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Chapter 4: Industrial processes

4.1 Sector overview

New Zealand’s industrial processes sector totalled 4336.7 Gg CO2 equivalent (CO2-e) in 2005 and represented 5.6 per cent of total greenhouse gas emissions. Emissions from industrial processes are now 1045.4 Gg CO2-e (31.8 per cent) above the 1990 baseline of 3291.2 Gg CO2-e (Figure 4.1.1). The sector is dominated by emissions from the metal production category (carbon dioxide (CO2) and perfluorocarbons (PFCs)) at 53.0 per cent of sectoral emissions.

Figure 4.1.1 Industrial processes sector emissions 1990–2005

 

Year

Gg CO2 equivalent

1990

3,291.24

1991

3,577.93

1992

3,643.80

1993

3,639.84

1994

3,250.14

1995

3,404.98

1996

3,568.01

1997

3,310.25

1998

3,594.65

1999

3,657.3

2000

3,590.67

2001

3,865.13

2002

4,066.01

2003

4,351.65

2004

4,197.35

2005

4,336.65

Figure 4.1.2 Industrial processes sector emissions in 2005 (all figures Gg CO2-equivalent)

 

Category

Gg CO2 equivalent

Percent of total

Mineral Products

702.5

16.2

Chemical Industry

573.2

13.2

Metal Production

2,297.6

53.0

Consumption of Halocarbons and SF6

763.4

17.6

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. Carbon dioxide emissions related to energy production, eg, 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 and urea

  • production of hydrogen.

The industrial processes categories use a few 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 1990–2005 (MED, 2006).

Data on non-CO2 emissions are gathered through a questionnaire distributed directly to industry by consultants contracted to the Ministry of Economic Development. The questionnaire requests information on greenhouse gas emissions and production, as well as on any relationship the companies have established between the two. This information is supplemented by further material from industry groups and other statistical sources. The IPCC default emission factors are applied to industry production data where no country-specific information is available. Full details of emission estimates and aggregate emission factors are included in the calculation worksheets in Annex 8.

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 (MED, 2006a). The uncertainty surrounding estimates of non-CO2 emissions is greater than for CO2 emissions and varies with 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

Emissions from the “mineral products” category comprised 702.5 CO2-e in 2005. Overall, emissions in this category have grown by 173.5 Gg equivalent (32.8 per cent) from the 1990 level of 529.0 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. The emissions profile is dominated by production of cement (80.9 per cent) and lime (18.3 per cent). For both lime and cement production, only the emissions related to the calcination process are included in this category with the emissions from the combustion of coal reported in the energy sector.

4.2.2 Methodological issues

Cement production

There are two cement production companies operating in New Zealand. Estimates of CO2 emissions from cement production are calculated by both companies using the IPCC Tier 2 methodology (IPCC, 1996;2001). Because confidentiality of data is an issue, clinker data and the corresponding implied emission factors are not included in the CRF tables. Total process CO2 emissions from cement production are reported. The amount of clinker produced by each 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 due to the chemical composition of clinker produced in New Zealand.

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.

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

Year

Indexed implied emission factor-cement

1990

1

1991

1

1992

1

1993

1

1994

1

1995

1

1996

1

1997

0.970588235

1998

0.958823529

1999

0.960784314

2000

0.958823529

2001

0.945098039

2002

0.901960784

2003

0.835294118

2004

0.782352941

2005

0.901960784

 

Year

Indexed cement production

Indexed clinker production

1990

1

1

1991

0.936395691

0.975447103

1992

1.105678459

1.063669032

1993

1.257710951

1.089777978

1994

1.327520186

1.107588407

1995

1.372402618

1.177267938

1996

1.371060455

1.120308213

1997

1.415353052

1.167730233

1998

1.363084798

1.071364533

1999

1.4805764

1.185102218

2000

1.479876764

1.182168201

2001

1.513513551

1.191697309

2002

1.636678745

1.22664515

2003

1.72416527

1.188305197

2004

1.691632879

1.092369345

2005

1.736641885

1.293358731

 

