Attachment B - 2020 Greenhouse Gas Emission Inventory for Govt. Operations

City of Phoenix — Community and Cultural Investment Subcommittee (2022-09-07)

Extracted text (via pymupdf) 69927 characters

2020 Greenhouse Gas
Emissions Inventory for
Government Operations
A comprehensive report
prepared for
May 2022
sustainabilitysolutions.asu.edu
Attachment B

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

And

Arizona State University’s Walton Sustainability Solutions Initiatives:
William Campbell, Portfolio Manager
Lizzy Bruns, Graduate Student

And

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

We wish to acknowledge the numerous city departments’ staff for supplying the data
needed to produce the 2020 Greenhouse Gas Emissions Inventory for Government
Operations. We would also like to acknowledge the personnel of Avantpage Translation
for their Spanish translation services.

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.

iii

Table of Contents
List of Tables ........................................................................................................................ i
List of Figures ...................................................................................................................... ii
Acronyms ............................................................................................................................ iii
Executive Summary............................................................................................................ 1
1
Introduction .................................................................................................................. 4
2
Major Findings ............................................................................................................. 5
2.1
Revisions .............................................................................................................. 6
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 ........................................... 9
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 ...... 11
3.4.3
Alternative Fuel Estimates for Employee Commuting ............................... 11
3.4.4
Estimating Compost Emissions ................................................................. 11
3.4.5
Estimating Aviation GHG Emissions for 2020 ........................................... 12
4
Results ....................................................................................................................... 13
4.1
Summary ............................................................................................................ 13
4.1.1
2005 to 2020: What has Changed? ........................................................... 13
4.1.2
Emissions Sources and Distribution .......................................................... 15
4.1.3
GHG Emissions Reductions Since 2005 ................................................... 16
5
Findings by Sector for 2020 ...................................................................................... 18
5.1
Buildings and Facilities ...................................................................................... 18
5.1.1
2005 to 2020: What has Changed? ........................................................... 18
5.1.2
Emissions Sources and Distribution .......................................................... 18
5.1.3
GHG Metrics: Buildings and Facilities ....................................................... 20
5.2
City Vehicle Fleet ............................................................................................... 21
5.2.1
2005 to 2020: What has Changed? ........................................................... 21

5.2.2
Emissions Sources and Distribution .......................................................... 22
5.2.3
GHG Metrics: Vehicle Fleet........................................................................ 23
5.3
Water Services ................................................................................................... 24
5.3.1
2005 to 2020: What has Changed? ........................................................... 24
5.3.2
Emissions Sources and Distribution .......................................................... 24
5.3.3
GHG Metrics: Water Services .................................................................... 27
5.4
Solid Waste ........................................................................................................ 28
5.4.1
2005 to 2020: What has Changed? ........................................................... 28
5.4.2
Emissions Sources and Distribution .......................................................... 28
5.4.3
27th Avenue Compost Facility .................................................................... 30
5.4.4
GHG Metrics: Solid Waste ......................................................................... 30
5.5
Employee Commute .......................................................................................... 31
5.5.1
2005 to 2020: What has Changed? ........................................................... 31
5.5.2
Emissions Sources and Distribution .......................................................... 31
5.5.3
City Action Highlights ................................................................................. 32
6
City of Phoenix GHG Metrics .................................................................................... 33
Appendix A: Greenhouse Gas Equivalents ..................................................................... 34
Appendix B: City of Phoenix’s Government Operations Boundary ................................. 35
Appendix C: Solar Projects .............................................................................................. 37
Appendix D: Findings by Scope ....................................................................................... 38

List of Tables
Table 1. GHG Emissions by Scope and Sector Between 2005 and 2020 ....................... 7
Table 2. 2020 Buildings and Facilities Emissions by Subsector ..................................... 20
Table 3. Buildings and Facilities Emissions Indicators.................................................... 20
Table 4. City Fleet Fuel Consumption By Type By Year ................................................. 23
Table 5. City Fleet Indicators Change ............................................................................. 23
Table 6. GHG emissions at the 23rd Avenue and 91st Avenue WWTPs ......................... 26
Table 7. Water Services Emissions Indicators ................................................................ 27
Table 8. 2020 Solid Waste Emissions by Landfill............................................................ 29
Table 9. GHG Emissions Indicators for Solid Waste ....................................................... 30
Table 10. Employee Commute Emissions by Fuel Type/Mode ...................................... 32
Table 11. Internal Government operations Indicators ..................................................... 33
Table A1. IPCC AR2, AR4, and AR5 Global Warming Potential (GWP) Values ........... 34
Table C1. Completed Solar Projects and Partnerships................................................... 37

