View all publications

Chapter 4: Industrial processes

4.1 Sector overview

New Zealand’s industrial processes sector totalled 4,233.1 Gg carbon dioxide equivalent (CO2-e) in 2006 and represented 5.4 per cent of total greenhouse gas emissions. Emissions from industrial processes are now 830.4 Gg CO2-e (24.4 per cent) above the 1990 baseline of 3402.7 Gg CO2-e (Figure 4.1.1). The sector is dominated by emissions from the metal production category (CO2 and perfluorocarbons (PFCs)) at 53.3 per cent of sectoral emissions.

Figure 4.1.1 Industrial processes sector emissions from 1990 to 2006 (all figures are Gg CO2-e)

Year

Gg CO2 equivalent

1990

3,402.7

1991

3,553.9

1992

3,622.1

1993

3,297.6

1994

3,242.7

1995

3,386.7

1996

3,554.0

1997

3,298.8

1998

3,512.8

1999

3,666.1

2000

3,643.3

2001

3,767.5

2002

3,975.5

2003

4,280.1

2004

4,042.4

2005

4,245.7

2006

4,233.1

Figure 4.1.2 Change in industrial processes sector emissions from 1990 to 2006 (all figures are Gg CO2-e)

Note: The per cent change for other production and the production of halocarbons and SF6 is not occurring within New Zealand. The per cent change for the consumption of halocarbons and SF6 is not applicable (NA) as there is no known production of HFCs in 1990.

Category

1990
(Gg CO2-equivalent)

2006
(Gg CO2-equivalent)

Mineral products

546.1

734.5

Chemical industry

626.4

447.0

Metal production

2,400.1

2,257.6

Other production

Not occurring

Not occurring

Production of halocarbons and SF6

Not occurring

Not occurring

Consumption of halocarbons and SF6

Not applicable

Not applicable

The emissions included 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 included in the energy sector. CO2 emissions related to energy production, for example, refining crude oil and the production of synthetic petrol from natural gas, are also considered 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

  • oxidisation 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.

Within the industrial processes sector, some of the categories employ common data sources and emission factors. For this reason, general information about methodologies and uncertainties are included in this section as an overview.

4.1.1 Methodological issues

Emissions of CO2 from industrial processes are compiled by the Ministry of Economic Development (MED) from information collected through industry surveys. The results are reported in New Zealand Energy Greenhouse Gas Emissions 1990–2006 (Ministry of Economic Development, 2007a).

Activity data for the non-CO2 gases are collated via an industry survey. Currently the only CH4 emissions from the industrial processes sector are from methanol production. Emissions of HFCs and PFCs are estimated using the IPCC Tier 2 approach and SF6 emissions from large users are assessed via the Tier 3a approach (IPCC, 2000).

Activity data and emission factors are included in the excel workbooks available for download with this report from the Ministry for the Environment’s website.

4.1.2 Uncertainties

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.

4.2 Mineral products (CRF 2A)

4.2.1 Description

In 2006, the “mineral products” category accounted for 734.5 Gg CO2-e (17.4 per cent) of emissions from the industrial processes sector. Emissions in this category have grown by 188.4 Gg CO2-e (34.5 per cent) from the 1990 level of 546.1 Gg CO2-e. There are no emissions of CH4 or N2O from the mineral products category.

This category includes emissions produced from chemical transformations in the production of cement and lime, soda ash production and use, asphalt roofing, limestone and dolomite use, road paving with asphalt and glass production. Cement production accounts for 560.7 Gg CO2-e (76.3 per cent) of emissions from the mineral products category. Lime production accounts for 124.8 Gg CO2-e (17.0 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.