Year

Indexed implied emission factor-clinker

1990

1

1991

0.999418599

1992

0.998861045

1993

0.998868588

1994

0.998689722

1995

0.998662634

1996

0.998924087

1997

0.99984057

1998

1.000302657

1999

0.999603785

2000

1.000046085

2001

1.000250446

2002

1.001115631

2003

1.002083811

2004

0.994497535

2005

0.995518677

 

Year

Indexed imported clinker

1990

1

1991

0.656

1992

0.8096

1993

0.6288

1994

0.6752

1995

0.536

1996

0.896

1997

0.5648

1998

0.5088

1999

0.3712

2000

0.3744

2001

61.568

2002

145.9264

2003

302.9808

2004

362.6112

2005

234.9136

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 clinker production activity data increasing over the time-series 1990–2005 while the implied CO2 emission factor for cement production has been decreasing. The exception to this is from 2004 to 2005 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. The decrease in the CO2 implied emission factor can be explained by the greater increase in cement production in recent years compared to the CO2 emissions, which have remained relatively steady. This has been due to the increase in imported clinker and a change in national standards for cement production in 1995 which permitted mineral additions to cement of up to 5 per cent by weight (CCANZ, 1995).

Sulphur dioxide is emitted in small quantities from the cement making process. The amount of SO2 is determined by the sulphur content of the raw material (limestone). The IPCC guidelines (IPCC, 1996) report that 70–95 per cent of the SO2 will be absorbed by the alkaline clinker product. New Zealand uses an SO2 emission factor calculated using industry-specific information. This emission factor was updated during 2005 with improved information from industry. The emission factor was calculated using information from a sulphur mass balance study on one company’s dry kiln process. This enabled the split between sulphur originating in the fuel and sulphur in the raw clinker material as sodium and potassium salts to be determined. The average emission factor is calculated as 0.64 kg SO2/t clinker and is weighted to take into account the relative activity of the two cement companies.

Lime production

There are three companies in New Zealand which make up the burnt lime industry. Carbon dioxide emissions from lime production are supplied to the MED by industry. Emissions are calculated by multiplying the amount of lime produced by an emission factor. 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 to all lime. This was the only information available for this source. Since 2002, plant-specific emission factors have been used. There has been little change in the implied emission factor which has varied from 0.72 t CO2/t lime to 0.73 t CO2 / t lime from 1990 to 2005.

The SO2 emissions emitted during lime production vary depending on the processing technology and the input materials. An industrial processes survey undertaken in 2005 resulted in an updated value for the average SO2 emission factor. The average emission factor is 0.48 kg SO2/t lime and is weighted to take sulphur measurements at the various lime plants into account.

Limestone and dolomite use

Emissions arising from cement and burnt lime processes are reported under the cement and lime production categories as specified in the IPCC, Guidelines (1996 section 2.5.1). The current exception to this is the use of limestone in the production of iron and steel by the major steel producer in New Zealand. In the iron production process coal is blended with limestone to achieve the required primary concentrate specifications. Currently all CO2 process emissions from iron and steel production, including limestone use, are reported under the iron and steel category (2.C.1). New Zealand will aim to report emissions from limestone use in iron and steel production separately in future submissions.

Non-calcined uses of limestone for agricultural purposes (liming of soils) is reported in the Land use, land-use change and forestry sector.

Soda ash production and use

There is no soda ash production in New Zealand. A consultant who surveyed the industrial processes sector in 2005 was able to make preliminary estimates of CO2 emissions resulting from the use of soda ash in glass production (CRL Energy Ltd, 2006a). The manufacturer was able to provide information on the amount of imported soda ash it used in 2005. It also provided approximate proportions of recycled glass over the last 10 years to enable back calculations because the soda ash amount is in fixed proportion to the production of new (rather than recycled) glass. Linear extrapolation of activity data from 1990 to 1995 was carried out in the absence of actual data. 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 only one company manufacturing asphalt roofing in New Zealand. Indirect emissions of NMVOCs and CO are calculated using the default IPCC emission factors (IPCC, 1996) and activity data supplied by the company. The industrial processes survey undertaken in 2005 revealed an updated estimation of activity data for this source. The data has been updated and back calculated for the entire time-series.

