Prepared for
Greater Wellington Regional Council
Co No.: N/A
Greater Wellington
Region GHG Emissions
Inventory 2024
10-Dec-2024
Commercial-in-Confidence
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Prepared for – Greater Wellington Regional Council – Co No.: N/A
AECOM
Greater Wellington Region GHG Emissions Inventory 2024
Commercial-in-Confidence
Greater Wellington Region GHG Emissions Inventory 2024
Client: Greater Wellington Regional Council
Co No.: N/A
Prepared by
,
10-Dec-2024
Job No.: 60737611
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Greater Wellington Region GHG Emissions Inventory 2024
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Quality Information
Document
Greater Wellington Region GHG Emissions Inventory 2024
Ref
60737611
Date
10-Dec-2024
Originator
Adam Swithinbank and Renee McKay
Checker/s
Suzanne Lowe
Verifier/s
Anthony Hume
Revision History
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Rev
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Details
Name/Position
Signature
1
10-Dec-2024
Final
Anthony Hume –
Practice Lead,
Sustainability and
Resilience
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Greater Wellington Region GHG Emissions Inventory 2024
Commercial-in-Confidence
Table of Contents
Executive Summary
1
1.0
Introduction
2
2.0
Approach
2
2.1
Data Collection Approach
3
3.0
Greater Wellington Emissions Inventory for FY24
4
3.1
Total Gross Emissions
4
3.2
Emission Sectors and Sources
4
3.3
Transport
6
3.4
Agriculture
6
3.5
Stationary Energy
6
3.6
Industrial Processes and Product Use (IPPU)
7
3.7
Waste
7
3.8
Total Gross Emissions by Greenhouse Gas
8
3.9
Biogenic Emissions
8
4.0
Gross Emissions Changes
9
4.1
Changes Since Baseline Year
9
4.2
Longer Term Changes
10
5.0
Territory Authorities in Greater Wellington
11
5.1
Overview
11
5.2
Wellington City
12
5.3
Hutt City
13
5.4
Upper Hutt City
13
5.5
Porirua City
14
5.6
Kāpiti Coast District
15
5.7
Carterton District
16
5.8
Masterton District
16
5.9
South Wairarapa District
17
6.0
Closing Statement
18
Appendix A
7.0
Appendix A: Additional Inventory Results
C
7.1
FY19 to FY22 Inventory Updates
C
7.2
FY19 to FY24 Inventory Results (Region)
D
7.3
FY19 to FY24 Inventory Results (Territorial Authorities)
E
8.0
Appendix B: Assumptions and Data Sources
M
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1
Executive Summary
This report details the Greenhouse Gas (GHG) emissions within the geographic boundaries of the
Greater Wellington Regional area administered by the Greater Wellington Regional Council. The
emissions have been measured and reported using the production-based Global Protocol methodology
for Community-Scale Greenhouse Gas Emissions Inventory (GPC). This document reports GHG
emissions produced in or resulting from activity during the 2024 government financial year (FY24: 1st
July 2023 to 30th June 2024).
The Greater Wellington Region's most recent complete GHG emissions inventory was produced for the
FY22 financial year. For the FY24 inventory, Greater Wellington Regional Council (GWRC) have
engaged AECOM to produce a streamlined inventory for FY23 and FY24. Data covering approximately
90% of emissions produced in Greater Wellington has been collected and calculated in a manner
consistent with the last inventory. The remaining emission sources have been estimated based on the
FY22 inventory. This is consistent with the approach used for the FY23 Wellington City Emissions
Inventory.
Greenhouse gas emissions are generally reported in this document in units of carbon dioxide equivalent
emissions (CO2e) and are referred to as ‘emissions’.
The GHG emission inventory results for each territorial authority in the Greater Wellington Region are
provided in section
5.0. Net emissions (i.e., including forestry and land-use change) are outside the
scope of this inventory.
Findings of the Greater Wellington Region FY24 inventory include:
•
Total gross emissions in Greater Wellington were
3,725,477 tCO2e.
•
Transport (e.g. emissions resulting from road, marine, and air travel) represented 41% of Greater
Wellington’s total gross emissions, with on-road petrol and diesel consumption accounting for 28%
of total gross emissions.
•
Agriculture represented 33% of Greater Wellington’s total gross emissions. Enteric fermentation
(methane released from the digestive process of cattle and sheep) represented 24% of total gross
emissions.
•
Stationary Energy (e.g., emissions relating to electricity and natural gas consumption) produced
17% of total gross emissions, mainly from grid-connected electricity use and natural gas
consumption.
•
Industrial Processes and Product Use (IPPU) (e.g. emissions from refrigerant gases and
aerosols) represented 5% of Greater Wel ington’s total gross emissions.
•
Waste (e.g.
emissions from landfill and wastewater treatment) was responsible for 4% of Greater
Wellington’s total gross emissions.
Emissions changes since the Baseline Year:
•
Greater Wellington uses FY19 as its baseline year against which to track emissions and progress
towards emission reduction targets.
•
Annual total gross emissions decreased 7% from FY19 to FY24 driven by a reduction in petrol
and diesel fuel use in the Region, a reduction in air travel to and from the region post-COVID-19, a
decrease in landfill emissions due to improvements in landfill gas capture, and a decrease in the
emissions intensity of electricity per unit consumed from the grid.
Long-term emissions changes:
•
Greater Wellington has estimated annual emissions to cover FY01 to FY24.
•
Annual total gross emissions decreased 17% from FY01 to FY24 driven by a reduction in the
number of livestock in the Region, a decrease in landfill emissions due to improvements in landfill
gas capture, and a decrease in the emissions intensity of electricity per unit consumed due to the
greater use of renewable energy generation in Aotearoa New Zealand.
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1.0
Introduction
Greater Wellington Regional Council commissioned AECOM New Zealand Limited (AECOM) to assist
in developing a production-based community-scale Greenhouse Gas (GHG) emissions footprint for the
Greater Wellington regional area for the 2023 and 2024 financial years (FY23 and FY24). The financial
year used here covers 1st July to 30th June (Government financial year). The study boundary
incorporates the jurisdiction of the Greater Wellington Regional Council. The Greater Wellington Region
is hereafter referred to as Greater Wellington for ease.
The purpose of the GHG emissions inventory for FY24 is to estimate the relative scale of GHG
emissions produced in the Greater Wellington area and the relative contribution of different emission
sources to Greater Wellington’s total emissions. The results of this inventory can be used to assess
trends and changes in the emissions produced in Greater Wellington over time.
2.0
Approach
The method used to calculate emissions follows the Global Protocol for Community-Scale Greenhouse
Gas Emissions Inventory v1.1 (GPC) guidelines, published by the World Resources Institute (WRI) in
2021
. The GPC methodology follows a production-based approach and allocates emissions to
industries rather than final users. Production-based approaches exclude global emissions relating to
consumption (i.e., embodied emissions relating to products produced elsewhere but consumed within
the geographic area, such as imported food products, cars, phones, clothes, etc.).
This emissions footprint assesses both direct and indirect emissions sources. Direct emissions are
production-based and occur within the geographic area (Scope 1 in the GPC reporting framework).
Indirect emissions are produced outside the geographic boundary (Scope 2 and 3) but are allocated to
the consumption location. An example of indirect emissions are those associated with electricity
consumption supplied by the national grid (Scope 2). All other indirect emissions, such as cross-
boundary travel (e.g., flights) and energy transmission and distribution losses, are Scope 3.
The FY24 GHG emission inventory calculation method differs from previous GHG emission inventories
completed for Greater Wellington by AECOM. Data for this inventory has been collected for a selected
list of emission sources covering approximately 90% of Greater Wellington’s emissions. Selected
emission sources were calculated as per previous inventories, and the remaining sources have been
estimated based on the FY22 (1st July 2021 to 30th June 2022) inventory, applying a population change
adjustment where appropriate.
The inventory is based on data and reporting guidance available at the time of calculation, using
reasonable assumptions in line with the GPC reporting guidance, and may need to be updated in the
future to account for changes in data availability or reporting guidance.
The emission factors and Global Warming Potential values (GWPs) used in these calculations use
those from the Ministry for the Environment (MfE) National Emissions Inventory (2024) and IPCC Sixth
Assessment report (2021). This represents the best practice for reporting GHG emissions at the
regional level. The previously published FY19 to FY22 inventory results have been updated using these
emission factors to allow direct comparison across this timeframe.
Greenhouse gas emissions are generally reported in this document in Carbon Dioxide Equivalent
Emissions (CO2e) units and are referred to as ‘emissions’.
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2.1
Data Collection Approach
The data collection approach for the FY24 GHG emissions inventory is shown i
n Figure 1. This figure
details for each emission source whether data has been collected, adjusted based on the population
change between FY22 and FY24, or not adjusted from FY22. Data sources where data was collected
represent approximately 90% of Greater Wellington’s total gross emissions.
Figure 1
Data Collection Approach for each Emission Source
A description of the method used, and major assumptions made during data collection and analysis
have been detailed within
Appendix B – Assumptions.
Considering the uncertainty associated with the results is essential, particularly given the different
datasets used. At the national level, in New Zealand’s Greenhouse Gas Inventory, the estimate of gross
emissions uncertainty was ±8.8% (MfE, 2024).
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3.0
Greater Wellington Emissions Inventory for FY24
3.1
Total Gross Emissions
Total emissions can be reported as both gross emissions (excluding forestry harvesting and
sequestration) and net emissions (including forestry harvesting and sequestration). This report solely
reports gross emissions at the request of GWRC. This report focussed on FY24, however the annual
emissions inventory for FY23 has also been calculated and results are presented in Appendix A.
During FY24, Greater Wellington’s
total gross emissions amounted to
3,725,477 tCO2e. Transport
and Agriculture emissions are Greater Wellington's most significant contributors to total gross
emissions. Sectio
n 4.0 details the change in Greater Wellington’s gross emissions since the baseline
year (FY19) as well as changes over the longer term (since FY01).
The population of Greater Wellington in FY24 was approximately 550,500 people, resulting in per capita
gross emissions of 6.8 tCO2e/person.
3.2
Emission Sectors and Sources
Figure 2 and
Table 1 illustrate the six sectors that comprise the emissions inventory
. Table 2 shows the
breakdown of Greater Wel ington’s emissions by source. A discussion of emissions from each sector
follows in Sections 3.3 through Section 3.7.
Due to rounding, there may be some discrepancies between totals and the sum of results in the tables.
