2018_City_of_Phoenix_Govt_Ops_GHG_Report_FINAL.PDF

City of Phoenix — Transportation, Infrastructure and Innovation Subcommittee (2020-06-03)

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2018 Local Government
Operations
Greenhouse Gas
Emissions Inventory
A comprehensive report
prepared for
April 2020
sustainabilitysolutions.asu.edu

Acknowledgements
This report is a joint effort by the City of Phoenix:

Nancy Allen, Environmental Programs Manager
Rosanne Albright, Environmental Programs Coordinator
Dr. Matthew Potzler, Environmental Air Quality and Climate Specialist
Joe Gibbs, Environmental Air Quality Specialist

And

Arizona State University’s Walton Sustainability Solutions Initiatives:
Bill Campbell, Portfolio Manager
Mahindra Venkat, Graduate Student

And

Northern Arizona University’s School of Informatics, Computing, and Cyber Systems
Dr. Richard Rushforth, Assistant Research Professor

We would like to recognize the financial support from Aviation, Public Works, Water and
Transit Departments. In addition, we wish to acknowledge the numerous city
departments’ staff for supplying the data needed to produce the 2018 Greenhouse Gas
Emissions Inventory for Government Operations.

Finally, we would like to thank City of Phoenix employees, residents, and business
owners, who are on the ground supporting the City’s efforts and who are working toward
reducing their own greenhouse gas emissions.
Note: The data and calculations presented in this report may not be exact due to rounding errors within
the GHG emissions template.

Table of Contents
List of Tables .................................................................................................................... i
List of Figures .................................................................................................................. ii
Acronyms ........................................................................................................................ iii
Executive Summary ........................................................................................................ 1
1
Introduction ............................................................................................................... 4
2
Major Findings .......................................................................................................... 5
3
Methodology ............................................................................................................. 8
3.1
Local Government Operations Protocol ............................................................. 8
3.2
Scope Classifications and Sectors ..................................................................... 8
3.3
City of Phoenix Government Operations Boundary .......................................... 10
3.4
Inventory Changes Since 2005 ........................................................................ 10
3.4.1
Estimating Tailpipe Emissions of Methane and Nitrous Oxide ................... 11
3.4.2
2005 Wastewater Treatment Methane and Nitrous Oxide Emissions ........ 12
3.4.3
Alternative Fuel Estimates for Employee Commuting ................................ 12
3.4.4
Estimating Compost Emissions ................................................................. 12
4
Results .................................................................................................................... 13
4.1
Summary .......................................................................................................... 13
4.1.1
2005 to 2018: What has Changed? ........................................................... 13
4.1.2
Emissions Sources and Distribution .......................................................... 15
4.1.3
GHG Emissions Reductions Since 2005 ................................................... 17
5
Findings by Sector for 2018 .................................................................................... 19
5.1
Buildings and Facilities ..................................................................................... 19
5.1.1
2005 to 2018: What has Changed? ........................................................... 19
5.1.2
Emissions Sources and Distribution .......................................................... 20
5.1.3
GHG Metrics: Buildings and Facilities ....................................................... 22
5.2
City Vehicle Fleet ............................................................................................. 23
5.2.1
2005 to 2018: What has Changed? ........................................................... 23

iii

5.2.2
Emissions Sources and Distribution .......................................................... 24
5.2.3
GHG Metrics: Vehicle Fleet ....................................................................... 26
5.3
Water Services ................................................................................................. 27
5.3.1
2005 to 2018: What has Changed? ........................................................... 27
5.3.2
Emissions Sources and Distribution .......................................................... 28
5.3.3
GHG Metrics: Water Services .................................................................... 31
5.4
Solid Waste ...................................................................................................... 32
5.4.1
2005 to 2018: What has Changed? ........................................................... 32
5.4.2
Emissions Sources and Distribution .......................................................... 32
5.4.3
27th Avenue Compost Facility .................................................................... 34
5.4.4
GHG Metrics: Solid Waste ......................................................................... 34
5.5
Employee Commute ......................................................................................... 35
5.5.1
2005 to 2018: What has Changed? ........................................................... 35
5.5.2
Emissions Sources and Distribution .......................................................... 35
5.5.3
City Action Highlights ................................................................................. 36
6
City of Phoenix GHG Metrics .................................................................................. 36
7
Biogenic Emissions ................................................................................................. 37
Appendix A: Greenhouse Gas Equivalents ................................................................... 39
Appendix B: City of Phoenix’s Government Operations Boundary ................................ 40
Appendix C: Solar Projects & Partnerships ................................................................... 42
Appendix D: Findings by Scope .................................................................................... 44

List of Tables
Table 1. GHG Emissions by Scope and Sector Between 2005 and 2018 ....................... 7
Table 2. 2018 GHG Emissions by Scope and Subsector .............................................. 17
Table 3. 2018 Buildings and Facilities Emissions by Subsector .................................... 21
Table 4. Departmental Energy Consumption and Solar Power Generation .................. 22
Table 5. Buildings and Facilities Emissions Indicators and Percent of Change ............ 22
Table 6. Changes in Total City Fleet Fuel Consumption ............................................... 26
Table 7. City Fleet Indicators Change ........................................................................... 26
Table 8. GHG emissions at the 23rd Avenue and 91st Avenue WWTPs ........................ 31
Table 9. Water Services Emissions Indicators .............................................................. 31
Table 10. 2018 Solid Waste Emissions by Landfill ........................................................ 33
Table 11. GHG Emissions Indicators for Solid Waste ................................................... 34
Table 12. Employee Commute Emissions by Fuel Type/Mode in 2005 and 2018 ........ 36
Table 13. Internal Government operations Indicators.................................................... 37
Table 14. Sources and Quantities of Biogenic Emissions (MT CO₂e) ........................... 38
Table A1. IPCC AR2, AR4, and AR5 Global Warming Potential (GWP) Values ........... 39
Table C1. Completed and Planned Solar Projects ........................................................ 42

List of Figures
Figure ES-1. City of Phoenix Government Operations GHG Emissions and Population
Between 2005 and 2018. ................................................................................................ 3
Figure 1. City of Phoenix GHG Emissions from 2005 to 2018. ........................................ 5
Figure 2. Overview of LGOP Scopes and Emissions Sources. ....................................... 9
Figure 3. GHG Emissions by City Sector for 2005, 2012, 2015, and 2018 .................... 14
Figure 4. 2018 Emissions by Scope and Subsector ...................................................... 16
Figure 5. Emissions Changes between 2005 and 2018. ............................................... 17
Figure 6. Buildings and Facilities GHG Emissions Between 2005 and 2018 ................. 20
Figure 7. Vehicle Fleet Emissions by Fuel Between 2005 and 2018 ............................. 25
Figure 8. Water Services Emissions Changes Between 2005 and 2018 ....................... 29
Figure 9. Wastewater Treatment GHG Emissions Between 2005 and 2018 ................. 30
Figure 10. Phoenix Landfills Emissions Changes between 2005 and 2018 .................. 33
Figure D1. 2018 Emissions by Scope ........................................................................... 45
Figure D2. Government operations comparison, 2005, 2012, 2015 and 2018 .............. 45
Figure D3. Breakdown of 2018 Scope 1 Emissions ...................................................... 46
Figure D4. Breakdown of 2018 Scope 2 Emissions ...................................................... 47
Figure D5. Breakdown of 2018 Scope 3 Emissions ...................................................... 48

iii

Acronyms
AR

IPCC Assessment Report (Numbered 2 through 5)
ASU

Arizona State University
AZNM

Arizona and New Mexico eGRID Subregion
CARB

California Air Resources Board
CCAR

California Climate Action Registry
CEQ

President’s Council on Environmental Quality
CH4

Methane
CNG

Compressed Natural Gas
CO2

Carbon Dioxide
CO2e

Carbon Dioxide Equivalent Emissions
eGRID

EPA’s Emissions and General Resource Integrated Database
EIA

U.S. Energy Information Administration
EPA

Environmental Protection Agency
FERC

Federal Energy Regulatory Commission
FTE

Full-time equivalent
GGE

Gasoline Gallon Equivalent
GHG

Greenhouse Gas
GAC

Granular Activated Carbon
GWP

Global Warming Potential
ICLEI

International Council for Local Environmental Initiatives
IPCC

Intergovernmental Panel on Climate Change
JPA

Joint Powers Authority
LED

Light Emitting Diode
LEED

Leadership in Energy and Environmental Design
LGOP

Local Government Operations Protocol
LNG

Liquefied Natural Gas
LPG

Liquefied Petroleum Gas
MT

Metric Tons
MWh

megawatt-hour
NAU

Northern Arizona University
NERC

North American Electric Reliability Corporation
N2O

Nitrous Oxide
T&D

Transmission & Distribution
TRP

Trip Reduction Program
UNFCCC

United Nations Framework Convention on Climate Change
WWT

Wastewater Treatment
WWTP

Wastewater Treatment Plant

Executive Summary
The City of Phoenix 2018 Greenhouse Gas Emissions Inventory for Government
Operations is the fourth update to the City of Phoenix (the City) government operations
GHG emissions inventory. The initial GHG inventory of government operations covered
calendar year 2005 and was published in 2009. This report provided both a baseline
GHG inventory and technical support for the City of Phoenix 2009 Climate Action Plan
for Government Operations. The climate action plan projected that GHG emissions from
the City’s government operations would increase by 14% over 2005 level if no actions
were taken. As a result, the Phoenix City Council, in December 2008, adopted a
mandate to reduce GHG emissions from government operations to 5% below the 2005
GHG emissions levels by 2015.