4.2.2 Methodological issues

Cement production

Currently, there are two cement production companies operating in New Zealand, Holcim New Zealand Ltd and Golden Bay Cement. From 1995 to 1998 inclusive, another smaller cement company was in operation. Estimates of CO2 emissions from cement production are calculated by the companies using the IPCC Tier 2 methodology (IPCC, 1996 and 2000)). Total process CO2 emissions from cement production are reported. The clinker data and corresponding implied emission factors are not included in the CRF tables as this information is considered confidential by the companies. The amount of clinker produced by each cement plant is multiplied by a plant-specific emission factor for the clinker. The emission factors used 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.

A plant-specific clinker kiln dust correction factor is included in one company’s CO2 emissions calculation. The other company does not include a correction factor as it operates a “dry” process with no calcinated clinker kiln dust lost to the system.

Figure 4.2.1 shows trends in New Zealand clinker production, imported clinker and the implied emission factors for cement and clinker. The information is indexed to respect the confidentiality of the data.

The figure shows clinker production increasing over the time-series 1990–2006 while the implied CO2 emission factor for cement production has been decreasing. The exception to this trend is from 2004 to 2006 when imports of clinker decreased. The cement companies have been importing increasing amounts of clinker in recent years to meet the high demand for cement in New Zealand. An increase in imported clinker has decreased CO2 emissions while overall cement production has continued to increase. 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.

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). New Zealand uses an emission factor for SO2 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. The SO2 emission factor has not been updated for the 2006 activity data. The 2008 inventory submission uses the 2005 value of 0.64 kg SO2/t clinker as this is considered to still accurately reflect the New Zealand situation.

Figure 4.2.1 Indexed cement production data including clinker production, clinker imports and cement and clinker implied emission factor

Year

Indexed implied emission factor-cement

1990

1.00

1991

1.00

1992

1.00

1993

1.00

1994

1.00

1995

1.00

1996

1.00

1997

0.97

1998

0.96

1999

0.96

2000

0.96

2001

0.95

2002

0.90

2003

0.84

2004

0.78

2005

0.90

2006

0.84

Clinker implied emission factor (indexed)

Year

Indexed implied emission factor-clinker

1990

1.00

1991

1.00

1992

1.00

1993

1.00

1994

1.00

1995

1.02

1996

1.01

1997

1.02

1998

1.02

1999

1.00

2000

1.00

2001

1.00

2002

1.00

2003

1.00

2004

0.99

2005

1.00

2006

1.00

Clinker and cement production in New Zealand (indexed)

Year

Indexed cement production

Indexed clinker production

1990

1.00

1.00

1991

0.94

0.98

1992

1.11

1.06

1993

1.26

1.09

1994

1.33

1.11

1995

1.37

1.18

1996

1.37

1.12

1997

1.42

1.17

1998

1.36

1.07

1999

1.48

1.19

2000

1.48

1.18

2001

1.51

1.19

2002

1.64

1.23

2003

1.72

1.19

2004

1.69

1.09

2005

1.74

1.29

2006

1.83

1.27

Clinker imported (indexed)

Year

Indexed imported clinker

1990

1.00

1991

0.66

1992

0.81

1993

0.63

1994

0.68

1995

0.54

1996

0.90

1997

0.56

1998

0.51

1999

0.37

2000

0.37

2001

61.57

2002

145.93

2003

302.98

2004

362.61

2005

234.91

2006

205.13

Lime production

There are three companies producing burnt lime in New Zealand. Carbon emissions from lime production are supplied to the MED by the lime production companies. Emissions are calculated by multiplying the amount of lime produced by an emission factor. 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. There has been little change in the implied emission factor varying from 0.72 t CO2/t lime to 0.73 t CO2/t lime from 1990 to 2006.

The SO2 emissions emitted during lime production vary depending on the processing technology and the input materials. An average emission factor for SO2 from was calculated as 0.5 kg SO2/t lime. The emission factor was weighted to take sulphur measurements at the various lime plants into account (CRL Energy Ltd, 2006). The 2005 emission factor is used with the 2006 activity data.

Limestone and dolomite use

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 sources 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 sector.

