including emissions from fuel emissions).
The chemical industry category reports emissions from the production of chemicals. The major chemical processes occurring in New Zealand that fall into this category are the production of ammonia and urea, methanol, hydrogen, superphosphate fertiliser and formaldehyde. There is no production of nitric acid, adipic acid, carbide, carbon black, ethylene, dichloroethylene, styrene, coke or caprolactam in New Zealand.
In 2007, emissions from the chemical industry category comprised 603.2 Gg CO2-e (13.0 per cent) of emissions from the industrial processes sector. Emissions have increased by 153.1 Gg CO2-e (34.0 per cent) from the 1990 level of 450.1 Gg CO2-e. In 2007, CO2 emissions from ammonia production accounted for 360.1 Gg CO2-e (59.7 per cent) of emissions in the chemical industry category. In 2007, ammonia production was a qualitative key category (Table 1.5.1).
Methane emissions from the chemical industry category have decreased 27.4 Gg CO2-e (60.0 per cent) between 2004 and 2007. The only known source of CH4 in the industrial processes sector is from methanol production. The decrease in CH4 emissions was due to the closure of the Motunui methanol production plant in November 2004. In 2007, there was only one methanol production plant in operation at Waitara.
Ammonia is manufactured in New Zealand by the catalytic steam reforming of natural gas. Liquid ammonia and CO2 are reacted together to produce urea. The total amount of natural gas supplied to the plant is provided to the Ministry of Economic Development by Balance Agri-nutrients Ltd who operates the ammonia production plant. In accordance with IPCC guidelines (IPCC, 1996) it is assumed that the carbon in urea is eventually released after it is applied to the land. Emissions of CO2 are calculated by multiplying the quantities of gas (from different gas fields) by their respective emission factors. Ammonia production in New Zealand uses gas from three different fields. The CO2 emission factors vary from Kapuni (84.1 kt/PJ), Kaimiro (65.2 kt/PJ) to Maui (52.2 kt/PJ). The proportion of gas from each of these fields used in ammonia production changed on an annual basis. This explains the fluctuation in the CO2 implied emission factor over the 1990–2007 time series.
Non-carbon dioxide emissions are considered by industry experts to arise from fuel combustion rather than from the process of making ammonia and are therefore covered in the energy sector.
Formaldehyde is produced at five plants (owned by two different companies) in New Zealand. Non-methane volatile organic compound emissions are calculated from company supplied activity data and a New Zealand-specific emission factor of 1.5 kg NMVOC/t of product. Emissions of CO and CH4 are not reported under this subcategory as these emissions relate to fuel combustion and are consequently reported in the energy sector.
Until recently, methanol was produced at two plants by MethaNexx New Zealand. In November 2004, the Motunui plant was closed and methanol is now only produced at the Waitara plant. Carbon dioxide emissions are reported in the energy sector (manufacturing industries and construction) as the emissions relate to fuel combustion. The process used to calculate CO2 emissions is shown in Box 3.1.
The major non-fuel related emissions from the methanol process are CH4 and NMVOCs. Emissions are calculated from company supplied activity data and emission factors. The IPCC default factor for CH4 (2kg CH4/t product) is applied and is assessed to be appropriate for New Zealand (CRL Energy, 2006). The NMVOC emissions factor, 5 kg NMVOC/t product, was estimated in 2001 from American Petroleum Institute methods for calculating vapour emissions from storage tanks. Emission factors for NOx (0.9 kg NOx/t product) and CO (0.1 kg CO/t product) were measured in 1999 and are considered to still accurately reflect the New Zealand situation.
The production of sulphuric acid during the manufacture of superphosphate fertiliser produces indirect emissions of SO2. In New Zealand there are two companies, Balance Agri-nutrients and Ravensdown, producing superphosphate. Each company owns two production plants. Three plants produce sulphuric acid. One plant imports the sulphuric acid.
Activity data supplied in 2005 has been used for 2006 and 2007. Plant-specific emission factors used in previous years were applied to the 2007 data. No reference is made to superphosphate production in the IPCC guidelines (IPCC, 1996). For sulphuric acid the IPCC guidelines recommend a default emission factor of 17.5 kg SO2 (range of 1 to 25) per tonne of sulphuric acid. However, New Zealand industry experts have recommended that this is a factor of two to 10 times too high for the New Zealand industry. Consequently, emission estimates are based on emission factors supplied by industry.
Emissions of CO2 from hydrogen production are supplied directly to the Ministry of Economic Development by the two production companies. The majority of hydrogen produced in New Zealand is made by the New Zealand Refining Company as a feedstock at the Marsden Point refinery. Another company, Degussa Peroxide Ltd, produces a small amount of hydrogen that is converted to hydrogen peroxide. The hydrogen is produced from CH4 and steam. Carbon dioxide is a by-product of the reaction and is vented to the atmosphere. Company-specific emission factors are used to determine the CO2 emissions from the production of hydrogen.
