HomeMy WebLinkAbout#11 Greenhouse Gas Inventory AGENDA ITEM #11
Public Utility District m
MEETING DATE: January 17, 2024
TO: Board of Directors
FROM: Steven Keates, Special Projects Administrator
Michael Salmon, Chief Financial Officer
SUBJECT: Consideration of Accepting the 2022 Greenhouse Gas Inventory
Report for TDPUD.
APPROVED BY:
Brian C. Wright, General Manager
RECOMMENDATION:
Board receive this report and direct staff to file the final Greenhouse Gas Inventory for
calendar year 2022
BACKGROUND:
In early 2023, TDPUD staff initiated a Greenhouse Gas Inventory to reliably quantify the
District's current emissions' footprint— with specific emphasis on those emissions
occurring in calendar year 2022. The study was completed in late 2023, and the report
has been finalized for publication.
ANALYSIS AND BODY:
The attached report provides a full treatment of the data & results as reported at the
board workshop on September 6, 2023. The data collected through this inventory, and
their analysis, are critical in supporting TDPUD's strategic initiatives. The report
submitted in this item is written to provide the Board and public results for the GHG
Inventory.
GOALS AND OBJECTIVES:
District Code 1 .05.020 Objectives:
1. Responsibly serve the public.
2. Provide a healthy and safe work environment for all District employees.
3. Provide reliable and high quality water supply and distribution system to meet
current and future needs.
4. Provide reliable and high quality electric supply and distribution system to meet
current and future needs.
5. Manage the District in an environmentally sound manner.
6. Manage the District in an effective, efficient and fiscally responsible manner.
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District Code 1.05.030 Goals:
1. Manage for Financial Stability and Resiliency
2. Environmental Stewardship: Create a sustainable resilient environment for all our
communities.
3. Engage with our customers and communities in a welcoming and transparent way to
identify opportunities.
4. Take the best of private sector thinking to modernize the utility and add value to our
communities.
FISCAL IMPACT:
This item has no fiscal impact.
ATTACHMENTS:
1. GHG Inventory Report_CY2022_Draft
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1 40010' TRUCKEE DONNER
Public Utility District
2022 TDPUD GREENHOUSE GAS INVENTORY
REPORT - DRAFT DOCUMENT
TRUCKEE DONNER PUBLIC UTILITY DISTRICT
11570 Donner Pass Road,Truckee,Ca 96161
Page 23 of 109
Table of Contents
1 Executive Summary...........................................................................................................................................1
1.1 Report Organization ..................................................................................................................................1
1.2 Summary of Findings.................................................................................................................................1
1.2.1 Scope 1 Emissions Key Findings.........................................................................................................1
1.2.2 Scope 2 Emissions Key Findings.........................................................................................................2
1.2.3 Scope 3 Emissions Key Findings.........................................................................................................2
2 Background and Context for 2022 GHG Inventory............................................................................................1
2.1 Regulatory and Legislative Context for the GHG Inventory.......................................................................1
2.2 Objectives for Proposed Greenhouse Gas Inventory.................................................................................2
3 Approach(es) Used in GHG Inventory................................................................................................................3
3.1 General Inventory Methodologies.............................................................................................................3
3.2 Organizational and Reporting Boundaries.................................................................................................3
3.2.1 Electric Utility General Description....................................................................................................4
3.2.2 Water Utility General Description .....................................................................................................5
3.2.3 Defining an Organizational Boundary for the Inventory....................................................................5
3.2.4 Reporting Boundary...........................................................................................................................6
3.3 GHG Emission Sources and Inventory Scoping..........................................................................................6
3.3.1 Quantifying Emissions........................................................................................................................7
3.3.2 Emissions Factors...............................................................................................................................7
4 Study Findings: Organizational Emissions..........................................................................................................9
4.1 Scope 1 Emissions: Direct Anthropogenic.................................................................................................9
4.1.1 Stationary Combustion Emissions ...................................................................................................11
4.1.2 Mobile Combustion Emissions.........................................................................................................14
4.1.3 Fugitive Emissions............................................................................................................................16
4.1.4 Process Emissions............................................................................................................................16
4.2 Scope 2 Emissions: Indirect Direct Anthropogenic..................................................................................17
4.2.1 Differences in Reported GHG Emissions..........................................................................................19
4.2.2 Emissions Intensities for Generation Resources..............................................................................19
4.2.3 Indirect Emissions (Scope 2)Analysis Results..................................................................................21
4.3 Scope 3 Emissions: Indirect Emissions Outside of Organization Value Chain..........................................22
4.3.1 Fuel Combustion from Employee Commuting.................................................................................23
4.3.2 Electricity Delivered to Customers ..................................................................................................24
4.3.3 Wastewater Treatment ...................................................................................................................26
Page 24 of 109
1 Executive Summary
In early 2023,TDPUD staff initiated a Greenhouse Gas Inventory to reliably quantify The District's current
emissions footprint—with specific emphasis on those emissions occurring in calendar year 2022.The data
collected through this inventory, and their analysis, are critical in supporting TDPUD's strategic initiatives.This
document is written to provide the Board and public results for the GHG Inventory.