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. Solvents are rarely added to asphalt, so asphalt paving is not considered a significant source of emissions. New Zealand still uses a wet “cut-back” bitumen method rather than bitumen emulsions common in other countries.

The IPCC Guidelines (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 2002 inventory, 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 Ltd, 2006a) 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 in 2004 the fraction was 0.60. The emissions of NMVOCs in the common reporting format have been updated for the time-series 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. The IPCC Guidelines (1996) report that NMVOC may be emitted from the manufacture of glass and provide a default emissions factor of 4.5 kg NMVOC per tonne of glass output. It has been assumed that the IPCC emissions 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 so are not reported under industrial processes. The industrial processes survey undertaken in 2005 obtained estimates of CO2 from soda ash use (see soda ash production and use section above) and SO2 emissions from sodium sulphate decomposition.

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 are assessed by the contractor from the questionnaires and correspondence with industry sources (CRL Energy Ltd, 2006a).

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 is a key category (level assessment) for 1990 and 2005. In the preparation of this inventory, the data for these emissions underwent Tier 1 quality checks.

In the process of compiling non-CO2 emissions, activity data are re-checked with industry experts where possible. The small number of companies in this category assists in achieving the complete coverage of the category.

4.2.5 Source-specific recalculations

During 2006 both cement companies were contacted and they provided complete time-series of CO2 emissions from 1990 to 2005. These values were compared against the data archived at the Ministry for Economic Development. It was discovered there were small differences in some of the values from one company compared with the data available at the Ministry for Economic Development. As a result of discussions between the company, the Ministry for Economic Development and the Ministry for the Environment the data were revised. The data the company held was deemed to be the most accurate and consistent throughout the time-series. This has resulted in CO2 emissions attributed to the mineral products category being recalculated for the entire time-series.

4.3 Chemical industry (CRF 2B)

4.3.1 Description

This category reports emissions from the production of ammonia, nitric and adipic acid, silicon and calcium carbide, and other chemicals. The major chemical processes occurring in New Zealand that fall into this category are the production of ammonia and urea, methanol, hydrogen, fertiliser (superphosphate) and formaldehyde. There is no production of nitric acid, adipic acid, carbide, carbon black, ethylene, dichloroethylene, styrene, coke or caprolactam in New Zealand.

Emissions from the chemical industry category comprised 573.2 Gg CO2-e emissions in 2005 and have increased 126.2 Gg CO2-e (28.2 per cent) from the 447.0 Gg CO2-e estimated in 1990.

Carbon dioxide emissions from ammonia/urea production account for 60.4 per cent of emissions in this category.

Methane emissions from the chemical industry have decreased 31.3 Gg CO2-e (68.5 per cent) between 2004 and 2005. There are two reasons for this. The first is the shut down of the Motunui methanol production plant in November 2004. This leaves only one methanol production plant at Waitara. The second is decrease in ammonia production between 2004 and 2005 (production varies from year to year).

4.3.2 Methodological issues

Ammonia/urea

Ammonia is manufactured in New Zealand by the catalytic steam reforming of natural gas at New Zealand’s sole ammonia/urea plant. The total amount of gas supplied to the plant is provided to the Ministry for Economic Development by the company operating the 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) used in ammonia production by their respective emission factors. Gas from three different fields is used in ammonia production in New Zealand. The emission factors vary from Kapuni (84.1 kt/PJ), Kaimiro (65.2 kt/PJ) to Maui (51.8 to 53.2 kt/PJ). The proportion of gas from each of these fields used in ammonia production changes on an annual basis and this explains the fluctuation in the CO2 implied emission factor over the 1990–2005 time-series. Ammonia production decreased between 2004 and 2005. For more details on the gas emission factors refer to Annex 2.