In 2013, the City conducted a GHG emissions inventory for calendar year 2012 to track
progress toward the 2015 GHG emissions reduction goal. The City of Phoenix 2012
Greenhouse Gas Emissions Inventory for Government Operations found that GHG
emissions from government operations had decreased 7.2%, exceeding the City’s 2015
goal. Shortly thereafter, the Phoenix City Council adopted a new goal to reduce
government operations GHG emissions to 15% below 2005 levels by 2015. The City of
Phoenix 2015 Greenhouse Gas Emissions Inventory for Government Operations found
that government operations GHG emissions were reduced by 15.6%, thus meeting the
updated 2015 GHG emissions goal. In 2017, the City updated its government
operations GHG emissions reduction goal to 40% below 2005 levels by 2025. The City
of Phoenix 2018 Greenhouse Gas Emissions Inventory for Government Operations is
the first inventory update since setting the 2025 GHG emissions reduction goal, and
provides updated information for tracking progress toward the 2025 goal.

The major findings of the City of Phoenix 2018 Greenhouse Gas Emissions Inventory
for Government Operations are listed below.
• 2018 government operations GHG emissions were 10,714 MT CO2e (1.7%)
below 2015 and 110,442 MT CO2e (15.4%) below 2005 levels.
• GHG emissions for 2015 were revised upwards to reflect updated data from EPA
on the GHG emissions intensity of the regional electricity grid. Emissions from
electrical use are determined by multiplying the amount of electricity consumed
by an emissions factor given in carbon dioxide emissions per megawatt-hour
generated. This is determined by the EPA and is named the Emissions and
Generation Resource Integrated Database (eGRID) emissions factor. It takes

into account the environmental emissions characteristics of power plants (coal,
natural gas, nuclear, solar, etc.) and groups the plants by region. In 2014, EPA
changed the power plant grouping methodology and three coal power plants
(Navajo, Four Corners and San Juan) were moved from the Arizona New Mexico
(AZNM) region to Northwest Western Power (NWPP). This resulted in an eGRID
emissions factor of 879 lb. CO2e per MWh. This value was quite low, but did not
accurately reflect the sources of electricity being used by the region. In 2016,
EPA placed these plants back in the AZNM region. The 2016 eGRID emissions
factor was 1,049 lb. CO2e per MWh. This updated value was then used to
recalculate emissions from the 2015 GHG inventory to better reflect the
emissions intensity of the regional power grid. Between 2005 and 2015, the
City’s GHG emissions fell by 13.9%.
• Between 2015 and 2018, the GHG intensity of the regional electricity grid fell by
2.1%. Accordingly, GHG emissions from purchased electricity fell by 18,620 MT
CO2e.
o Buildings and Facilities GHG emissions from purchased electricity fell
16,925 MT CO2e between 2015 and 2018.
o GHG emissions Traffic Signals and Streetlights have decreased 10,090
MT CO2e (22%) since 2005 and 2,556 MT CO2e (6.6%) since 2015, with
some additional reduction from retrofitting traffic signals and streetlights
with LED bulbs.
o Water Services GHG emissions from purchased electricity increased 849
MT CO2e (0.7%) since 2015 due to a 2.8% increase in electricity
consumption from 254,622,318 kWh to 261,788,472 kWh.
• GHG emissions from the City’s vehicle fleet has increased 11,042 MT CO2e
since 2015 due to the addition of 2.4 million service miles by Public Transit to
meet T2050 goals.
o Specifically, Public Transit diesel fuel consumption increased by 756,631
gallons (46%) over 2015 levels to 2,392,579 gallons in 2018.
• GHG emissions from landfills fell 11,121 MT CO2e as the City’s closed landfills
continue to emit less methane.
• While the 27th Avenue Compost Facility is a new source of GHG emissions,
emitting 8,125 MT CO2e in 2018, the facility will save more GHG emissions over
its lifetime by reducing waste disposal at the SR-85 landfill.

Since 2015 Phoenix has implemented, or is in the process of implementing, several
projects in order to meet and surpass its original emissions reduction goal. These
projects include:
• Construction of the 27th Avenue Compost Facility.
• LED conversion of Traffic Lights and Streetlights that was completed in 2019.
• Continued expansion of the Valley Metro light rail system.
• Construction of PHX SkyTrain.
• The City generated 22,346,675 kWh of solar energy in 2018.

GHG emissions reductions have been achieved while population has grown by 282,292
over the same period (Figure ES-1). Accordingly, the per capita GHG intensity of the
City’s government operations have fallen from 0.49 to 0.36 MT CO2e per resident
between 2005 and 2018.

Figure ES-1. City of Phoenix Government Operations GHG Emissions and Population Between 2005 and 2018.

1 Introduction
In December 2008, the Phoenix City Council adopted a goal to reduce GHG emissions
from government operations to 5% below reported 2005 levels by 2015. To achieve this
goal, the City of Phoenix (City) established baseline GHG emissions and developed The
City of Phoenix 2009 Climate Action Plan for Government Operations. The report
forecasted a 14% increase in GHG emissions by 2015 if Phoenix maintained a
business-as-usual approach and did not take efforts to curb GHG emissions.
In 2013, the City commissioned Arizona State University’s Rob and Melani Walton
Sustainability Solutions Service to conduct a local government operations GHG
emissions inventory for 2012 to track progress toward the 2015 goal. The 2012
government operations GHG emissions inventory found that the City had already
reduced GHG emissions by 7.2%, meeting the 5% reduction goal. As a result, Phoenix
City Council adopted a new goal to reduce government operations GHG emissions 15%
below 2005 levels by 2015. The 2015 government operations GHG emissions inventory
found that the City achieved its 15% GHG emissions reduction goal. In 2017, the City
updated its government operations GHG emissions reduction goal to 40% below 2005
levels by 2025. However, this report revises 2015 GHG emissions total upward to reflect
updated EPA data on the GHG emissions intensity of the regional electricity grid. This
updated value was then used to recalculate emissions from the 2015 GHG inventory to
better reflect the emissions resulting from utilizing the regional power grid. Using
updated data, 2015 GHG emissions from City government operations fell by 13.9%.
The City of Phoenix 2018 Greenhouse Gas Emissions Inventory for Government
Operations summarizes the City’s progress toward reducing GHG emissions from
government operations 40% below 2005 levels by 2025.
The report structure is as follows:
• Section 2 provides an overview of the major findings of the 2018 GHG emissions
inventory of government operations.
• Section 3 describes the GHG emissions inventory boundary along with
methodological background and updates for the 2018 GHG Emissions reports.
• Section 4 summarizes results by reporting sector: Buildings and Facilities, City
Vehicle Fleet, Water Distribution and Wastewater Treatment Processes, Solid
Waste, and Employee Commute.
• Section 5 provides internal and external benchmarks for Phoenix operations.
• Section 6 summarizes biogenic CO₂ emissions, which are non-fossil CO₂
emissions that are not included in Phoenix’s total emissions.

2 Major Findings
In 2018, GHG emissions from City government operations were 605,701 MT CO₂e,
which is 15.4% below 2005 levels and 1.7% below 2015 levels (Figure 1).

Figure 1. City of Phoenix GHG Emissions from 2005 to 2018.

Additionally, all previous GHG emissions totals were revised in order to utilize the latest
IPCC GWP (AR5) for CH4 and N2O. Additionally, the 2015 GHG emissions total was
further revised to utilize the eGRID 2016 emissions factor for electricity consumption
rather than the eGRID 2014 emissions factor. Revised GHG emissions totals from City
government operations are:
2005: 716,143 MT CO₂e revised upwards from 696,490 MT CO₂e;
2012: 644,723 MT CO₂e revised upwards from 629,054 MT CO₂e; and
2015: 616,415 MT CO₂e revised upwards from 588,525 MT CO₂e.

The City reduced GHG emissions through a combination of internal and external
measures. Internal measures include increased waste diversion rates, city-led solar
power projects, energy efficiency upgrades, the incorporation of alternative fuels into the
vehicle fleet fuel portfolio, and upgrades to landfill gas capture systems.

External measures include a decrease in the EPA’s Emissions & Generation Resource
Integrated Database (eGRID) regional factor1. The carbon intensity of the AZNM
subregion fell by approximately 22%, translating into an emissions factor reduction from
1,316 lb. CO₂e/MWh in the eGRID 2005 to 1,027 lb. CO₂e/MWh in the eGRID 2018
data. eGRID 2018 is the latest publication year for eGRID data, so this emissions factor
is used for the 2018 calendar year. The 2015 GHG emissions were updated to use the
eGRID 2016 emissions factor instead of the 2014 eGRID emission factor. The eGRID
emissions factor for the AZNM subregion was anomalously low at 879 lb. CO₂e/MWh in
the eGRID 2014 dataset due to EPA methodology changes. GHG-intensity of the AZNM
subregion was 1,049 lb. CO₂e/MWh in the eGRID 2016 dataset. In 2014, these changes
resulted in the removal of 3 coal power plants (Navajo, Four Corners and San Juan)
from the Arizona New Mexico (AZNM) region to Northwest Western Power (NWPP). For
each GHG inventory, the decrease in the GHG intensity of the electricity grid has been
a significant contributor of emissions reductions by the City.