1.1 Report Organization
This greenhouse gas inventory measurement& implementation planning document is organized into the
following sections:
■ Section 1:
Definition of Key Terms
Carbon Emissions This term is used to broadly include each of the(6)gasses listed in AB 32(2006).
These gasses include: carbon dioxide, methane, nitrous oxide,sulfur hexafluoride,
hydrofluorocarbons and perfluorocarbons. It is typically convenient to normalize
reported GHG emissions into units of Carbon Dioxide equivalent(CO2e)
Carbon Dioxide equivalent A reporting metric which normalizes emissions of different GHG gasses on the basis
(COze) of their global warming potential (GWP)to the equivalent amount of carbon dioxide
with the same GWP
Global Warming Potential The relative potency of different greenhouse gasses to trap heat within Earth's
atmosphere(known as the greenhouse effect).
Net Carbon Reduction A net reduction of carbon emissions assesses the balance between carbon sources
(e.g.any release of GHG emissions)and carbon sinks(e.g. activities which pull carbon
emissions from the atmosphere and render their greenhouse effect inert). Equivalent
reductions can therefore be garnered through reduction of emissions at the source or
activities which create/expand a carbon sink.
Zero-Carbon Resource A term used in SB 100 to refer to a specific type of electricity generation resource.SB
100 does not define"zero-carbon resources,"and the state had no legal definition
before the bill becoming law.The joint agencies interpreted "zero-carbon resources"
to mean energy resources that either qualify as"renewable" in the most recent RPS
(Renewables Portfolio Standard) Eligibility Guidebook or generate zero greenhouse
gas emissions on site.SB 100 workshops and documents refer to these criteria as
"RPS+"
P a g e 11 Section 1: Executive Summary
Page 26 of 109
1 and 2. Furthermore, limited data/literature are publicly available from local agencies which would enable a
more rigorous analysis.The Tahoe Regional Planning Agency published a Greenhouse Gas Inventory in 2021
which included emissions from wastewater for the Tahoe Basin (treated at TTSA). However, only total emissions
were reported and no intermediate calculations or normalized results24 were published.The best available
research at the time of this inventory on emissions for wastewater treatment was found in the US GHG
inventory published in 201925 in which the EPA establishes a top-down approach for estimating national level
emissions for domestic wastewater treatment.
The EPA reports estimates that 9.4 million Tons of CO2 equivalent26 were generated by wastewater treatment in
2017. It also considers emissions proportional to the daily production of wastewater by the population (per
person) determined by the US Census. This inventory estimates that the wastewater emissions produced due
to domestic water produced by TDPUD to be 478 Tons in calendar year 2022. This was estimated by scaling the
EPA reported estimates by the US census population in 2017 (330 million)27 to the census population of Truckee
in 2022 of 16,850.