Figure 2: Greater Wellington’s FY24 total gross GHG emissions split by sector (tCO2e)
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Table 1
Greater Wellington FY24 emissions by sector
Percentage of
Emissions Source
Emissions (tCO2e)
Total Gross
Emissions (%)
Transport
1,544,113
41.4%
Agriculture
1,213,503
32.6%
Stationary Energy
642,422
17.2%
Industrial Processes and Product Use (IPPU)
182,768
4.9%
Waste
142,670
3.8%
Total Gross Emissions
3,725,477
100%
Table 2
Greater Wellington FY24 emissions by source
Percentage of
Emissions Source
Emissions (tCO2e)
Total Gross
Emissions (%)
On-Road Transport
1,025,445
28%
Enteric Fermentation from Livestock
901,402
24%
Other Agriculture Emissions
312,101
8%
Electricity Consumption (including transmission and
298,126
8%
distribution losses)
Natural Gas (including transmission and distribution
230,165
6%
losses)
Air Travel
222,599
6%
Marine Transport
184,607
5%
Refrigerant and Air Conditioning Gases (IPPU)
171,548
5%
Solid Waste
113,806
3%
Off-Road Transport
105,069
3%
Stationary Diesel and Petrol Use
56,998
2%
LPG (Stationary Use)
36,331
1%
Wastewater Treatment (incl. household septic
28,864
1%
tanks)
Other Stationary Energy
20,803
1%
Other Industrial Gases (IPPU)
11,220
<1%
Rail
6,393
<1%
Total Gross Emissions
3,725,477
100%
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3.3
Transport
Transport was the highest emitting sector in Greater Wellington in FY24, producing 1,544,113 tCO2e
(41% of total gross emissions). Petrol and diesel use represented 73% of the Transport emissions in
Greater Wellington (630,739 tCO2e and 494,567 tCO2e, respectively).
Diesel and petrol transport emissions are split into on-road and off-road use. On-road transport,
consisting of all standard road vehicles (cars, trucks, buses, etc.), was responsible for 66% of Transport
emissions and 28% of total gross emissions. Off-road transport, consisting of all fuel used for off-road
vehicles (agricultural tractors and vehicles, forklifts, etc.), was responsible for 7% of Transport
emissions.
The next largest emission source in the transport sector was air travel, contributing 14% of the sector’s
emissions and 6% of total gross emissions. Marine Transport emissions (including marine freight, cruise
ships, inter-island ferries, and local ferries) produced 12% of Transport emissions and 5% of total gross
emissions. Cruise ship emissions have been included in Greater Wellington’s emissions inventory for
the first time using a method developed by AECOM for Wellington City Council. Cruise ship emissions
represented 2% of Greater Wel ington’s emissions inventory in FY24.
Rail emissions produced <1% of the sector’s emissions. Rail emissions were calculated for both rail
freight and public commuter electric trains.
Cross-boundary journey emissions (e.g., for air travel, marine transport, and rail) are based on the fuel
consumed during journeys to and from Greater Wellington, with emissions split equally between the
origin and destination locations. It is acknowledged that marine transport and air travel hubs in Greater
Wellington support an area wider than the immediate Wellington Region.
3.4
Agriculture
Agricultural livestock and crop farming emissions were responsible for 33% of Greater Wellington’s total
gross emissions in FY24. Enteric fermentation represented 74% of agricultural emissions. Enteric
fermentation is the methane (CH4) released from the digestive process of cattle and sheep. The second
highest source of agricultural emissions was produced from nitrous oxide (N2O) released by
unmanaged manure from grazing animals on pasture.
Livestock was responsible for the majority of the Agriculture sector’s GHG emissions. Sheep accounted
for 45% of agricultural emissions in FY24 while accounting for 84% of the total number of livestock in
Greater Wellington. Dairy and non-dairy cattle accounted for 23% and 24% of agricultural emissions in
Greater Wellington, respectively, despite representing 15% of the total number of livestock due to their
more significant annual GHG emissions impact per head compared to sheep. Fertiliser use and other
livestock (e.g. pigs and deer) represented the remaining 4% of agricultural emissions.
Agriculture continues to be the largest contributor to the total gross emissions for Masterton, South
Wairarapa, and Carterton districts.
It is important to note that these agricultural results do not include emissions related to the consumption
of agricultural products supplied to Greater Wellington as per the GPC methodology.
3.5
Stationary Energy
Stationary Energy was the third-highest emission source in FY24, producing 17% of Greater
Wel ington’s total gross emissions.
Electricity consumption (including transmission and distribution losses) accounted for 46% of Stationary
Energy emissions and 8% of Greater Wellington’s total gross emissions in FY24. Electricity
consumption emissions depend upon the amount of consumption (in kWh) and the emissions intensity
of the national grid (tCO2e/kWh), which changes annually. The emissions intensity of the grid was
relatively low in FY24 relative to recent years but higher than in FY23.
Natural gas consumption, including transmission and distribution losses from the reticulated gas
system, accounted for 36% of Stationary Energy emissions (6% of total gross emissions).
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The remaining stationary energy emissions were produced by LPG, petrol, diesel, coal, biofuels, and
landfill biogas used for energy generation.
Biogenic CO2 emissions from biofuels and landfill gas flaring have not been included in these totals as
per GPC guidance and are reported separately in section
3.9.
3.6
Industrial Processes and Product Use (IPPU)
IPPU includes emissions associated with the consumption of industrial products and synthetic gases
containing GHGs for refrigerants, foam blowing, fire extinguishers, aerosols, metered dose inhalers and
Sulphur Hexafluoride for electrical insulation and equipment production. No known industrial processes
(as defined in the GPC requirements) are present in Greater Wellington (e.g., aluminium manufacture).
IPPU contributed 5% to total gross emissions in FY24. The most significant contributor to IPPU
emissions was refrigerant gases, which produced 94% of IPPU emissions.
IPPU emissions do not include energy use for industrial manufacturing, which is included in the relevant
Stationary Energy sub-category (e.g., coal, electricity and/or petrol and diesel). These emissions are
based on nationally reported IPPU emissions and apportioned based on population due to the difficulty
of allocating emissions to geographic locations.
3.7
Waste
Waste processed in Greater Wellington (solid waste, wastewater, and compost) comprised 4% of
Greater Wellington’s total gross emissions in FY24.
Solid waste produced 77% of total Waste emissions. Solid waste emissions include emissions from
open (operating) landfill sites (32,091 tCO2e) and closed landfill sites (77,373 tCO2e). Both open and
closed landfills emit landfill (methane) gas from the breakdown of organic materials disposed of in the
landfill for many years after waste enters the landfill. The reported emissions here relate to the
emissions produced in FY24 from all waste produced in Greater Wellington that has entered landfill
sites over the last 50+ years, as per the GPC guidance for region-level reporting. This approach differs
from other reporting methods, which estimate the future emissions related to waste entering the landfill
in the reporting year.
Open landfill emissions relate to emissions from waste produced in Greater Wellington and sent to
landfill sites accepting waste in the most recent reporting year. Some landfill sites in Greater Wellington
have landfill gas capture systems that reduce emissions released into the atmosphere. Landfill gas
capture has improved in recent years, contributing to reduced annual solid waste emissions. Owing to
the lack of gas capture systems at closed landfill sites, emissions from closed landfill sites were greater
than those from currently open sites. It is noted that the annual emissions from closed landfill sites will
continue to decrease over time as no new waste enters these sites.
Wastewater treatment (treatment plants and individual septic tanks) accounted for 20% of total Waste
emissions. Most households in Greater Wellington (88%) are connected to wastewater treatment
plants, which resulted in emissions of 21,338 tCO2e from wastewater treatment and processing.
Households not connected to wastewater treatment plants (i.e., using individual septic tanks) produced
7,526 tCO2e in wastewater emissions. Due to methane production, septic tanks have a higher
emissions intensity per quantity of wastewater than the wastewater treatment plants in Greater
Wellington.
Waste diverted from landfill for commercial composting in Greater Wellington includes horticultural,
animal waste products, green waste, bark, and sawdust. Composting this organic waste produces lower
emissions than if sent to a landfill. Diverted and composted organic waste produced 4,343 tCO2e in
FY24.
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3.8
Total Gross Emissions by Greenhouse Gas
Each greenhouse gas has a different level of impact on climate change, which is accounted for when
converting quantities of each gas into units of carbon dioxide equivalent (CO2e). This assessment uses
conversion figures (i.e. global warming potentials with climate change feedback) from the IPCC 6th
Assessment Report (2021). Other/Unknown gases are either industrial gases (e.g. SF6), or where
calculation of the carbon dioxide equivalent emissions was possible however it was difficult to
determine the breakdown of these emissions into the respective greenhouse gases.
Table 3: Greater Wellington’s total gross emissions by greenhouse gas
Global Warming
Greenhouse Gas
Tonnes
Tonnes of CO
Potential (GWP)
2e
Carbon Dioxide (CO2)
2,060,412
1
2,060,412
Biogenic Methane (CH4)
39,306
27.2
1,069,134
Non-biogenic Methane (CH4)
1,100
29.8
32,790
Nitrous Oxide (N2O)
1,177
273
321,412
Other / Unknown Gas (in CO2e)
241,728
1
241,728
Total
2,343,725
-
3,725,477
3.9
Biogenic Emissions
Biogenic CO2 emissions result from the combustion of biomass materials that store and sequester CO2,
including materials used to make biofuels (e.g., trees, crops, vegetable oils, or animal fats). Biogenic
CO2 emissions from plants and animals are excluded from gross emissions as they are part of the
natural carbon cycle.
Table 4: Biogenic Carbon Dioxide in Greater Wellington in FY24 (Excluded from gross emissions)
Biogenic Carbon Dioxide (CO2) (Excluded from gross emissions)
Biofuel
127,017
tCO2
Landfill Gas (Biogas)
56,146
tCO2
Total Biogenic CO2
183,163
tCO2
Biogenic CH4 emissions (e.g., produced by farmed cattle via enteric fermentation) are included in gross
emissions due to their relatively large impact on global warming relative to biogenic CO2. Biogenic
methane represented 2% of the total gross tonnage of GHG emissions in Greater Wellington but 30% of
total gross GHG emissions when expressed in CO2e. This is due to the relatively higher global warming
impact of methane per tonne compared to carbon dioxide
. Table 5 shows biogenic methane in Greater
Wellington in FY24 in tonnes of methane by emission source.
Table 5: Biogenic Methane in Greater Wellington in FY24 (Included in gross emissions)
Biogenic Methane (CH4) (Included in gross emissions)
Enteric Fermentation
33,140
tCH4
Landfill Gas
4,016
tCH4
Manure Management
1,126
tCH4
Wastewater Treatment
530
tCH4
Biofuel
398
tCH4
Composting (Green Waste)
97
tCH4
Total Biogenic CH4
39,306
tCH4
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4.0
Gross Emissions Changes
This section presents changes and trends in emissions since Greater Wel ington’s baseline year (FY19)
and longer-term changes since the FY01 financial year (2000/01).