Between 2015 and 2018, GHG emissions from City government operations decreased
in almost every subsector except Fleet Fuels and Water Services, which increased
11,042 MT CO2e (9.3%) as shown in Table 1. Between 2015 and 2018, the increase in
Fleet Fuels GHG emissions were driven by increased CNG consumption (2,911,892
GGE) and diesel fuel consumption (801,961 gallons), which resulted in 18,413 MT
CO2e and 8,915 MT CO2e additional GHG emissions, respectively. However, over the
same period, LNG consumption fell 2,985,337 gallons and B20 biodiesel consumption
fell 366,741 gallons, reducing Fleet Fuel GHG emissions 13,434 MT CO2e. and 3,000
MT CO2e, respectively. In the Water Services sector, GHG emissions from electricity
usage and natural gas combustion only increased by 1,013 MT CO2e (0.8%) between
2015 and 2018 despite population growing by 4.8% over that same time period.

Other reductions in the City’s government operations GHG emissions are due to a
decrease in fugitive and process emissions – emissions from landfills, wastewater
treatment, and compost operations. Increases in City solar power generation has
helped to decrease emissions at city buildings and facilities. The switch to LED traffic
signals and streetlights has also reduced the GHG emissions from purchased utilities.

1 The eGRID database inventories the environmental attributes of electric power generation and its effect on air emissions for every
power plant in the United States. Phoenix is in the Arizona and New Mexico (AZNM) subregion. The Emissions & Generation
Resource Integrated Database (eGRID), developed by the EPA in collaboration with the Energy Information Administration (EIA),
the North American Electric Reliability Corporation (NERC), and the Federal Energy Regulatory Commission (FERC), is a
comprehensive source of data on the environmental characteristics of almost all electric power generated in the United
States. Detailed information can be found at http://www.epa.gov/cleanenergy/energy-resources/egrid/index.html.

Table 1 shows GHG emissions for City government operations subsectors for 2005-
2018 in comparison to population growth. All subsectors have seen a decrease in
emissions since 2005, but have leveled off since 2015. Further policy actions must be
taken to decrease emissions.

Table 1. GHG Emissions by Scope and Sector Between 2005 and 2018
Scope 1
2005
2012
2015
2018
2005-2018
Change
2005-2018
% Change
Stationary Combustion
7,404
7,329
6,377
6,085
-1,318
-17.8%
Fleet Fuels
132,709
133,425
118,706
129,748
-2,960
-2.2%
Fugitive and Process Emissions
142,165
87,073
131,932
129,707
-12,458
-8.8%
Scope 1 Total Emissions
282,277
227,827
257,015
265,540
-16,080
-5.9%

Scope 2
2005
2012
2015
2018
2005-2018
Change
2005-2018
% Change
Buildings Electricity
184,285
183,851
156,639
139,714
-44,571
-24.2%
Street Lighting
38,502
36,416
33,933
32,069
-6,433
-16.7%
Traffic Signals
7,733
7,157
4,755
4,075
-3,657
-47.3%
Water Services
155,368
137,793
121,153
122,002
-33,366
-21.5%
Scope 2 Total Emissions
385,888
365,217
316,481
297,860
-88,028
-22.8%

Scope 3
2005
2012
2015
2018
2005-2018
Change
2005-2018
% Change
Employee Commute
30,272
35,042
31,350
29,518
-754
-2.5%
Transmission and Distribution Loss
17,705
13,640
10,810
11,901
-5,804
-32.8
Granular Activated Carbon Hauling and
Regeneration
0
2,996
760
881
881
—
Scope 3 Total Emissions
47,977
51,679
42,919
42,301
-5,677
11.8%

GHG Inventory
2005
2012
2015
2018
2005-2018
% Change
2005-2018
% Change
Total Scope 1 and 2 Emissions
668,165
593,044
573,496
563,400
-104,765
-15.7%
Total Scope 1, 2, & 3 Emissions
716,143
644,723
616,415
605,701
-110,442
-15.4%
City of Phoenix Population
1,377,980
1,473,405
1,537,058
1,660,272
282,292
20.5%

3 Methodology
3.1 Local Government Operations Protocol
Phoenix’s 2005 baseline emissions inventory was based on the Local Government
Operations Protocol (LGOP), developed by the International Council for Local
Environmental Initiatives (ICLEI – now officially called ‘ICLEI- Local Governments for
Sustainability’), the California Climate Action Registry (CCAR), the California Air
Resources Board (CARB), and The Climate Registry (The Registry). The LGOP serves
as a national standard for quantifying and reporting emissions associated with
government operations. To ensure consistency, the ASU and NAU team has used the
2010 version (Version 1.1) of the protocol for the 2005, 2012, 2015, and 2018 emissions
inventories.

The LGOP provides a methodology for the calculation of GHG emissions from
numerous sources and for the development of a comprehensive inventory report.
Activity data are collected from a GHG emissions source and multiplied by an emission
factor (e.g., metric tons CO₂ emitted per kWh) to calculate the total emissions. Where
activity data are not available, they are modeled. The LGOP provides emission factors
for most calculation methodologies used in the report. Measured or calculated
emissions are then converted to carbon dioxide equivalent emissions (CO₂e) using the
IPCC AR5 GWP factors2 shown in Appendix A.

3.2 Scope Classifications and Sectors
GHG emissions from government operations are categorized as Scope 1, 2, or 3
emissions. Scope categories indicate whether GHG emissions are direct or indirect in
order to improve transparency and to inform different types of climate policies and
goals. The Scope categories are illustrated in Figure 2.

• Scope 1: All direct emissions from operational sources owned or controlled by the
City.
• Scope 2: Indirect emissions associated with the consumption of purchased or
acquired electricity, steam, heating or cooling that occur at sources not owned or
controlled by the City.

2 Greenhouse Gas Protocol, 2016. Global Warming Potential Values. URL:
https://www.ghgprotocol.org/sites/default/files/ghgp/Global-Warming-Potential-Values%20%28Feb%2016%202016%29_1.pdf

• Scope 3 (optional under the protocol for cities to include in their inventories): All
other indirect emissions not covered in Scope 2, such as transport-related activities
in vehicles not operated by Phoenix (e.g., employee commuting and business
travel) and other outsourced activities. This report includes employee commuting
and outsourced granular activated carbon (GAC) hauling and regeneration activity
as Scope 3 emissions.
This report is organized into five sectors to make it more compatible for policy making
and project management teams.

• Buildings and Facilities
• City Vehicle Fleet
• Water Distribution and Wastewater Treatment
• Solid Waste
• Employee Commute

Figure 2. Overview of LGOP Scopes and Emissions Sources.3

3 Source: The City of Phoenix 2005 GHG Emissions Inventory for Government Operations (2009). Adopted from World Resources
Institute GHG Protocol Corporate Accounting and Reporting Standard (Revised Edition), Chapter 4, 2004.

3.3 City of Phoenix Government Operations Boundary
The LGOP provides two approaches for defining the boundaries of what to include in
the government operations GHG inventory: the first approach is operational control and
includes those operations in which the local government has the authority to introduce
and implement operating policies; the second is financial control and includes those
operations that are fully consolidated in financial accounts. More detail on both
approaches can be found in the LGOP Version 1.14.

This inventory uses the operational control approach as it most accurately represents
GHG emissions sources within the City’s control. The boundaries of the 2018 inventory
generally follow the same guidelines as the 2005 baseline inventory. However, Scope 3
GHG emissions – emissions resulting granular activated carbon (GAC) hauling and
regeneration and electricity transmissions and distribution (T&D) loss – and biogenic
emissions were added into the 2012 inventory, and have been included in each
inventory since. The 27th Avenue Compost Facility is the only new GHG emissions
source added in the 2018 inventory. A detailed description of considerations of the
City’s operational control boundary is located in Appendix B.

3.4 Inventory Changes Since 2005
The 2018 GHG emissions inventory methodology generally follows that of the 2005
inventory. With each emissions inventory, technical improvements are made to more
accurately quantify emissions. In 2010, ICLEI and partners released the latest LGOP
Version 1.1. This update included several changes to figures, methods, and other
factors. Additionally, the 2005 and 2012 GHG emissions inventory utilized
Intergovernmental Panel on Climate Change (IPCC) AR2 Global Warming Potential
(GWP) emissions factors; the 2015 GHG emissions inventory utilized IPCC AR4 GWP
emissions factors; and the 2018 GHG emissions inventory utilizes IPCC AR5 GWP.
This procedure of updated GWP factors, found in the EPA U.S. Greenhouse Gas
Inventory Report, complies with the United Nations Framework Convention on Climate
Change (UNFCCC) reporting guidelines for national inventories, requiring the use of the
latest GWPs for national GHG emissions inventories5.

The following changes have been made to the City government operations GHG
emissions inventory since the baseline inventory:

4 ICLEI USA, 2020. Greenhouse Gas Protocols. URL: https://icleiusa.org/ghg-protocols/
5 UNFCCC Secretariat, 2014. Report of the Conference of the Parties on its nineteenth session, held in Warsaw from 11 to 23
November 2013. Decision 24/CP.19, paragraph 2. URL: http://unfccc.int/resource/docs/2013/cop19/eng/10a03.pdf.

• Estes Landfill was added to all inventory years;
• Employee commuting emissions at sites with less than 50 employees added to
the 2005 inventory year;
• In 2005, wastewater treatment emissions were estimated using population-based
data. In 2012, 2015, 2018 site-specific data were used where applicable;
• Inventory-year specific T&D loss rates are used;
• Biogenic emissions are calculated for all inventory years;
• The 2018 inventory year utilizes eGRID 2018, which is the most up-to-date
eGRID data available;
• In 2005, the City did not have any solar power, while 2018 has electricity
production data from solar installations; and
• The 2018 GHG emissions inventory includes emissions from the 27th Avenue
Compost Facility.