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 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 are more appropriately included in the energy sector.

Methanol

Methanol is produced at two plants in New Zealand. Carbon dioxide emissions are reported in the energy sector. The process to calculate CO2 emissions is shown in Box 3.1 (energy sector: manufacturing industries and construction).

The major non-fuel related emissions from the process are NMVOCs. Emissions are calculated from company-supplied activity data and emission factors. The NMVOC emissions factor was estimated in 2001 from American Petroleum Institute methods for calculating vapour emissions from storage tanks. NOx and CO emission factors were measured in 1999. It is assumed the IPCC default factor for CH4 (2g CH4/kg production) is appropriate for New Zealand (CRL Energy Ltd, 2006a).

Fertiliser

Superphosphate is produced by two companies (each with three plants) in New Zealand. Most of these plants produce sulphuric acid as a first step. One plant however now imports acid. Both companies have supplied activity data and emission factors for SO2, which is the only indirect greenhouse gas emitted from the production of superphosphate fertiliser. The majority of these emissions are released during sulphuric acid production. No reference is made to superphosphate production in the IPCC Guidelines (1996). A default emissions factor of 17.5 kg SO2 (range of 1 to 25) per tonne of sulphuric acid is recommended but it is assessed by New Zealand industry experts to be a factor of two to ten times too high for the New Zealand industry. Emission estimates are therefore based on industry supplied emission factors and activity levels. Checks were made with the supplied emission factors for superphosphate and one set was identified as an outlier. The SO2 emission factor for the other company was assessed to be appropriate for both companies’ superphosphate output.

Hydrogen

Emissions of CO2 from hydrogen production are supplied directly to the Ministry for Economic Development by the two production companies involved. 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 produces a small amount of hydrogen which is converted to hydrogen peroxide. The hydrogen is produced from CH4 and steam. CO2 is a by-product of the reaction and is vented to the atmosphere. The implied emission factor for hydrogen produced in New Zealand is 5.98 kt CO2 per kt of hydrogen produced (MED, 2006a).

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 Ltd, 2006a). 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% (CH4)

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

The CO2 emission factors for the gases used for ammonia production (from the Maui, Kapuni and Kaimiro gas fields) have been updated by the Ministry of Economic Development. In previous submissions the proportions of Maui and treated gas from the Kapuni gas field have been assumed to be 50 per cent from each gas field. The Energy Data File (MED, 2006b) reports annual production of the local gas fields for 1970–2005. For the 1990–2005 inventory annual production of the gas fields have been used to calculate weighted average annual CO2 emission factors.

4.4 Metal production (CRF 2C)

4.4.1 Description

The “metal production” category reports emissions from the production of iron and steel, ferroalloys, aluminium and the SF6 used in aluminium and magnesium foundries. The major metal production activities occurring in New Zealand are the production of iron, steel and aluminium. Carbon dioxide emissions from “iron and steel production” is a key category (level assessment) for 1990 and 2005. Carbon dioxide emissions from “aluminium production” is a key category in 1990 but not for 2005 (table 1.5.2). Perfluorocarbon emissions from “aluminium production” is a key category in the trend analysis (table 1.5.3). New Zealand has no production of coke, sinter or ferroalloys.

Emissions from the “metal production” category were 2,297.6 Gg CO2-e in 2005. Emissions from this category decreased 0.4 per cent from the 2,305.8 Gg CO2-e recorded in 1990. Carbon dioxide emissions account for 96.5 per cent of emissions in this category with another 3.5 per cent from PFCs. In 2005, the level of CO2 emissions increased by 429.5 Gg CO2-e (24.0 per cent) above the 1990 baseline. Perfluorocarbon emissions have decreased from the 515.6 Gg CO2-e in 1990 to 80.7 Gg CO2-e in 2005, a decrease of 434.9 Gg CO2-e (84.3 per cent).