To calculate the FY23 and FY24 inventory years for this inventory, updated emission factors and global
warming potential values since the last published inventory for Greater Wellington (June 2023) have
been used. To enable direct comparison of annual emissions since the baseline year, the FY19 to FY22
inventory years have been updated using the same emission factors and global warming potential
values as for FY23 and FY24. These changes alongside the inclusion of cruise ship emissions to the
FY19 to FY22 inventory, are explained in detail in Section 7.1.
The updated FY19 to FY22 inventory results presented here differ from those previously published by
Greater Wellington, particularly for agriculture, waste, and IPPU. The results presented in this report
supersede previously published inventory results.
4.1
Changes Since Baseline Year
Greater Wellington uses FY19 as its baseline year against which to track emissions and progress
towards emission reduction targets. Annual total gross emissions decreased by 7% from FY19 to FY24.
This decrease was driven by reduced Transport, Waste, and Stationary Energy emissions.
Transport emissions decreased 8% between FY19 and FY24, primarily due to a reduction of on-road
transport emissions (-7%) and air travel emissions (-15%). The number of international flights in FY24
was still below pre-COVID levels for air travel.
Stationary Energy emissions have also decreased (-4%), with electricity emissions lower than in FY19.
Despite an increase in electricity consumption there was a reduction in the emission intensity of
electricity per unit generated. A greater proportion of grid electricity generation from renewable energy
sources during this period has reduced the emissions intensity of electricity consumption during the
reporting period.
Waste emissions have also reduced by 28% during this time, primarily due to improved gas capture
methods at open landfill sites and a gradual reduction in emissions from closed landfill sites.
Industrial Processes and Product Use (IPPU) emissions have increased by 2%, following nationwide
trends, particularly because of an increase in the usage of refrigerant and air conditioning gases.
4,000,000
3,500,000
3,000,000
2,500,000
e 2
2,000,000
tCO
1,500,000
1,000,000
500,000
-
FY19
FY20
FY21
FY22
FY23
FY24
Stationary Energy
Transport
Waste
IPPU
Agriculture
Figure 3
Change in Greater Wellington total gross emissions from FY19 to FY24
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4.2
Longer Term Changes
Greater Wellington has estimated annual emissions each year from FY01 to FY24. Before the FY19
year, differences in the methodology and data used to calculate emissions exist; however, these
differences do not prevent the ability to assess trends in emissions over this period.
Annual total gross emissions have decreased by 17% from FY01 to FY24. The decrease has been
driven by reductions in Waste (-65%), Stationary Energy (-28%), and Agriculture emissions (-29%). Of
note are emissions reductions due to the improvements to landfill emission capture, improvements in
the emissions intensity of the electricity grid, and a reduction in livestock numbers. These reductions
were partially balanced by increased Transport fuel emissions (+10%) and IPPU emissions (+486%).
As the population has increased (by 25%), and gross emissions have decreased (by 17%), per capita
gross emissions have reduced by 33%.
5,000,000
4,500,000
4,000,000
3,500,000
3,000,000
e 2 2,500,000
tCO
2,000,000
1,500,000
1,000,000
500,000
-
Stationary Energy
Transportation
Waste
IPPU
Agriculture
Figure 4
Change in Greater Wellington total gross emissions from FY01 to FY24
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5.0
Territory Authorities in Greater Wellington
5.1
Overview
The Greater Wellington regional area contains eight territorial authorities, comprised of Wellington City,
Porirua City, Kāpiti Coast District, Hutt City, Upper Hutt City, Masterton District, Carterton District, and
South Wairarapa District. These areas are those under the jurisdiction of the respective city or district
council.
Using the GPC methodology, emissions are predominantly allocated to where they are produced (e.g.
on-road transport and agriculture), with grid electricity generation emissions allocated to where the
electricity is consumed. For cross-boundary transport emissions (e.g. air travel, marine freight, and
cruise ships), emissions are calculated for each journey and allocated equally between the origin and
destination location. Emissions related to air travel to/from Wellington airport, marine freight, and inter-
island ferries to/from Wellington have been allocated across the region based on the relative population
size of each territorial authority, meaning that all territorial authorities have some air travel and marine
transport emissions. Cruise ship emissions related to travel to/from CentrePort have been solely
allocated to Wellington City.
Figure 5 shows total gross emissions for the territorial authorities in the Greater Wellington Region, split
by sector.
Wellington City is the territorial authority with the highest annual emissions in the region, representing
27% of Greater Wel ington’s total gross emissions. Transport and Stationary Energy represent most of
Wel ington City’s emissions inventory, with the remaining smaller proportion produced by IPPU, Waste,
and Agriculture. Wellington City’s emissions profile generally reflects all territorial authorities in Greater
Wellington except the three territorial authorities in Wairarapa.
The GHG emissions profile of the three Wairarapa districts (Carterton, Masterton, and South
Wairarapa) are dominated by Agricultural emissions, mainly from livestock, with relatively small
Transport and Stationary Energy emissions.
1,000,000
800,000
e
600,000
2
tCO
400,000
200,000
-
Wellington Masterton
Hutt City
South
Kāpiti Coast Carterton Porirua City Upper Hutt
City
District
Wairarapa
District
District
City
District
Stationary Energy
Transportation
Waste
IPPU
Agriculture
Figure 5 Total gross emissions by territorial authority in the Greater Wellington region FY24 (tCO2e).
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This section presents an overview of the FY24 emissions inventory for each territorial authority area in
Greater Wellington. A detailed breakdown of each territorial authority’s FY24 emissions inventory and
gross emissions changes since FY19 is provided in section 7.3.
The full emissions inventory results for each territorial authority have been supplied separately covering
the FY23 and FY24 reporting years and the updated FY19-FY22 reporting years which supersede
those previously published (as described in section 7.3).
Due to rounding, there may be some discrepancies between totals and the sum of results in the tables.
5.2
Wellington City
Table 6
Wellington City FY24 emissions by sector (tCO2e)
FY24 Emissions
Percentage of Total
Emissions Source
(tCO2e)
Gross Emissions (%)
Transport
567,518
56%
Stationary Energy
314,775
31%
Industrial Processes and Product Use (IPPU)
72,048
7%
Waste
44,560
4%
Agriculture
11,491
1%
Total Gross Emissions
1,010,392
100%
During FY24, Wellington City's total gross emissions were 1,010,392 tCO2e. Transport and Stationary
Energy emissions were the City’s most significant contributors to total gross emissions.
Transport was the highest emitting sector estimated in Wellington City, producing 567,518 tCO2e (56%
of total gross emissions). Petrol and diesel use represented 65% of the Transport emissions in
Wellington City (213,791 tCO2e and 155,197 tCO2e, respectively). Diesel and petrol transport emissions
are split into on-road and off-road use. On-road transport, consisting of all standard road vehicles (cars,
trucks, buses, etc.), was responsible for 60% of Transport emissions and 33% of total Wellington City
gross emissions. Cruise ship emissions have been included in Greater Wel ington’s emissions inventory
for the first time using a method developed by AECOM for Wellington City Council. Cruise ship
emissions represented 6% of Wellington City’s emissions inventory in FY24.
The next largest emission source in Wellington City was Stationary Energy, contributing 31% to the
city’s total gross emissions. Electricity consumption (including transmission and distribution losses)
accounted for 48% of Stationary Energy emissions and 15% of Wel ington City’s total gross emissions.
In contrast, natural gas consumption, including transmission and distribution losses from the reticulated
gas system, accounted for 40% of Stationary Energy emissions (12% of total gross emissions).
Electricity consumption emissions depend upon the amount of consumption (in kWh) and the emissions
intensity of the national grid (tCO2e/kWh), which changes annually. The emissions intensity of the grid
was relatively low in FY24 compared to recent years but higher than in FY23.
When combined, estimated emissions from Waste (e.g., from landfill and wastewater treatment),
Industrial Processes and Product Use (e.g., from refrigerant gases and aerosols), and Agriculture
accounted for 13% of Wellington City’s total gross emissions.
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5.3
Hutt City
Table 7
Hutt City FY24 emissions by sector (tCO2e)
FY24 Emissions
Percentage of Total
Emissions Source
(tCO2e)
Gross Emissions (%)
Transport
303,487
59%
Stationary Energy
142,775
28%
Industrial Processes and Product Use (IPPU)
37,781
7%
Waste
28,016
5%
Agriculture
2,603
<1%
Total Gross Emissions
514,662
100%
During FY24, Hutt City's total gross emissions were 514,662 tCO2e. Transport and Stationary Energy
emissions were the city’s most significant contributors to total gross emissions.
Transport was the highest emitting sector estimated in Hutt City, producing 303,487 tCO2e (59% of total
gross emissions). Petrol and diesel use represented 77% of the Transport emissions in Hutt City
(135,859 tCO2e and 98,624 tCO2e, respectively).
Diesel and petrol transport emissions are split into on-road and off-road use. On-road transport,
consisting of all standard road vehicles (cars, trucks, buses, etc.), was responsible for 71% of Transport
emissions and 42% of total gross emissions.
The next largest emission source in Hutt City was Stationary Energy, contributing 28% to the city’s total
gross emissions. Electricity consumption (including transmission and distribution losses) accounted for
49% of Stationary Energy emissions and 14% of Hutt City’s total gross emissions, while natural gas
consumption, including transmission and distribution losses from the reticulated gas system, accounted
for 35% of Stationary Energy emissions (10% of total gross emissions). Electricity consumption
emissions depend upon the amount of consumption (in kWh) and the emissions intensity of the national
grid (tCO2e/kWh), which changes annually. The emissions intensity of the grid was relatively low in
FY24 compared to recent years but higher than in FY23.
When combined, estimated emissions from Waste (e.g., from landfill and wastewater treatment),
Industrial Processes and Product Use (e.g., refrigerant gases and aerosols), and Agriculture accounted
for 13% of Hutt City’s total gross emissions.
5.4
Upper Hutt City
Table 8
Upper Hutt City FY24 emissions by sector (tCO2e)
FY24 Emissions
Percentage of Total
Emissions Source
(tCO2e)
Gross Emissions (%)
Transport
129,474
62%
Stationary Energy
44,560
21%
Industrial Processes and Product Use (IPPU)
15,973
8%
Agriculture
10,787
5%
Waste
6,655
3%
Total Gross Emissions
207,449
100%
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During FY24, Upper Hutt City total gross emissions amounted to 207,449 tCO2e. Transport emissions
were Upper Hutt City’s most significant contributor to total gross emissions, followed by Stationary
Energy.