Small amounts of limestone are used in the production of iron and steel by the company New Zealand Steel. In the iron production process, the coal is blended with limestone to achieve the required primary concentrate specifications. Previously all CO2 process emissions from iron and steel production, including limestone use, were reported under the iron and steel category in the CRF tables (2.C.1). For the 2008 inventory submission New Zealand has separated emissions arising from limestone, coke and electrodes used in the iron and steel making process from the rest of the process CO2 emissions and reported these emissions under the limestone and dolomite use category (2A.3). Currently data cannot be broken down any further (ie, only limestone emissions from iron and steel production). Emissions from limestone/coke/electrode use make up 1 to 2 per cent of total process iron and steel emissions.

Soda ash production and use

There is no soda ash production in New Zealand. A survey of the industrial processes sector in 2005 made preliminary estimates of CO2 emissions resulting from the use of soda ash in glass production (CRL Energy Limited, 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 last 10 years to enable CO2 emissions from soda ash to be estimated from 1996 to 2005. This is because the soda ash amount 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 2006 was provided by the glass manufacturer through an external consultant. The IPCC default emission factor of 415 kg CO2 per tonne of soda ash is applied to calculate the CO2 emissions.

Asphalt roofing

There is one company manufacturing asphalt roofing in New Zealand, Bitumen Supply Ltd. Default IPCC emission factors of 0.05 kg NMVOC/t product and 0.0095 kg CO/t product respectively are used to calculate NMOVC and CO emissions respectively (IPCC, 1996). A survey of indirect greenhouse gases was not undertaken for the 2006 calendar year. In the absence of updated data, activity data for 2005 was used for 2006.

Road paving with asphalt

Data on bitumen production and emission rates are provided by the three main road paving companies operating in New Zealand. 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 the methodology shown in Box 4.1 for calculating the total NMVOC emissions from the use of solvents in the roading industry. The industrial processes survey undertaken in 2005 (CRL Energy Limited, 2006) showed that the fraction of 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 have been updated to reflect this changing fraction.

Box 4.1 Calculation of NMVOC emissions from road paving asphalt

NMVOC emitted = A x B x C x D

where

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)

Glass production

There is one major glass manufacturer in New Zealand, O-I New Zealand. The IPCC guidelines (IPCC, 1996) state NMVOCs may be emitted from the manufacture of glass and suggest a default emissions factor of 4.5 kg NMVOC/tonne of glass output. It has been assumed that the IPCC default emission factor for NMVOC is based on total glass production which 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 undertaken in 2007 (CRL Energy Limited, 2007). Refer to the soda ash production and use section above.

4.2.3 Uncertainties and time-series consistency

Uncertainties in CO2 emissions are assessed as ± 5 per cent as discussed in section 4.1.2. Uncertainties in non-CO2 emissions have been assessed by a contractor from the questionnaires and correspondence with industry sources (CRL Energy Limited, 2006). These are documented in Table 4.2.1.

Table 4.2.1 Uncertainty in non-CO2 emissions from “mineral products”

Product Uncertainty in activity data Uncertainty in emission factors

Cement

0%

± 40%

Lime

± 1%

± 80%

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%

4.2.4 Source-specific QA/QC and verification

Carbon dioxide emissions from cement production are a key category (level assessment). In the preparation of this inventory, the data for these emissions underwent Tier 1 quality checks.

4.2.5 Source-specific recalculations

Activity data and the CO2 emissions attributed to cement production has been updated and recalculated for the years 1995-1998. The revision has been due to the inclusion of data from a small cement company operating in New Zealand who produced clinker from 1995-1998. This data had not been included in previous submissions.

Emissions arising from limestone, coke and electrodes used in the iron and steel making process have been reported separately from the rest of the process CO2 emissions for the first time in the 2008 inventory submission. This has resulted in recalculations for the 1990-2005 time series for both the limestone and dolomite use and iron and steel categories. Data provided by the iron and steel companies cannot be broken down any further (ie, limestone emissions on their own). Emissions from limestone/coke/electrode use make up 1 to 2 per cent of total process iron and steel emissions.