List of Figures

Figure ES-1. City of Phoenix Government Operations GHG Emissions and Population
Between 2005 and 2020. ................................................................................................... 3
Figure 1. City of Phoenix GHG Emissions from 2005 to 2020. ......................................... 5
Figure 2. Overview of LGOP Scopes and Emissions Sources. ........................................ 9
Figure 3. GHG Emissions by City Sector......................................................................... 14
Figure 4. Total Emissions by Scope and Subsector ....................................................... 15
Figure 5. Percent of Total Emissions by Scope and Subsector ...................................... 16
Figure 6. Emissions Changes between 2005 and 2020. ................................................ 17
Figure 7. Buildings and Facilities GHG Emissions Between 2005 and 2020 ................. 19
Figure 8. Vehicle Fleet Emissions by Fuel Between 2005 and 2020 ............................. 22
Figure 9. Water Services Emissions Changes Between 2005 and 2020 ....................... 25
Figure 10. Wastewater Treatment GHG Emissions Between 2005 and 2020 ............... 26
Figure 11. Phoenix Landfills Emissions Changes between 2005 and 2020................... 29
Figure D1. GHG Emissions by Scope ............................................................................. 38
Figure D2. Government operations comparison, 2005 through 2020 ............................ 38
Figure D3. Breakdown of 2020 Scope 1 Emissions ........................................................ 39
Figure D4. Breakdown of 2020 Scope 2 Emissions ........................................................ 40
Figure D5. Breakdown of 2020 Scope 3 Emissions ........................................................ 41

iii

Acronyms
AR

IPCC Assessment Report (Numbered 2 through 5)
ASU

Arizona State University
AZNM

Arizona and New Mexico eGRID Subregion
B20

A biodiesel blend consisting of 20% biodiesel and 80% diesel fuel
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 2020 Greenhouse Gas Emissions Inventory for Government
Operations is the fifth 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 2020 Greenhouse Gas Emissions Inventory for Government Operations is
the second inventory update since setting the 2025 GHG emissions reduction goal, and
provides demonstrated progress towards the 2025 goal and a data-driven basis for
developing climate actions to meet the 2025 goal.

The major findings of the City of Phoenix 2020 Greenhouse Gas Emissions Inventory
for Government Operations are listed below.
o 2020 government operations GHG emissions were 68,829 MT CO2e
(11.4%) below 2018 levels and 180,467 MT CO2e (25.2%) below 2005
levels.
o Between 2018 and 2020, the GHG intensity of the regional electricity grid
fell by 17.3%. Over the same period, GHG emissions from purchased
electricity fell by 23.0% (68,636 MT CO2e), indicating additional reductions
due to City actions. Through energy retrofits, energy use has declined in
City buildings every year since 2016.
o Buildings and Facilities GHG emissions from purchased electricity fell
31,296 MT CO2e between 2018 and 2020. Facilities managed by the

Public Works, Street Transportation and the Phoenix Convention Center
departments, realized a 19 percent electricity use savings since 2016.
o GHG emissions from Traffic Signals and Streetlights decreased 66.8%
below 2005 levels and 57.5% below 2018 levels.
o Water Services GHG emissions from purchased electricity decreased
16,550 MT CO2e (13.6%) between 2018 and 2020 despite electricity
consumption increasing by 11,725 MWh.
o GHG emissions from the City’s vehicle fleet has increased 14,985 MT
CO2e since 2018. Increased Vehicle Fleet emissions is attributed to higher
levels of CNG and B20 consumption.
o GHG emissions from landfills was similar between 2018 and 2020,
increasing by 362 MT CO2e.
o GHG emissions from wastewater treatment decreased 20.6% (28,949 MT
CO2e) between 2018 and 2020 and were 4.1% (345 MT CO2e) below
2005 levels due to the capture and reuse of methane biogas at the 91st
Avenue Wastewater Treatment Plant (WWTP).
o The 27th Avenue Compost Facility emitted 6,360 MT CO2e in 2020, 21.7%
decrease below 2018 levels. The facility will save GHG emissions over its
lifetime by reducing green-organic 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:
o $16.9 million in the 27th Avenue Compost Facility.
o $30 million in LED Streetlight project replacing 100,000 streetlights
o $25 million in a biogas facility at the 91st Avenue WWTP
o $30 million in retrofits underway to reduce energy use in city buildings
o $530 million in transit since 2016 under the Phoenix Transportation Plan
(T2050) for extended bus and paratransit operating hours, and increased
local bus frequency to every 30 minutes or less citywide.

The City has achieved significant GHG emissions reductions despite growing by
approximately 300,000 people since 2005 (Figure ES-1). Accordingly, the per capita
GHG intensity of the City’s government operations have fallen from 0.48 to 0.30 MT
CO2e per resident between 2005 and 2020. For more information on City of Phoenix
actions to reduce GHG emissions, please read the City of Phoenix Climate Action Plan
2021 Edition.

Figure ES-1. City of Phoenix Government Operations GHG Emissions and
Population Between 2005 and 2020.

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 a baseline GHG emissions level for City
operations 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.
The City of Phoenix 2020 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 GHG emissions
inventory of government operations.
• Section 3 describes the GHG emissions inventory boundary along with
methodological background and updates for the 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 2020, GHG emissions from City government operations were 535,675 MT CO₂e,
which is 25.2% below 2005 levels and 11.4% below 2018 levels (Figure 1).

Figure 1. City of Phoenix GHG Emissions from 2005 to 2020.