Uncertainties in CO2 emissions are assessed as ±5 per cent (section 4.1.2). Uncertainties in non-CO2 emissions are assessed from the questionnaires and correspondence with industry sources (CRL Energy, 2006). These are documented in Table 4.3.1.
|Product||Uncertainty in activity data||Uncertainty in emission factors|
|Methanol||±0%||±50% (NOx and CO) ±30% (NMVOCs) ±80% (CH4)|
|Fertiliser||±10% sulphuric acid ±10% superphosphate||±15% sulphuric acid ±25 to ±60% superphosphate (varies per plant)|
New Zealand has specified CO2 from ammonia production as a qualitative key category due to the large increase in nitrogenous fertiliser-use observed in the agriculture sector since 1990. The ammonia produced in New Zealand is used in the production of urea fertiliser. In the preparation of this inventory, the data for these emissions underwent IPCC Tier 1 quality checks.
The recalculations in ammonia production were due to updated emission factors. In this submission, the weighted average of all gas fields has been applied.
The metal production category reports CO2 emissions from the production of iron and steel, ferroalloys, aluminium and magnesium. The major metal production activities occurring in New Zealand are the production of steel (from ironsand and scrap steel) and aluminium. A small amount of SF6 was used in a magnesium foundry until around 1998. New Zealand has no production of coke, sinter or ferroalloys. In 2007, CO2 emissions from the iron and steel production subcategory were a key category (level assessment), and perfluorocarbon emissions from the aluminium production subcategory were a key category in the trend analysis.
In 2007, emissions from the metal production category were 2,265.6 Gg CO2-e (49.2 per cent) of emissions from the industrial processes sector. Emissions from this category decreased 5.6 per cent from the 1990 level of 2,399.2 Gg CO2-e. Carbon dioxide emissions accounted for 98.2 per cent of emissions in this category with another 1.8 per cent from PFCs. In 2007, the level of CO2 emissions increased by 471.1 Gg CO2-e (26.9 per cent) above the 1990 level. Perfluorocarbon emissions have decreased from the 642.2 Gg CO2-e in 1990 to 40.3 Gg CO2-e in 2007, a decrease of 601.9 Gg CO2-e (93.7 per cent). This decrease is due to improvements made by the aluminium smelter. These improvements are discussed further in the following section.
There are two steel producers in New Zealand. New Zealand Steel Ltd produces iron using the “alternative iron making” process (Ure, 2000) from titanomagnetite ironsand. The iron is then processed into steel. Pacific Steel Ltd operates an electric arc furnace to process scrap metal into steel.
The majority of the CO2 emissions from the iron and steel subcategory are produced through the production of iron from titanomagnetite ironsand. The CO2 emissions arise from the use of coal as a reducing agent and the consumption of other carbon-bearing materials such as electrodes. The carbon content of the ironsand is negligible with iron (in the form of magnetite) the predominant chemical in the sand (Ure, 2000), and has therefore not been counted for.
Sub-bituminous coal and limestone in the multi-hearth furnaces are heated and dried together with the ironsand. This iron mixture is then fed into the reduction kilns, where it is converted to 80 per cent metallic iron. Melters then convert this into molten iron. The iron, at a temperature around 1480°C, is transferred to the Vanadium Recovery Unit, where vanadium-rich slag is recovered for export and further processing into a steel strengthening additive. The molten pig iron is then converted to steel in a Klockner Oxygen Blown Maxhutte (KOBM) oxygen steel-making furnace. Further refining occurs at the ladle treatment station, where ferroalloys are added to bring the steel composition up to its required specification. The molten steel from the ladle treatment station is then transferred to the continuous caster, where it is cast into slabs.
The IPCC Tier 2 approach is used for calculating CO2 emissions from the iron and steel plant operated by New Zealand Steel Ltd. Emissions from pig iron and steel production are not estimated separately as all of the pig iron is transformed into steel. A plant specific emission factor is applied to the sub-bituminous coal used as a reducing agent. The emission factor is calculated based on the specific characteristics of the coal used.
Care has been taken not to double-count coal use for iron and steel-making. New Zealand energy statistics for coal are disaggregated into coal used in steel making and coal used in other industries and sectors. The coal used in the iron-making process acts both as a reductant and an energy source. However, the amount of coal used as an energy source is small compared to the amount used as a reducing agent. Data does not exist to accurately split the amount of coal used in energy and industrial processes. All coal used for iron and steel production is reported under the industrial processes sector, whereas gas used in the production has been reported in the energy sector.
Pacific Steel Ltd melts approximately 250 kt of recycled steel annually in an electric arc furnace. The process CO2 emissions from the electric arc furnace arise from charge additions of carbon with the scrap metal and the oxidation of carbon electrodes. No meaningful CO2 emissions data is available from the company before the year 2000. Emissions are calculated by multiplying steel production by an emission factor based on the average implied emission factor for the plant for the years 2000–2004 (approximately 0.1 t CO2/t steel). The implied emission factor has been calculated using a mass-balance approach. This calculation is based on the principle of the net difference between the amount of carbon contained in the raw materials and the amount of carbon sequestered in the finished product. From the mass-balance approach analysis the emission factor for the years 2000–2004 lies within the range of 0.088 – 0.104 tCO2/t steel, with an average of 0.097 t CO2/t steel.