The decrease in PFC emissions is because the sole aluminum smelter in New Zealand now has low anode effect duration by world standards. Anode effects are caused by depletion of alumina. The technology now in use introduces alumina into the pot quickly and extinguishes the anode effect. The smelter processes alumina in relatively large quantities by modern standards (50 kg per “feed” compared to 2 kg per “feed”).

4.4.2 Methodological issues

Iron and steel

There are two steel producers in New Zealand. One produces iron using the “alternative iron making” process from titanomagnetite ironsand. The iron is then processed into steel. The other company operates an electric arc furnace to process scrap metal into steel.

The company which produces steel from titanomagnetite ironsand produces the bulk of CO2 emissions for this subcategory through the use of coal as a reducing agent and the quantities of other non-fuel carbon-bearing ingredients used in the process 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 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 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 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.

New Zealand uses a Tier 2 approach for calculating emissions from iron and steel production. New Zealand does not account for emissions from pig iron and steel production separately as all of the pig iron is transformed into steel. The carbon in the ironsand is negligible (Ure, 2000) and therefore not accounted for. The emission factor applied to the sub-bituminous coal used as a reducing agent is 93.7 kt CO2/PJ. This 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 in the energy sector as well as the industrial processes sector. New Zealand energy statistics for coal are disaggregated into coal used in steel making and coal used in other industries and sectors. The coal acts as both a reductant and an energy source in the iron-making process. Data does not exist to accurately split the amount of coal used in energy and industrial processes so it is all reported under industrial processes.

The second steel company melts approximately 250 kt of recycled steel annually in an electric arc furnace. Before being tapped from the furnace into a hot ladle, the molten steel is subsequently refined (fine tuning of temperature and chemistry) before continuous casting into billets. The process CO2 emissions from the electric arc furnace arise from charge additions of carbon with the scrap and the oxidation of carbon electrodes. No meaningful CO2 emissions data were 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 0.0968 t CO2/t steel.

The non-CO2 emission factors for the indirect greenhouse gases (CO, SO2 and NOSx) for both steel plants are based on measurements in conjunction with mass balance (for SO2) and technical reviews (CRL Energy Ltd, 2006a).

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 on site is Centre Worked Prebaked (CWPB). Carbon anode oxidisation is responsible for almost 90 per cent of the CO2 emissions from aluminium production.

The carbon consumption is multiplied by 3.812 to convert carbon to CO2 (as compared with 3.666 if the standard atomic weights ratio of 44/12 is used). This factor was determined by Rio Tinto Aluminium to account for additional carbon used in the carbon bake furnace process as well as the consumption of carbon in the reduction cell. The factor was developed based on average historic consumption of coke and pitch across Rio Tinto Aluminium’s Australian and New Zealand smelters to calculate CO2 emissions (Hamilton, 2007). Various fuels such as heavy fuel oil, LPG, petrol and diesel are used in the aluminium production process and associated emissions are included in the energy sector (MED, 2005; Bloor, 2006a).

Emissions of two 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 Tier 2 method. This involves using the IPCC default coefficients for Centre Worked Prebaked technology in the slope equation together with smelter-specific operating parameters of anode effect frequency and duration. Anode effect frequency is multiplied by duration to get anode effect minutes per cell day.

EF (kg CF4 or C2F6 per tonne of Al) = Slope × AE min/cell day

Slope = 1.698 × (p/CE)

AE min/cell day = AEF × AED

Where:

Slope = 0.14 for CF4 and 0.018 for C2F6 kgPFC/tAl/AE – minutes/cell day

(CWPB default values from IPCC GPG)

AEF = Number of anode effects per cell day

AED = Anode effect duration in minutes

(Tier 2 and 3b equations, IPCC Good Practice Guidance)

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 and the slope factor to provide an estimate of CF4 and C2F6 emissions. The IPCC default slope coefficients of 0.14 and 0.018 for Centre Worked Prebaked technology are used. The smelter advises that there are no plans to directly measure PFC emissions so 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

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 inventory for 2005.