Finally, GHG emissions for 2015 were revised upwards to reflect updated data from
EPA on the GHG emissions intensity of the regional electricity grid. GHG emissions
from electricity consumption are calculated by multiplying the amount of electricity
consumed by an emissions factor given in CO2e emissions per MWh generated. EPA
determines the emissions factor in eGRID, takes into account the environmental
emissions characteristics of power plants (coal, natural gas, nuclear, solar, etc.), and
groups power plants to estimate the GHG intensity of electricity production for U.S.
regions. In 2014, EPA changed the power plant grouping methodology and moved three
coal power plants (Navajo, Four Corners, and San Juan) from the Arizona New Mexico
(AZNM) subregion, which the City is in, to the Northwest Western Power (NWPP)
subregion. The methodology change resulted in an AZNM emissions factor of 879 lb.
CO2e per MWh, which was quite low, and did not accurately reflect regional electricity
generation. In 2016, EPA placed the three coal power plants back in the AZNM
subregion. The 2016 AZNM eGRID emissions factor was 1,049 lb. CO2e per MWh. The
2016 AZNM eGRID value was used to recalculate electricity emissions for the 2015
GHG inventory to represent the GHG emissions intensity of the regional power grid
more accurately. Between 2005 and 2015, the City’s GHG emissions fell by 13.9%.

3.4.1 Estimating Tailpipe Emissions of Methane and Nitrous Oxide
The methodology used to estimate tailpipe methane (CH4) and nitrous oxide (N2O)
emissions changed between the 2005 and 2015 GHG emissions inventories. In 2005,
the Clean Air-Cool Planet’s GHG modeling software was used to estimate fleet
emissions of CH4 and N2O. The 2018 inventory uses the Climate Registry’s simple

estimation method for tailpipe CH4 and N2O emissions based upon fuel carbon dioxide
content, providing a standard estimation of these emissions across fuel and vehicle
types. Using this method, CH4 and N2O emissions factors were developed for 2005,
2012, 2015, and 2018 using the EPA Inventory of U.S. Greenhouse Gas Emissions and
Sinks6. This method avoids the need to track vehicle mileage.

3.4.2 2005 Wastewater Treatment Methane and Nitrous Oxide Emissions
Wastewater treatment CH4 and N2O emissions for 2005 were obtained from the City of
Phoenix 2015 Greenhouse Gas Emissions Inventory for Government Operations.
Please refer to that report for an explanation for the backcasting methodology to
estimate 2005 emissions levels.

3.4.3 Alternative Fuel Estimates for Employee Commuting
Employee commuting data is based on an annual survey conducted by the Maricopa
County Trip Reduction Program (TRP) regarding commuting throughout the work week.
Alternative fuel combustion data were obtained Energy Information Administration (EIA)
Annual Energy Outlook to estimate alternative fuel employee commuting. It was
assumed that national alternative fuel combustion levels provided a proxy for alternative
fuel combustion patterns for City employees7.

3.4.4 Estimating Compost Emissions
In 2017, the City began operating the 27th Avenue Compost Facility. While a compost
operation did exist within City boundaries prior to 2018, this facility was neither owned
nor operated by the City. GHG emissions from composting were calculated according to
EPA methodology for estimating national-level emissions from composting in the
Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-20178.

6 U.S. EPA (2019). Inventory of U.S. Greenhouse Gas Emissions and Sinks. URL: https://www.epa.gov/ghgemissions/inventory-us-
greenhouse-gas-emissions-and-sinks 2.
7 U.S. Energy Information Administration (2013). Annual Energy Outlook. URL: https://www.eia.gov/outlooks/aeo/
8 U.S. EPA. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2017. URL:
https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-1990-2017

4 Results
4.1 Summary

4.1.1 2005 to 2018: What has Changed?

With the 2018 GHG emissions inventory of government operations, the City is
developing a dataset of how GHG emissions from government operations have evolved
since 2005 (Figure 3). Numerous projects and activities undertaken by the City since
2005 have affected the GHG emissions from government operations over the last
thirteen years. Projects and activities, and how they have affected the 2018 City
government operations GHG emissions, are listed below.

• The installation of advanced methane capture systems at landfills reduced
fugitive methane emissions from City landfills.
• Transitioning City Fleet to B20 biodiesel and CNG from diesel have reduced
public transit GHG emissions since 2005. Fuel consumption increased between
2015 and 2018 in order to meet T2050 goals.
• Energy efficiency upgrades to buildings and facilities, streetlights, traffic signals,
water treatment and distribution, and wastewater treatment.

2018 Overall Findings
City of Phoenix government operations decreased GHG
emissions 15.4% below 2005 levels.

Emissions Sources*
• Buildings and Facilities** — 188,205 MT CO2e
• City Vehicle Fleet — 129,748 MT CO2e
• Employee Commute — 29,518 MT CO2e
• Solid Waste — 119,508 MT CO2e
• Water Distribution and Wastewater Treatment — 138,721 MT CO2e

*Above GHG emissions represent all emissions within a sector across all emissions scopes.
** Excludes Water Services.

• Solar power facilities, such as the Lake Pleasant solar installation, reduce the
amount of electricity the City purchases from the electricity grid.
• The construction of the Sky Train at the Phoenix Sky Harbor International Airport
has reduced fossil fuel usage for ground transportation, but further study is
required to accurately estimate the GHG emissions reduction from the Sky Train.
• Implementing diversion policies, such as the utilization of the 27th Avenue
Compost Facility to divert material from the landfill and produce an
environmentally beneficial, salable product.

Beyond projects and activities undertaken by the City, the GHG intensity of the regional
electricity grid – the Arizona-New Mexico (AZNM) eGRID subregion – has fallen by 22%
from 1,316 lb. CO₂e/MWH in 2005 to 1,027 lb. CO₂e/MWH in 2018. The closing of the
Navajo Generation Station in 2019, as well as other regional coal power plant closures
planned for the next five years, will further reduce the GHG intensity of AZNM subregion
of the electricity grid.

Figure 3. GHG Emissions by City Sector for 2005, 2012, 2015, and 2018

Between 2005 and 2018, the City’s population increased by 20.5% from 1,377,9809 to
1,660,27210 residents. Some government operation GHG emissions are population
dependent – e.g., aspects of solid waste disposal, wastewater treatment and discharge,
and vehicle fleet emissions – the majority of the City’s GHG emissions are electricity-
dependent. The regional electricity grid becoming less carbon-intensive has had a
stronger influence on the City government operations GHG emissions than population
growth. If the reduction in the GHG intensity of the regional electricity grid had not
occurred, GHG emissions from City government operations would have decreased only
by 3.3% between 2005-2018 – instead GHG emissions decreased 15.6%. A less
carbon-intensive regional electricity grid, which includes the solar power development
undertaken by the City, has resulted in an additional 12.3% GHG emissions reduction.

4.1.2 Emissions Sources and Distribution
City government operations GHG emissions are largely attributed to four sectors:
Buildings and Facilities, Vehicle Fleet, Water Services, and Fugitive and Process
Emissions from solid waste disposal and wastewater treatment. Figure 4 provides an
overview of the relative magnitude of GHG emissions by Scope and Subsector.

9 U.S. Census Bureau (2005). American Community Survey. URL:
https://factfinder.census.gov/bkmk/table/1.0/en/ACS/05_EST/S0101/1600000US0455000
10 U.S. Census (2020). Quick Facts: Phoenix city, Arizona. URL: https://www.census.gov/quickfacts/phoenixcityarizona

Figure 4. 2018 Emissions by Scope and Subsector

Scope 1 and Scope 2 GHG emissions account for 94% of GHG emissions from City
government operations. Purchased electricity (Scope 2 emissions) accounts for 50% of
City government operations GHG emissions (Table 2) and, more specifically, Buildings
and Water Services represents 23% and 20% of total GHG emissions, respectively.
Scope 1 GHG emissions from Fleet Fuels and Fugitive and Process Emissions each
account for approximately 21% of total GHG emissions. Combined, these four sectors
comprise 85% of City government operations GHG emissions. As the regional electricity
grid becomes less GHG-intensive, Scope 2 GHG emissions will comprise a smaller
proportion of the City government operations GHG emissions inventory.

Table 2. 2018 GHG Emissions by Scope and Subsector

Scope 1
Scope 2
Scope 3
Sector
GHG
Emissions
(MT CO2e)
% of Total
Emissions
GHG
Emissions
(MT CO2e)
% of Total
Emissions
GHG
Emissions
(MT CO2e)
% of Total
Emissions
Stationary Combustion
6,085
1%

Fleet Fuels
129,748
21%

Fugitive and Process Emissions
129,707
21%

Buildings Electricity

139,714
23%

Street Lighting

32,069
5%

Traffic Signals

4,075
1%

Water Services

122,002
20%

Employee Commute

29,518
5%
Transmission and Distribution

11,901
2%
GAC Hauling and Regeneration

881
0%
Total
265,540
44%
297,860
49%
42,301
7%
4.1.3 GHG Emissions Reductions Since 2005
Total emissions fell from the 716,143 MT CO2e in 2005, to 605,701 MT CO2e in 2018.
Scope 1 and 2 GHG emissions have decreased in all emissions sectors. All GHG
emissions subsectors have decreased emissions since 2005 (Figure 5).

Figure 5. Emissions Changes between 2005 and 2018.

The Buildings Electricity and Water Services subsectors and have had the largest
observed decreases in GHG emissions between 2005 and 2018 – 24% (Buildings
Electricity) and 21% (Water Services). The observed GHG emissions reductions in
these subsectors were driven by several factors. First, the regional electricity grid
became less GHG intensive. A less GHG intensive regional electricity grid has led to the
reduction of 83,745 MT CO2e. City efforts to build and purchase solar power has led to
a reduction of 10,414 MT CO2e, of which 9,116 MT CO2e resulted from solar power
projects developed by the Water Services Department. Finally, energy efficiency
projects have led to GHG emissions reductions, but exact emissions reductions are
difficult to quantify.
Additional factors that contribute to the observed GHG emissions reduction include:
• Solar power generation reduced emissions by 10,414 MT CO2e in 2018.
• The aging of closed landfills that emit less methane over time; and
• Transitioning city buses to CNG from LNG and diesel.

