New Zealand’s Greenhouse Gas Inventory 1990–2006

• Executive Summary
• Chapter 1: Introduction
• Chapter 2: Trends in greenhouse gas emissions
• Chapter 3: Energy
• Chapter 4: Industrial processes
• Chapter 5: Solvent and other product use
• Chapter 6: Agriculture
• Chapter 7: Land use, land-use change and forestry (LULUCF)
• Chapter 8: Waste
• Chapter 9: Other
• Chapter 10: Recalculations and improvements
• References
• Annex 1: Key categories
• Annex 2: Methodology and data collection for estimating emissions from fossil fuel combustion
• Annex 3: Detailed methodological information for other sectors
• Annex 4: CO₂ reference approach and comparison with sectoral approach, and relevant information on the national energy balance
• Annex 5: Assessment of completeness and (potential) sources and sinks of greenhouse gas emissions and removals excluded
• Annex 6: Quality assurance and quality control
• Annex 7: Uncertainty analysis (Table 6.1 of the IPCC Good Practice Guidance)
• Annex 8: Supplementary information under Article 7.1 of the Kyoto Protocol

Annex 2: Methodology and data collection for estimating emissions from fossil fuel combustion

New Zealand emission factors are based on GCV (gross calorific value). Energy activity data and emission factors in New Zealand are conventionally reported in gross terms, with some minor exceptions. The convention adopted by New Zealand to convert GCV to NCV (net calorific value) follows the Organisation for Economic Co-operation and Development (OECD) and International Energy Agency (IEA) assumptions:

• NCV = 0.95 x GCV for coal and liquid fuels

• NCV = 0.90 x GCV for gas.

Emission factors for gas, coal, biomass and liquid fuels used in New Zealand are shown in Tables A2.1–A2.3.

Table A2.1 CO₂ emission factors used in the energy sector

	Emission factor (t CO2/TJ)	Emission factor (t C/TJ)
Gas
Maui	52.0 (2006)	14.2 (2006)
Treated	53.5 (2006)	14.6 (2006)
Kapuni LTS	84.1	22.9
Weighted average of Maui and Kapuni treated	52.3 (2006)	14.3 (2006)
Methanol – mixed feed (1990–1994)	62.4	17.0
Methanol – LTS (1990–1994)	84.0	22.9
Kaimiro	65.2	17.8
Ngatoro	53.1	14.5
Rimu	53.7	14.6
Waihapa/Ngaere + Tariki/Ahuroa (1990)*	56.2	15.3
Waihapa/Ngaere + Tariki/Ahuroa (2002)	54.2	14.8
McKee	54.3	14.8
Mangahewa	52.3	14.3
Turangi	55.6	15.2
Pohokura	55.1	15.0
Liquid fuels
Regular petrol (all petrol 1990–1995)	66.2	18.1
Petrol – premium (1996 and onwards)	67.0	18.3
Diesel	69.5	19.0
Aviation fuels	68.1	18.6
Av gas	65.0	17.7
Other	72.9	19.9
Fugitive – flared	65.1	17.8
LPG	60.4	16.5
Heavy fuel oil	73.5	20.0
Light fuel oil	72.0	19.6
Averaged fuel oil	73.0	19.9
Bitumen (asphalt)	76.1	20.8
Biomass
Biogas	101.0	27.5
Wood (industrial)	104.2	28.4
Wood (residential)	104.2	28.4
Coal
All sectors (sub bit)	91.2	24.9
All sectors (bit)	88.8	24.2
All sectors (lignite)	95.2	26.0

* For the years 1991–2001, the emissions factors for these gas streams are interpolated between the 1990 and 2002 values.