4.3 Chemical industry (CRF 2B)

4.3.1 Description

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 2006, emissions from the chemical industry category comprised 626.4 Gg CO2-e (14.8 per cent) of emissions from the industrial processes sector. Emissions from the chemical industry have increased by 179.4 Gg CO2-e (40.1 per cent) from the 447.0 Gg CO2-e estimated in 1990. Carbon dioxide emissions from ammonia production accounted for (60.9 per cent) of emissions in the chemical industry category.

Methane emissions from the chemical industry have decreased 28.7 Gg CO2-e (62.8 per cent) between 2004 and 2006. The closure of the Motunui methanol production plant in November 2004 caused this decrease in emissions. There is one methanol production plant in operation at Waitara.

4.3.2 Methodological issues

Ammonia/urea

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 MED by the company operating 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 (52.0 kt/PJ). The proportion of gas from each of these fields used in ammonia production changes on an annual basis. This explains the fluctuation in the CO2 implied emission factor over the 1990–2006 time-series.

Non-CO2 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

Formaldehyde is produced at five plants (owned by two different companies) in New Zealand. NMVOC emissions are calculated from company-supplied activity data and a country-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 reported in the energy sector.

Methanol

Until recently methanol was produced at two plants by Methanex 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 to calculate CO2 emissions is shown in Box 3.1 (chapter 3).

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 Limited, 2006). The NMVOC emissions factor, 5kgNMVOC/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.

Fertiliser

The production of sulphuric acid (H2SO4) during the manufacture of superphosphate fertiliser is largely responsible for the indirect emissions of SO2. In New Zealand there are two companies, Ballance and Ravensdown, involved in the production of superphosphate. Each company owns two production plants. Three plants produce sulphuric acid. One plant imports the sulphuric acid.

Both companies supplied activity data for 2006 to the Ministry for the Environment. Plant specific emission factors used in previous years were applied to the 2006 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 ten times too high for the New Zealand industry. Consequently, emission estimates are based on industry supplied emission factors and activity levels.

Hydrogen

Emissions of CO2 from hydrogen production are supplied directly to the MED 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 Limited, produces a small amount of hydrogen which 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.

4.3.3 Uncertainties and time-series consistency

Uncertainties in CO2 emissions are 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 Limited, 2006). These are documented in Table 4.3.1.

Table 4.3.1 Uncertainty in non-CO2 emissions from the “chemical industry”

Product Uncertainty in activity data Uncertainty in emission factors

Ammonia /Urea

± 0%

± 30%

Formaldehyde

± 2%

± 50% (NMVOCs)

Methanol

± 0%

± 50% (NOx and CO)

± 30% (NMVOCs)

± 80% (CH 4 )

Fertiliser

± 10% sulphuric acid

± 10% superphosphate

± 15% sulphuric acid

± 25 to ± 60% superphosphate (varies per plant)

4.3.4 Source-specific QA/QC and verification

New Zealand specifies CO2 from ammonia production as a qualitative key category because of the large increase in nitrogenous fertiliser use observed in the agriculture sector. 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 Tier 1 quality checks.

4.3.5 Source-specific recalculations

There was a minor recalculation for ammonia production for 2003 due to rounding. There were no other recalculations for this category.

4.4 Metal production (CRF 2C)

4.4.1 Description

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 from 1990-1999. New Zealand has no production of coke, sinter or ferroalloys. Carbon dioxide emissions from “iron and steel production” and “aluminium production” are key categories (level assessment). Perfluorocarbon emissions from “aluminium production” are a key category in the trend analysis.