The City reduced GHG emissions through a combination of internal and external
measures. Internal measures include energy efficiency upgrades, the incorporation of
alternative fuels into the vehicle fleet fuel portfolio, and upgrades to landfill gas capture
systems. For additional internal measures, please refer to the City of Phoenix Climate
Action Plan for 2021. External measures include a decrease in the EPA’s Emissions &
Generation Resource Integrated Database (eGRID) regional factor1. Between 2005 and
2020, the GHG intensity of the Arizona-New Mexico (AZNM) subregion fell by
approximately 35%, from 1,316 lb. CO₂e emitted per MWh of electricity generated (lb.

1 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.

CO₂e/MWh) to 850 lb. CO₂e/MWh. The 2019 closure of the Navajo Generation Station,
operated by Salt River Project, substantially reduced the GHG intensity of electricity in
the Arizona-New Mexico subregion.

Between 2018 and 2020, GHG emissions from City government operations decreased
in every subsector except Fleet Fuels, which increased 14,985 MT CO2e (11.5%) as
shown in Table 1. The increase in Fleet Fuels GHG emissions were driven by increased
CNG consumption (1,404,331 GGE) and B20 fuel consumption (1,281,289 gallons),
which resulted in 8,880 MT CO2e and 10,440 MT CO2e additional GHG emissions,
respectively. However, over the same period, gasoline consumption remained relatively
unchanged (3% increase) and diesel consumption decreased by 12%. In the Water
Services sector, GHG emissions from electricity usage decreased by 16,650 MT CO2e
(13.6%) despite an increase in electricity consumption of 11,725 (4%). Water Services
natural gas consumption increased by 25% between 2018 and 2020. GHG emissions
from employee commuting decreased in 2020 most likely due to the COVID-19
pandemic as some employees were able to telework to perform their duties; the change
in commuting patterns caused by the pandemic reduced commuting-related GHG
emissions by 22% compared to 2018.

2.1 Revisions
Minor revisions were made to the GHG emissions totals from City government
operations. These revisions are detailed below.
2005: No revisions were made to the 2005 inventory.
2012: 644,819 MT CO₂e revised upwards from 644,723 MT CO₂e.
o Audit found incorrect Excel formula that omitted 96 MT CO₂e from liquified
natural gas consumption.
2015: 616,351 MT CO₂e revised downwards from 616,415 MT CO₂e
o Audit found incorrect Excel formula that overestimated N2O emissions
from the 91st Avenue wastewater treatment plant by 64 MT CO₂e.
2018: 604,505 MT CO₂e revised downwards from 605,701 MT CO₂e.
o Audit found incorrect Excel formulas that overestimated emissions from
Fugitive and Process Emissions by 61 MT CO₂e.
o Updated state-level Transmission and Distribution loss data, which
decreased emissions by 1,135 MT CO₂e.

Table 1 shows changes GHG emissions for City government operations and population between 2005 and 2020.

Table 1. GHG Emissions by Scope and Sector Between 2005 and 2020
Scope 1
2005
2012
2015
2018
2020
2005-2020
Change
2005-2020
% Change
Stationary Combustion
7,404
7,329
6,377
6,085
6,447
-957
-12.9%
Fleet Fuels
132,709
133,521
118,706
129,748
144,734
12,025
9.1%
Fugitive and Process Emissions
142,165
87,073
131,868
129,646
124,798
-17,187
-12.1%
Scope 1 Total Emissions
282,277
227,923
256,951
265,479
276,158
-6,119
-2.2%

Scope 2
2005
2012
2015
2018
2020
2005-2020
Change
2005-2020
% Change
Buildings Electricity
184,285
183,851
156,646
139,714
108,418
-75,867
-41.2%
Street Lighting
38,502
36,416
33,935
32,069
12,224
-26,278
-68.3%
Traffic Signals
7,733
7,157
4,755
4,075
3,130
-4,602
-59.5%
Water Services
155,368
137,793
121,158
122,002
105,452
-49,916
-32.1%
Scope 2 Total Emissions
385,888
365,217
316,494
297,860
229,225
-156,664
-40.6%

Scope 3
2005
2012
2015
2018
2020
2005-2020
Change
2005-2020
% Change
Employee Commute
30,272
35,042
31,350
29,518
20,799
-9,473
-31.3%
Transmission and Distribution Loss
17,705
13,640
10,810
10,766
8,548
-9,158
-51.7%
Water Services
0
2,996
760
881
946
946
-
Scope 3 Total Emissions
47,977
51,679
42,920
41,165
30,293
-17,685
-36.9%

GHG Inventory
2005
2012
2015
2018
2020
2005-2020
Change
2005-2020
% Change
Total Scope 1 and 2 Emissions
668,165
593,140
573,445
563,339
505,383
-162,782
-24.4%
Total Scope 1, 2, & 3 Emissions
716,143
644,818
616,365
604,505
535,675
-180,467
-25.2%
City of Phoenix Population
1,377,980
1,499,274
1,612,199
1,654,675
1,680,992
303,012
22.0%

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 previous GHG 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: Direct emissions from City owned or controlled operations.
• 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.
• 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

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

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

3.3 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.