PUPTruckee
E Annual — E EPA
POP�US 2017
Where:
Are the calculated GHG emissions (in units of CO2e) attributed to wastewater
E/anuai processed by TTSA for domestic water produced by TDPUD.
The population of the Town of Truckee in 2022 as determined by the US Census.This
POpTruckee value is 16,850 persons.
The US census population used in the EPA GHG inventory. This value is 330 million
POPus2os� persons.
24 For example,emissions per million gallons of water treated.
26 https://www.epa.gov/sites/default/files/2019-04/documents/us-ghg-inventory-2019-chapter-7-waste.pdf
26 See Table 7-10 in 2019 US GHG inventory(Chapter 7)
27 Also reported in Table 7-9 in 2019 US GHG inventory(Chapter 7)
P a g e 127 Section 4: Study Findings: Organizational Emissions
Page 55 of 109
1 Executive Summary
In early 2023,TDPUD staff initiated a Greenhouse Gas Inventory to reliably quantify The District's current
emissions footprint—with specific emphasis on those emissions occurring in calendar year 2022.The data
collected through this inventory, and their analysis, are critical in supporting TDPUD's strategic initiatives.This
document is written to provide the Board and public results for the GHG Inventory.
1.1 Report Organization
This greenhouse gas inventory measurement& implementation planning document is organized into the
following sections:
■ Section 1:
Definition of Key Terms
Carbon Emissions This term is used to broadly include each of the(6)gasses listed in AB 32(2006).
These gasses include: carbon dioxide, methane, nitrous oxide,sulfur hexafluoride,
hydrofluorocarbons and perfluorocarbons. It is typically convenient to normalize
reported GHG emissions into units of Carbon Dioxide equivalent(CO2e)
Carbon Dioxide equivalent A reporting metric which normalizes emissions of different GHG gasses on the basis
(COze) of their global warming potential (GWP)to the equivalent amount of carbon dioxide
with the same GWP
Global Warming Potential The relative potency of different greenhouse gasses to trap heat within Earth's
atmosphere(known as the greenhouse effect).
Net Carbon Reduction A net reduction of carbon emissions assesses the balance between carbon sources
(e.g.any release of GHG emissions)and carbon sinks(e.g. activities which pull carbon
emissions from the atmosphere and render their greenhouse effect inert). Equivalent
reductions can therefore be garnered through reduction of emissions at the source or
activities which create/expand a carbon sink.
Zero-Carbon Resource A term used in SB 100 to refer to a specific type of electricity generation resource.SB
100 does not define"zero-carbon resources,"and the state had no legal definition
before the bill becoming law.The joint agencies interpreted "zero-carbon resources"
to mean energy resources that either qualify as"renewable" in the most recent RPS
(Renewables Portfolio Standard) Eligibility Guidebook or generate zero greenhouse
gas emissions on site.SB 100 workshops and documents refer to these criteria as
"RPS+"
P a g e 11 Section 1: Executive Summary
Page 26 of 109
■ Executive Summary—Provides a summary of inventory results and their implications.
■ Section 2: Background and Context for 2022 GHG Inventory—Offers the reader critical background
information and context driving the current inventory and the context within which its results should be
understood.
■ Section 3:Approach(es) Used in GHG Inventory—Discusses the overall approach (and frameworks)
which were used to measure and report GHG emissions for The District.
■ Section 4: Study Findings: Organizational Emissions—Provides a detailed explanation of calculated
emissions and their derivation.
1.2 Summary of Findings
This inventory applied a scoping framework discussed in Section 3.3 to organize and report emissions findings
according to industry standards.The results are shown in Table 1-1 where it can be seen that 9,404 Tons of COze
emissions are directly attributed to TDPUD activities and operations during calendar year 2022 (Scope 1
emissions). An additional 239 Tons of COze are attributed to the electricity used by TDPUD facilities and
infrastructure for the same period.