In 2006, emissions from the “metal production” category were 2,257.6 Gg CO2-e (53.3 per cent) of emissions from the industrial processes sector. Emissions from this category decreased 5.9 per cent from the 1990 level of 2,400.1 Gg CO2-e. Carbon dioxide emissions account for 96.3 per cent of emissions in this category with another 3.7 per cent from PFCs. In 2006, the level of CO2 emissions increased by 419.6 Gg CO2-e (23.9 per cent) above the 1990 baseline. Perfluorocarbon emissions have decreased from the 641.7 Gg CO2-e in 1990 to 82.5 Gg CO2-e in 2006, a decrease of 559.2 Gg CO2-e (87.1 per cent).

The decrease in PFC emissions is because the Tiwai Point aluminium smelter has made improvements in reduction cell control and reduction cell operating practices.

4.4.2 Methodological issues

Iron and steel

There are two steel producers in New Zealand. Blue Scope Steel Limited produces iron using the “alternative iron making” process (Ure, 2000) from titanomagnetite ironsand. The iron is then processed into steel. Pacific Steel 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 carbon dioxide 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). 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.

A Tier 2 approach is used for calculating CO2 emissions from the iron and steel plant operated by New Zealand Steel. Emissions from pig iron and steel production are not estimated separately as all of the pig iron is transformed into steel. The carbon content in the ironsand is negligible (Ure, 2000) and therefore not accounted for. 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.

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.

Pacific Steel 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 are 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 Limited, 2006).

Aluminium

Aluminium production activity data and associated CO2 and PFC emissions are supplied by Rio Tinto Aluminium, New Zealand’s sole aluminium smelter operator. The technology type used by the smelter is Centre Worked Prebaked (CWPB). Carbon anode oxidisation is responsible for almost 90 per cent of the CO2 emissions from aluminium production.

The aluminium smelter calculates the process CO2 emissions using the Aluminium Sector Addendum to the WBCSD/WRI Greenhouse Gas Protocol released in October 2006 by the IPCC and International Aluminium Institute (IAI). The IPCC/IAI methodology breaks the prebake anode process into three stages (baked anode consumption, pitch volatiles consumption and packing coke consumption). This methodology more accurately reflects the use of carbon in the process.

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.

Emission estimates of PFCs (CF4 and C2F6) from the production of aluminium are also supplied by the aluminium smelter. The PFC emissions from aluminium smelting are calculated using the IPCC/IAI Tier 2 methodology summarised below:

PFC (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 are logged and stored electronically to give 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 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.

For estimates of indirect greenhouse gases, the IPCC default emission factor is used for NOx emissions. Plant-specific emission factors are used for CO and SO2. An industry supplied value of 110 kg CO per tonne (IPCC range 135–400 kg CO per tonne) is based on measurements and comparison with Australian CO emission factors. Sulphur dioxide emissions are calculated from the input sulphur levels and direct monitoring.

Other metal production

Small amounts of sulphur hexafluoride (approximately 3 Gg CO2-e per year) 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.

4.4.3 Uncertainties and time-series consistency

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 Limited, 2006). These are documented in Table 4.4.1.

Table 4.4.1 Uncertainty in non-CO2 emissions from “metal production”

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% (CRL Energy Limited, 2006).

4.4.4 Source-specific QA/QC and verification

Carbon dioxide emissions from “iron and steel production” and “aluminium production” are key categories. Perfluorocarbon emissions from aluminium production are a key category (trend assessment). In the preparation of this inventory, the data for these sub-categories underwent Tier 1 quality checks.

4.4.5 Source-specific recalculations

As explained under the mineral products section, New Zealand has been able to separate emissions arising from limestone, coke and electrodes used in the iron and steel making process from the rest of the process CO2 emissions for the first time in the 2008 inventory submission. This has resulted in recalculations for the 1990-2005 time series for both the mineral products (limestone and dolomite use) and metal production (iron and steel production) categories.

Activity data and resulting CO2 and PFC emissions from aluminium production was updated for the 1990 – 2006 time series. Rio Tinto Aluminium provided a new time series of data to reflect CO2 and PFC emissions calculated using the methodologies outlined in the Aluminium Sector Addendum to the WBCSD/WRI Greenhouse Gas Protocol. The addendum was released in October 2006 by the IPCC and International Aluminium Institute (IAI).