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.
4 ICLEI USA, 2020. Greenhouse Gas Protocols. URL: https://icleiusa.org/ghg-protocols/

This inventory uses the operational control approach as it most accurately represents
GHG emissions sources within the City’s control. The boundaries of the City operations
GHG inventory 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 GHG emissions source was
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 2020 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; the 2018 and 2020 GHG emissions inventory utilizes IPCC AR5
GWP; and the 2020 GHG emissions inventory utilizes IPCC AR6 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:
o Estes Landfill was added to all inventory years;
o Employee commuting emissions at sites with more than 50 employees
added to the 2005 inventory year;
o In 2005, wastewater treatment emissions were estimated using
population-based data. Site-specific data were used where applicable in
2012, 2015, 2018, and 2020;
o Inventory-year specific T&D loss rates are used;
o Biogenic emissions are calculated for all inventory years;
o The 2020 inventory year utilizes eGRID 2020, which is the most up-to-
date eGRID data available; and

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.

o The 2020 GHG emissions inventory includes emissions from the 27th
Avenue Compost Facility.

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 2020 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 the
previous inventories 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: 1990-20198.

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

3.4.5 Estimating Aviation GHG Emissions for 2020
The 2018 levels Jet Fuel A and Aviation Gasoline consumption for Police Department
Aircraft were assumed for 2020. This assumption was made due to incomplete
reporting, which showed the reduction of fuel consumption by multiple orders of
magnitude, related to the consumption of these fuels. If the reported 2020 data are
proven to be correct, these emissions will be revised in a future GHG emissions
inventory.

4 Results
4.1 Summary

4.1.1 2005 to 2020: What has Changed?

The 2020 GHG emissions inventory of City operations is an additional data point in
support of the City’s 15-year track record of reducing GHG emissions (Figure 3).
Numerous projects and activities undertaken by the City since 2005 have significantly
reduced the GHG intensity of City operations. Projects and activities, and how they
have affected the 2020 City government operations GHG emissions, are listed below.

o The installation of advanced methane capture systems at landfills reduced
fugitive methane emissions from City landfills.
o Transitioning City Fleet to B20 and CNG from diesel has reduced the
GHG intensity of Public Works activities.
o Public Transit has transitioned all its diesel consumption to B20 and
increased use of LNG, reducing GHG intensity, while fuel consumption
has increased since 2015 in order to meet T2050 goals.
o Energy efficiency upgrades to buildings, facilities, streetlights, traffic
signals, water treatment and distribution, and wastewater treatment have
reduced 2020 electricity consumption 8% below 2005 and 4% below 2015
levels.

2020 Overall Findings
GHG emissions from City of Phoenix government operations
have decreased 25.2% below 2005 levels.

Emissions Sources*
o Buildings and Facilities** — 129,264 MT CO2e
o City Vehicle Fleet — 144,734 MT CO2e
o Employee Commute — 20,799 MT CO2e
o Solid Waste — 116,884 MT CO2e
o Water Services — 115,447 MT CO2e

*Above GHG emissions represent all emissions within a sector across all emissions scopes but
excludes Transmission and Distribution Loss in the regional electricity grid, which was 8,458 MT
CO2e in 2020.
** Excludes Water Services.

o The 27th Avenue Compost Facility diverts material from the SR-85 landfill,
reducing landfill GHG emissions while producing an environmentally
beneficial commercial 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 35.4%
over the last fifteen years. The 2019 retirement of the Navajo Generation Station,
among other factors, reduced the GHG intensity of the regional electricity grid by 11.2%
between 2018 and 2020.The planned retirement of additional regional coal power plants
over the next decade will further reduce the GHG intensity of the regional electricity grid.

Figure 3. GHG Emissions by City Sector

Between 2005 and 2020, the City’s population increased by 22% from 1,377,9809 to
1,680,99210 residents. While some government operations are population dependent –
e.g., solid waste generation and water distribution and wastewater treatment – the City’s
GHG emissions are largely electricity-dependent. The significant decarbonization of the
regional electricity grid has effectively decoupled population growth from GHG
emissions from City government operations. Had the regional electricity grid not
decarbonized, GHG emissions from City operations would have decreased by only
7.0% between 2005 and 2020. Instead, GHG emissions decreased by over 25%.

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. Figure 4 provides an overview of the relative magnitude of GHG
emissions by Scope and Subsector.

Figure 4. Total 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 (2022). City and Town Population Totals: 2010-2019. URL: https://www.census.gov/data/tables/time-
series/demo/popest/2010s-total-cities-and-towns.html

Scope 1 and Scope 2 GHG emissions account for 94% of GHG emissions from City
government operations. Scope 1 emissions account for more than 50% of City
government operations GHG emissions (Figure 5) and, more specifically, Fleet Fuels
and Fugitive and Process Emissions represents 27.0% and 23.3% of total GHG
emissions, respectively. Scope 2 GHG emissions from Buildings Electricity and Water
Services each account for approximately 20% of total GHG emissions. Combined, these
four sectors comprise over 90% of GHG emissions from City government operations. 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.