5 Findings by Sector for 2018
5.1 Buildings and Facilities

5.1.1 2005 to 2018: What has Changed?
• Between 2005 and 2018, the GHG emissions intensity of the AZNM subregion of
the U.S. electricity grid fell by 22%.
• The City began to generate its own solar power and now generates 3.3% of all
electricity consumed by government operations.
• These two factors are the largest drivers of the decrease in GHG emissions
trends.

Building and Facilities Findings
Total Emissions: 303,945 MT CO₂e
50% of government operations emissions
22.7% decrease from 2005 levels

Emissions Sources
• Building Electricity Consumption
• Building Natural Gas Consumption
• Streetlights Electricity Consumption
• Traffic Signals Electricity Consumption
• Water Services Electricity and Natural Gas Consumption*

City Action Highlights
• Solar Power Generation totaled 22,346,675 kWh
• To date, the City has installed:
o 94,865 LED Street Lights
o 63,090 LED Signal Indications
o 9,308 LED Pedestrian Indications

*Water Services electricity and natural gas consumption are included because this section
describes trends for all electricity and natural gas consumption.

5.1.2 Emissions Sources and Distribution
GHG emissions in the Buildings and Facilities sector occur directly from the combustion
of natural gas purchased from a natural gas utility and indirectly from the purchase of
electricity (Figure 6).

Figure 6. Buildings and Facilities GHG Emissions Between 2005 and 2018

GHG emissions from the combustion of purchased natural gas fell by 17.8% between
2005 and 2018,with 4.6% between 2015 and 2018. Additionally, GHG emissions from
purchased electricity decreased 22.8% below 2005 levels and by 5.9% below 2015
levels. The steep decline in Buildings and Facilities GHG has occurred due to multiple
City actions. A less GHG intensive regional electricity grid has led to the reduction of
83,745 MT CO2e. City efforts to build and purchase solar power has led to a reduction
of 10,414 MT CO2e, of which 9,116 MT CO2e resulted from solar power projects
developed by the Water Services Department. Refer to Appendix C & D for a list of City
solar projects. Finally, energy efficiency projects have led to GHG emissions
reductions, but exact emissions reductions are difficult to quantify.

Electricity consumption by Streetlights and Traffic Signals have shown marked
decreases. Streetlights electricity consumption peaked in 2015 at 71,316,538 kWh and
has since fallen 4% to 68,812,574 kWh, which is only 7% above 2005 levels. Traffic
Signals electricity consumption in 2018 were 30% lower than reported consumption in
2005 and 2012. The observed decrease in electricity consumption has occurred over a
period during which the City has invested heavily in LED retrofits of Streetlights and
Traffics Signals. These energy efficiency upgrades, along with a less GHG intensive
electricity grid, have resulted in 47% fewer GHG emissions from traffic signals between
2005 and 2018 and a reduction of 14% since 2015.

Table 3. 2018 Buildings and Facilities Emissions by Subsector
Subsector
Electricity
Consumption
(kWh)
Solar Power
Generation
(kWh)
Natural Gas
Consumption
(therms)
GHG
Emissions
(MT CO2e)
Buildings and
Facilities
299,794,866
2,785,675
1,000,901
145,035
Street Lighting
8,744,680
--
--
32,069
Traffic Signals
68,812,574
--
--
4,075
Water Services
261,788,472
19,561,000
143,807
122,766
Total
639,140,592
22,346,675
1,144,708
303,945

Solar power generation has had a significant role in the reduction of emissions for
Buildings and Facilities. Between 2005 and 2018, Phoenix has continued its
commitment towards its goal of obtaining 15% of electricity from renewable sources.
Solar projects offset 3.3% of Buildings and Facilities electricity demand. Table 4 shows
the breakdown of onsite solar power generation by department. The Aviation and Water
Services Departments generated the most solar power – 2,270,760 and 19,561,000
kWh, respectively – and Water Services Department has the highest proportion of its
electricity demand met by solar power (7%). Overall, the City was able to avoid 10,633
MT CO2e. Further renewable energy policies and projects must be developed to
continue to decrease emissions from Buildings and Facilities.

Table 4. Departmental Energy Consumption and Solar Power Generation
Department*
2018 Usage
(kWh)
2018 Solar
Power
Generation
(kWh)
% Departmental
Electricity Demand
Met by Solar
Avoided GHG
Emissions
(MT CO2e)
Aviation
146,025,156
2,270,760
2%
1,058
Convention Center
27,653,971
0
0%
0
Fire
14,441,510
15,635
0%
7.29
Human Services
1,599,797
62,683
4%
29
PRLD - Recreation
32,070,516
57,394
0%
27
Public Transit
1,145,577
32,623
3%
15
Public Works
35,968,380
346,580
1%
162
Water Services
261,788,472
19,561,000
7%
9,116
Total
537,372,239
22,346,675
4%
10,414
*Departments without solar power generation are not included in the table.

5.1.3 GHG Metrics: Buildings and Facilities
Table 5 provides a list GHG metrics for City buildings and facilities. Since 2005, the per
capita GHG emissions intensity for government operations has fallen 37% and the per
FTE GHG emissions intensity city operations has fallen 24%.

Table 5. Buildings and Facilities Emissions Indicators and Percent of Change
Indicator
2005
2012
2015
2018
Building Space (sq. ft.)
25,948,884
30,624,893
12,599,324
11,495,864
Building Space GHG Emissions Intensity (kg CO₂e per sq. ft)
7.35
6.22
12.89
12.62
Per Capita GHG Emissions Intensity (kg CO₂e per resident)
138.4
129.3
105.7
87.4
Electricity GHG Emissions per CDD (kg CO₂e per CDD)
39.1
36.3
30.9
28.3
FTE GHG Emissions Intensity (kg CO₂e per FTE)
13.00
12.64
11.08
9.92

5.2 City Vehicle Fleet

5.2.1 2005 to 2018: What has Changed?
• The size of Public Works fleet peaked in 2015 with 7,389 vehicles and has since
dropped to 7,340 vehicles.
• The majority of the diesel fleet vehicles operated by Public Works and Aviation
have converted to B20 biodiesel and CNG. However, Ultra Low Sulfur diesel fuel
continues to be used in specific situations, such as emergency generators and
fueling sites with low throughput. Aviation has plans to convert to electric-
powered ground equipment.
• The completion of the PHX SkyTrain in 2021 will decrease emissions as the
CNG-powered passenger fleet will be retired.
• At 2018 consumption-levels, the adoption of CNG and B20 biodiesel in lieu of
diesel consumption avoids the emission of 56,067 MT CO2e. Transitioning diesel
City Vehicle Fleet Findings
Total Emissions: 129,748 MT CO₂e
21.4% of government operations emissions
2.2% decrease from 2005 levels

Emissions Sources
• Gasoline
• Diesel
• Compressed Natural Gas (CNG)
• Biodiesel
• Liquefied Natural Gas (LNG)
• Liquefied Petroleum Gas (LPG)
• Ethanol
• Aviation gasoline (Police Department Aircraft)
• Jet Fuel A (Police Department Aircraft)
City Action Highlights
• Biodiesel alternative fuel program
• Ethanol alternative fuel program
• Adoption of CNG in Public Transit

fleet to CNG vehicles has reduced 31,709 MT CO2e of GHG emissions, while the
adoption of B20 biodiesel has saved 24,358 MT CO2e.
• GHG emissions from diesel and CNG have increased since 2015 due to the
addition of 2.4 million service miles as part of the City’s Transportation 2050 Plan
to increase local bus frequency by building out the existing city bus network,
increasing service hours of bus operations, and introducing new bus routes,
which includes the introduction of bus rapid transit corridors.

5.2.2 Emissions Sources and Distribution
In 2018, CNG vehicles were the largest source Vehicle GHG emissions followed by
gasoline vehicles. The increase in CNG vehicle emissions has resulted from the shift
away from diesel vehicles. GHG emissions from diesel vehicles were highest in 2005
and decreased 53% by 2018. GHG emissions from diesel vehicles increased by 8,195
MT CO2e between 2015 and 2018 due to an increase in public transit service miles to
meet T2050 goals. GHG emissions from gasoline, B20 biodiesel, and E85 ethanol
vehicles have remained largely flat since 2012. Additionally, aviation-based emissions
from Jet Fuel A and Aviation Gasoline, which are a small percentage of Vehicle Fleet
GHG emissions, have also remained flat.

Figure 7 shows Vehicle Fleet GHG emissions by fuel type and have slightly decreased
by 2.2% since 2018, largely due to the inclusion of alternative fuels. GHG emissions for
B20 biodiesel and E85 ethanol are shown. Only the fossil fuel component of biofuel
GHG emissions – 80% of each gallon of B20 biodiesel and 15% of each gallon of E85
ethanol – is counted toward GHG emission totals plotted in Figure 7.

Figure 7. Vehicle Fleet Emissions by Fuel Between 2005 and 2018

As shown in Table 6, CNG fuel consumption has increased 89% between 2015 and
2018. The CNG fuel consumption increase occurred along with an increase in diesel
fuel consumption by 45% and a decrease in LNG consumption by 85% between 2015
and 2018. The major changes to the levels of CNG, diesel, and LNG fuel consumption
was driven by Public Transit, which increased CNG fuel consumption by 147%,
increased diesel fuel consumption by 46%, and decreased LNG consumption by 85%.
Fuel increases were due to Public Transit increasing service miles by 2.4 million miles.
The City began replacing LNG buses with more efficient CNG busses in 2013; all LNG
buses will be retired by the end of FY 2020. No other major changes in fuel
consumption were observed between 2015 and 2018.