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 Ltd, 2006a). 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 Ltd, 2006a).

4.4.4 Source-specific QA/QC and verification

Carbon dioxide emissions from “iron and steel production” and “aluminium production” are key categories for 1990 (level assessment). In 2005 only iron and steel is a key category (level assessment).

In 2005, PFCs from aluminium production is a key category (trend assessment). In the preparation of this inventory, the data for these emissions underwent Tier 1 quality checks.

4.4.5 Source-specific recalculations

There were some minor recalculations of CO2 emissions from the “iron and steel” category due to increased precision in data entry into the CRF Reporter.

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 2005, emissions from this category totalled 7.1 Gg NMVOC. This was an increase of 1.2 Gg NMVOCs since 1990.

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.

Mechanical pulp production in 2005 was responsible for 54 per cent of all pulp production with chemical production responsible for 46 per cent (CRL Energy Ltd, 2006a). 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 Ltd, 2006a). 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 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. In 2005, NMVOC emissions were estimated to be 6.3 Gg an increase of 1.1 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 Ltd, 2006a). 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 a non 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 this 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 741.6 Gg CO2-e in 2005. There was no known use of HFCs in 1990. This large increase is due to the replacement of ozone-depleting CFCs and HCFCs with HFCs. HFC emissions are identified as a key category in the level and trend analysis of the 2005 inventory (tables 1.5.2 and 1.5.3).

SF6 emissions have increased from 9.5 Gg CO2-e in 1990 to 21.8 Gg CO2-e in 2005, an increase of 130.9 per cent. The majority of SF6 emissions are from the consumption and disposal of SF6 associated with its 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 80–90 per cent of total SF6 used in electrical equipment.

4.7.2 Methodological issues

HFCs/PFCs

Information on bulk imports of HFCs and PFCs each year is based on data supplied by the Ministry of Economic Development. This information is derived from an annual survey of all importers and distributors of these chemicals. This provides a basis for estimating potential emissions. To report actual emissions, further information is collected from importers and distributors to identify the end users and proportion of bulk chemical used in each sub-source category.

Several additional importers were identified for the latest survey (2005/06) compared with the previous survey carried out in 2004. The New Zealand methodology follows the IPCC Tier 2 approach which accounts for the time lag between consumption and emissions of the chemicals. A summary of calculation methods and emission factors for HFCs is included in table 4.7.1.

Potential emissions for HFCs and PFCs have been calculated using the Tier 1b approach. Due to a lack of disaggregated HFC and PFC data for “refrigeration and mobile air conditioning equipment”, potential emissions from this category have been pro-rated. This has been done using the actual amounts of each HFC and PFC gas reported for refrigeration and mobile air conditioning.

Table 4.7.1 Halocarbon and SF6 calculation methods and emission factors

HFC source Calculation method Emission factor

Aerosols

IPCC GPG 2000 Eqn 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 Eqn 3.44

Top-down approach does not require emission factors

Stationary refrigeration/air conditioning

IPCC GPG 2000 Eqn 3.40

Top-down approach does not require emission factors

Fire protection

IPCC GPG 2000 Eqn 3.51

Bottom-up approach using emission rate of 0.015

SF6 source

Calculation method

Emission factor

Electrical equipment

IPCC GPG 2000 Eqn 3.17

Tier 3 approach based on overall consumption and disposal with country-specific emission factor of 1% and this was supplemented by information from equipment manufacturers and servicing contractors using IPCC default emission factor of 2% (Tier 2b approach)

Other applications

IPCC GPG 2000 Eqn 3.22

No emission factor required as 100% is emitted within two years

Aerosols

Activity data on aerosol usage are provided by the only New Zealand aerosol manufacturer using HFCs and the Aerosol Association of Australia/New Zealand. The New Zealand manufacturer 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 2005 are provided by the sole New Zealand supplier. 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.