Figure 5. Percent of Total Emissions by Scope and Subsector

4.1.3 GHG Emissions Reductions Since 2005
Each GHG emissions subsectors have decreased emissions since 2005, except Fleet
Fuels, which increased due to increased service needs (Figure 6).

Figure 6. Emissions Changes between 2005 and 2020.

The Buildings Electricity and Water Services subsectors and have had the largest
observed decreases in GHG emissions between 2005 and 2020; GHG emissions from
Buildings Electricity fell by 41% and Water Services by 32%. 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 156,664 MT CO2e below 2005 levels. 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:
o Decreased emissions from closed City landfills;
o Capturing generated biogas at the 91st Avenue Wastewater Treatment
Plant;
o A change in commuting patterns (increased teleworking) compared to
previous inventory years.

5 Findings by Sector for 2020
5.1 Buildings and Facilities

5.1.1 2005 to 2020: What has Changed?
• Between 2005 and 2020, the GHG emissions intensity of the AZNM subregion of
the U.S. electricity grid fell by 35%.

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 7).
Building and Facilities Findings
Total Emissions: 235,671 MT CO₂e
44.0% of government operations emissions
40.1% decrease from 2005 levels

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

City Action Highlights
o To date, the City has installed:
▪ 94,875 LED Street Lights
▪ 63,324 LED Signal Indications
▪ 9,320 LED Pedestrian Indications

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

Figure 7. Buildings and Facilities GHG Emissions Between 2005 and 2020

GHG emissions from natural gas combustion fell by 14% between 2005 and 2020 and
4.9% between 2018 and 2020. Additionally, GHG purchased electricity emissions
decreased 40.6% below 2005 levels and 27.6% below 2018 levels. Table 2 shows 2020
summary data. The steep decline in Buildings and Facilities GHG emissions is primarily
due to a significant reduction in the GHG intensity of the regional electricity grid. City
efforts to build and purchase solar power are located Appendix C. Further development
of the city’s renewable energy portfolio is necessary to continue to decrease emissions
from Buildings and Facilities.

Streetlights electricity consumption peaked in 2015 at 71,316,538 kWh and has since
fallen 46% to 31,705,340 kWh. In 2020, Traffic Signals electricity consumption was 27%
lower than reported consumption in 2005 and 7% lower than 2018. The decrease in
electricity consumption has occurred over a period during which the City has invested
heavily in LED retrofits of Streetlights and Traffics Signals. Energy efficiency upgrades,
along with a less GHG intensive electricity grid, have reduced GHG emissions from
traffic signals and streetlights by 62%.

Table 2. 2020 Buildings and Facilities Emissions by Subsector
Subsector
Electricity Consumption
(kWh)
Natural Gas Consumption
(therms)
GHG Emissions
(MT CO2e)
Buildings and Facilities
281,207,257
1,033,173
113,910
Street Lighting
31,705,340
--
12,224
Traffic Signals
8,119,517
--
3,130
Water Services
273,513,529
179,591
106,407
Total
594,545,642
1,212,764
235,671

5.1.3 GHG Metrics: Buildings and Facilities
Table 3 provides a list GHG metrics for City buildings and facilities.

Table 3. Buildings and Facilities Emissions Indicators
Indicator
2005
2012
2015
2018
2020
Building Space (sq. ft.)
25,948,884
30,624,893
12,599,324
11,495,864
15,047,461
Building Space GHG Emissions Intensity
(kg CO₂e per sq. ft)
7.35
6.22
12.89
12.62
7.57
Per Capita GHG Emissions Intensity
(kg CO₂e per resident)
138.4
127.1
100.7
87.7
67.8
Electricity GHG Emissions per CDD
(kg CO₂e per CDD)
39.1
36.3
30.9
28.3
19.3
FTE GHG Emissions Intensity (kg CO₂e
per FTE)
13.00
12.64
11.08
9.92
9.92

5.2 City Vehicle Fleet

5.2.1 2005 to 2020: What has Changed?
o The size of Public Works fleet peaked in 2015 with 7,389 vehicles and has
since dropped to 7,340 vehicles.
o Public Works and Aviation have converted the majority of the diesel
vehicle fleet to B20 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.
o The completion of the PHX SkyTrain in 2021 will decrease emissions as
the CNG-powered passenger fleet is used less frequently.
o GHG emissions from B20 and CNG have increased since 2018 due to
added service miles as part of the City’s Transportation 2050 (T2050) Plan
to increase local bus frequency, build out the existing city bus network,
increase service hours of bus operations, and introduce new bus routes.