The non-CO2 emission factors for the indirect greenhouse gases (CO, SO2 and NOx) for both steel plants are based on measurements in conjunction with mass balance (for SO2) and technical reviews (CRL Energy, 2006).
There is only one aluminium smelter in New Zealand, Rio Tinto Alcan Ltd (NZAS). The smelter produces aluminium from raw material using the centre worked prebaked (CWPB) technology. In 2007, aluminium emissions were 619.3 Gg CO2-e, a decrease of 466.2 Gg CO2-e (42.9 per cent) from the 1990 level of 1,085.5 Gg CO2-e. In 2007, emissions from aluminium production were a key category for New Zealand (trend).
Aluminium production is a source for CO2 and PFC emissions. Carbon dioxide is emitted during the oxidation of the carbon anodes. The PFCs are emitted from the cells during anode effects. An anode effect occurs when the aluminium oxide concentration in the reduction cell electrolyte is low. The emissions from combustion of various fuels used in the aluminium production process, such as heavy fuel oil, LPG, petrol and diesel, are included in the energy sector. The indirect emissions are reported at the end of this section.
NZAS calculates the process CO2 emissions using the Aluminium Sector Addendum to the World Business Council for Sustainable Development and the World Resources Institute Greenhouse Gas Protocol, released in October 2006 by the IPCC and International Aluminium Institute (IAI). The IPCC/IAI method breaks the prebake anode process into three stages (baked anode consumption, pitch volatiles consumption and packing coke consumption).
Estimates of PFC emissions are also supplied by NZAS to the Ministry of Economic Development. The PFC emissions from aluminium smelting are calculated using the IPCC/IAI Tier 2 methodology summarised below:
Perfluorocarbon emissions (t CO2-e) = Hot metal production × slope factor × anode effect duration (min/cell-day) × global warming potential.
The smelter captures every anode effect, both count and duration, through its process control software. All monitoring data is logged and stored electronically to provide the anode effect minutes per cell day value. This is then multiplied by the tonnes of hot metal, the slope factor and the global warming potential to provide an estimate of CF4 and C2F6 emissions. The slope values of 0.143 for CF4 and 0.0173 for C2F6 are applied as they are specific to the CWPB technology and are sourced from the Aluminium Sector Addendum to the WBCSD/WRI Greenhouse Gas Protocol.
The smelter advises that there are no plans to directly measure PFC emissions. A smelter-specific long-term relationship between measured emissions and operating parameters is not likely to be established in the near future.
As Figure 4.4.1 indicates, the emissions from aluminium production have fluctuated over the time series. These fluctuations are identified and explained in Table 4.4.1 Data for 1991 and 1992 has been interpolated, due to limited data availability.
Table 4.4.1 Variations in New Zealand’s aluminium emissions and the reasons
|Increase in CO2 and PFC emissions in 1996.||Commissioning of the Line 4 cells.|
|Decrease in CO2 emissions in 1995.||Good anode performance compared to 1994 and 1996.|
|Decrease in CO2 emissions in 1998.||Good anode performance.|
|Decrease in CO2 emissions in 2001, 2003 and 2006.||Less cells operating from reduced aluminium production due to reduced electricity supply.|
|Good anode performance contributed in 2001.|
|Increase in CO2 emissions in 1995.||All cells operating, including introduction of additional cells.|
|Increasing aluminium production rate from the cells.|
|Decrease in PFC emissions in 1995.||Reduced anode frequencies.|
|The implementation of the change control strategy to all reduction cells.|
|Repairs made to cells exerting higher frequencies.|
|PFC emissions remained high in 1997.||Instability over the whole plant as the operating parameters were tuned for the material coming from the newly commissioned dry scrubbing equipment (removes the fluoride and particulate from the main stack discharge).|
|Decrease in PFC emissions in 1998.||Cell operating parameter control from the introduction of modified software. This software has improved the detection of an anode effect onset and will initiate actions to prevent the anode effect from occurring.|
|PFCs remain relatively static in 2001, 2003 and 2006.||Increased emissions from restarting the cells.|
Aluminium production also produces indirect emissions. The most significant are CO emissions from the anode preparation. There is also a small amount of CO emitted during the electrolysis reaction in the cells. For estimates of indirect greenhouse gases, plant specific emission factors were used for CO and SO2. Sulphur dioxide emissions are calculated from the input sulphur levels and direct monitoring. An industry supplied value of 110 kg CO per tonne (IPCC range 135–400 kg CO per tonne) was based on measurements and comparison with Australian CO emission factors. The IPCC default emission factor was used for NOx emissions.