Table 1-1 Summary of GHG Emissions by Scope for CY 2022
Emissions
Scope [Tons COA
Scope 1: Direct Anthropogenic 9,394
Scope 2: Indirect-Direct Anthropogenic 239
Scope 3: Indirect Emissions 33,516
For reasons discussed later in Section 3.3 and Section 4,the reported emissions cannot be aggregated across
scopes and must be understood solely within the context of the Scope they are reported. While 33,516 Tons of
CO2e are reported under Scope 3, it must be understood that these emissions are those over which TDPUD has
little to no direct control as they are predominately due to downstream use of the electricity and water TDPUD
sells to its customers.
1.2.1 Scope 1 Emissions Key Findings
Within Scope 1 it was found that most emissions are from electricity generated by electric generation assets in
which TDPUD has direct financial equity(approximately 93%of the reported emissions).These emissions are
attributed to TDPUD's resource portfolio and addressing these emissions (i.e. any attempt to reduce their
magnitude) requires a fully integrated approach to resource planning which balances both resource acquisition
and local demand-side interventions.The nuances of resource planning are beyond the scope of this inventory;
however,the results of this inventory and its data products are important inputs into The District's current
integrated resource planning efforts.
The remaining 630 Tons of CO2e emissions are largely attributed to TDPUD fleet vehicle operations and natural
gas used for water and space heating. At the time of this report,TDPUD has already purchased a light duty
electric truck to begin electrifying its light duty pool vehicle fleet—with plans to continue replacing pool vehicle
with electric. Fuel and vehicle use data provided insufficient data resolution in 2022 to provide meaningful
differentiation between water and electric utility operations. However, it remains true that building efficiency
and fleet vehicle operations represent the largest portion of The District's emissions over which TDPUD has
direct and immediate control.
P a g e 11 Section 1: Executive Summary
Page 27 of 109
1.2.2 Scope 2 Emissions Key Findings
Scope 2 emissions are specifically limited to those cause by generation of the electricity used by the organization
over the reporting period. For TDPUD this includes all electricity used by its headquarters facility, electric
department operations, water department operations, and any other facilities such as datacenters, etc.The vast
majority of electricity used in District operations (approximately 88%) is consumed by the Water Department in
operating well pumps and other pumping infrastructure to reliably supply high quality water to its customers.
Transmission losses,while important to include for comprehensiveness, are a minor component within the
Scope 2 emissions (approximately 1.5%) and TDPUD has little agency in impacting these emissions other than
simply reducing electricity consumption and thereby the amount lost in the transmission process.
1.2.3 Scope 3 Emissions Key Findings
Similar to Scope 1, emissions in Scope 3 are dominated by electricity generation and therefore proportional to
customer demands (e.g. consumption of electricity in TDPUD's service territory). Again,TDPUD has some
influence on these emissions through its resource procurement. It is also expected that The District's efforts in
developing an integrated resource plan which addresses these emissions (balanced with its other missional
objectives) will become increasingly important as the local community makes progress towards electrifying
building end-uses which were traditionally served by natural-gas.' Conservation certainly retains a critical role in
helping to reduce the speed at which electricity consumption increases due to building an transportation
electrification. However,the emphasis is shifting away from 'efficient'widgets and towards sustainable
behaviors and practices.
Also included in Scope 3 are approximately 815 Tons of CO2e emissions resulting from employee commuting and
final treatment of the domestic water TDPUD produces to its customers.2 Again, while TDPUD does not have
direct control over any of these emissions, it can influence them in a positive direction through water
conservation programs and through policies which incentivize more sustainable modes commute.
'Namely space and water heating
z Note that water used for irrigation goes directly back into the watershed and does not impact local wastewater treatment
facilities.
P a g e 12 Section 1: Executive Summary
Page 28 of 109
2 Background and Context for 2022 GHG Inventory
An initial 2008 Baseline Greenhouse Gas Emissions Re-Inventory was prepared for TDPUD in 2012 by Sierra
Business Council (SBC).This inventory was then updated in 2013 by SBC to compare 2012 re-inventoried
emissions against the original 2008 baseline.The 2012 Inventory applied an operational control approach to
define The District's organizational boundary used to determine which emissions were reported/inventoried.