Transport was the highest emitting sector estimated in Upper Hutt City, producing 129,474 tCO2e (62%
of total gross emissions). Petrol and diesel use represented 77% of the Transport emissions in Upper
Hutt City (57,455 tCO2e and 41,708 tCO2e respectively). Diesel and petrol transport emissions are split
into on-road and off-road use. On-road transport, consisting of all standard road vehicles (cars, trucks,
buses, etc.), was responsible for 70% of Transport emissions and 44% of total gross emissions.
The next largest emission source in Upper Hutt City was Stationary Energy, contributing 21% to the
city’s total gross emissions. Natural gas consumption, including transmission and distribution losses
from the reticulated gas system, accounted for 48% of Stationary Energy emissions (10% of total gross
emissions), while electricity consumption (including transmission and distribution losses) accounted for
31% of Stationary Energy emissions and 7% of Upper Hutt’s total gross emissions. Electricity
consumption emissions depend upon the amount of consumption (in kWh) and the emissions intensity
of the national grid (tCO2e/kWh), which changes annually. The emissions intensity of the grid was
relatively low in FY24 compared to recent years but higher than in FY23.
When combined, estimated emissions from Waste (e.g., from landfill and wastewater treatment),
Industrial Processes and Product Use (e.g., refrigerant gases and aerosols), and Agriculture accounted
for 16% of Upper Hutt’s total gross emissions.
5.5
Porirua City
Table 9
Porirua City FY24 emissions by sector (tCO2e)
FY24 Emissions
Percentage of Total
Emissions Source
(tCO2e)
Gross Emissions (%)
Transport
174,527
67%
Stationary Energy
41,224
16%
Industrial Processes and Product Use (IPPU)
20,631
8%
Agriculture
12,888
5%
Waste
12,298
5%
Total Gross Emissions
261,568
100%
During FY24, Porirua City total gross emissions were 261,568 tCO2e. Transport emissions were the
most significant contributors to total gross emissions, followed by Stationary Energy.
Transport produced 174,527 tCO2e in FY24 (67% of total gross emissions). Petrol and diesel use
represented 78% of the Transport emissions in Porirua City (78,903 tCO2e and 57,278 tCO2e
respectively). Diesel and petrol transport emissions are split into on-road and off-road use. On-road
transport, consisting of all standard road vehicles (cars, trucks, buses, etc.), was responsible for 71% of
Transport emissions and 48% of total gross emissions.
The next largest emission source in Porirua City was Stationary Energy, contributing to 16% of the city’s
total gross emissions. Electricity consumption (including transmission and distribution losses)
accounted for 17% of Stationary Energy emissions and 3% of Porirua’s total gross emissions. In
comparison, natural gas consumption, including transmission and distribution losses from the
reticulated gas systems, accounted for 53% of Stationary Energy emissions (8% of total gross
emissions). Electricity consumption emissions depend upon the amount of consumption (in kWh) and
the emissions intensity of the national grid (tCO2e/kWh), which changes annually. The emissions
intensity of the grid was relatively low in FY24 compared to recent years but higher than in FY23.
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When combined, estimated emissions from Waste (e.g., from landfill and wastewater treatment),
Industrial Processes and Product Use (e.g., refrigerant gases and aerosols), and Agriculture accounted
for 18% of Porirua City’s total gross emissions.
5.6
Kāpiti Coast District
Table 10
Kāpiti Coast District FY24 emissions by sector (tCO2e)
FY24 Emissions
Percentage of Total
Emissions Source
(tCO2e)
Gross Emissions (%)
Transport
179,733
57%
Stationary Energy
50,300
16%
Agriculture
35,474
11%
Waste
30,332
10%
Industrial Processes and Product Use (IPPU)
19,336
6%
Total Gross Emissions
315,176
100%
During FY24, Kāpiti Coast total gross emissions amounted to 315,176 tCO2e. Transport and Stationary
Energy emissions were Kāpiti Coast’s most significant contributors to total gross emissions.
Transport was the highest emitting sector estimated in Kāpiti Coast, producing 179,733 tCO2e (57% of
total gross emissions). Petrol and diesel use represented 78% of the Transport emissions in Kāpiti
Coast (81,451 tCO2e and 59,128 tCO2e respectively).
Petrol and diesel transport emissions are split into on-road and off-road use. On-road transport,
consisting of all standard road vehicles (cars, trucks, buses, etc.), was responsible for 72% of Transport
emissions and 41% of total gross emissions.
The next largest emission source in Kāpiti Coast was Stationary Energy, contributing to 16% of the
district’s total gross emissions. Electricity consumption (including transmission and distribution losses)
accounted for 53% of Stationary Energy emissions and 9% of Kāpiti Coast’s total gross emissions.
Electricity consumption emissions depend upon the amount of consumption (in kWh) and the emissions
intensity of the national grid (tCO2e/kWh), which changes annually. The emissions intensity of the grid
was relatively low in FY24 compared to recent years but higher than in FY23. Natural gas consumption,
including transmission and distribution losses from the reticulated gas system, accounted for 22% of
Stationary Energy emissions.
When combined, estimated emissions from Waste (e.g., from landfill and wastewater treatment),
Industrial Processes and Product Use (e.g., from refrigerant gases and aerosols), and Agriculture
accounted for 27% of Kāpiti Coast’s total gross emissions.
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5.7
Carterton District
Table 11
Carterton District FY24 emissions by sector (tCO2e)
FY24 Emissions
Percentage of Total
Emissions Source
(tCO2e)
Gross Emissions (%)
Agriculture
212,274
77%
Transport
45,767
17%
Stationary Energy
12,212
4 %
Waste
3,541
1%
Industrial Processes and Product Use (IPPU)
3,422
1%
Total Gross Emissions
277,216
100%
During FY24, Carterton City total gross emissions amounted to 277,216 tCO2e. Agriculture emissions
were Carterton’s most significant contributors to total gross emissions, followed by Transport.
Agriculture produced 212,274 tCO2e in FY24 (77% of total gross emissions). Livestock Enteric
Fermentation represented 74% of the Agriculture emissions in Carterton (156,718 tCO2e). Unmanaged
Manure on Pasture accounted for 12% (25,533 tCO2e) with Agricultural Leaching and Deposition
responsible for 8% (17,606 tCO2e) Sheep and cattle represented most agricultural emissions in
Carterton.
Carterton's next largest emission source was Transport, producing 45,767 tCO2e (17% of total gross
emissions). Petrol and diesel use represented 82% of the Transport emissions in Carterton (16,200
tCO2e and 21,154 tCO2e respectively).
Total estimated emissions from Waste (e.g. emissions from landfill and wastewater treatment),
Industrial Processes and Product Use (e.g. emissions from refrigerant gases and aerosols), and
Stationary Energy accounted for 7% of Carterton’s total gross emissions.
5.8
Masterton District
Table 12
Masterton District FY24 emissions by sector (tCO2e)
FY24 Emissions
Percentage of Total
Emissions Source
(tCO2e)
Gross Emissions (%)
Agriculture
514,659
79%
Transport
89,792
14%
Stationary Energy
26,682
4%
Waste
12,459
2%
Industrial Processes and Product Use (IPPU)
9,651
1%
Total Gross Emissions
653,243
100%
During FY24, Masterton district total gross emissions amounted to 653,243
tCO2e. Agriculture
emissions were Masterton’s most significant contributors to total gross emissions, followed by
Transport.
Agriculture produced 514,659 tCO2e in FY24 (79% of total gross emissions). Livestock Enteric
Fermentation represented 74% of the Agriculture emissions in Masterton (383,272 tCO2e). Unmanaged
Manure on Pasture accounted for 13% (65,359 tCO2e), with Agricultural Leaching and Deposition
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responsible for 9% (44,372 tCO2e). Sheep and cattle represented most agricultural emissions in
Masterton.
Masterton's next largest emission source was Transport, producing 89,792 tCO2e (14% of total gross
emissions). On-road petrol and diesel use represented 63% of Transport emissions in Masterton
(56,835 tCO2e).
Total estimated emissions from Waste (e.g. emissions from landfill and wastewater treatment),
Stationary Energy, and Industrial Processes and Product Use (e.g. emissions from refrigerant gases
and aerosols) accounted for 7% of Masterton’s total gross emissions.
5.9
South Wairarapa District
Table 13
South Wairarapa District FY24 emissions by sector (tCO2e)
FY24 Emissions
Percentage of Total
Emissions Source
(tCO2e)
Gross Emissions (%)
Agriculture
413,327
85%
Transport
53,814
11%
Stationary Energy
9,894
2%
Waste
4,809
1%
Industrial Processes and Product Use (IPPU)
3,926
<1%
Total Gross Emissions
485,770
100%
During FY24, South Wairarapa’s total gross emissions were 485,770 tCO2e. Agriculture emissions are
by far the most significant contributors to total gross emissions.
Agriculture produced 413,327 tCO2e in FY24 (85% of total gross emissions). Livestock Enteric
Fermentation represented 74% of the Agriculture emissions in South Wairarapa (306,242 tCO2e).
Unmanaged Manure on Pasture accounted for 12% (48,684 tCO2e) with Agricultural Leaching and
Deposition responsible for 8% (33,451 tCO2e). Sheep and cattle represented the vast majority of
agricultural emissions in South Wairarapa.
The next largest emission source in South Wairarapa was Transport, producing a total of 53,814 tCO2e
(11% of total gross emissions). Petrol and diesel use represented 83% of the Transport emissions (19,
312 tCO2e and 25,217 tCO2e respectively).
Total estimated emissions from Waste (e.g. emissions from landfill and wastewater treatment),
Industrial Processes and Product Use (e.g. emissions from refrigerant gases and aerosols), and
Stationary Energy accounted for 4% of South Wairarapa’s total gross emissions.
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6.0
Closing Statement
Greater Wellington’s GHG emissions inventory provides information for decision-making and action by
the council, Greater Wellington stakeholders, city and district councils, and the wider community. We
encourage the council to use the results of this study to update current climate action plans, set and
measure emission reduction targets, and track changes in emissions over time.
The emissions footprint developed for Greater Wellington covers emissions produced in the Stationary
Energy, Transport, Waste, IPPU, and Agriculture sectors using the GPC reporting framework. Sector-
level data allows Greater Wellington to target and work with the sectors that contribute the most
emissions to the footprint.