Table A2.2 CH₄ emission factors used in the energy sector

	Emission factor t CH4/PJ	Source
Natural gas
Electricity – boilers	2.745	IPCC Tier 2 (Table 1–15) average for natural gas boilers and large gas-fired turbines >3 MW
Commercial	1.08	IPCC Tier 2 (Table 1–19) natural gas boilers
Residential	0.9	IPCC Tier 2 (Table 1–18) gas heaters
Domestic transport (CNG)	567	IPCC Tier 2 (Table 1–43) passenger cars (uncontrolled)
Other stationary (mainly industrial)	1.26	IPCC Tier 2 (Table 1–16) small natural gas boilers
Liquid fuels
Stationary sources
Electricity – residual oil	0.855	IPCC Tier 2 (Table 1–15) residual oil boilers – normal firing
Electricity – distillate oil	0.855	IPCC Tier 2 (Table 1–15) distillate oil boilers – normal firing
Industrial (including refining) – residual oil	2.85	IPCC Tier 2 (Table 1–16) residual oil boilers
Industrial – distillate oil	0.19	IPCC Tier 2 (Table 1–16) distillate oil boilers
Industrial – LPG	1.045	IPCC Tier 2 (Table 1–18) propane/butane furnaces
Commercial – residual oil	1.33	IPCC Tier 2 (Table 1–19) residual oil boilers
Commercial – distillate oil	0.665	IPCC Tier 2 (Table 1–19) distillate oil boilers
Commercial – LPG	1.045	IPCC Tier 2 (Table 1–18) propane/butane furnaces
Residential – distillate oil	0.665	IPCC Tier 2 (Table 1–18) distillate oil furnaces
Residential – LPG	1.045	IPCC Tier 2 (Table 1–18) propane/butane furnaces
Agriculture – stationary	3.8	IPCC Tier 2 (Table 1–49) diesel engines (agriculture)
Mobile sources
LPG	28.5	IPCC Tier 2 (Table 1–44) passenger cars (uncontrolled)
Petrol – 1990 onwards	18.525	IPCC Tier 2 (Table 1–27) passenger cars (uncontrolled – mid-point of average g/MJ)
Diesel – 1990 onwards	3.8	IPCC Tier 2 (Table 1–32) passenger cars (uncontrolled – g/MJ)
Navigation (fuel oil and diesel)	6.65	IPCC Tier 2 (Table 1–48) ocean-going ships
Aviation fuel/kerosene	1.9	IPCC Tier 2 (Table 1–48) jet and turboprop aircraft
Coal
Combustion
Electricity generation	0.665	IPCC Tier 2 (Table 1–15) pulverised bituminous combustion – dry bottom, wall fired
Cement	0.95	IPCC Tier 2 (Table 1–17) cement, lime coal kilns
Lime	0.95	IPCC Tier 2 (Table 1–17) cement, lime coal kilns
Industry	0.665	IPCC Tier 2 (Table 1–16) dry bottom, wall fired coal boilers
Commercial	9.5	IPCC Tier 2 (Table 1–19) coal boilers
Residential	285	IPCC Tier 1 (Table 1–7) coal – residential
Biomass
Wood stoker boilers	14.25	IPCC Tier 2 (Table 1–16) wood stoker boilers
Wood – fireplaces	285	IPCC Tier 1 (Table 1–7) wood – residential
Biogas	1.08	IPCC Tier 2 (Table 1–19) gas boilers

Table A2.3 N₂O emission factors used in the energy sector

	Emission factor t N2O/PJ	Source
Natural gas
Electricity generation	0.09	IPCC Tier 1 (Table 1–8) natural gas – all uses
Commercial	2.07	IPCC Tier 2 (Table 1–19) natural gas boilers
Residential	0.09	IPCC Tier 1 (Table 1–8) natural gas – all uses
Domestic transport (CNG)	0.09	IPCC Tier 1 (Table 1–8) natural gas – all uses
Other stationary (mainly industrial)	0.09	IPCC Tier 1 (Table 1–8) natural gas – all uses
Liquid fuels
Stationary Sources
Electricity – residual oil	0.285	IPCC Tier 2 (Table 1–15) residual oil boilers – normal firing
Electricity – distillate oil	0.38	IPCC Tier 2 (Table 1–15) distillate oil boilers – normal firing
Industrial (including refining) – residual oil	0.285	IPCC Tier 2 (Table 1–16) residual oil boilers
Industrial – distillate oil	0.38	IPCC Tier 2 (Table 1–16) distillate oil boilers
Commercial – residual oil	0.285	IPCC Tier 2 (Table 1–19) residual oil boilers
Commercial – distillate oil	0.38	IPCC Tier 2 (Table 1–19) distillate oil boilers
Residential (all oil)	0.19	IPCC Tier 2 (Table 1–18) furnaces
LPG (all uses)	0.57	IPCC Tier 1 (Table 1–8) oil – all sources except aviation
Agriculture – stationary	28.5	IPCC Tier 2 (Table 1–49) diesel engines – agriculture
Mobile sources
LPG	0.57	IPCC Tier 1 (Table 1–8) oil – all sources except aviation
Petrol	1.425	IPCC Tier 2 (Table 2.7 in GPG (IPCC, 2000)) US gasoline vehicles (uncontrolled)
Diesel	3.705	IPCC Tier 2 (Table 2.7 in GPG (IPCC, 2000)) all US diesel vehicles
Fuel oil (ships)	1.9	IPCC Tier 2 (Table 1–48) ocean going ships
Aviation fuel/kerosene	1.9	IPCC Tier 1 (Table 1–8) oil – aviation
Coal
Electricity generation	1.52	IPCC Tier 2 (Table 1–15) pulverised bituminous combustion – dry bottom, wall fired
Cement	1.33	IPCC Tier 1 (Table 1–8) coal – all uses
Lime	1.33	IPCC Tier 1 (Table 1–8) coal – all uses
Industry	1.52	IPCC Tier 2 (Table 1–16) dry bottom, wall fired coal boilers
Commercial	1.33	IPCC Tier 1 (Table 1–8) coal – all uses
Residential	1.33	IPCC Tier 1 (Table 1–8) coal – all uses
Biomass
Wood (all uses)	3.8	IPCC Tier 1 (Table 1–8) wood/wood waste – all uses
Biogas	2.07	IPCC Tier 2 (Table 1–19) natural gas boilers

A2.1 Emissions from liquid fuels

A2.1.1 Activity data and uncertainties

The Delivery of Petroleum Fuels by Industry Survey conducted by Statistics New Zealand is assumed to have a five per cent uncertainty associated with the sectoral energy allocation although the annual totals are likely to be more certain (Ministry of Economic Development, 2006).