These initial probes into The District's greenhouse gas (GHG) emissions focused on day-to-day District
operations, electricity distributed to (and consumed by) customers, and some Scope 3 sources such as employee
commuting.The study concluded that the most significant emissions source for The District was its delivered
electricity, a Scope 2 emission over which the district has only partial control. This emission source also saw
significant reduction relative to the 2008 baseline due to an increase of'clean' electricity generation within the
District's Renewable Portfolio Standard (RPS).The Water Department was responsible for approximately 58%of
the District's Scope 1 operational emissions, with the remaining coming from the electric department.
No updates have been made to the GHG emissions estimated by the 2012 Inventory while The District has
continued to improve its RPS with additional sources of clean electricity and has maintained robust conservation
programming for its customers since the last inventory in 2012.The 2012 Inventory numbers no longer reflect
The District's current emissions footprint.
2.1 Regulatory and Legislative Context for the GHG Inventory
It should be noted that, currently,there are no regulations which require TDPUD to inventory its district-wide
GHG footprint. Rather, this endeavor sits above and beyond of the underlying regulatory landscape in response
to the District's own Net Carbon Reduction strategic initiative.This initiative is a combination of the "100%clean
renewable energy" and "local clean generation" initiatives.The ultimate goal behind these initiatives is to
reduce the amount of carbon in Truckee's environment, and that being produced by Truckee's actions.
However,the former initiatives emphasized energy procurement as a means of GHG mitigation, without
considering how and when the community uses electricity.TDPUD commits to make meaningful progress
towards GHG mitigation through cost-effective energy purchase, beneficial investments into conservation, and
data-driven innovation.
While this inventory is implemented in response to TDPUD's own strategic initiatives,the State of California has
implemented a number of ambitious policies over the last two decades in efforts to mitigate anthropogenic
climate change which overlap with the objectives of this project. One particularly significant piece of legislation
was AB 32 (Global Warming Solutions Act of 2006)from which many current state programs find their genesis—
including California's Carbon Cap &Trade Program.AB 32 specifically directs the California Air Resources Board
(CARB)to oversee that statewide GHG emissions be reduced to 1990 levels by 2020. CARB subsequently
established its Carbon Cap&Trade program in 2008 for which it then set mandatory GHG reporting
requirements for electricity importers (among other emissions sources).
In addition to CARB's mandatory GHG reporting requirements, the District reports its generation sources (and
their carbon intensities) annually to the CEC in response to its Renewable Portfolio Standard (RPS)targets
established in SB 1078 (2002), and expanded by the more recent SB 100. SB 100 mandates that renewable and
"zero-carbon" resources supply 100%of electric retail sales to end-use customers by 2045 (with 60% being
3 See Section 3.2.3 for GHG boundaries and approaches.
P a g e 1 1 Section 2: Background and Context for 2022 GHG Inventory
Page 29 of 109
renewable and 40% "zero-carbon"). It also establishes several interim targets along the way in 2035 (60%/30%
respectively), and 2040 (60%/35% respectively).
The California RPS and CARB mandatory GHG reporting requirements are specifically referenced here as they
specifically quantify emissions (Tons of CO2e) for TDPUD's electricity procurements in a public capacity.There
exists a fundamental difference between the objectives underlying the engineering assumptions and reporting
standards established by these two statewide programs and those applied in this GHG inventory. Namely, many
of the assumed emissions intensities for generation sources in the RPS and CARB reporting standards are driven
more-so by political discourse than engineering analysis. An example of this can be found in the difference
between carbon intensities reported for"small-hydro" and "large hydro" in the RPS reporting standard (with
small hydro assumed to have zero emissions and large hydro treated as "unspecified"). Furthermore, the
division between small and large-hydro sources is based on generator size and not on any material difference in
how small or large-hydro generator sources operate.