4.5 Other production (CRF 2D)

4.5.1 Description

The “other production” category includes emissions from the production of pulp and paper, and food and drink. In 2006, emissions from this category totalled 7.4 Gg NMVOC. This was an increase of 1.4 Gg NMVOCs since the 1990 level of 6.0 Gg CO2-e.

4.5.2 Methodological issues

Pulp and paper

There are a variety of pulping processes in New Zealand. These include:

  • chemical (Kraft)

  • chemical thermomechanical

  • thermomechanical

  • mechanical.

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 MAF. 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 Limited, 2006). Emissions of CO and NOx from these processes are related to fuel combustion and not reported under industrial processes.

Food and drink

NMVOCs are produced during the fermentation of cereals and fruits in the manufacture of alcoholic beverages. They are also produced during all processes in the food chain which follow after the slaughtering of animals or harvesting of crops. Estimates of indirect greenhouse gas emissions fro 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. The 2006 NMVOC estimates from food and drink have been estimated using linear extrapolation due to no industry survey. In 2006, NMVOC emissions were estimated to be 6.5 Gg an increase of 1.3 Gg since 1990.

4.5.3 Uncertainties and time-series consistency

Uncertainties in non-CO2 emissions are assessed by the contractor from the questionnaires and correspondence with industry sources (CRL Energy Limited, 2006). These are documented in Table 4.5.1.

Table 4.5.1 Uncertainty in non-CO2 emissions from “other production”

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)

4.5.4 Source-specific QA/QC and verification

“Other production” is not a key category and no specific QA/QC activities were performed. Where possible, activity data are cross-referenced between companies and industry associations to verify the data.

4.5.5 Source-specific recalculations

There are no source-specific recalculations performed for this category in the 2008 inventory submission.

4.6 Production of halocarbons and SF6 (CRF 2E)

New Zealand does not manufacture halocarbons and SF6. Emissions from consumption are reported under section 4.7

4.7 Consumption of halocarbons and SF6  (CRF 2F)

4.7.1 Description

Emissions from hydrofluorocarbons (HFCs) totalled 593.0 Gg CO2-e in 2006. There was no known use of HFCs in 1990. The first consumption of HFCs in New Zealand was reported in 1992. The large increase in HFC emissions is due to the replacement of ozone-depleting CFCs and HCFCs with HFCs. HFC emissions are identified as a key category (level and trend).

SF6 emissions have increased from 9.5 Gg CO2-e in 1990 to 13.2 Gg CO2-e in 2006, an increase of 3.8 Gg CO2-e (40.0 per cent). The majority of SF6 emissions are from use in electrical equipment.

HFCs 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 major source categories:

  • aerosols

  • solvents

  • foam

  • mobile air conditioning (MAC)

  • stationary refrigeration and air conditioning

  • fire protection

  • “other”.

The emissions inventory for SF6 is broken down into two source categories: electrical equipment and “other”. In New Zealand, one electricity company accounts for 75–80 per cent of total SF6 used in electrical equipment.

4.7.2 Methodological issues

HFCs/PFCs

Bulk import data of HFCs and PFCs is based on an annual survey of importers and distributors of these chemicals. Activity data was collected to identify the end users of the imported bulk chemicals. This data was used to estimate the proportion of bulk chemical used in each sub-source category. The total quantity of HFCs imported each year was estimated from data supplied by Statistics New Zealand. Non-bulk imports of HFCs and bulk imports of PFCs and SF6 are more difficult to determine as import tariff codes are not specific enough to identify these chemicals. For example, HFC134a, the most commonly used HFC, is imported in a wide range of aerosol products. Information on the consumption of aerosol products was obtained from the Aerosol Association of Australia/New Zealand and from New Zealand manufacturers of aerosol products.