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Commercial-in-Confidence
Appendix A
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link to page 25 link to page 26
AECOM
Greater Wellington Region GHG Emissions Inventory 2024
Commercial-in-Confidence
7.0
Appendix A:
Additional Inventory Results
Due to rounding, there may be minor discrepancies between totals and the sum of results in the tables.
Further detailed breakdowns of emissions have been provided to the Greater Wellington Regional
Council and the respective city and district councils separately from this report.
7.1
FY19 to FY22 Inventory Updates
To calculate the FY23 and FY24 inventory years for this inventory, updated emission factors and global
warming potential values since the last published inventory for Greater Wellington (June 2023) have
been used. To enable direct comparison of annual emissions since the baseline year (FY19), the FY19
to FY22 inventory years have been updated using the same emission factors and global warming
potential values as for FY23 and FY24.
The updated FY19 to FY22 results presented in this report differ from those previously published and
supersede the previously published inventory results.
The updated FY19 to FY22 results for the Greater Wellington Region and the territorial authorities
within it are presented alongside the FY23 and FY24 years in sections
7.2 and 7.3.
Global Warming Potential Values
• Global warming potential values are used to calculate the carbon dioxide equivalent (CO2e) impact
of methane, nitrous oxide, and other greenhouse gases. The previous inventory used IPCC AR5
values with climate feedbacks (IPCC, 2014). For this report IPCC AR6 values (IPCC, 2021) have
been used.
• Using AR6 values instead of AR5 values has reduced the estimated CO2e impact of methane by
approximately 20% and the estimated CO2e impact of nitrous oxide by approximately 8%,
particularly affecting the results for agriculture and waste. The CO2e impact of industrial gases such
as refrigerants has been increased between AR5 and AR6, impacting the IPPU results.
Emission Factors
• The previous inventory used Ministry for the Environment 2022 emission factor values. For this
report Ministry for the Environment 2022 values have been used. This update has affected most
emission sources to a small extent. The largest impacts of this update were in natural gas
transmission and distribution losses, jet kerosene, aviation gas, and biofuels.
Other updates
• Minor updates to data on IPPU emissions, aviation gas, and coal have also been applied to the
FY19 to FY22 calculations to allow direct comparison with the FY23 and FY24 years.
• Cruise ship emissions have been included in Greater Wel ington’s emissions inventory for the first
time.
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7.2
FY19 to FY24 Inventory Results (Region)
Table 14
Greater Wellington FY19 to FY24 emissions by sector (including updated results for FY19 to FY22)
FY19
FY20
FY21
FY22
FY23
FY24
Emissions Source
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
Transport
1,682,623
1,485,869
1,423,226
1,343,717
1,502,805
1,544,113
Agriculture
1,263,315
1,336,958
1,265,229
1,217,354
1,214,188
1,213,503
Stationary Energy
671,177
683,486
813,759
642,091
506,646
642,422
Industrial Processes
and Product Use
179,292
178,744
177,159
182,768
182,768
182,768
(IPPU)
Waste
198,475
183,970
178,480
168,134
149,837
142,670
Total Gross
3,994,882
3,869,027
3,857,852
3,554,064
3,556,244
3,725,477
Emissions
Table 15
Greater Wellington FY19 to FY24 emissions by source (including updated results for FY19 to FY22)
FY19
FY20
FY21
FY22
FY23
FY24
Emissions Source
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
On-Road Transport
1,097,132
996,002
1,089,262
999,199
1,046,875
1,025,445
Air Travel
262,227
193,853
74,040
109,202
174,460
222,599
Electricity
321,194
337,869
457,188
302,496
168,274
298,126
Consumption
Natural Gas
232,852
230,484
238,574
226,913
223,518
230,165
Marine Transport
205,800
186,160
141,317
124,883
167,951
184,607
Other Transport
117,464
109,854
118,607
110,433
113,519
111,463
Stationary Diesel and
60,024
55,757
60,028
56,044
58,195
56,998
Petrol Use
LPG (Stationary Use)
34,669
34,879
36,209
35,866
35,866
36,331
Other Stationary
22,439
24,497
21,760
20,773
20,794
20,803
Energy
Solid Waste
167,537
152,065
146,091
137,820
120,213
113,806
Wastewater Treatment
(incl. household septic
30,937
31,906
32,389
30,314
29,624
28,864
tanks)
Refrigerant and Air
Conditioning Gases
166,266
166,329
165,663
171,548
171,548
171,548
(IPPU)
Other Industrial Gases
13,026
12,416
11,496
11,220
11,220
11,220
(IPPU)
Enteric Fermentation
934,871
989,824
941,849
905,691
901,958
901,402
from Livestock
Other Agriculture
328,444
347,134
323,380
311,664
312,229
312,101
Emissions
Total Gross
3,994,882
3,869,027
3,857,852
3,554,064
3,556,244
3,725,477
Emissions
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7.3
FY19 to FY24 Inventory Results (Territorial Authorities)
Wellington City
Table 16: Wellington City FY19 to FY24 emissions by sector (including updated results for FY19 to FY22)
FY19
FY20
FY21
FY22
FY23
FY24
Emissions Source
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
Transport
605,365
544,411
458,191
434,250
543,547
567,518
Stationary Energy
326,464
332,485
403,679
314,647
246,580
314,775
Industrial Processes
and Product Use
71,824
71,435
70,495
72,048
72,048
72,048
(IPPU)
Waste
78,655
64,383
62,311
59,513
52,633
44,560
Agriculture
12,282
12,499
12,231
12,176
12,176
11,491
Total Gross
1,094,590 1,025,213 1,006,906
892,634
926,984
1,010,392
Emissions
Table 17
Wellington City FY19 to FY24 emissions by source
FY19
FY20
FY21
FY22
FY23
FY24
Emissions Source
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
On-Road Transport
350,601
325,895
338,730
308,961
348,152
337,893
Electricity
160,748
173,010
236,014
154,105
85,977 151,052
Consumption
Natural Gas
126,842
120,764
129,229
124,164
121,967
125,401
Marine Transport
112,083
105,038
52,861
47,832
88,737
105,393
Air Travel
103,647
76,343
28,279
41,926
67,404
86,389
Refrigerant and Air
66,606
66,473
65,921
67,625
67,625
67,625
Conditioning Gases
Solid Waste
68,947
54,675
52,246
49,837
43,009
35,654
Off-Road Transport
33,631
31,969
32,667
30,305
34,383
33,483
Stationary Diesel and
18,138
17,173
17,550
16,215
18,530
18,001
Petrol Use
LPG (Stationary)
13,888
13,939
14,408
14,134
14,058
14,263
Wastewater Treatment
9,708
9,708
10,065
9,676
9,624
8,906
Enteric Fermentation
9,468
9,641
9,518
9,463
9,463
8,907
from Livestock
Rail
5,403
5,166
5,655
5,226
4,870
4,361
Other Industrial Gases
5,218
4,962
4,574
4,423
4,423
4,423
Biofuel and Biogas
3,272
3,156
3,131
3,097
3,118
3,127
(Stationary)
Coal (Stationary)
3,577
4,442
3,346
2,931
2,931
2,931
Other Agriculture
2,814
2,858
2,712
2,712
2,712
2,584
Emissions
Total Gross
1,094,590 1,025,213 1,006,906
892,634
926,984
1,010,392
Emissions
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Commercial-in-Confidence
Hutt City
Table 18: Hutt City FY19 to FY24 emissions by sector (including updated results for FY19 to FY22)
FY19
FY20
FY21
FY22
FY23
FY24
Emissions Source
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
Transport
295,079
253,248
267,758
254,891
294,438
303,487
Stationary Energy
150,633
152,347
179,098
140,482
110,682
142,775
Industrial Processes
and Product Use
37,004
36,882
36,562
37,781
37,781
37,781
(IPPU)
Waste
40,602
39,981
40,927
38,992
29,291
28,016
Agriculture
2,499
2,864
2,827
2,604
2,603
2,603
Total Gross
525,818
485,321
527,171
474,749
474,794
514,662
Emissions
Table 19
Hutt City FY19 to FY24 emissions by source
FY19
FY20
FY21
FY22
FY23
FY24
Emissions Source
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
On-Road Transport
194,561
171,836
206,290
189,881
215,422
214,365
Natural Gas
53,827
54,474
53,832
50,113
49,555
50,556
Electricity
76,075
77,667
103,716
69,792
39,041
70,067
Consumption
Air Travel
53,400
39,416
14,666
21,985
35,584
45,552
Refrigerant and Air
34,316
34,320
34,189
35,462
35,462
35,462
Conditioning Gases
Solid Waste
36,837
36,144
37,166
35,156
25,547
24,150
Marine Transport
28,131
24,659
26,379
24,073
21,983
21,983
Off-Road Transport
18,596
16,840
19,732
18,476
21,126
21,081
Stationary Diesel and
10,067
9,057
10,690
9,973
11,473
11,439
Petrol Use
LPG (Stationary)
7,155
7,197
7,473
7,415
7,425
7,524
Wastewater Treatment
3,766
3,837
3,761
3,835
3,743
3,866
Other Industrial Gases
2,688
2,562
2,372
2,319
2,319
2,319
(IPPU)
Enteric Fermentation
1,900
2,173
2,171
2,005
1,999
1,999
from Livestock
Biofuel and Biogas
1,666
1,658
1,652
1,652
1,652
1,652
(Stationary)
Coal (Stationary)
1,843
2,293
1,735
1,537
1,537
1,537
Other Agriculture
599
691
655
599
604
604
Emissions
Rail
392
497
691
475
323
506
Total Gross
525,818
485,321
527,171
474,749
474,794
514,662
Emissions
Revision 1 – 10-Dec-2024
Prepared for – Greater Wellington Regional Council – Co No.: N/A
AECOM
Greater Wellington Region GHG Emissions Inventory 2024
Commercial-in-Confidence
Upper Hutt City
Table 20: Upper Hutt City FY19 to FY24 emissions by sector (including updated results for FY19 to FY22)
FY19
FY20
FY21
FY22
FY23
FY24
Emissions Source
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
Transport
124,347
110,947
113,966
107,542
125,135
129,474
Stationary Energy
45,970
46,926
52,741
43,843
37,815
44,560
Industrial Processes
and Product Use
15,513
15,471
15,359
15,973
15,973
15,973
(IPPU)
Agriculture
10,776
11,650
12,049
11,247
10,787
10,787
Waste
10,101
10,325
11,195
10,752
6,861
6,655
Total Gross
206,707
195,320
205,311
189,357
196,572
207,449
Emissions
Table 21
Upper Hutt City FY19 to FY24 emissions by source
FY19
FY20
FY21
FY22
FY23
FY24
Emissions Source
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
On-Road Transport
81,393
75,751
87,242
79,623
90,662
90,655
Natural Gas
22,565
22,851
22,614
21,187
20,744
21,313
Air Travel
22,386
16,534
6,161
9,295
15,088
19,300
Refrigerant and Air
14,386
14,397
14,362
14,993
14,993
14,993
Conditioning Gases