In this GHG inventory, staff applied a physical first-principals focused assessment of GHG emission intensities for
each generation technology in TDPUD's portfolio. Staff approached each source objectively on the engineering
behind its electricity-production processes and plant lifecycle.This approach was selected to be consistent with
the strategic initiative's objective of achieving meaningful (e.g., tangible, and empirically verifiable) progress
towards GHG mitigation. Furthermore, such an approach is necessary to meet the TDPUD's objective of
managing The District in an environmentally sound manner, and ultimately reach its goal of Environmental
Stewardship (Creating a sustainable resilient environment for all our communities).
2.2 Objectives for Proposed Greenhouse Gas Inventory
Consistent with the mission and goals established in the 2021 TDPUD strategic plan,A GHG Inventory was
implemented in 2023 to account for GHG emissions occurring in calendar year 2022.This study built off previous
GHG inventory studies to:
■ Update the District's GHG Inventory to reflect current emission levels.
■ Generate a detailed understanding of District GHG emission sources and their magnitudes.
■ Coordinate with the Town of Truckee and other local agencies to ensure that this study is
complimentary with other local GHG inventories such that they collectively assess regional GHG
emissions.
Finally, this Inventory will establish the baseline emissions used to measure future progress towards The
District's decarbonization goals.
P a g e 12 Section 2: Background and Context for 2022 GHG Inventory
Page 30 of 109
3 Approach(es) Used in GHG Inventory
The 2022 GHG Inventory will follow the protocols defined under the General Reporting Protocol Version 3
(GRPv3) and incorporated the additional requirements and reporting guidance provided by the Electric Power
Sector Protocol (EPSP) and the Water Energy Nexus Registry Protocol (WENRP).
3.1 General Inventory Methodologies
In a general sense, all GHG inventories will follow the following process:
■ Determine the organizational/inventory study boundary and scope—Arguably the most difficult and
most important step in performing GHG inventory as this defines both which emission sources are
considered as well as their attribution.This step also has implications on whether or not study results
will coordinate with inventories developed by other organizations.
■ Identify emission sources and their scopes—Emission sources can be direct or indirect and are
organized into several "scopes" which define varying levels of attribution or agency for which the
organization is responsible over the emission generating activities.
■ Measure and quantify identified emissions—Once emissions are identified and scoped, data must be
collected to quantify the magnitude of GHG gasses being emitted using an appropriate level of rigor.
GHG gases are normalized into units of Carbon Dioxide Equivalent (CO2e).
■ Report findings—Findings are compiled into a final report which summarizes the overall organizational
footprint while then providing additional details consistent with the organization's objectives for the
inventory. Results are also compiled into a standard reporting format for upload into CRIS for public
reporting of GHG emissions.
It must be recognized that anthropogenic GHG emissions rarely have a single attributable source. For example,
electricity is demanded by a community of consumers, sourced, and distributed by local utility companies, and
generated by electric generators which can be located well outside of the community using it. Multiple actors
therefore have agency over the activities leading to GHG emissions resulting from the generation, distribution,
and consumption of electricity.
Inventory boundaries are used to help differentiate actors, agency, and scope for reported GHG emissions.The
inventory specifically defines an organizational boundary(delineates actors and agency ascribed to emissions
sources) and a reporting boundary(the scope of emissions within an organizational boundary considered within
the inventory).The final inventory boundary results in the intersection between the organizational and reporting
boundaries.
Within the boundaries, emissions sources are further classified into one of three scopes.These scopes create an
accounting framework which facilitates specific attribution of anthropogenic emissions and, when correctly
applied, eliminates the double-counting of emissions across multiple actors.
In this section a general methodology is outlined for the 2022 GHG Inventory for Truckee Donner Public Utility
District.
3.2 Organizational and Reporting Boundaries
Before defining the organizational and reporting boundaries used for the 2022 inventory, it is important to
outline some key details with respect to The District's organizational structure, mission, and operational
footprint.