City Vehicle Fleet Findings
Total Emissions: 144,734 MT CO₂e
27% of government operations emissions
9.1% increase 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

5.2.2 Emissions Sources and Distribution
CNG, gasoline, B20 vehicles were the largest source Vehicle Fleet GHG emissions in
2020, respectively. CNG and B20 consumption has increased as diesel consumption
has decreased; 2020 diesel consumption was 41% of the 2005 levels. However, diesel
consumption has increased since 2015 due to an increase in public transit service miles
to meet T2050 goals. GHG emissions from gasoline and E85 ethanol has remained
largely flat since 2012. Jet Fuel A and Aviation GHG emissions Gasoline, a small
percentage of Vehicle Fleet emissions, have also remained flat. Jet Fuel A and Aviation
Gas consumption levels were carried over from the 2018 inventory to account for
incomplete reporting. Figure 8 shows Vehicle Fleet GHG emissions by fuel type. Only
the fossil fuel component of biofuel GHG emissions – 80% of each gallon of B20 and
15% of each gallon of E85 ethanol – is counted towards the GHG emissions.

Figure 8. Vehicle Fleet Emissions by Fuel Between 2005 and 2020

Table 4 shows fuel consumption levels by fuel type and inventory year. The major
changes to the levels of CNG, B20, and LNG fuel consumption is driven by Public
Transit vehicle fleet and service levels. The City began replacing LNG buses with more
efficient CNG busses in 2013; all LNG buses are retired. The LNG that is used by the
Public Transit vehicle fleet is converted to CNG. No other major changes in fuel
consumption were observed between 2015 and 2020.

Table 4. City Fleet Fuel Consumption By Type By Year
Fuel Type
Unit
2005
2012
2015
2018
2020
Gasoline
gallon
3,172,441
3,976,124
3,813,990
3,936,224
4,064,327
Diesel
gallon
5,452,613
3,324,829
1,777,341
2,579,301
2,282,301
B20
gallon
0
3,034,345
3,394,710
3,027,969
4,309,358
Compressed Natural Gas (CNG)
GGE*
1,744,813
1,349,993
3,239,129
6,151,022
7,555,353
Liquefied Natural Gas (LNG)
gallon
7,917,008
6,222,272
3,528,633
543,296
38,866
E85 Ethanol
gallon
0
287,438
340,753
311,460
335,145
Liquified Petroleum Gas (LPG)^
gallon
14,392
0
0
0
0
Aviation Gasoline (AvGas) ^
gallon
2,401
5,975
4,961
4,875
4,875
Jet Fuel A^
gallon
163,160
222,283
202,119
192,739
192,739
* GGE – Gasoline Gallon Equivalent
^ Jet Fuel A and Aviation Gas consumption levels were carried over from the 2018 inventory to account for incomplete reporting

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 5). The data
shown in Table 5 are for Public Works vehicles only.

Table 5. City Fleet Indicators Change
Indicator
2005
2012
2015
2018
2020
Number of Vehicles
6,090
7,387
7,389
7,340
7,548
MT CO₂e per Vehicle
9.2
7.1
6.6
6.7
6.3

5.3 Water Services

5.3.1 2005 to 2020: 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 Services department treated 102.6 billion gallons of water and
41.1 billion gallons of wastewater. The volume of water treated has increased 4%
since 2005 while the volume of wastewater treated has decreased 6%.
• 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.

5.3.2 Emissions Sources and Distribution
GHG emissions can occur from natural gas combustion, electricity consumption, CH4
generation during wastewater treatment, and N2O emissions from wastewater effluent
discharge. Scope 3 GHG emissions also occur during GAC filter regeneration. Between
Water Services Findings
Total Emissions: 115,447 MT CO₂e
21.6% of government operations emissions
25% 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
• The onsite harvesting of biogas at the 91St Avenue Wastewater Treatment
plant has reduced GHG emissions from wastewater treatment.

2005 and 2020, Water Services GHG emissions have decreased 30% (Figure 9). The
overwhelming majority of Water Services GHG emissions occur from electricity
consumption, and benefit from the decarbonization of the regional electricity grid. Most
wastewater treatment GHG emissions – methane flaring and wastewater discharge –
are population-driven. Projected population increases over the next decade will
potentially increase GHG emissions in this sector unless further mitigation efforts are
undertaken. However, the capture and reuse of methane generated during wastewater
treatment (biogas) will substantially reduce GHG emission from methane flaring.

Figure 9. Water Services Emissions Changes Between 2005 and 2020

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, such as biogas capture. Wastewater treatment GHG are
shown in Figure 10.

Figure 10. Wastewater Treatment GHG Emissions Between 2005 and 2020

GHG emissions at the 23rd Avenue and 91st Avenue WWTPS are shown in Table 6.
During 2020, the 91st Avenue WWTP, which is the larger of the two WWTPs, emitted
roughly the same amount of GHGs as the 23rd Avenue WWTP. The 91st Avenue WWTP
accepts wastewater from Glendale, Mesa, Scottsdale, and Tempe. In previous inventory
years, the 91st Avenue WWTP emitted more than double the 23rd Avenue WWTP. The
reduction in GHG emissions at the 91s Avenue WWTP observed in 2020 occurred
because of the reuse of captured methane emissions (biogas). Currently, the City
accounts for all GHG emissions at the 91st Avenue WWTP because the plant is under
the City’s operational control.