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 is 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 IPCCC Tier 1b approach. Very little data is available on bulk imports of individual HFC and PFC gases. 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 Halocarbon and SF6 calculation methods and emission factors

HFC source Calculation method Emission factor

Aerosols

IPCC GPG 2000 Equation 3.35

IPCC default factor of 50% of the initial charge per year

Foam

IPCC GPC 2000 Table 3.17

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 approach

First fill: 0.5%

Stationary refrigeration/ air conditioning

IPCC GPG 2000 Equation 3.40

N/A

Fire protection

IPCC GPG 2000 Equation 3.51

Top-down approach using emission rate of 0.015

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 75-85% 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

Aerosols

Activity data on aerosol usage are 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. Data on the total number of doses contained in metered dose inhalers used from 1999 to 2006 are provided by Pharmac, the New Zealand drug purchasing agency. The weighted average quantity of propellant per dose was calculated from information supplied by industry. There were no HFCs used in aerosols before 1996 and HFC–134a was not used in metered dose inhalers before 1995.

Equation 3.35 (IPCC, 2000) is used to calculate HFC emissions from aerosol use in New Zealand. HFC emissions from metered dose inhalers in 2006 were 48.0 Gg CO2-e and emissions from other aerosols in 2006 were 22.2 Gg CO2-e.

Solvents

A survey of distributors of solvent products and solvent recycling firms did not identify any use of HFCs or PFCs as solvents (CRL Energy Limited, 2007).

Foam

The 2007 halocarbon survey (CRL Energy Limited, 2007) found two companies who use HFCs for foam blowing and another company had used HFC in recent years but not in 2006 (CRL Energy Limited, 2007). The use of HFCs in foam blowing started in 2000. From 2000 to 2003 the HFC used was HFC–134a. From 2004, a mixture of HFC–245fa/365mfc has been imported for use. A global warming potential for this mixture has not been agreed to by the IPCC and UNFCCC. On recommendation by the in-country review team in 2007 (UNFCCC, 2007) New Zealand has reallocated these emissions to the section called “information on additional greenhouse gases” in the CRF tables.

Stationary refrigeration/air conditioning

New Zealand uses a top-down Tier 2 approach and country-specific data to obtain HFC emissions from stationary refrigeration and air conditioning (IPCC equation 3.40; IPCC, 2000):

Emissions = (annual sales of new refrigerant) – (total charge of new equipment) + (original total charge of retiring equipment) – (amount of intentional destruction)

To estimate the actual emissions of HFCs and PFCs, all refrigeration equipment has been split into two groups: factory charged equipment and all other equipment which is charged with refrigerant on site. This is because some information is available on the quantities of factory charged imported refrigeration 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 that 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 Limited, 2007).

HFC and PFC emissions from stationary refrigeration and air conditioning were 337.9 Gg CO2-e in 2006.

Mobile air conditioning

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 are retrofitted (with “aftermarket” units) to new trucks and buses and to second-hand cars.

This section does not consider refrigerated transport, which is included in the stationary refrigeration/air conditioning sub-category.

New Zealand uses the Tier 2 top-down approach (IPCC equation 3.44, IPCC, 2000):

Annual emissions of HFC–134a = 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 made on the percentage of MAC installations. Operation and disposal data are obtained from a survey of the industry and the New Zealand Transport Registry Centre.

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 and PFC emissions in New Zealand (CRL Energy Limited, 2007).

HFC emissions from mobile air conditioning were 192.2 Gg CO2-e in 2006.

Fire protection

HFCs and PFCs are used as substitutes to halons in portable and fixed fire protection equipment. Halons have traditionally been used in areas that contain high-value equipment and where risks to personal safety are high. These include computer rooms, data centres and on aircraft.

HFC-based foams have only been used in fire protection systems in New Zealand since 1994. Within the New Zealand fire protection industry, the two main supply companies were 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 top-down approach (IPCC, 2000) is used for estimating emissions from this sub-category. For each year, an emission rate of 1.5 per cent, based on industry information, is applied to the total amount of HFC installed to get annual HFC-227ea emissions.