Small amounts of SF6 were used as a cover gas in a magnesium foundry to prevent oxidation of molten magnesium from 1990–1999. The company has since changed to zinc technology so SF6 is no longer used and emitted.
The only other metals produced in New Zealand are gold and silver. Companies operating in New Zealand confirm they do not emit indirect gases (NOx, CO and SO2) with one using the Cyanisorb recovery process to ensure everything is kept under negative pressure to ensure no gas escapes to the atmosphere. Gold and silver production processes are listed in IPCC (1996) as sources of non-CO2 emissions. However, no details or emission factors are provided and no published information on emission factors has been identified. Consequently, no estimation of emissions from this source has been included in New Zealand’s greenhouse gas inventory.
Uncertainty in CO2 emissions is assessed as ±5 per cent as discussed in section 4.1.2. Uncertainties in non-CO2 emissions are assessed by the contractor from the questionnaires and correspondence with industry sources (CRL Energy, 2006). These are documented in Table 4.4.1.
|Product||Uncertainty in activity data||Uncertainty in emission factors|
|Iron and steel||0%||±20–30% (CO)±70% (NOx)|
|Aluminium||0%||±5% (SO2)±40% (CO)±50% (NOx)±30% (PFCs)1|
1 There is no independent means of assessing the calculations of PFC emissions from the smelter. Given the broad range of possible emission factors indicated in the IPCC (2000) Table 3.10, and in the absence of measurement data and precision measures, the total uncertainty is assessed to be ±30 per cent (CRL Energy, 2006).
Carbon dioxide emissions from the iron and steel production and aluminium production subcategories were key categories in 2007. Perfluorocarbon emissions from aluminium production were also a key category (trend assessment). In the preparation of this inventory, the data for these subcategories underwent IPCC Tier 1 quality checks.
The time series for emissions from steel production have been updated. New Zealand separated emissions from limestone, coke and electrodes used in the iron and steel-making process from the industrial process CO2 emissions for the first time in the 2008 inventory submission. In this submission, emissions from the use of limestone, coke and electrodes were instead separated from total emissions, including energy emissions from steel production. This is a more accurate way of reporting these emissions. Emissions from steel production were also recalculated for one company between 2000–2006 based on fuel input, production figures and estimated CO2.
The PFC emissions from aluminium production have been updated based on the current dataset supplied by NZAS. Data for 1991 and 1992 remained unavailable for this submission. In the previous submission, the interpolation of these years was supplemented by industry assumptions. However, after discussions with NZAS, a linear regression of the data was used in this submission, with no assumptions influencing the data. The Ministry for the Environment has been working closely with NZAS to improve the consistency, completeness and accuracy of the time series. Further improvements will be included in the 2010 submission.
The other production category includes emissions from the production of pulp and paper, and food and drink. In 2007, emissions from this category totalled 7.4 Gg NMVOC. This was an increase of 1.5 Gg NMVOC from the 1990 level of 5.9 Gg CO2-e.
There are a variety of pulping processes in New Zealand. These include:
Pulp production in New Zealand is evenly split between mechanical pulp production and chemical production. Estimates of emissions from the chemical pulping process are calculated from production figures obtained from the Ministry of Agriculture and Forestry. Emission estimates from all chemical pulping processes have been calculated from the industry-supplied emission factors for the Kraft process. In the absence of better information, the NMVOC emission factor applied to the chemical pulping processes is also applied to the thermomechanical pulp processes (CRL Energy, 2006). Emissions of CO and NOx from these processes are related to fuel combustion and not reported under industrial processes.
Emissions of NMVOCs are produced during the fermentation of cereals and fruits in the manufacture of alcoholic beverages. These emissions are also produced during all processes in the food chain that follow after the slaughtering of animals or harvesting of crops. Estimates of indirect greenhouse gas emissions for the period 1990–2005 have been calculated using New Zealand production figures from Statistics New Zealand and relevant industry groups with default IPCC emission factors (IPCC, 1996). No New Zealand-specific emission factors could be identified. Subsequent NMVOC estimates from food and drink have been estimated using linear extrapolation as no industry survey was conducted. In 2007, NMVOC emissions were estimated to be 6.6 Gg, an increase of 1.4 Gg from the 1990 level of 5.2 Gg.
Uncertainties in non-CO2 emissions are assessed by the contractor from the questionnaires and correspondence with industry sources (CRL Energy, 2006). These are documented in Table 126.96.36.199.
Table 188.8.131.52 Uncertainty in New Zealand’s non-CO2 emissions from the other production category
|Product||Uncertainty in activity data||Uncertainty in emission factors|
|Pulp and paper||5%||±50% (chemical pulp) ±70% (thermal pulp)|
|Food – alcoholic beverages||±5% (beer) ±20% (wine) ±40% (spirits)||±80% (beer and wine) ±40% (spirits)|
|Food – food production||±5–20% (varies with food type)||±80% (IPCC factors)|
Other production was not a key category and no specific QA/QC activities were performed. Where possible, activity data is cross-referenced between companies and industry associations to verify the data.