Table 6. 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
1,933
194
2,126
Process N2O Emissions
Effluent Discharge
386
1,341
1,726
Nitrification/Denitrification
1,083
3,159
4,242
Total
3,322
3,402
4,693

5.3.3 GHG Metrics: Water Services
Water Services indicators in Table 7 below shows that the GHG intensity of drinking
water served by the City has consistently decreased since 2005.

Table 7. Water Services Emissions Indicators
Indicator
2005
2012
2015
2018
2020
Gallons of Drinking Water Treated (billion gallons)
105.9
98.9
95.4
99.2
102.6
MT CO₂e per Billion Gallons Treated
1,624
1,571
1,426
1,394
1,164
Water Treatment Plants
6
5
5
5
5
MT CO₂e per WTP
28,659
31,075
27,203
27,650
23,876
Million Gallons of Wastewater Treated
69.5
42.2
40.3
40.8
41.1
MT CO₂e per Million Gallons Wastewater Treated
2,473
3,682
3,375
3,388
2,905

5.4 Solid Waste

5.4.1 2005 to 2020: 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 landfill 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 as it is the only active
landfill in the City, while methane emissions from the other City landfills will decrease as
they are now closed (Figure 11).
Solid Waste Findings

Total Emissions: 116,884 MT CO₂e
21.8% of government operations emissions
13% decrease from 2005 levels

Emissions Sources
• City landfills emitted 110,523 MT CO2e
• The 27th Avenue Compost Facility emitted 6,360 MT CO2e

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

Figure 11. Phoenix Landfills Emissions Changes between 2005 and 2020

Table 8 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 8. 2020 Solid Waste Emissions by Landfill
Facility
2005
2012
2015
2018
2020
Skunk Creek
67,375
24,589
19,400
18,047
13,803
27th Avenue
28,476
13,013
9,257
7,403
7,643
Del Rio
4,902
4,760
6,986
4,367
4,859
Deer Valley
3,394
2,548
2,641
1,664
2,241
19th Avenue
4,377
429
3,468
3,598
2,676
Estes
25,200
21,896
20,636
19,432
18,284
SR-85
0
11,064
60,116
56,820
61,016
Total
133,725
78,300
122,504 111,331 110,523

Landfill GHG emissions in this report will differ from data reported to the EPA
Greenhouse Gas Reporting Program. The City operations GHG emissions inventory
utilizes landfill methane flaring formulas contained in the LGOP methodology, 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
33,213 tons of compost in CY 2020, resulting in the emission of 133 MT CH4 and 10 MT
N2O. Total GHG emissions from the compost facility were 6,360 MT CO2e.

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 9 shows Solid Waste sector GHG indicators for the City.

Table 9. GHG Emissions Indicators for Solid Waste
Indicator
2005
2012
2015
2018
2020
Amount of Waste in Place (short tons)
44,030,052
50,257,923
52,405,666
54,666,679
56,335,520
Kg CO₂e Per Ton of Solid Waste in Landfills
3.04
1.56
2.34
2.19
2.07
Compost Processed (short tons)
—
—
—
46,768
33,213

5.5 Employee Commute

5.5.1 2005 to 2020: What has Changed?
o City employees fill out surveys as part of the Trip Reduction Program
(TRP) overseen by Maricopa County Air Quality Department.
o 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 previous GHG emissions inventories.
o Employee commuting using city vehicles is counted in the City Vehicle
Fleet sector to avoid double counting.
o The ongoing SARS-CoV2 (COVID-19) pandemic facilitated the City’s
development and implementation of the City’s Telework Program, which
reduced the 2020 Employee Commuting GHG emissions.

5.5.2 Emissions Sources and Distribution
Employee commuting GHG emissions occur from the fuel use for personal vehicles,
vanpools, bus transit, and light rail is used to account for commuting emissions (Table
10). 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 an
increase in hybrid-electric and plug-in electric vehicle employee commuting miles.
Employee Commute Findings

Total Emissions: 20,799 MT CO₂e
3.9% of government operations emissions
31.3% 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

Table 10. Employee Commute Emissions by Fuel Type/Mode
Year
Commuting
Miles
GHG Emissions
(MT CO₂e)
2005
84,325,745
30,272
2012
99,937,270
35,042
2015
88,496,426
31,350
2018
87,386,610
29,518
2020
60,556,831
20,799

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
Table 11 details GHG Indicators for City of Phoenix government operations.