P a g e 13 Section 3:Approach(es) Used in GHG Inventory
Page 31 of 109
Truckee Donner Public Utility District was established on August 9, 1927 as a Public Utility District under Division
7 of the State Public Utilities Code.At the time of its establishment,The District provided electric service only.
Since 1935,The District has also provided water service within the Truckee and Donner Lake areas,with the
Electric System and the District's water system maintained and operated separately.The District is primarily
located in eastern Nevada County, with a small area of the District (approximately 1.5 square miles) located in
neighboring Placer County.The District is situated in the Sierra Nevada Mountains approximately 180 miles
northeast of San Francisco and 32 miles west of Reno, Nevada. Lake Tahoe is approximately 12 miles south of
The District's boundaries.
Approximate TDPUD ti
�.' Electric Service Territory
14,
v u
—
.y; I I�
f
Figure 3-1 Approximate Boundaries for TDPUD Electric Service Territory
Hir-hdale Wale,system
Service A—
u o Truckee
Truckee Water System
Service Area
NEVADA COUNTY
PLACER COUNTY
Figure 3-2 Approximate Boundaries for TDPUD Water Service Territory
3.2.1 Electric Utility General Description
The District has broad general powers over the generation of electricity within District boundaries, including the
powers of eminent domain,to contract,to construct works,to fix rates and charges for commodities or services
furnished, to lease its properties and to incur indebtedness.The current population within the District's 47
square mile service area is estimated to be approximately 16,200 residents. Many landowners within The
P a g e 14 Section 3:Approach(es) Used in GHG Inventory
Page 32 of 109
District have their primary residences elsewhere and use their property within the District as secondary and
vacation homes. As of December 31, 2021, the District provided electric service to 12,931 residential and 1,619
commercial, governmental, institutional and other customers.The District is the sole provider of retail electric
service within its service area.
The District is a network transmission service customer under the currently effective joint Open Access
Transmission Tariff with NV Energy, an investor-owned utility.The District uses NV Energy's network service to
import into and transport across NV Energy's transmission grid all of the energy that is necessary to serve the
District's load.This load is served from four substations and one distribution interconnection with NV Energy.
The substations and interconnection voltages include Donner Lake Substation (60 kV),Tahoe Donner Substation
(60 kV),Truckee Substation (60 kV), Martis Valley Substation (120 kV) and the Glenshire metering point(14.4
kV).The Electric System includes more than 232 miles of 12.47 kV and 14.4 kV distribution lines, including
approximately 97 miles of underground distribution cables and approximately 135 miles of overhead pole lines.
The District does not generate electricity itself.The District's sources of electrical power include resources
owned and/or operated by Utah Association of Municipal Power Systems (UAMPS), Western Area Power
Administration (WAPA), and Truckee-Carson Irrigation District (TCID).The District has entered into various
agreements with these entities for electrical power which is generated from wind, landfill gas, hydroelectric
projects, natural gas, and other sources.
3.2.2 Water Utility General Description
The District has broad general powers over the use of water within District boundaries, including the right of
eminent domain and the authority to acquire, control, distribute, store, spread, sink, treat, purify, reclaim,
process and salvage any water for beneficial use,to provide sewer service,to sell treated or untreated water, to
contract with the United States, other political subdivisions, public utilities and other persons, and, subject to
certain State Constitutional limits,to levy taxes on lands.As of December 31, 2021, the District provided water
service to 12,709 residential and 767 commercial,governmental, institutional and other customers.The District
is the sole provider of water service within its service area.
The District's sole source of water is groundwater that is extracted from 13 active wells in the Martis Valley
Groundwater Basin (the Basin). Groundwater from the Basin is of high quality and is not treated extensively
prior to delivery to customers. The District also has surface water rights in Donner Lake,the Truckee River and
six local springs, although the District does not currently utilize these surface water rights. In addition to
groundwater wells,the Water System includes: 25 pump stations, 33 active water storage tanks with a
combined storage capacity of approximately 9.6 million gallons, approximately 220 miles of distribution
pipelines varying from 2 inches to 24 inches in diameter, 47 pressure zones, and 35 active control valve stations.