Electricity
14,722
15,406
21,043
13,990
7,747
13,873
Consumption
Marine Transport
12,530
10,995
11,895
10,638
10,350
10,350
Off-Road Transport
7,780
7,404
8,342
7,751
8,894
8,916
Enteric Fermentation
8,290
8,954
9,411
8,779
8,399
8,399
from Livestock
Solid Waste
8,487
8,680
9,584
9,108
5,256
4,998
Stationary Diesel and
4,211
3,992
4,521
4,182
4,828
4,838
Petrol Use
LPG (Stationary)
3,000
3,019
3,139
3,135
3,148
3,188
Other Agriculture
2,486
2,697
2,638
2,468
2,388
2,388
Emissions
Wastewater Treatment
1,614
1,644
1,612
1,644
1,604
1,657
Other Industrial Gases
1,127
1,075
997
981
981
981
(IPPU)
Biofuel and Biogas
698
696
694
698
698
698
(Stationary)
Coal (Stationary)
773
962
729
650
650
650
Rail
258
263
325
235
143
254
Total Gross
206,707
195,320
205,311
189,357
196,572
207,449
Emissions
Revision 1 – 10-Dec-2024
Prepared for – Greater Wellington Regional Council – Co No.: N/A
AECOM
Greater Wellington Region GHG Emissions Inventory 2024
Commercial-in-Confidence
Porirua City
Table 22: Porirua City FY19 to FY24 emissions by sector (including updated results for FY19 to FY22)
FY19
FY20
FY21
FY22
FY23
FY24
Emissions Source
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
Transport
205,603
183,691
177,195
175,344
173,787
174,527
Stationary Energy
40,103
42,373
45,470
41,152
37,186
41,224
Industrial Processes
and Product Use
20,102
20,030
19,864
20,631
20,631
20,631
(IPPU)
Agriculture
13,956
14,142
13,397
13,119
12,888
12,888
Waste
15,540
15,733
13,948
11,488
12,306
12,298
Total Gross
295,305
275,968
269,874
261,734
256,798
261,568
Emissions
Table 23
Porirua City FY19 to FY24 emissions by source
FY19
FY20
FY21
FY22
FY23
FY24
Emissions Source
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
On-Road Transport
146,569
135,087
140,604
136,527
128,947
124,497
Air Travel
29,009
21,406
7,968
12,005
19,484
24,934
Natural Gas
18,934
21,400
22,159
21,196
20,685
21,775
Refrigerant and Air
18,642
18,638
18,575
19,364
19,364
19,364
Conditioning Gases
Off-Road Transport
13,816
13,015
13,317
13,121
12,597
12,211
Marine Transport
15,819
13,787
14,765
13,391
12,576
12,576
Enteric Fermentation
10,767
10,915
10,399
10,171
9,980
9,980
from Livestock
Solid Waste
11,930
12,071
10,246
8,411
8,638
8,912
Electricity
7,792
7,799
10,124
6,995
3,827
6,945
Consumption
Stationary Diesel and
7,584
7,120
7,286
7,171
6,868
6,644
Petrol Use
LPG (Stationary)
3,887
3,908
4,060
4,049
4,066
4,119
Wastewater Treatment
3,610
3,662
3,702
3,077
3,668
3,387
Other Agriculture
3,190
3,227
2,998
2,948
2,909
2,909
Emissions
Other Industrial Gases
1,460
1,391
1,289
1,267
1,267
1,267
(IPPU)
Biofuel and Biogas
905
901
897
902
902
902
(Stationary)
Coal (Stationary)
1,001
1,246
943
839
839
839
Rail
389
396
540
300
183
309
Total Gross
295,305
275,968
269,874
261,734
256,798
261,568
Emissions
Revision 1 – 10-Dec-2024
Prepared for – Greater Wellington Regional Council – Co No.: N/A
AECOM
Greater Wellington Region GHG Emissions Inventory 2024
Commercial-in-Confidence
Kāpiti Coast
Table 24: Kāpiti Coast District FY19 to FY24 emissions by sector (including updated results for FY19 to FY22)
FY19
FY20
FY21
FY22
FY23
FY24
Emissions Source
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
Transport
200,050
167,894
173,513
157,825
175,052
179,733
Stationary Energy
53,493
54,195
64,923
49,647
37,994
50,300
Agriculture
34,674
38,959
37,745
35,216
35,474
35,474
Waste
27,617
27,242
25,252
24,102
27,298
30,332
Industrial Processes and
18,849
18,848
18,705
19,336
19,336
19,336
Product Use (IPPU)
Total Gross Emissions
334,684
307,137
320,138
286,127
295,153
315,176
Table 25
Kāpiti Coast District FY19 to FY24 emissions by source
FY19
FY20
FY21
FY22
FY23
FY24
Emissions Source
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
On-Road Transport
140,530
119,593
135,326
119,102
129,135
128,517
Solid Waste
23,232
23,042
20,940
20,766
24,258
27,268
Electricity Consumption
30,106
31,200
41,614
27,710
15,115
26,836
Air Travel
30,697
22,970
10,477
14,099
20,769
25,946
Enteric Fermentation
25,076
28,256
27,614
25,734
25,885
25,885
from Livestock
Refrigerant and Air
17,480
17,539
17,491
18,149
18,149
18,149
Conditioning Gases
Off-Road Transport
13,237
11,550
12,807
11,480
12,581
12,554
Marine Transport
15,173
13,355
14,353
12,805
12,350
12,350
Natural Gas
10,684
10,994
10,739
10,254
10,568
11,120
Other Agriculture
9,599
10,702
10,131
9,482
9,589
9,589
Emissions
Stationary Diesel and
7,271
6,303
7,013
6,256
6,878
6,858
Petrol Use
LPG (Stationary)
3,645
3,678
3,823
3,795
3,802
3,855
Wastewater Treatment
4,386
4,200
4,312
3,336
3,040
3,065
Other Industrial Gases
1,369
1,309
1,214
1,187
1,187
1,187
Biofuel and Biogas
848
847
845
845
845
845
(Stationary)
Coal (Stationary)
939
1,172
888
787
787
787
Rail
412
426
550
340
217
366
Total Gross Emissions
334,684
307,137
320,138
286,127
295,153
315,176
Revision 1 – 10-Dec-2024
Prepared for – Greater Wellington Regional Council – Co No.: N/A
AECOM
Greater Wellington Region GHG Emissions Inventory 2024
Commercial-in-Confidence
Carterton District
Table 26: Carterton District FY19 to FY24 emissions by sector (including updated results for FY19 to FY22)
FY19
FY20
FY21
FY22
FY23
FY24
Emissions Source
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
Agriculture
218,809
234,435
221,231
211,715
212,274
212,274
Transport
61,474
55,263
57,705
53,246
46,439
45,767
Stationary Energy
13,729
13,753
16,374
13,103
9,614
12,212
Waste
4,793
5,559
5,214
4,663
3,652
3,541
Industrial Processes
and Product Use
3,247
3,252
3,263
3,422
3,422
3,422
(IPPU)
Total Gross
302,052
312,262
303,787
286,148
275,400
277,216
Emissions
Table 27
Carterton District FY19 to FY24 emissions by source
FY19
FY20
FY21
FY22
FY23
FY24
Emissions Source
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
Enteric Fermentation
160,753
172,383
163,550
156,514
156,718
156,718
from Livestock
Other Agriculture
58,056
62,052
57,681
55,201
55,556
55,556
Emissions
On-Road Transport
46,971
42,968
46,355
42,268
34,447
33,158
Electricity
6,829
6,969
9,385
6,307
3,486
6,187
Consumption
Off-Road Transport
5,881
5,597
5,990
5,668
4,466
4,283
Air Travel
4,685
3,476
1,309
1,991
3,242
4,096
Marine Transport
3,447
2,973
3,639
2,907
3,642
3,642
Refrigerant and Air
3,011
3,026
3,051
3,212
3,212
3,212
Conditioning Gases
Biofuel and Biogas
2,846
2,846
2,848
2,850
2,850
2,850
(Stationary)
Stationary Diesel and
3,265
3,101
3,320
3,135
2,462
2,360
Petrol Use
Solid Waste
2,823
2,730
2,459
2,228
2,055
1,944
Wastewater Treatment
1,969
2,829
2,756
2,435
1,597
1,597
LPG (Stationary)
628
635
667
672
677
677
Rail
490
249
413
413
642
589
Other Industrial Gases
236
226
212
210
210
210
(IPPU)
Coal (Stationary)
162
202
155
139
139
139
Total Gross
302,052
312,262
303,787
286,148
275,400
277,216
Emissions
Revision 1 – 10-Dec-2024
Prepared for – Greater Wellington Regional Council – Co No.: N/A
AECOM
Greater Wellington Region GHG Emissions Inventory 2024
Commercial-in-Confidence
Masterton District
Table 28: Masterton District FY19 to FY24 emissions by sector (including updated results for FY19 to FY22)
FY19
FY20
FY21
FY22
FY23
FY24
Emissions Source
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
Agriculture
549,568
566,123
531,264
518,518
514,659
514,659
Transport
117,700
104,681
106,616
97,748
89,875
89,792
Stationary Energy
29,884
30,137
37,203
28,319
19,341
26,682
Waste
15,244
14,974
14,162
13,429
12,838
12,459
Industrial Processes
and Product Use
9,027
9,083
9,157
9,651
9,651
9,651
(IPPU)
Total Gross
721,424
725,000
698,403
667,665
646,364
653,243
Emissions
Table 29
Masterton District FY19 to FY24 emissions by source
FY19
FY20
FY21
FY22
FY23
FY24
Emissions Source
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
Enteric Fermentation
409,008
421,408
396,801
386,712
383,272
383,272
from Livestock
Other Agriculture
140,560
144,715
134,463
131,806
131,387
131,387
Emissions
On-Road Transport
80,513
73,651
79,457
72,451
59,046
56,835
Marine Transport
13,988
11,510
13,047
9,791
13,885
13,885
Electricity
18,987
19,377
26,093
17,536
9,692
17,202
Consumption
Air Travel
13,026
9,707
3,673
5,616
9,173
11,628
Refrigerant and Air
8,371
8,452
8,563
9,059
9,059
9,059
Conditioning Gases
Solid Waste
11,078
10,706
9,777
8,943
8,320
7,926
Off-Road Transport
10,166
9,681
10,360
9,811
7,751
7,439
Wastewater Treatment
4,166
4,268
4,385
4,487
4,517
4,533
Stationary Diesel and
5,596
5,315
5,691
5,374
4,221
4,045
Petrol Use
Biofuel and Biogas
3,107
3,109
3,114
3,122
3,122
3,122
(Stationary)
LPG (Stationary)
1,745
1,772
1,872
1,894
1,914
1,921
Other Industrial Gases
656
631
594
592
592
592
(IPPU)
Coal (Stationary)
450
565
435
393
393
393
Rail
7
132
79
79
20
5
Total Gross
721,424
725,000
698,403
667,665
646,364
653,243
Emissions
Revision 1 – 10-Dec-2024
Prepared for – Greater Wellington Regional Council – Co No.: N/A
AECOM
Greater Wellington Region GHG Emissions Inventory 2024
Commercial-in-Confidence
South Wairarapa District
Table 30: South Wairarapa District FY19 to FY24 emissions by sector (including updated results for FY19 to FY22)
FY19
FY20
FY21
FY22
FY23
FY24
Emissions Source
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
Agriculture
420,750
456,286
434,485
412,759
413,327
413,327
Transport
73,006
65,733
68,282
62,871
54,532
53,814
Stationary Energy
10,900
11,270
14,272
10,899
7,433
9,894
Waste
5,922
5,774
5,470
5,194
4,961
4,809
Industrial Processes
and Product Use
3,726
3,743
3,754
3,926
3,926
3,926
(IPPU)
Total Gross
514,304
542,805
526,262
495,650
484,178
485,770
Emissions
Table 31
South Wairarapa District FY19 to FY24 emissions by source
FY19
FY20
FY21
FY22
FY23
FY24
Emissions Source
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
(tCO2e)
Enteric Fermentation
309,610
336,093
322,383
306,312
306,242
306,242
from Livestock
Other Agriculture
111,140
120,192
112,101
106,447
107,085
107,085
Emissions
On-Road Transport
55,993
51,221
55,258
50,386
41,064
39,526
Electricity
5,935
6,442
9,199
6,060
3,391
5,964
Consumption
Off-Road Transport
7,007
6,669
7,137
6,753
5,319
5,103
Air Travel
5,377
4,000
1,506