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 Ltd, 2006b).

Foam

The survey revealed one New Zealand manufacturer importing HFCs for foam blowing and some of the products are exported overseas for use in refrigeration manufacture. There is insufficient data to estimate the proportion of HFC exported (CRL Energy Ltd, 2006b). The manufacturer started HFC usage 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, so on recommendation by the review team 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, 2001):

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. 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 (which is 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 (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. In most instances these types of systems are assembled and charged on site, although some imported units may already be pre-charged. Self-contained commercial equipment includes frozen food display cases, reach-in refrigerators and freezers, beverage merchandisers and vending machines.

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.

New Zealand uses the Tier 2 top-down approach (IPCC equation 3.44, IPCC, 2001):

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 and assumptions made on the percentage MAC installations. Operation and disposal data are obtained from the industry survey and the New Zealand Transport Registry Centre.

Fire protection

HFCs and PFCs are used as substitutes to halons in portable (streaming) and fixed (flooding) fire protection (fire suppression) 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.

The bottom-up approach is used for estimating emissions from this sub-source category. For each year, an emission rate of 1.5 per cent is applied to the total amount of HFC installed to get annual HFC-227ea emissions.

SF6

Actual and potential emissions of SF6 result primarily from the use of SF6 in electrical switchgear. For the 2005 inventory, emissions were calculated using the Tier 3a approach for the majority of electrical switchgear emissions and supplemented by information from equipment manufacturers and servicing contractors. One company, representing 80–90 per cent of the total SF6 held in equipment, provided sufficient information for the Tier 3a approach. A Tier 2b approach was taken for the rest of the industry. 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 Ltd, 2006b). Potential emissions of SF6 were calculated and included in the 2005 inventory. In 2005, potential emissions were less than actual emissions because there was less SF6 imported in 2005 compared with previous years.

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 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 Ltd. 2006a)

HFC source Uncertainty estimates

Aerosols

± 56% for aerosol imports, ± 60% in locally manufactured aerosols and ± 10% from emissions from MDIs

Solvents

Not occurring

Foam

± 50% in activity level and ± 50% in emission factors.

Stationary refrigeration/air conditioning

± 10% on total HFC/PFC imported and in locally charged equipment, ± 30% in factory charged equipment

± 28% in total HFC/PFC proportion used for charging new commercial refrigeration units

Mobile air conditioning

Combined uncertainty ± 43%

Fire protection

Combined uncertainty ± 32%

SF 6source

Uncertainty estimates

Electrical equipment

Combined uncertainty ± 20%

Other applications

± 30% for tracer usage activity data

± 50% for medical use activity data

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

Emissions from the mixture HFC–245fa/365mfc has been reallocated to the section called “information on additional greenhouse gases” in the CRF tables. A global warming potential for this mixture has not been agreed to by the IPCC and UNFCCC so cannot be included under the foam subcategory.

Potential emissions for HFCs and PFCs have been recalculated for the time-series 1990–2004. Potential emissions for the full time-series were included in the last inventory submission but because of a lack of disaggregated bulk chemical data for the “refrigeration and mobile air conditioning equipment” subcategory, potential emissions for the category were not estimated. This led to an underestimation of total potential emissions. The potential-to-actual HFC and PFC ratio was reported to be less than one. The estimates from “refrigeration and mobile air conditioning equipment” were pro-rated in this inventory submission to improve total potential emissions. This has been calculated using the actual amounts of each HFC and PFC gas reported for “refrigeration and mobile air conditioning equipment”.

4.8 Other (CRF 2G)

4.8.1 Description

Panel products

Activity data are obtained from industry and supplemented with statistics from the Ministry of Agriculture and Forestry. 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 2005 were 1.5 Gg. This is an increase of 0.7 Gg since 1990.