There are no source-specific recalculations performed for this category in this inventory submission.
New Zealand does not manufacture halocarbons and SF6. Emissions from consumption are reported under section 4.7
In 2007, emissions from the consumption of hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs) totalled 858.0 Gg CO2-e (18.6 per cent) of emissions from the industrial processes sector. There was no consumption of HFCs or PFCs in 1990. The first consumption of HFCs in New Zealand was reported in 1992 and the first consumption of PFCs in 1995. The large increase in HFC emissions is due to the replacement of ozone-depleting CFCs and HCFCs with HFCs. In 2007, emissions from the consumption of HFCs were identified as a key category (level and trend assessment).
In 2007, sulphur hexafluoride (SF6) emissions were 14.7 Gg CO2-e, this is an increase of 2.4 Gg CO2-e (19.2 per cent) from the 1990 level of 12.3 Gg CO2-e. The majority of SF6 emissions are from use in electrical equipment.
Hydrofluorocarbons and PFCs are used in a wide range of equipment and products from refrigeration systems to aerosols. No HFCs or PFCs are manufactured within New Zealand. Perfluorocarbons are produced from the aluminium-smelting process (as discussed in section 4.4.2). The use of synthetic gases, especially HFCs, has increased since the mid-1990s when CFCs and HCFCs began to be phased out under the Montreal Protocol. In New Zealand, the Ozone Layer Protection Act (1996) sets out a programme for phasing out the use of ozone-depleting substances by 2015. According to the 1996 IPCC guidelines, emissions of HFCs and PFCs are separated into seven subcategories:
mobile air conditioning (MAC)
stationary refrigeration and air conditioning
The emissions inventory for SF6 is broken down into two subcategories: electrical equipment and “other”. In New Zealand, one electricity company accounts for 75–80 per cent of total SF6 used in electrical equipment.
Activity data on the bulk imports and end use of HFCs and PFCs in New Zealand was collected through an annual survey of HFC and PFC importers and distributers. This data was used to estimate the proportion of bulk chemical used in each sub-source category. The total quantity of bulk chemical HFCs imported each year was compared with import data supplied by Statistics New Zealand. Imports of HFCs in products and bulk imports of PFCs and SF6 are more difficult to determine as import tariff codes are not specific enough to identify these chemicals.
New Zealand uses the IPCC Tier 2 approach to calculate emissions from the consumption of HFCs and PFCs (IPCC, 2000). The Tier 2 approach accounts for the time lag between consumption and emissions of the chemicals. A summary of the methodologies and emission factors used in emission estimates are included in Table 4.7.1.
Potential emissions for HFCs and PFCs are included for completeness as required by the Climate Change Convention reporting guidelines (UNFCCC, 2006). Potential emissions for HFCs and PFCs have been calculated using the IPCC Tier 1b approach. Very little data is available on bulk imports of individual HFC and PFC gases into New Zealand. Potential emissions have been estimated using the fraction of actual individual HFC and PFC emissions and applying this fraction to the total of all bulk HFCs and PFCs imported into New Zealand.
Table 4.7.1 New Zealand’s halocarbon and SF6 calculation methods and emission factors
|HFC source||Calculation method||Emission factor|
|Aerosols (including metered does inhalers)||IPCC 2006 Equation 7.6||IPCC default factor of 50% of the initial charge per year|
|Foam||IPCC 2006||IPCC default factor of 10% initial charge in first year and 4.5% annual loss of initial charge over an assumed 20-year lifetime|
|Mobile air conditioning||IPCC GPG 2000 Equation 3.44||Top down approachFirst fill: 0.5%|
|Stationary refrigeration/ air conditioning||IPCC 2006 Equation 7.9||N/A|
|Fire protection||IPCC 2006||Top-down approach using emission rate of 1.5%|
|SF6 source||Calculation method||Emission factor|
|Electrical equipment||IPCC GPG 2000 Equation 3.17||Tier 3 approach based on overall consumption and disposal. Company-specific emission factors measured annually and averaging ~1% for the main utility (representing 75% of total holdings)This was supplemented by data from other utilities and an equipment manufacturer using the IPCC default emission factor of 2% (Tier 2b approach)|
|Other applications||IPCC GPG 2000 Equation 3.22||No emission factor required as 100% is emitted within two years|
New Zealand reports HFC 134a emissions from metered dose inhalers and other aerosols separately. Aerosols accounted for 26.0 Gg CO2-e in 2007, an increase of 24.4 Gg CO2-e from the 1996 level of 1.6 Gg CO2-e. The use of HFCs in aerosols is not known to have occurred in New Zealand before 1996. In 2007, metered dose inhalers accounted for 49.6 Gg CO2-e, an increase of 49.1 Gg CO2-e from the 1995 level of 0.5 Gg CO2-e. The consumption of HFCs in metered dose inhalers is not known to have occurred in New Zealand before 1995. Aerosols and metered dose inhalers are not a key subcategory.