2,285
3,717
4,755
Marine Transport
4,629
3,843
4,379
3,446
4,428
4,428
Refrigerant and Air
3,455
3,483
3,510
3,685
3,685
3,685
Conditioning Gases
Solid Waste
4,204
4,016
3,673
3,370
3,130
2,955
Stationary Diesel and
3,892
3,696
3,957
3,737
2,935
2,813
Petrol Use
Wastewater Treatment
1,719
1,758
1,797
1,824
1,830
1,854
LPG (Stationary)
720
730
767
771
776
785
Other Industrial Gases
271
260
244
241
241
241
(IPPU)
Biofuel and Biogas
168
168
170
172
172
172
(Stationary)
Coal (Stationary)
186
233
178
160
160
160
Rail
- 0
2
2
4
2
Total Gross
514,304
542,805
526,262
495,650
484,178
485,770
Emissions
Revision 1 – 10-Dec-2024
Prepared for – Greater Wellington Regional Council – Co No.: N/A
AECOM
Greater Wellington Region GHG Emissions Inventory 2024
Commercial-in-Confidence
8.0
Appendix B:
Assumptions and Data Sources
The calculation method for the FY24 GHG emission inventory for Greater Wellington differs from
previous GHG emission inventories completed for Greater Wellington by AECOM. Data for this GHG
emissions inventory has been collected for a list of emission sources which cover approximately 90% of
Greater Wellington’s emissions. These emission sources were calculated as per previous inventories,
and remaining sources have been based on the FY22 GHG emissions inventory, with some of these
sources adjusted based on population change where this was deemed relevant.
The following table details assumptions, exclusions and whether data has been collected, adjusted or
not adjusted based on the FY22 emissions inventory.
Sector /
Assumptions and Exclusions
Category
General
Geographical
LGNZ local council mapping boundaries have been applied.
Boundary
Population
Population figures are provided by StatsNZ.
The 2022 calendar year population was used for the 2023 financial year
population, with the 2023 calendar year used for the 2024 financial year
population.
Global Warming
Emissions are expressed on a carbon dioxide-equivalent basis (CO2e) using the
Potential Used
100-year Global Warming Potential (GWP) values from the IPCC 6th
Assessment Report (AR6).
Full Inventory
Emissions for all sources broken down by individual main greenhouse gases are
provided in the supplementary spreadsheet information supplied with this report.
GPC Production
GPC reporting is predominately production-based (as opposed to consumption-
Approach
based) but includes indirect emissions from energy consumption.
Production-based emissions reporting is generally preferred by policy-makers
due to robust established methodologies such as the GPC, which enables
comparisons between different studies. Production-based approaches exclude
globally produced emissions relating to consumption (e.g., embodied emissions
relating to products produced elsewhere but consumed within the geographic
area such as imported food products, cars, phones, clothes etc.).
Cross-boundary movements such as air travel and marine freight journeys
departing or arriving in Greater Wellington have been included with emissions
related to the journeys split equally between the origin and destination, despite
the emissions being produced outside the Greater Wellington geographical
boundary, as per the GPS requirements.
Emission Factors
All emission factors have detailed source information in the calculation tables
within which they are used. Where possible, the most up to date, NZ-specific
emission factors have been applied. This inventory uses applicable emission
factors predominantly from the New Zealand Ministry of the Environment
Measuring emissions: A guide for organisations: 2024 detailed guide. The
emission factors for electricity are obtained from MBIE data fro the financial
year.
Transport Emissions
Petrol and Diesel: Total petrol and diesel consumption in Greater Wellington was calculated from
total petrol and diesel sold in the Wellington Region which was then apportioned
out to the territorial authorities within the region based on the total distance
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travelled by vehicles in each territorial authority in the financial year (known as
Vehicle Kilometres Travelled or VKT).
Allocating fuel consumption across a region based on VKT does not account for
the likely makeup of the vehicle fleet of a particular geographic area (e.g. where
a more rural area may use more diesel, or a more urban area may have more
hybrid or electric vehicles travelling).
Fuel sold in an area does not always mean that the fuel is used in that area,
however this approach is considered to be a robust and comparable estimate of
fuel consumption in a geographic area.
Total petrol and diesel fuel use was then divided by likely end use. The division
into Transport and Stationary Energy end use (and within Transport, on-road
and off-road) was calculated using fuel end use data provided by the Energy
Efficiency and Conservation Authority (EECA) in April 2020.
-
On-road Transport is defined as all standard transport vehicles used on
roads e.g. cars, bikes, buses.
-
Off-road Transport is defined as machinery for Agriculture, construction
and other industry used off-roads.
-
Stationary Energy petrol and diesel use is defined as fuel not used for
transport either on or off roads. Petrol and diesel used for Stationary
Energy has been reported in the Stationary Energy sector.
This method produces results for off-road and stationary uses of petrol and
diesel that are heavily impacted by changes in on-road transport uses of petrol
and diesel as this represents the largest proportion of petrol and diesel sales.
Better data and understanding of off-road and stationary uses of petrol and
diesel are required to improve the applicability of these results.
Data collected for FY23 and FY24.
Rail Diesel
Consumption was calculated by Kiwi Rail using the induced activity method for
system boundaries. The following assumptions were made:
-
Net Weight is product weight only and excludes container tare (the
weight of an empty container)
-
The Net Tonne-Kilometres (NTK) measurement has been used. NTK is
the sum of the tonnes carried, multiplied by the distance travelled.
-
National fuel consumption rates have been used to derive litres of fuel
for distance.
-
Type of locomotive engine used, and jurisdiction topography, have not
been incorporated in the calculations.
Using the induced activity method, the trans-boundary routes were determined,
and the number of stops taken along the way derived. The total litres of diesel
consumed per route was then split between the departure territorial authority,
arrival territorial authority and any territorial authority the freight stopped at along
the way. If the freight travelled through but did not stop within a territorial
authority, no emissions were allocated.
This data is subject to commercial confidentiality.
Data was not available for FY22 therefore the FY21 value has been used for
FY22.
Data collected for FY23 and FY24.
Jet Kerosene
Calculated using the induced activity method as per rail diesel.
An estimate of fuel use was calculated for flights arriving and departing from
Wellington and Kāpiti Airports:
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The schedule of flights arriving and departing from the airport containing
details on the aircraft used for each flight was used to calculate fuel
consumption.
-
Flight distances and aircraft fuel burn rates were used for these
calculations.
-
As per the induced activity method, only 50% of emissions calculated
per one-way arrival and departure were allocated to Greater Wellington.
The remaining 50% of each leg was allocated to the originating or
destination location.
An estimation of fuel use from military, freight, private, and other flights for FY22
has been estimated based on data provided in 2023.
Wellington Airport has been treated as a regional airport, so emissions have
been split between the territorial authorities in the region on a population basis.
Kāpiti Airport has been treated as a local airport with all emissions allocated to
Kāpiti Coast District.
Data collected for FY23 and FY24.
Aviation Gas
Aviation gas is mostly used by small aircraft for relatively short flights.
Data for Wellington and Kāpiti airports was not available for the FY22 inventory,
so an assumption was made based on similar sized airports in New Zealand.
This is the same assumption used in the FY20 inventory.
Wellington Airport has been treated as a regional airport, so emissions have
been split between the territorial authorities in the region on a population basis.
Kāpiti Airport has been treated as a local airport with all emissions allocated to
Kāpiti Coast District.
No estimate of aviation gas usage has been made for aerodromes and other
flights outside these two airports. This is expected to be a small emission
source.
Adjustment of FY22 results based on population change for FY23 and FY24.
Marine Diesel –
Calculated using the induced activity method as per rail diesel and jet kerosene.
Freight
An estimate of fuel use was calculated for vessels arriving and departing from
CentrePort (Wellington Port):
-
The schedule of vessels arriving and departing from Wellington Port
containing details on size of the vessel was used to calculate fuel
consumption.
-
Shipping distances and vessel fuel burn rates were used for these
calculations.
-
As per the induced activity method, only 50% of emissions calculated
per one-way arrival and departure were allocated to Wellington Port.
The remaining 50% of each leg was allocated to the originating or
destination Port.
International shipping passing through CentrePort was split by weight of cargo
into ‘Logs’ and ‘All other cargo’. Emissions generated by ‘Al other cargo’ has
been allocated on a per capita basis between all territorial authorities in the
Wellington Region. Emissions generated by ‘logs’ was split between territorial
authorities, proportionally, by the percentage share of district forest area of
harvest age (>26 years old).
