Attachment C: Palo Alto 2022 Municipal Greenhouse Gas Emissions Inventory Overview of Methodology for Quantifying Greenhouse Gas Emissions The 2022 Municipal Greenhouse Gas (GHG) Emissions Inventory follows the calculation and reporting standards outlined in the International Council for Local Environmental Initiatives’ (ICLEI) Local Government Operation (LGO) Protocol1, which aligns with the Global Protocol for Community-Scale GHG Emissions Inventories (GPC) local government operations protocol.2 Under the LGO Protocol, GHG Emissions from Palo Alto’s municipal operations can be classified into four main sectors:
•Buildings and other facilities (e.g., stationary combustion) •Streetlights and Traffic Signals (e.g., electricity use) •City vehicle and equipment fleet (e.g., mobile combustion) •Wastewater facilities (e.g., wastewater treatment and discharge) •Indirect emissions (e.g., employee commuting, landfilled solid waste generation) Activities taking place within a city can generate GHG emissions that occur inside the city boundary as well as outside the city boundary. To distinguish among them, the LGO Protocol groups emissions into three categories based on where they occur:
•Scope 1 emissions: GHG emissions from sources located within the city boundary •Scope 2 emissions: GHG emissions occurring as a consequence of the use of grid- supplied electricity, heat, steam and/or cooling within the city boundary •Scope 3 emissions: All other GHG emissions that occur outside the city boundary as a result of activities taking places within the city boundary Palo Alto’s 2022 Municipal GHG Emissions
In 2022, the City emitted a total of 15,784 metric tons of carbon dioxide equivalent (MT of CO2e) from municipal operations. As shown in Table 1, GHG emissions from Palo Alto’s municipal operations are from five main sectors: buildings and other facilities, streetlights and traffic signals, city vehicles and equipment, wastewater facilities, and indirect emissions. Since the methodology has changed significantly for certain sectors since the first Municipal GHG Inventory was conducted in 2005, it is no longer possible to do a true comparison with previous Municipal GHG inventories. However, the methodologies for buildings and other facilities, streetlights and traffic signals, and city vehicles and equipment are similar enough to make rough comparisons. For reference only, in 2005 the City emitted a total of 40,499 MT of CO2e from municipal operations.
1 LGO Protocol Rulebook; https://icleiusa.org/resources/local-government-operations-lgo-protocol/ 2 GPC Inventories for local government operations;
https://ghgprotocol.org/sites/default/files/standards/GPC_Full_MASTER_RW_v7.pdf
Table 1: 2022 Palo Alto Municipal GHG Emissions
Sector
2022 GHG
emissions
(MT CO2e)
Percent of
total
emissions (%)
Buildings and Other Facilities 3,398 21.5%
Streetlights and Traffic Signals 0 0%
City Vehicles and Equipment Fleet 1,676 10.6%
Wastewater Facilities (Regional Water Quality Control Plant) 5,953 37.7% Indirect Emission Sources 4,758 30.1%
Total 15,784 100%
Note: Percentages and MT CO2e may not add to the total due to rounding The majority of municipal GHG emissions—about 38 percent—are attributed to the Regional Water Quality Control Plant (RWQCP). Since the RWQCP is owned and operated by the City, 100 percent of GHG emissions are attributed to the City and falls under Scope 1. These GHG emissions include indirect nitrous oxide (N2O) emissions from wastewater effluent (about 92 percent of total wastewater GHG emissions), indirect nitrous oxide emissions from the nitrification/denitrification of wastewater (about seven percent of total wastewater GHG emissions), and natural gas combustion/leakage (about one percent of total wastewater GHG emissions).
The second major contributor to municipal GHG emissions includes GHG emissions from indirect sources, or the City’s Scope 3 sources. These sources account for about 30 percent of total GHG emissions and include GHG emissions resulting from employee commute mobile combustion (about 39 percent of total indirect source GHG emissions) and methane emissions resulting from landfilled solid waste (about 61 percent of total indirect source GHG emissions).
Landfilled solid waste methane emissions are a product of decomposing organic material generated and sent to the landfill by municipal operations. This subsector attributes methane emissions based on total landfilled solid waste generated in the inventory year and does not account for pre-existing landfilled solid waste methane emissions.