Table 6. Changes in Total City Fleet Fuel Consumption
Fuel Type
Unit
2005
2012
2015
2018
Gasoline
gallon
3,172,441
3,976,124
3,813,990
3,936,224
Diesel
gallon
5,452,613
3,324,829
1,777,341
2,579,301
B20 Biodiesel
gallon
0
3,034,345
3,394,710
3,027,969
Compressed Natural Gas (CNG)
GGE*
1,744,813
1,349,993
3,239,129
6,151,022
Liquefied Natural Gas (LNG)
gallon
7,917,008
6,200,897
3,528,633
543,296
E85 Ethanol
gallon
0
287,438
340,753
311,460
Liquified Petroleum Gas (LPG)
gallon
14,392
0
0
0
Aviation Gasoline (AvGas)
gallon
2,401
5,975
4,961
4,875
Jet Fuel A
gallon
163,160
222,283
202,119
192,739
*GGE – Gasoline Gallon Equivalent
5.2.3 GHG Metrics: Vehicle Fleet
Emissions per vehicle maintained by Public Works fell from approximately 9.2 to 6.7 MT
CO₂e per vehicle, despite an increase to the number of vehicles (Table 7). The data
shown in Table 7 are for Public Works vehicles only.

Table 7. City Fleet Indicators Change
Indicator
2005
2012
2015
2018
Number of Vehicles
6,090
7,387
7,389
7,340
MT CO₂e per Vehicle
9.2
7.1
6.6
6.7

5.3 Water Services
5.3.1 2005 to 2018: What has Changed?
• The Cave Creek Water Reclamation Plant was taken offline in January 2010 as
an efficiency measure due to wastewater flows into the plant being at only half of
the plant capacity. Future wastewater flows will be reviewed to determine if there
is a need to return the plant to service.
• In January 2007, the Lake Pleasant Water Treatment Plant (WTP) came online.
The Verde WTP was closed in December 2011 and the lease with the Salt River
Pima Maricopa Indian Community for the use of the site was extended.
• In 2018, the Water Servicers department treated 110.5 billion gallons of water
and 65.6 billion gallons of waste water. The volume of water treated has
increased 4% since 2005 while the volume of wastewater treated has decreased
6%.
• The Water Services department finished construction of a 7.5 MW solar power
facility at the Lake Pleasant WTP in 2013. The overall reduction of GHG
emissions was largely due to the onsite solar power generation by Water
Services.
• The emissions from the hauling and regeneration of granular activated carbon
(GAC) for water treatment did not occur in 2005, but have been included in the
GHG inventory since 2012.
Water Services Findings
Total Emissions: 138,721 MT CO₂e
22.9% of government operations emissions
19.3% decrease from 2005 levels
Emissions Sources
• Water distribution stationary & process emissions
• 23rd Avenue and 91st Avenue wastewater treatment plants stationary &
process emissions
• Granular activated carbon (GAC) hauling and regeneration
• Electricity and natural gas use
City Action Highlights
• Water Service Department’s Lake Pleasant solar facility generates 19.56
million kWh
• Water conservation and less volumes at WTPs and WWTPs have reduced
pumping and treatment energy requirements

5.3.2 Emissions Sources and Distribution
Water Services sector GHG emissions are generated by a variety of sources. GHG
emissions can occur from the combustion of purchased natural gas, the consumption of
purchased electricity, methane generation during water treatment, and N2O emissions
from wastewater effluent. GHG emissions also occur during the hauling and
regeneration of GAC filters used in the treatment process to remove disinfection
byproducts.

GHG emissions from Water Services decreased 18.8% between 2005 and 2018, but
have increased 2.8% since 2015. The emissions decreases since 2005 have occurred
due to energy efficiency measures, like plant closures, and onsite solar power
generation. While there are a variety of potential Water Services GHG emissions
sources, only one activity makes up the vast majority of GHG emissions from this
sector. Electricity consumption by Water Services has comprised over 90% of GHG
emissions from this sector (Figure 8). These emissions can be offset by renewable
energy credits in addition to further on-site renewable energy development and battery
storage projects. Some Water Services emissions from the treatment of wastewater –
methane flaring and wastewater discharge –are largely population-driven. Projected
population increases over the next decade will potentially increase GHG emissions in
this sector unless further mitigation efforts are undertaken.

Figure 8. Water Services Emissions Changes Between 2005 and 2018

The changes in the GHG emissions observed at the 23rd Avenue and 91st Avenue
WWTPs are due to a combination of population change as well as the changes in
operation at the WWTPs. Therefore, these emissions Changes in emissions for each
Water Services subsector are shown in Figure 9.

Figure 9. Wastewater Treatment GHG Emissions Between 2005 and 2018

GHG emissions at the 23rd Avenue and 91st Avenue WWTPS are shown in Table 8. The
91st Avenue WWTP is the larger of the two WWTPs and emits more than twice the GHG
emissions of the 23rd Avenue Plant. The increase in GHG emissions between the 91st
Avenue and 23rd Avenue comes from process N2O emissions; CH4 emissions from the
incomplete combustion of digester gas is similar at both WWTPs.

The 91st Avenue WWTP accepts wastewater from Glendale, Mesa, Scottsdale, and
Tempe. Currently, the City accounts for all GHG emissions at the 91st Avenue WWTP
because the plant is under the City’s operational control. As other cities develop their
own emissions inventories, the emissions from 91st Ave. may be distributed differently.

Table 8. GHG emissions at the 23rd Avenue and 91st Avenue WWTPs
Wastewater GHG Emissions Source
Wastewater Treatment Plant
Total
23rd Avenue
91st Avenue
Stationary CH4 Emissions
Incomplete Digester Gas
Combustion

1,860
1,911
3,771
Process N2O Emissions
Effluent Discharge
428
1,486
1,914
Nitrification/Denitrification
1,034
3,480
4,515
Total
3,322
6,877
10,199

5.3.3 GHG Metrics: Water Services
Water Services indicators in Table 9 below shows that the GHG intensity of drinking
water served by the City has consistently decreased since 2005.

Table 9. Water Services Emissions Indicators
Indicator
2005
2012
2015
2018
Gallons of Drinking Water Treated (billion gallons)
105.9
112.4
106.0
110.5
MT CO₂e per Billion Gallons Treated
1,556
1,310
1,238
1,203
Water Treatment Plants
6
5
5
5
MT CO₂e per WTP
27,471
29,447
26,236
26,593
Million Gallons of Wastewater Treated
69,523
69,524
65,442
65,600
MT CO₂e per Million Gallons Wastewater Treated
2.37
2.12
2.00
2.03

5.4 Solid Waste

5.4.1 2005 to 2018: What has Changed?
• In 2006, the State Route 85 (SR-85) landfill was opened and features an ongoing
installation of a landfill gas collection system, which includes horizontal wells that
can capture gas while waste is still being placed in the landfill.
• In 2017, the City opened the 27th Avenue Compost Facility. This facility will
reduce long-term GHG emissions associated with the hauling and disposal of
green & organic solid waste at the SR-85 Landfill.

5.4.2 Emissions Sources and Distribution
The SR-85 landfill, which opened in 2006, is the only operational landfill managed by
the City. The SR-85 has an active landfill gas collection system which has a 65%
collection efficiency. Collection efficiencies at City landfills ranged from 50-85%. The Del
Rio Landfill is the only City landfill that does not have a landfill gas collection system.
Methane emissions are expected to increase at the SR-85 landfill in the future as it is
the only active landfill in the City. However, methane emissions are expected to decline
at the other City landfills as these landfills are closed (Figure 10).
Solid Waste Findings

Total Emissions: 119,508 MT CO₂e
19.8% of government operations emissions
10% decrease from 2005 levels

Emissions Sources
• City landfills emitted 111,383 MT CO2e
• The 27th Avenue Compost Facility emitted 8,125 MT CO2e

City Action Highlights
• 27th Avenue Compost Facility will help avoid future GHG emissions

Figure 10. Phoenix Landfills Emissions Changes between 2005 and 2018

Table 10 provides an overview of the amount of methane (CH₄) collected and flared, the
resulting methane released after flaring, and the MT CO₂e emissions produced from the
released methane at each facility.

Table 10. 2018 Solid Waste Emissions by Landfill
Landfill
Tons CH₄
Collected/Flared
Tons CH₄
Released
MT CO₂e
Emissions
Skunk Creek
4,970
645
18,047
27th Avenue
2,232
264
7,403
Del Rio
312
158
4,419
Deer Valley
208
59
1,664
19th Avenue
472
129
3,598
Estes
694
694
19,432
SR-85
7,163
2,029
56,820
Total
16,051
3,978
111,383

Landfill GHG emissions in this report will differ from data reported to the EPA for its
GHG mandatory reporting. This GHG update uses formulas contained in the LGOP to
calculate emissions, while EPA utilizes a different methodology for both GHG emissions
and estimated gas collection system capture rates. EPA specifies use of a capture rate

formula which relies on cover type and area, this GHG update estimates capture rates
at city landfills using operational indicators, such as status of ongoing gas well
installation at SR-85, which includes horizontal wells, surface monitoring, flare data, and
landfill cover maintenance.