FY23 calculated for the Wellington City Emissions Inventory 2023. No
adjustment of the FY23 results for FY24.
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Marine Diesel
Port operational vessels:
(Local)
-
Fuel use has been provided directly from Wellington Port (CPL) for
FY21
-
The FY21 figure has also been used for years since.
-
All emissions from this source have been allocated to Wellington City
Local ferries:
-
Diesel fuel use has been provided directly by the ferry operator.
-
Electricity usage has been provided directly by the ferry operator
(beginning in FY22)
-
All emissions from this source have been allocated to Wellington City
Private use, other commercial operators, and commercial fishing:
-
Most small private boats use fuel purchased at vehicle gas stations so
this consumption will be included in off-road transport petrol and diesel
emissions.
-
No data was available to determine emissions from other commercial
operators, and commercial fishing.
Adjustment of FY22 results based on population change for FY23 and FY24.
Marine fuels –
Data has been provided by the ferry operators in commercial confidence.
Inter-island ferries
Assumptions of fuel use have been used where data was not provided.
No adjustment of FY22 results for FY23 and FY24.
Cruise Ships
The GHG emissions from cruise ships for FY19 to FY24 has been calculated as
part of a separate piece of work for Wellington City Council to understand the
impact on Wellington City’s emissions inventory profile.
Cruise ship emissions have been estimated using the induced activity method
as per rail diesel, jet kerosene, and marine freight.
An estimate of fuel use was calculated for each vessel arriving and departing
from Greater Wellington based on the estimated fuel consumption of each
vessel, the distance travelled to and from Wellington, and while stationary in
port.
As per the induced activity method, for emissions produced during the journey
to/from Wellington the emissions are allocated equally between Greater
Wellington and the next/last port.
Within Greater Wel ington, 100% of Greater Wellington’s cruise ship emissions
are allocated to Wellington City.
Data collected for FY23 and FY24.
LPG
Total North Island consumption data was used and then split on a per capita
basis to determine the territorial authority’s consumption. National LPG end use
data has been used to breakdown consumption into Stationary Energy and
Transport usage, these are then reported separately in their respective
categories.
Adjustment of FY22 results based on population change for FY23 and FY24.
Stationary Energy Emissions
Consumer Energy
Stationary Energy demand (e.g. electricity use, natural gas, etc.) is broken down
End Use
by the sector in which they are consumed. We report Stationary Energy demand
in the following categories: industrial (which includes Agriculture, forestry, and
fishing); commercial; and residential. These sectors follow the Australia New
Zealand Standard Industrial Classification 2006 definitions.
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In addition to Agriculture, forestry and fishing, the industrial sector includes
mining, food processing, textiles, chemicals, metals, mechanical/electrical
equipment and building and construction activities.
Emissions from petrol and diesel used for Stationary Energy are not broken
down into these sectors.
Energy demand used for transport is reported in the Transport sector.
Electricity
Electricity demand has been calculated using grid demand trends from the EMI
Consumption
websit
e (www.emi.ea.govt.nz) to obtain raw grid exit point data for Greater
Wellington. Reconciled demand has been used as per EMI's confirmation.
The breakdown into sectors is based on NZ average consumption per sector
(residential, commercial, and industrial).
Data collected for FY23 and FY24.
Public Transport
Electricity used in the public transport system is included in the Transport sector
Electricity
(where known).
Data collected for FY23 and FY24.
Private Transport
Electricity used for private transport (e.g. electric cars, electric bikes, electric
Electricity
micro-mobility) has not been separated from other Stationary Energy electricity
consumption due to a lack of reliable data.
Coal
National coal consumption data has been provided by MBIE for 2022. Regional
Consumption
industrial coal data has been provided by EECA.
National residential and commercial coal consumption has been divided
between territorial authorities on a per capita basis.
Regional industrial coal consumption has been divided between territorial
authorities on a per capita basis.
No adjustment of FY22 results for FY23 and FY24.
Biofuel and Wood
For FY24, national biofuel consumption data has been provided by the Ministry
Consumption
for the Environment (MfE, 2023) for the 2021 year. This is the most recent year
available.
Biofuel consumption has been divided between territorial authorities on a per
capita basis.
Biofuel emissions are considered to be biogenic. Biofuel CO2 emissions are not
included in total gross emissions but are reported separately.
FY20, FY21, and FY22 use the FY19 figure, adjusted for population change.
No adjustment of FY22 results for FY23 and FY24.
LPG
North Island LPG sales data (tonnes) has been provided by the LPG
Consumption
Association for 2020 and 2021. Data interpolated between known data points or
copied from the most recent data point where data is not available.
‘Auto’ and ‘Forklift’ sales represent Transport uses of LPG. All other sales
represent Stationary Energy uses of LPG.
Sales have been divided between territorial authorities on a per capita basis.
The breakdown into sectors (Residential, Commercial, and Industrial) is based
on NZ average consumption per sector as per MfE data.
Adjustment of FY22 results based on population change for FY23 and FY24.
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Petrol and Diesel
Total petrol and diesel consumption in Greater Wellington was calculated from
(Stationary
total petrol and diesel sold in the Wellington Region which was then apportioned
Energy end use)
out to the territorial authorities within the region based on the total distance
travelled by vehicles in each territorial authority in the financial year (known as
Vehicle Kilometres Travelled or VKT). As most petrol and diesel is used for
transport uses, this provides the most accurate way of calculating this data.
Total petrol and diesel fuel use was then divided by likely end use. The division
into Transport and Stationary Energy end use (and within Transport, on-road
and off-road) was calculated using fuel end use data provided by the Energy
Efficiency and Conservation Authority (EECA) in April 2020.
-
On-road Transport is defined as all standard transport vehicles used on
roads e.g. cars, bikes, buses.
-
Off-road Transport is defined as machinery for Agriculture, construction
and other industry used off-roads.
-
Stationary Energy petrol and diesel use is defined as fuel not used for
transport either on or off roads. Petrol and diesel used for Stationary
Energy has been reported in the Stationary Energy sector.
This method produces results for stationary uses of petrol and diesel that are
heavily impacted by changes in transport uses of petrol and diesel. Better data
and understanding of stationary uses of petrol and diesel are required to
improve the applicability of these results.
Data collected for FY23 and FY24.
Natural Gas
Natural gas consumption data has been provided by FirstGas. Territorial
Consumption
Authorities supplied by gas from each Point of Connection (POC) have been
confirmed by FirstGas.
Data collected for FY23 and FY24.
Biogenic
Some Carbon Dioxide (CO2) emissions are considered to be biogenic. These
Emissions
are CO2 emissions where the carbon has been recently derived from CO2
present in the atmosphere (for example, some agricultural and Waste
emissions). These emissions are not included in calculating total CO2e.
Agricultural Emissions
Agriculture
Agriculture emissions relates to emissions produced by livestock, crops and
fertiliser in the geographic area. Agriculture emissions do not relate to imported
foods or goods (reported in a consumption-based footprint), or agricultural
activities such as farm transport or food processing within the geographic area
(these are reported in this inventory under Transport or Stationary Energy
respectively).
Regional agricultural data from StatsNZ for 2023 has been used to calculate
agricultural emissions, with the 2023 value used for 2024. Territorial authority-
level livestock numbers and fertiliser data was taken from the 2017 Agricultural
Census (StatsNZ) with the change in regional data used to estimate the change
in livestock and fertiliser use in the individual territorial authorities since 2017.
Data collected for FY23 and FY24.
Solid Waste Emissions
Landfill Emissions
Landfill Waste volume and landfill gas capture system information has been
provided by the respective council departments.
Solid Waste emissions from landfill are measured using the IPCC First Order
Decay method that covers landfill activity between 1950 and the present day, as
per the GPC reporting requirements. This method accounts for the gradual
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release of emissions from waste over a long period of time, and so calculates
the emissions produced per year from waste in landfill (including emissions from
closed landfill sites).
This approach differs from that used by individual councils for their
organisational footprints which includes council-owned landfill sites. The
predominant organisational footprint method calculates the likely future
emissions from the waste entering landfill that year, and attributes those
emissions to that year (and doesn’t include emissions from waste already in the
landfill, or emissions from closed landfill sites).
Waste volume:
-
Where information is not available, waste volumes have been estimated
based on historical national data on a per capita basis (MfE, 2023).
-
Contaminated soil has been excluded from the calculation to be
consistent with previous years as it is considered to be inert for the
purposes of this assessment (this differs from Council’s organisational
emissions inventory)
Landfill gas capture system efficiency and Landfill gas flaring / burning for
energy generation:
-
Data or assumptions provided directly from council or landfill
management contacts
Emissions are allocated to territorial authorities based on where the waste was
produced, even if the waste is disposed in landfill outside the territorial authority.
Data collected for FY23 and FY24.
Wastewater Emissions
Wastewater
Wastewater Treatment Plants:
Treatment Plants
-
Calculation of emissions includes emissions released directly from
wastewater treatment, flaring of captured gas (if present) and from
discharge onto land/water.
-
Wastewater treatment plant emissions have been calculated following
the WaterNZ (2021) guidance based on information provided at the time
of calculation.
-
Where data was not available, assumed values have been used based
on the WaterNZ (2021) guidance.
-
Emissions relating to discharge of biosolids sent to landfill has been
included in the Solid Waste emissions source.
-
The results for each treatment plant may differ from emissions
calculated for other purposes (e.g. council organisational GHG
reporting) due to the different requirements of GHG reporting for
different purposes.
-
Emissions are allocated to territorial authorities based on where the
wastewater was produced, even if the wastewater is treated outside the
territorial authority.
Data collected for FY23 and FY24.
Individual Septic
Individual Septic Tanks:
Tanks
-
Populations not connected to known wastewater treatment plants are
assumed to be using septic tanks.
-
The population not connected to centralised wastewater treatment has
been estimated based on the number of rateable properties not
connected to sewerage.
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Adjustment of FY22 results based on population change for FY23 and FY24.
Industrial Processes and Product Use Emissions
Industrial
It is assumed that there are no significant non-energy related emissions of
processes
greenhouse gases from industrial processes in the Region (e.g. aluminium
manufacture).
Data collected for FY23 and FY24.
Industrial Product
National data covering industrial product use (e.g. fire extinguishers,
Use
refrigerants) have been estimated based on data provided in the New Zealand
Greenhouse Gas Emissions 1990-2021 report (MfE 2023). Emissions are
estimated on a per capita basis applying a national average per person.
Data collected for FY23 and FY24.
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