The third major contributor to municipal GHG emissions includes GHG emissions from natural gas usage in Buildings and Other Facilities (excluding the RWQCP), considered a Scope 1 source.
These GHG emissions accounted for 22 percent of total GHG emissions and are driven by natural gas combustion (about 97 percent of total Buildings and Other Facilities GHG emissions), and natural gas leakage (about three percent of total Buildings and Other Facilities GHG emissions).
The final contributor to municipal GHG emissions includes the City’s Vehicle and Equipment Fleet, considered a Scope 1 source (except for the City’s Electric Vehicles (EVs), which are considered a Scope 2 source due to the energy source being purchased electricity). Together,
these account for about 11 percent of total GHG emissions and are mainly driven by the City’s on-road vehicle fleet powered by gasoline, diesel, and compressed natural gas (CNG) (about 92 percent of total Vehicle and Equipment Fleet GHG emissions) and off-vehicle/equipment fleet powered by gasoline and diesel (about eight percent of total Vehicle and Equipment Fleet GHG emissions).
Since electricity in the City is carbon-neutral, there are no GHG emissions from electricity consumption in City-owned buildings and facilities, streetlight and traffic signals, EVs, or City water-energy consumption.
A comparison of the on-road vehicle GHG emissions by City Department and vehicle fuel type (diesel, gasoline, and CNG) can be found in Table 2. The fleet vehicles used by City Departments are used for the following purposes:
•Administrative Services Department – purchasing and printing •Community Services Department – administration, arts and culture, recreation, parks and golf
•Fire Department – operations, support
•Information Technology Department – information technology •Planning and Development Department – inspection services •Police Department – police, animal services
•Public Works Department – engineering, facilities management, equipment management, operations, wastewater treatment operations, storm drainage, refuse, Palo Alto airport operations
•Utilities Department – administrative services, electric operations, electric engineering, water / gas / wastewater engineering, water / gas / wastewater operations, resource management
Table 2: On-Road Vehicle GHG emissions by City Department and Vehicle Fuel Type City Department
Diesel
Vehicles
(MT CO2e)
Gasoline
Vehicles
(MT CO2e)
CNG Vehicles
(MT CO2e)
Total
(MT CO2e)
Administrative Services 8.11 0 0.23 8.34
Community Services 18.56 70.36 0.02 88.94
Fire 171.2 57.62 0.12 228.94
Information Technology 0 2.45 0 2.45
Planning and Development 0 17.4 0.66 18.06
Police 12.64 417.36 0 430
Public Works 109.37 225.73 2.7 337.8
Utilities 178.75 254.5 2.44 435.69
Total 498.63 1,045.42 6.17 1,550.22
A comparison of 2005 and 2022 Palo Alto Municipal GHG emissions is shown in Figure 1 and Table 3. As previously discussed, the methodology has changed significantly for certain sectors since the first Municipal GHG Inventory was conducted in 2005, so it is no longer possible to do a true comparison with previous Municipal GHG inventories. However, the methodologies for buildings and other facilities, streetlights and traffic signals, and city vehicles and equipment are similar enough to make rough comparisons.
Figure 1: 2005 vs. 2022 Palo Alto Municipal GHG Emissions Table 3: 2005 vs. 2022 Palo Alto Municipal GHG Emissions Sector
2005 GHG
emissions
(MT CO2e)
2022 GHG
emissions
(MT CO2e)
Percent Change
in 2022 from
2005 (%)
Buildings and Other Facilities 10,698 3,398 - 68.2%
Streetlights and Traffic Signals 748 0 - 100%
City Vehicles and Equipment Fleet 2,835 1,676 - 41%
Wastewater Facilities (Regional Water
Quality Control Plant) 11,269 5,953 -47.2%*
Indirect Emission Sources 5,567 4,758 -14.5%*
Power Generation Facilities 9,308 Not included n/a
Water Delivery Facilities 74 Not included n/a
Total 40,499 15,784 - 61%*
Note: Percentages and MT CO2e may not add to the total due to rounding * Not a true comparison due to different methodologies