5.4.3 27th Avenue Compost Facility
In 2017, the City opened the 27th Avenue Compost Facility. The facility processed
46,768 tons of compost in CY 2018, resulting in the emission of 170 MT CH4 and 13 MT
N2O. Total GHG emissions from the compost facility were 8,125 MT CO2e. This facility
will reduce long-term GHG emissions associated with the hauling and disposal of green
& organic solid waste at the SR-85 Landfill.

Over its lifetime, the 27th Avenue Compost Facility will have a net negative effect on
GHG emissions from City government operations. Though the facility does emit GHG
emissions, composting green organic solid waste will emit fewer GHG emissions than
disposal at the SR-85 Landfill. Since methane is the primary GHG emitted from
composting and landfilling, any GHG reduction will have a multiplier effect (Table A1).
Additionally, composting at the 27th Avenue Compost Facility reduces the number of
trips necessary to haul waste to the SR-85 Landfill, which in turn reduces Vehicle Fleet
emissions. For these reasons, GHG emissions reductions from the 27th Avenue
Compost Facility will be tangible and measurable in the future.

5.4.4 GHG Metrics: Solid Waste
Table 11 shows Solid Waste sector GHG indicators for the City.

Table 11. GHG Emissions Indicators for Solid Waste
Indicator
2005
2012
2015
2018
Amount of Waste in Place (short tons)
44,030,052
50,257,923
52,405,666
54,666,679
Kg CO₂e Per Ton of Solid Waste in Landfills
3.037
1.558
2.338
2.215
Compost Processed (short tons)
—
—
—
46,768
Kg CO₂e Per Ton of Compost Processed
—
—
—
173

5.5 Employee Commute

5.5.1 2005 to 2018: What has Changed?
• City employees fill out surveys as part of the Trip Reduction Program (TRP)
overseen by Maricopa County Air Quality Department. The TRP, which started in
1989, provides employers a yearly analysis of employee community statistics
and behaviors.
• Employee commuting from 2005 did not include miles by bus or light rail as this
data was not available. Bus and light rail commuting data were available for the
2012, 2015, and 2018 GHG emissions inventories.
• Employee commuting using city vehicles is counted in the City Vehicle Fleet
sector to avoid double counting.

5.5.2 Emissions Sources and Distribution
Employee commuting by employees in 2018 increased by 3.6% from 2005 levels to
87,386,610 miles. However, due to increasing motor vehicle fuel efficiency in the U.S.
auto fleet, required by the Energy Policy and Conservation Act, the associated GHG
emissions fell by 5.8% to 29,519 MT CO2e (Table 12). Employee commuting GHG
Employee Commute Findings

Total Emissions: 29,519 MT CO₂e
4.8% of government operations emissions
2.5% decrease from 2005 levels

Emissions Sources
• Gasoline
• Compressed Natural Gas (CNG)
• Electric and Hybrid Electric Vehicles
• Liquefied Petroleum Gas (LPG)
• Ethanol – E85
City Action Highlights
• Construction of light rail
• Employee Rideshare Program

emissions occur from the fuel use for personal vehicles, vanpools, bus transit, and light
rail is used to account for commuting emissions. Alternative fuel use was estimated
using annual transportation fuel usage data EIA Annual Energy Outlook. Emissions
from bus commuting are reported in the Public Transit sector. Instances of employees
commuting in city vehicles are counted as City Vehicle Fleet emissions. The employee
commuting data show that there was been an increase in hybrid-electric and plug-in
electric vehicle employee commuting miles since 2015.

Table 12. Employee Commute Emissions by Fuel Type/Mode in 2005 and 2018
Fuel Type
2005
2012
2015
2018
Commuting
Miles
MT CO₂e
Commuting
Miles
MT CO₂e
Commuting
Miles
MT CO₂e
Commuting
Miles
MT CO₂e
Gasoline
80,555,678
30,075
93,917,068
34,932
83,504,307
31,059
82,130,508
28,454
Hybrid
0
0
0
0
1,210,096
246
2,824,676
979
Electric
36,477
5
118,470
18
118,455
18
239,474
36
CNG
277,905
106
172,979
66
45,136
17
83,459
32
LPG
284,192
86
83,046
26
29,209
9
57,960
18
E85
12,609
0
766,210
0
0
0
0
0
Bus*,º
3,158,885
—
4,503,309
—
3,158,239
—
1,838,854
—
Light Rail‡,º
—
—
376,188
—
430,983
—
211,680
—
Totals
81,166,860
30,272
99,937,270
35,042
95,803,331
31,350
87,386,610
29,519
*Commuting miles for 2005 were backcast from 2015 levels using employment data.
‡ The Valley Metro Light Rail did not exist in 2005.
ºGHG Emissions not included in total.

5.5.3 City Action Highlights
The Phoenix Light Rail opened in 2008, providing city employees another opportunity to
commute by public transit. The city also continued its employee rideshare program,
providing carpool-parking subsidies, free bus/light rail passes for employees,
emergency ride home cab vouchers, telecommuting, flex-work schedules, bicycle
facilities and other incentives. However, given the structure of the current commuting
data it is difficult to estimate GHG emissions from commuting alternatives. Nonetheless,
the City can encourage employees to seek alternative modes of travel to commute to
work. In addition, unnecessary travel should be avoided when possible, potentially by
increasing telecommuting opportunities.

6 City of Phoenix GHG Metrics
GHG indicators measure the GHG emissions performance of various government
operations. Table 13 details GHG Indicators for City of Phoenix government operations.

Table 13. Internal Government operations Indicators
Government operations Indicators
2005
2012
2015
2018
Unit
Population
1,377,980
1,473,405
1,537,058
1,660,272
People
Employees
14,667
12,849
14,664
14,615
Employees
Building Area
25,948,884
30,624,893
12,599,324
11,495,864
Sq. ft.
Cooling Degree Day (CDD)
4,709
5,065
5,065
4,943
CDD
Building Area GHG Intensity
7.35
6.22
12.89
12.62
kg CO₂e per sq. ft
Per Capita GHG Intensity
138.4
129.3
105.7
87.4
kg CO₂e per resident
CDD Electricity GHG Intensity
39.1
36.3
30.9
28.3
kg CO₂e per CDD
FTE GHG Intensity
13.00
12.64
11.08
9.92
kg CO₂e per FTE
Drinking Water Treated
105.9
112.4
106.0
110.5
billion gallons
Drinking Water GHG Intensity
1,556
1,310
1,238
1,203
MT CO₂e per billion gallons
Water Treatment Plants (WTP)
6
5
5
5
number
WTP GHG Intensity
27,471
29,447
26,236
26,593
MT CO₂e per WTP
Wastewater Treated
69,523
69,524
65,442
65,600
million gallons
Wastewater GHG Intensity
2.37
2.12
2.00
2.03
MT CO₂e per million
gallons
Solid Waste in Place (WIP)
44,030,052
50,257,923
52,405,666
54,666,679
tons
Solid Waste GHG Intensity
3.037
1.558
2.338
2.1986
kg CO₂e per Ton WIP
Fleet Size
6,090
7,387
7,389
7,340
Number of Vehicles
Fleet Vehicle GHG Intensity
9.2
7.1
6.6
6.7
MT CO₂e per Fleet Vehicle
Vehicle Miles Traveled (VMT)
52,825,683
48,022,781
—
35,990,125
VMT
VMT GHG Intensity
1.06
1.09
—
1.36
kg CO₂e per VMT
Gasoline Consumption
3,172,441
3,976,124
3,813,990
3,936,224
gallons
Diesel Consumption
5,452,613
3,324,829
1,777,341
2,579,301
gallons
Diesel + B20 Biodiesel Consumption
5,452,613
6,359,174
5,172,051
5,607,270
gallons
CNG Consumption
1,744,813
1,349,993
3,239,129
6,151,022
GGE
Commuting Gasoline Miles Traveled
80,555,678
93,917,068
83,504,307
82,130,508
miles
Commuting Gasoline Miles Per
Employee
5,576
7,167
5,711
5,772
mile per FTE
% Single Occupancy Vehicle
73.8%
74.1%
75.8%
72.1%
%
Alternative Fuel Vehicle Miles
891,044
1,140,705
1,402,897
3,354,038
mile

7 Biogenic Emissions
Biogenic CO2 emissions are emissions from non-fossil carbon sources—such as
biodiesel and ethanol in blended biofuels—and the conversion of methane to carbon
dioxide resulting from methane flaring. According to the guidelines set by LGOP,
biogenic CO2 emissions are currently not considered to add carbon into the atmosphere
as these sources of CO2 are part of the natural carbon cycle and do not count toward

GHG emissions total. As part of the strategy to achieve net-zero GHG emissions, the
City can shift fossil fuel CO2 emissions to biogenic CO2 emissions that are not
replaceable with other forms of energy, like solar. This is being done with the continued
conversion of diesel fleet vehicles to biodiesel blends in addition to the development of
biomass-based sources of electricity. Table 14 shows biogenic emissions from City
government operations in 2005, 2012, 2015, and 2018.

Table 14. Sources and Quantities of Biogenic Emissions (MT CO₂e)
Biogenic CO₂ Summary
2005
2012
2015
2018
Biogenic Landfill
66,739
74,946
86,937
98,264
Biogenic B20 Biodiesel
0
5,735
6,416
5,723
Biogenic E85 Ethanol
0
1,405
1,665
1,522
On-Site Biogas Use-91st Ave. WWTP
3,978
2,701
2,213
2,622
Flared Biogenic Wastewater CO₂ – 91st Ave. & 23rd Ave. WWTPs
58,146
37,117
39,175
32,550
Total Biogenic
128,863
121,903
136,407
140,682
% of Fossil
18%
19%
22%
23%

Sources of biogenic emissions come from blended biofuels, such as B20 biodiesel and
E85 ethanol, municipal landfills, and wastewater treatment plants. For blended biofuels,
the biofuel component of the fuel is considered biogenic. Emissions, primarily N₂O and
CH₄, from the diesel or gasoline component are considered to be fossil emissions.