Activity data on aerosol usage was provided by Arandee Ltd, the only New Zealand aerosol manufacturer using HFCs, and the Aerosol Association of Australia/New Zealand. Arandee Ltd also provided activity data on annual HFC use, domestic and export sales, and product loading emission rates.
The Tier 1b method, equation 7.6 (IPCC, 2006), is used to calculate HFC 134a emissions from aerosol use in New Zealand. This is a mass-balance approach, based on import and sales data. The default emission factor of 0.50 per cent of the initial charge is applied to the sales of aerosol and metered dose inhalers.
Data on the total number of doses contained in metered dose inhalers used from 1999 to 2007 is provided by Pharmac, New Zealand’s government pharmaceutical purchasing agency. The weighted average quantity of propellant per dose is calculated from information supplied by industry. Activity data from 1995 to 1998 is based upon expert opinion (CRL Energy, 2008).
The significant increase in emissions over the time series from both aerosols and metered dose inhalers can be attributed to HFC-134a being used as a substitute propellant for HCFCs and CFCs, as discussed in section 4.7.1.
A survey of distributors of solvent products and solvent recycling firms did not identify any use of HFCs or PFCs as solvents (CRL Energy, 2008).
In New Zealand, only emissions from closed-cell foam (hard foam) are known to occur. In 2007, emissions from the use of HFC-134a in hard foam blowing were 0.12 Gg CO2-e. This is an increase of 0.05 Gg CO2-e (80 per cent) from the 2000 level of 0.07 Gg CO2-e. There is no known use of HFC-134a in foam blowing before 2000 within New Zealand.
The HFC-245fa/365mfc mixture is only known to be used in New Zealand in foam blowing from 2004 to 2007. These emissions are estimated to have increased from 0.1 tonne in 2004 to 0.6 tonne in 2007. However, a global warming potential for this mixture has not been agreed by the IPCC and UNFCCC. This mixture is reported in the common reporting format tables “Information on additional greenhouse gases”, as recommended by the in-country review team (UNFCCC, 2007).
For 2007, activity data was provided by the sole supplier of HFCs for foam blowing (CRL Energy, 2008).
The IPCC (2006) Tier 2 method is used to calculate emissions from foam blowing. The recommended default emission factor of 10 per cent of the initial charge in the first year and 4.5 per cent annual loss of the initial charge over an assumed 20-year lifetime is applied.
Hydrofluorocarbon and PFC emissions from stationary refrigeration and air conditioning were 573.4 Gg CO2-e in 2007. This is an increase from the 1992 level of 1.43 Gg CO2-e. In 1992, only HFC-134a was used, while in 2007 HFCs 32, -23, -152a, -134a, -125 and PFC-218 (C3F8) were consumed. There was no use of HFCs and PFCs before 1992.
The increase in emissions from 1992 to 2007 is due to HFCs and PFCs used as replacement refrigerants for CFCs and HCFCs in refrigeration and air-conditioning equipment (section 4.7.1).
New Zealand uses a top-down Tier 2b (Box 3.1) approach and New Zealand-specific data to obtain actual emissions from stationary refrigeration and air conditioning. Equation 7.9 (IPCC, 2006) is used to calculate emissions.
Emissions = (annual sales of new refrigerant) – (total charge of new equipment) + (original total charge of retiring equipment) – (amount of intentional destruction)
To estimate HFCs and PFCs emissions, all refrigeration equipment is split into two groups: factory-charged equipment and all other equipment that is charged with refrigerant on site. This is because some information is available on the quantities of factory-charged imported refrigeration and air-conditioning equipment and on the amount of bulk HFC refrigerant used in that equipment.
The amount of new refrigerant used to charge all other equipment (charged on site after assembly) is assumed to be the amount of HFC refrigerant sold each year minus that used to manufacture factory-charged equipment and that used to top up all non-factory-charged equipment.
Factory-charged equipment consists of all equipment charged in factories (both in New Zealand and overseas), including all household refrigerators and freezers and all factory-charged, self-contained refrigerated equipment used in the retail food and beverage industry. All household air conditioners and most medium-sized, commercial air conditioners are also factory charged, although some extra refrigerant may be added by the installer for piping.
It is estimated there are about 2.2 refrigerators and freezers per household in New Zealand. This calculation included schools, factories, offices and hotels (Roke, 2006). Imported appliances account for around half of new sales each year, with the remainder manufactured locally. New Zealand also exports a significant number of factory-charged refrigerators and freezers.
Commercial refrigeration includes central rack systems used in supermarkets, chillers used for commercial building air conditioning and process cooling applications, rooftop air conditioners and transport refrigeration systems, and cool stores. In many instances, these types of systems are assembled and charged on site, although most imported units may already be pre-charged. Self-contained commercial equipment is pre-charged and includes some frozen food display cases, reach-in refrigerators and freezers, beverage merchandisers and vending machines.