HFC emissions from fire protection were 1.3 Gg CO2-e in 2006.

SF6

Actual and potential emissions of SF6 result primarily from the use of SF6 in electrical switchgear. SF6 questionnaires were sent to the two importers of SF6 and New Zealand’s main users of SF6, the electricity transmission, generation and distribution companies (CRL Energy Limited, 2007). Actual emissions were calculated using the IPCC Tier 3a approach for the utility responsible for 75-85 per cent of the total SF6 held in electrical switchgear equipment. This data was supplemented by data from other utilities and an equipment manufacturer and servicing contractor. The additional data enabled a Tier 2b approach to be taken for the rest of the industry (CRL Energy Limited, 2007). Potential emissions of SF6 are calculated using total annual imports of SF6 into New Zealand. Potential SF6 emissions are usually 2 to 3 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 shows potential SF6 emissions are again greater than actual emissions.

Sulphur hexafluoride emissions from electrical equipment were 13.0 Gg CO2-e in 2006.

There are small amounts of SF6 released during tracer gas studies, medical uses and magnesium casting (as discussed in section 4.4.2).

4.7.3 Uncertainties and time-series consistency

The uncertainty in estimates of actual emissions from the use of HFCs and PFCs varies 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.

Table 4.7.2 Uncertainties in “consumption of halocarbons and SF6” (CRL Energy Limited, 2007)

HFC source Uncertainty estimates

Aerosols

Combined uncertainty ± 56%

Metered Dose Inhalers

Combined uncertainty ± 10%

Solvents

Not occurring

Foam

Combined uncertainty ± 70%

Stationary refrigeration/air conditioning

Combined uncertainty ± 39%

Mobile air conditioning

Combined uncertainty ± 37%

Fire protection

Combined uncertainty ± 32%

SF6 source

Uncertainty estimates

Electrical equipment

Combined uncertainty ± 21%

Other applications

± 50%

4.7.4 Source-specific QA/QC and verification

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 are verified against national totals where possible and unreturned questionnaires and anomalous data are followed up and verified to ensure an accurate record of activity data.

4.7.5 Source-specific recalculations

As a result of an improved survey of the HFC and PFC importers and distributors in 2007 (CRL Energy Limited, 2007) estimates of gas stocks and emissions over the time series have been revised. The main changes have occurred within the stationary refrigeration and mobile air conditioning sub-sectors.

A more detailed model of the household and commercial refrigeration and air conditioning sub-sectors was developed in 2007 (CRL Energy Limited, 2007). Revised assumptions in the equipment charge for the commercial refrigeration sub-sector have resulted in higher amounts of HFCs being used to charge equipment and hence lower emissions compared with the 2007 inventory submission.

The previous methodology used for calculating total charge of new equipment in the stationary refrigeration and air-conditioning sub-sector (IPCC, 1996) was inconsistent when addressing equipment for export. The methodology was amended to exclude HFCs exported in NZ manufactured equipment. This change resulted in HFC emissions being reduced by 25–30 tonnes per year between 2001 and 2006 compared with the 2007 inventory submission.

An improved understanding of the annual scrap rate of vehicles using mobile air-conditioning has resulted in HFC emissions increasing in the mobile air-conditioning subcategory compared to the 2007 inventory submission. An increase in emissions associated with mobile air-conditioning servicing was previously included under the stationary refrigeration subcategory. The reallocation of these emissions in the 2008 inventory submission has increased emissions in the mobile air-conditioning subcategory while decreasing the emissions in the stationary refrigeration subcategory.

4.8 Other (CRF 2G)

4.8.1 Description

Panel products

Activity data are obtained from industry and supplemented with statistics from the MAF. The NMVOC emission factors for particleboard 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 particleboard and fibreboard production in New Zealand. There is no information in the IPCC guidelines (1996) for this category.

NMVOC estimates for panel products in 2006 were 1.5 Gg. This is an increase of 0.7 Gg since 1990.