Appendix A: Greenhouse Gas Equivalents
Table A1. IPCC AR2, AR4, and AR5 Global Warming Potential (GWP) Values
Greenhouse Gas*
AR2 GWP Values1
AR4 GWP Values2
AR5 GWP Values3
Carbon Dioxide (CO₂)
1
1
1
Methane (CH₄)
21
25
28
Nitrous Oxide (N₂O)
310
298
265
*Only carbon dioxide, methane and nitrous oxide were included in the 2005 and 2015 inventories
1GWP values used in the previous City of Phoenix 2005 and 2012 local government operations GHG
emissions inventories.
2GWP values used in the City of Phoenix 2015 local government operations GHG emissions inventories.
3GWP values used in 2018 City of Phoenix GHG Emissions from Government Operations.

Appendix B: City of Phoenix’s Government
Operations Boundary

Wastewater Facilities
For the 2012 government operations GHG emissions inventory, the City considered
whether the 91st Avenue wastewater treatment plant (WWTP) emissions and if they
should be part of the inventory. This plant accepts wastewater from several other cities
and is operated under a formal Joint Powers Authority (JPA) agreement. Although the
LGOP accounting system recommends that JPA’s be excluded from the inventory, the
full emissions from this facility have been included, as the City operates the facility and
is listed as the responsible party on the facility’s air and water permits. Inclusion of the
plant’s full emissions has continued in the 2015 and 2018 GHG emissions inventories of
government operations.

Solid Waste Facilities
The 2018 inventory includes estimated emissions from the 27th Avenue Compost
Facility. As this facility was opened in 2017, the 2018 inventory is the first inventory
where city-owned compost operations are included.

Biogenic CO2 -Emissions
Biogenic CO2 emissions are emissions from non-fossil carbon sources—such as
biodiesel and ethanol in blended biofuels—and the conversion of methane to carbon
dioxide resulting from methane flaring. According to LGOP, biogenic CO2 emissions do
not add carbon into the atmosphere as these sources of CO2 are part of the natural
carbon cycle and do not count toward local government operations GHG emissions
total. The City can shift fossil CO2 emissions to biogenic CO2 emissions through the
continued conversion of diesel fleet vehicles to biodiesel blends in addition to the
development of biomass-based sources of electricity.

Leased Facilities
The City also reviewed options for including the facilities that are owned by Phoenix but
leased to other entities. Consistent with the operational control in the protocol, the
inventory would generally not include energy used at city-owned leased facilities.
However, a unique circumstance occurs at Phoenix Sky Harbor International Airport.
The airport could have excluded facilities that are leased to tenants (airlines,
restaurants, gift shops, etc. which account for 1/3 of the terminal areas and 1/3 of

common use areas) on a proportional basis because the costs of the energy used at
those airport facilities are allocated to tenants based on the size of revenue-generating
area. The City chose to include emissions from the entirety of the airport-owned
facilities as the airport runs the building energy systems and pays the energy bills.

Scope 3 Emissions
The City has chosen to report Employee Commute and GAC hauling and regeneration
emissions because it does not maintain direct operational control and therefore is not
required to report these emissions. However, because Phoenix has influence over its
employees commuting habits through various rideshare incentives and telecommuting,
it chose to include these emissions in the inventory as Scope 3 emissions (Scope
classifications are explained below). It also chose to report emissions from outsourced
GAC hauling and regeneration as Scope 3 emissions in the Water Services sector
because the city holds financial control; considers it an area over which it has influence.
Both sludge and solid waste hauling were included as Scope 1 emissions as those
contracts are considered more integral to government operations and control.

Appendix C: Solar Projects & Partnerships
Table C1. Completed and Planned Solar Projects
Solar Projects/Partnerships
Project #
Description
Completed
kW
Projected
kWh/year
1
Transit - Pecos Park & Ride (SRP Grid)
2004
100
147,000
2
N. Transfer Station Parking Lot (32 x 40w
fixtures)
2006
1.3
1,955
3
North Transfer Station
2006
7
10,700
4
Phoenix Convention Center - West Bldg
2007
100
125,800
5
Camp Colley (off grid)
2007
8.5
12,335
6
North Mountain Park Visitor Ctr.
2008
3.2
4,597
7
Pecos Community Center
2009
30
43,785
8
Paradise Village Apts (Housing)
2010
2
2,845
9
Helen Drake Senior Center
2011
40
58,285
10
McCarty on Monroe (Housing/NSD)
2011
30
44,100
11
Maryvale Pool
2011
15
22,050
12
Washington Adult Center
2011
10
14,700
13
Audubon Visitor Center
2011
30
44,100
14
US Airways Parking Garage
2011
238
347,385
15
ASU DT – Cronkite School of Journalism
2011
77
112,390
16
Burton Barr Central Library
2011
150
198,000
17
Fire Training Academy
2011
10
14,595
18
Fire Station #12
2011
10
14,595
19
Fire Station #1
2011
20
29,190
20
Sunnyslope CC – Main & Gym
2011
100
147,000
21
Aviation – East Economy Parking Garages
2011
1,290
2,004,565
22
Aviation – Rental Car Center
2011
4,100
6,388,700
23
DT Transit Building
2012
30
43,785
24
Phoenix Children’s Museum
2012
85
126,855
25
Water Department – Lake Pleasant WTP
2012
7,500
12,803,250
26
Metro Facilities Building
2012
90
141,750
27
Walker Building
2013
10.5
15,990
28
Washington St. Parking Garage (305 Garage)
2014
486.6
754,135
29
Adam St. Parking Garage (310 Garage)
2014
695.9
1,078,505
30
Valley Metro Light Rail- Operations Center
2015
783
1,151,010

Solar Projects/Partnerships
Project #
Description
Completed
kW
Projected
kWh/year
31
SR-85, DESERT STAR (APS utility-scale)
2015
15,625 24,609,375

Appendix D: Findings by Scope
Appendix C presents City government operations GHG emissions by GHG emissions
scope (Scope). GHG emissions by Scope are shown in Figures D1 and D2.

Figure D1. 2018 Emissions by Scope

Figure D2. Government operations comparison, 2005, 2012, 2015 and 2018

Scope 1
Scope 1 emissions contribute 44% of the city’s total emissions accounting for 265,540
MT CO₂e. From 2005 to 2018, Scope 1 emissions decreased 5.9%. Scope 1 is
comprised of stationary combustion, fleet fuels, and fugitive and process emissions from
landfills and wastewater treatment plants (Figure D3). Stationary sources of Scope 1
emissions come from use at city buildings, use for water distribution, and use for
wastewater treatment. The combustion of natural gas in buildings, and the resulting
emissions, decreased 17% between 2005 and 2018, while natural gas combustion for
water distribution treatment decreased 25%. The City’s fugitive and process GHG
emissions decreased 9% between 2005 and 2018. Fugitive methane emissions from
landfills were reduced by 17%, due to the installation of advanced landfill gas capture
systems at the Skunk Creek and the new SR-85 landfills. Fugitive and process
emissions from wastewater treatment increased significantly (21%) as city WWTPs
treated more effluent in 2018 than in 2005 due to population growth. The 27th Avenue
Compost Facility was a new source of fugitive and process emissions in 2018.

Figure D3.
Breakdown of 2018 Scope 1 Emissions
The City’s fuel portfolio has changed dramatically between 2005 and 2018 with the
addition of B20 biodiesel vehicles and E85 flex fuel vehicles. The incorporation of
biofuels into the fleet fuel portfolio helped to reduce Scope 1 emissions overal from the
city’s vehicle fleet by 2% between 2005 to 2018. However, an increase in Public Transit
service miles caused an 9% increase in emissions between 2015 and 2018.

Scope 2
Scope 2 GHG emissions are indirect GHG emissions from the off-site generation of
electricity used in municipal buildings, street lighting, traffic signals and wastewater
treatment. Scope 2 emissions from electricity generation are calculated from billed
electricity, so the benefits of on-site generation of electricity from solar enery projects
are not directly accounted for and buildings may consume more electricity (both solar
and grid-based generated) than what is billed (grid-based only).

Scope 2 emissions account for 50% of the City’s total emissions and totaled 304,113
MT CO₂e in 2018. Between 2005 to 2018, Scope 2 GHG emissions decreased 21%
(Figure D4) while purchased only decreased 1%. Between 2005 and 2018, the carbon
intensity of purchased electricity in Arizona decreased 22% due to increased natural
gas generation and decreased coal generation in the region electricity grid in
combination with increased renewable energy genration.

Figure D4. Breakdown of 2018 Scope 2 Emissions

Scope 3
Scope 3 is comprised of fuel emissions from employee commute, GAC Hauling and
Regeneration, and the total T&D loss in the electricity grid associated with electricity
purchased by the city. Although the city does not operationally control Scope 3
emissions, the LGOP encourages the reporting of activities relevant to a city’s GHG
programs and goals. The City chose to report emissions from these sectors because it
has some ability to impact those activities through various policies, programs, and
contracts.

Scope 3 emissions account for 7% of the City’s total emissions with a total of 42,301 MT
CO₂e. From 2005 to 2018, emissions from Scope 3 decreased 12%. GHG emissions
from employee commuting are the largest component (69%) of Scope 3 emissions
(Figure D5).

Figure D5. Breakdown of 2018 Scope 3 Emissions