Table 11. Internal Government operations Indicators
Government Operations Indicators
2005
2012
2015
2018
2020
Unit
Population
1,377,980
1,473,405
1,537,058
1,660,272
1,680,992
People
Employees
14,667
12,849
14,664
14,615
14,261
Employees
Building Area
25,948,884
30,624,893
12,599,324
11,495,864
15,047,761
Sq. ft.
Cooling Degree Day (CDD)
4,709
5,065
5,065
4,943
5,618
CDD
Building Area GHG Intensity
7.35
6.22
12.89
12.62
7.57
kg CO₂e per sq. ft
Per Capita GHG Intensity
138.4
129.3
105.7
87.4
67.8
kg CO₂e per resident
CDD Electricity GHG Intensity
39.1
36.3
30.9
28.3
19.3
kg CO₂e per CDD
FTE GHG Intensity
13.00
12.64
11.08
9.92
9.92
kg CO₂e per FTE
Drinking Water Treated
105.9
98.9
95.4
99.2
102.6
billion gallons
Drinking Water GHG Intensity
1,624
1,571
1,426
1,394
1,164
MT CO₂e per billion gallons
Water Treatment Plants (WTP)
6
5
5
5
5
number
WTP GHG Intensity
28,659
31,075
27,203
27,650
23,876
MT CO₂e per WTP
Wastewater Treated
69.5
42.2
40.3
40.8
41.1
million gallons
Wastewater GHG Intensity
2,473
3,682
3,375
3,388
2,905
MT CO₂e per million gallons
Solid Waste in Place (WIP)
44,030,052
50,257,923
52,405,666
54,666,679
56,335,520
tons
Solid Waste GHG Intensity
3.04
1.56
2.34
2.19
2.07
kg CO₂e per Ton WIP
Fleet Size
6,090
7,387
7,389
7,340
7,548
Number of Vehicles
Fleet Vehicle GHG Intensity
9.2
7.1
6.6
6.7
6.3
MT CO₂e per Fleet Vehicle
Vehicle Miles Traveled (VMT)
52,825,683
48,022,781
—
35,990,125
29,238,298
VMT
VMT GHG Intensity
1.06
1.09
—
1.36
1.62
kg CO₂e per VMT
Gasoline Consumption
3,172,441
3,976,124
3,813,990
3,936,224
4,064,327
gallons
Diesel Consumption
5,452,613
3,324,829
1,777,341
2,579,301
2,282,301
gallons
Diesel + B20 Consumption
5,452,613
6,359,174
5,172,051
5,607,270
6,591,659
gallons
CNG Consumption
1,744,813
1,349,993
3,239,129
6,151,022
7,555,353
GGE
Commuting Gasoline Miles Traveled
80,555,678
93,917,068
83,504,307
82,130,508
57,275,929
miles
Commuting Gasoline Miles Per Employee
5,576
7,167
5,711
5,772
4,045
mile per FTE
% Single Occupancy Vehicle
73.8%
74.1%
75.8%
72.1%
67.88%
%
Alternative Fuel Vehicle Miles
891,044
1,140,705
1,402,897
3,354,038
3,013,192
mile

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 and 2020 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 current GHG emissions inventory of
government operations.

Solid Waste Facilities
The 2020 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 and 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 Solar Projects and Partnerships
Solar Projects/Partnerships
Description
Completed
kW
Projected kWh/year
Aviation HQ
2020
580
917,126
SRP Solar Sleeve
2020
10,700
18,350,500

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. GHG Emissions by Scope

Figure D2. Government operations comparison, 2005 through 2020

Scope 1
Scope 1 emissions contribute 51% of the city’s total emissions accounting for 276,158
MT CO₂e. From 2005 to 2020, Scope 1 emissions decreased 2.2%. Scope 1 is
comprised of stationary combustion, fleet fuels, and fugitive and process emissions from
landfills and wastewater treatment plants (Figure D3). The combustion of natural gas in
buildings, and the resulting emissions, decreased 12.9% between 2005 and 2020, while
natural gas combustion for water distribution treatment decreased 25%. The City’s
fugitive and process GHG emissions decreased 12.1% between 2005 and 2020.
Fugitive methane emissions from landfills were reduced by 17%. Fugitive and process
emissions from wastewater treatment decreased by 4.1% because of the capture and
reuse of flared methane at the 91st Avenue WWTP. The 27th Avenue Compost Facility
was a new source of fugitive and process emissions in 2018.

Figure D3. Breakdown of 2020 Scope 1 Emissions

The City’s fuel portfolio has changed dramatically between 2005 and 2020 with the
addition of B20 vehicles, CNG, and E85 flex fuel vehicles; B20 vehicles are primarily
used in Public Transit. However, an increase in service miles has caused an increase in
Fleet Fules (Public Transity) emissions between 2015 and 2020.

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. On-site generation of electricity from solar energy projects are not
incorporated into the GHG inventory total and buildings may consume more electricity
(both solar and grid-based generated) than what is billed (grid-based only).

Scope 2 emissions account for 43% of the City’s total emissions and totaled 229,225
MT CO₂e in 2020. Between 2005 to 2020, Scope 2 GHG emissions decreased 40.6%
(Figure D4) while purchased electricity decreased only 8%. Between 2005 and 2020,
the carbon intensity of purchased electricity in Arizona decreased 35.4% 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 2020 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 6% of the City’s total emissions with a total of 42,301 MT
CO₂e. From 2005 to 2020, emissions from Scope 3 decreased 37%. GHG emissions
from employee commuting are the largest component (69%) of Scope 3 emissions
(Figure D5).

Figure D5. Breakdown of 2020 Scope 3 Emissions