Detailed information on the assumptions that have been used to build models of refrigerant consumption and banks for the domestic and commercial refrigeration categories, dairy farms, industrial and commercial cool stores, transport refrigeration and stationary air conditioning, can be found in the report on HFC and PFC emissions in New Zealand (CRL Energy, 2008).
In 2007, HFC-134a emissions from mobile air conditioning were 206.3 Gg CO2-e, an increase over the 1994 level of 6.3 Gg CO2-e. There was no use of HFCs as refrigerants for mobile air conditioning in New Zealand before 1994. This increase can largely be attributed to pre-installed, air-conditioning units in a large number of second-hand vehicles imported from Japan, as well as reflecting the global trend of increasing use of air conditioning in new vehicles.
The automotive industry has used HFC-134a as the refrigerant for mobile air conditioning in new vehicles since 1994. HFC-134a is imported into New Zealand for use in the mobile air-conditioning industry through bulk chemical importers/distributors and within the air-conditioning systems of imported vehicles. Industry sources report that air-conditioning systems were retrofitted (with “aftermarket” units) to new trucks and buses and to second-hand cars. Refrigerated transport is included in the stationary refrigeration/air-conditioning subcategory.
New Zealand has used a Tier 2b method, mass-balance approach (Box 3.2). This approach does not require emission factors (except for the minor first-fill component) as it is based on chemical sales and not equipment leak rates.
Emissions = First fill emissions + operation emissions + disposal emissions – intentional destruction
First-fill emissions are calculated from vehicle fleet numbers provided by the New Zealand Transport Registry Centre. Assumptions are made on the percentage of mobile air-conditioning installations. Operation and disposal data are obtained from a survey of the industry and data from Land Transport New Zealand.
Detailed information on the assumptions that have been used in the calculation of emissions from mobile air conditioning can be found in the report on HFC emissions in New Zealand (CRL Energy, 2008).
In 2007, HFC-227ea emissions from fire protection were 1.3 Gg CO2-e, an increase over the 1994 level of 0.06 Gg CO2-e. There was no use of HFCs in fire protection systems before 1994 in New Zealand. The increase was due to HFCs used as substitutes to halon in portable and fixed fire protection equipment.
Within the New Zealand fire protection industry, the two main supply companies are identified as using relatively small amounts of HFC-227ea. The systems installed have very low leak rates with most emissions occurring during routine servicing and accidental discharges.
A simplified version of the Tier 2b method, mass-balance approach (IPCC, 2006) has been used to estimate emissions. A New Zealand-specific annual emission rate of 1.5 per cent has been applied to the total amount of HFC installed. This rate is based on industry experience. Due to limited data, it has been assumed that HFC from any retirements was totally recovered for use in other systems.
In 2007, SF6 emissions from electrical equipment were 11.8 Gg CO2-e, an increase over the 1990 level of 9.5 Gg CO2-e.
The high dielectric strength of SF6 makes it an effective insulant in electrical equipment. It is also very effective as an arc-extinguishing agent, preventing dangerous over-voltages once a current has been interrupted.
Actual emissions are calculated using the IPCC (2000) Tier 3a approach for the utility responsible for 75 per cent of the total SF6 held in electrical switchgear equipment. This data is supplemented by data from other utilities. The additional data enables a Tier 2b approach to be taken for the rest of the industry (CRL Energy, 2008).
Activity and emissions data is provided by the two importers of SF6 and New Zealand’s main users of SF6, the electricity transmission, generation and distribution companies (CRL Energy, 2008.)
A Tier 1a method is used to calculate potential emissions of SF6, using total annual imports of SF6 into New Zealand. Potential SF6 emissions are usually two to three times greater than actual emissions in a given year. However, in 2005, potential emissions were less than actual emissions because there was less SF6 imported compared with previous years. Import data for 2006 and 2007 shows potential SF6 emissions are again greater than actual emissions.
Emissions from other SF6 applications in 1990 and 2007 were 2.9 Gg CO2-e. In New Zealand, other applications include medical uses for eye surgery, tracer gas studies, magnesium casting, plumbing services, tyre manufacture, and industrial machinery equipment. A Tier 2 method (IPCC, 2000) is applied and no emission factor is used as 100 per cent is assumed to be emitted over a short period of time.
Activity data for 2007 was provided by one main supplier for eye surgery, scientific use, plumbing, tyre manufacture and industry. Scientific use was also discussed with the National Institute of Water and Atmosphere and the Institute of Geological and Nuclear.
The uncertainty in estimates of actual emissions from the use of HFCs and PFCs varied with each application and is described in Table 4.7.2. For many sources, there is no statistical measure of uncertainty but a quantitative assessment is provided from expert opinion.
|HFC source||Uncertainty estimates|
|Aerosols||Combined uncertainty ±54%|
|Metered dose inhalers||Combined uncertainty ±10%|
|Foam||Combined uncertainty ±70%|
|Stationary refrigeration/air conditioning||Combined uncertainty ±41%|
|Mobile air conditioning||Combined uncertainty ±36%|
|Fire protection||Combined uncertainty ±32%|
|SF6 source||Uncertainty estimates|
|Electrical equipment||Combined uncertainty ±22%|
In the preparation of this inventory, the data for the consumption of halocarbons and SF6 underwent Tier 1 quality checks. During data collection and calculation, activity data provided by industry was verified against national totals where possible, and unreturned questionnaires and anomalous data were followed up and verified to ensure an accurate record of activity data.