Because the survey is run as a census there is no sampling error. The main sources of non-sample error are:

• Respondent error: Statistics New Zealand makes every effort to confirm values supplied by respondents, and given assurances of accuracy. Statistics New Zealand is bound to accept them. If a discrepancy is discovered at a later date, revised values are supplied at the earliest possible opportunity.

• Processing error: there is always the possibility of error, however, Statistics New Zealand has thorough checking procedures to ensure that the risk of processing errors is minimised.

A2.1.2 Emission factors and uncertainties

Carbon dioxide emission factors are described in Table A2.1. The CO₂ emission factors for oil products are from the New Zealand Refining Company, import data from industry and from Baines (1993⁵). The New Zealand Refining Company estimates the uncertainty in emission factors to be within five per cent (Ministry of Economic Development, 2006).

A2.2 Emissions from solid fuels

A2.2.1 Activity data and uncertainties

The New Zealand Coal Sales Survey conducted by Statistics New Zealand is an ongoing quarterly survey. The survey began in 1981. The survey is a full coverage of the sector and therefore there are no sampling errors. Non-sampling errors in the survey data may result from errors in the sample frame (eg, units with the wrong New Zealand Standard Industrial Classification), respondent error (eg, wrong values supplied) and errors made during processing survey results or non-response imputation. Statistics New Zealand adopts procedures to detect and minimise these potential errors.

The process of dividing coal use between different sectors will introduce uncertainty larger than the uncertainty in total coal sales. Uncertainty is also introduced from the assumption that coal used by sector is an average of the different ranks. These assumptions are thought to introduce an uncertainty of ± 5 per cent (Ministry of Economic Development, 2006).

The sectoral partitioning used for coal was examined in 2003 by officials from the Ministry for the Environment. There was concern in extrapolating sectoral allocations from 1995 to 2002 given some probable changes in sectoral coal usage. However, New Zealand coal industry experts did not consider a survey could be justified because of the difficulty and expense in collating and verifying data from a number of sectors. In addition, the major categories of coal exports, coal used by the residential sector and coal used for steel production and electricity generation are all known accurately and are not affected by the sectoral partitioning.

A2.2.2 Emission factors and uncertainties

The CO₂ emission factors for coal are shown in Table A2.1. The non-CO₂ emission factors are shown in Tables A2.2 and A2.3. The estimated uncertainty in coal emission factors is taken as ± 3 per cent (Ministry of Economic Development, 2006). An uncertainty of ± 2 per cent is used for the sub-bituminous coal used in public electricity generation. All New Zealand values are within 2 per cent of the revised 1996 IPCC default values (IPCC, 1996).

A2.3 Emissions from gaseous fuels

A2.3.1 Activity data and uncertainties

Vector Limited has contracts with large gas users that allow metering errors of ± 2 per cent. Whenever the error between the meter-reading and actual gas supplied exceeds 2 per cent, adjustments are made to the reported quantities of gas supplied. The uncertainty is therefore assumed to have an upper limit of ± 2 per cent (Ministry of Economic Development, 2006).

A2.3.2 Emission factors and uncertainties

As discussed in section 3.2.1.5, New Zealand now uses the Maui and Kapuni gas production data reported in the New Zealand Energy Data File (Ministry of Economic Development, 2007b) to support the calculation of a weighted average annual CO₂ emission factor for natural gas. This average emission factor is applied to a number of categories in the energy sector, such as the “manufacturing industries and construction category”.

The emission factors for the various gas fields in New Zealand are shown in Table A2.1. The emission factors are calculated by averaging daily gas composition data supplied by industry. Taking annual bounds, it is estimated that the uncertainty in the natural gas emission factors is ± 1.7 per cent (Ministry of Economic Development, 2006).

Table A2.4 Variation in CO₂ emission factors for natural gas

Year	Maui (kt CO2 / PJ)	Treated (kt CO2 / PJ)	Average (kt CO2 / PJ)
1990	53.2	52.4	53.1
1991	52.9	52.8	52.9
1992	52.9	52.8	52.8
1993	52.6	52.5	52.6
1994	52.4	52.2	52.4
1995	52.1	52.9	52.2
1996	52.2	52.9	52.3
1997	52.3	52.4	52.3
1998	52.1	52.2	52.1
1999	51.8	52.4	51.9
2000	52.1	52.1	52.1
2001	51.9	52.6	52.0
2002	52.3	52.5	52.3
2003	52.0	52.6	52.1
2004	51.9	53.7	52.2
2005	52.0	52.6	52.1
2006	52.0	53.5	52.3

A2.4 Energy balance for year ended December 2006

Table A2.5 New Zealand energy balance for year ended December 2006 (Ministry of Economic Development, 2007b (PDF, 13 KB)

 

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