The recalculations for the consumption of halocarbons and SF6 subcategory resulted in an increase of 21.6 Gg CO2-e (3.5 per cent) for the 2006 inventory year. This was largely due to an increase to contractors that resulted in updated assumptions.
Supply assumptions for the R404A (52 per cent HFC-143a, 44 per cent HFC-125 and 4 per cent HFC-134a) have been updated for the 2002 inventory year. In previous submissions, New Zealand assumed that R134A (100 per cent HFC-134a) imports should be reduced by 30 tonnes. Based upon expert opinion, New Zealand now assumes that 15 t of the reduction to R134A and 15 t to R404A. The result is a decrease of about 6 t each for HFC-125 and HFC-143a, and a 12.6 tonne increase in HFC-134a emissions in 2002 in this submission, compared with estimates in the 2008 submission.
Bulk import data for HFC-134a was reduced by 3.3 t per year from 2004–2006. This was due to new information from suppliers. Exported HFC-134a data was also updated for the same reason.
For 2006, an import of 2.3 t of R410A has been included based upon updated data.
An estimate has been provided for HFC contained in the pre-charged refrigeration systems on new ships (mainly luxury boats). This was 0.5 tonne R404A from 1997–2002 then 1.0 tonne R404A from 2003–2007.
Updated assumptions for pre-charged container units for 2006. This resulted in a 1.8 tonne reduction in 2006 and reductions for the phase-in period, 1.1 and 0.4 tonne increases for 1996 and 1997 respectively. This has a very minor impact on emissions as some of the equipment is assumed to be retired after 10 years in operation.
Assumptions for pre-charged container units were changed for 2006 (1.8 tonne reduction) and for the phase-in period (1.1 and 0.4 tonne increases for 1996 and 1997 respectively). This has a very minor impact on emissions as some of the equipment is assumed to be retired after 10 years in operation.
Assumptions were updated following the provision of more detailed information on the current sales distribution of new dairy refrigeration units. This led to a decrease in the amount charged into new equipment and the phase-in period of about 2.2 t for 1998–2001, 0.6 tonne for 2002–2003, 1.5 tonne for 2004, and 2.4 t for 2006–2006. Subsequently, HFC-134a, HFC-125 and HFC-143a (from R404a) emissions have increased.
The HFC amounts collected for destruction were previously based on a few analyses from 2005 with previous years estimated back to 2000. In this submission, all actual analyses have been provided, improving uncertainties for this factor. The result is estimate increases of 0.14, 0.21, 0.48, 0.00, 0.95, 1.46, 0.46 and 0.01 t for 1999–2006 respectively.
The assumption that between 2000 and 2006, quantities of HFC-23, HFC-152a and HFC-32 in 2000–2003 were destroyed, has been updated in this submission. It has instead been assumed there is no destruction for these HFCs in these years, as based on the data available this year, there is no known source of supply.
There was a small error corrected for HFC imports for fire protection. These imports have now been subtracted from total HFC/PFC bulk chemical imports in 2001. It has been assumed that 20.6 t of “other gases” were all HFC-134a. By subtracting 1.4 t for fire protection, the “other gases” were reduced to 19.2 t. The result is that stationary refrigeration and air-conditioning bulk HFC imports and actual emissions of HFC-134a were revised to be 1.4 t lower in 2001 than compared with the 2008 submission.
A minor correction to the “manufactured for New Zealand use” calculation term, included a 0.2 tonne of R410A that was previously omitted for commercial air-conditioning equipment manufactured in New Zealand in 2006.
Sulphur hexafluoride emissions from electrical equipment have been recalculated from 2000 to 2006, due to increased availability of SF6 holdings’ inventories for most electrical users and some maintenance monitoring records. This has improved understanding of the total nameplate capacity in each year and therefore the assumed losses. The largest change was the decrease of 5.8 per cent in 2000.
The recalculations of other applications of SF6 are due to increased availability of supplier data in 2007. This data has been interpolated back to 2000.
Activity data is obtained from industry and supplemented with statistics from the Ministry of Agriculture and Forestry. The NMVOC emission factors for particle board and medium-density fibreboard are derived from two major manufacturers. An assumption was made that the industry-supplied NMVOC emission factors are applicable to all particle board and fibreboard production in New Zealand. There is no information in the IPCC guidelines (1996) for this category.
Estimates of NMVOC emissions from panel products in 2007 were 1.3 Gg. This is an increase of 0.5 Gg over the 1990 level of 0.8 Gg.