3.2.3 Defining an Organizational Boundary for the Inventory
The organizational boundary defines the degree of ownership or control an organization exercises over specific
GHG emission activities and are categorized by the GRPv3 into one of three methods4: 1) Operational control, 2)
Financial Control, and 3) Equity Share.
This study defined the organizational boundary using an Equity Share Perspective for the District.This
corresponds to the GRP Option 1 defined in the EPSP.The equity share perspective provides an accounting of
activities wholly and partially owned by the district—with emissions being accounted according to the
organization's ownership share. This was chosen to report a full and transparent accounting of The District's
4 See pg. B-1 of the GRPv3 for full definitions of each.
P a g e 1 5 Section 3:Approach(es) Used in GHG Inventory
Page 33 of 109
local (e.g. regional) operational footprint as well as the GHG emissions resulting from operations for which the
District has ownership equity but no direct operational control. Inventory components for which The District has
100% direct operational control include:
■ Operations and Maintenance (O&M)for The District's electric Transmission & Distribution (T&D) System
■ O&M for the District's water pumping, treatment, and distribution infrastructure
■ Headquarter building O&M
■ Energy resources consumed by District stationary facilities (and mobile equipment)
Each of the above activities were included in The District's original 2008 baseline and 2012 inventory studies
which took an operational control perspective when defining the organizational boundary. As previously noted,
The District wishes to expand the boundary in the 2022 inventory to provide additional transparency with
respect to GHG emissions from TDPUD's interests.The expanded boundary also provides The District with
additional opportunities to identify, quantify, and mitigate GHG emissions connected to its interests.The
additional GHG emissions sources from which The District has equity interest include:
■ Energy resource consumption, O&M, and embedded product emissions from several electric generation
facilities which include Horse Butte Wind Farm (26%Share), Veyo Heat Recovery Project (23%Share),
and Nebo Power Station (3%Share)
■ Surface water rights to Donner Lake,Truckee River, and (6) local springs
The 2022 inventory study quantified GHG emissions associated with the District's equity interests in the above
sources (in addition to those previously identified for which the District has 100%operational control).
3.2.4 Reporting Boundary
The reporting boundary for the 2022 inventory included all emissions sources within the organizational
boundary with specific emphasis (rigor) applied to those emissions occurring within the Truckee-Tahoe
geographic region.The inventory captured emissions occurring in calendar year 2022 which will establish a
baseline GHG emissions level against which future emissions inventories will be compared to determine
progress made towards overall GHG reductions.
3.3 GHG Emission Sources and Inventory Scoping
The GRPv3 establishes a comprehensive accounting framework for categorizing direct and indirect
anthropogenic emissions. GHG emissions are classified as:
Scope 1 covers all anthropogenic GHG emissions directly emitted by an organization's
activities/operations. Such emissions include stationary combustion, mobile combustion, physical and
chemical processes, and fugitive sources. For power generation facilities this includes all combustion
emissions associated with the generation of electricity(regardless of who uses the electricity).The
GRPv3 defines several different categories within which Scope 1 emissions are reported. The EPSP and
WENRP then provide additional specificity for electricity providers and water management
organizations.
Scope 2 includes all anthropogenic GHG emissions indirectly associated with an organization through the
purchase of consumed energy (electricity, steam, district heating or cooling, etc.). Note that the EPSP
requires line losses across Transmission & Distribution systems within the organizations boundary
associated with the organization's electric power consumption be reported under Scope 2.
P a g e 16 Section 3:Approach(es) Used in GHG Inventory
Page 34 of 109
Scope 3 emissions cover remaining indirect anthropogenic emissions which fall outside of either Scopes
1 or 2. Examples include employee commutes, GHG emissions associated with purchased products,
indirect emissions from customer purchased/consumed electricity, etc.
In Section 4 (Study Findings:Organizational Emissions)the quantified emissions for each scope are discussed in
detail. It is important to note that emissions can only be meaningfully aggregated across separate organizations
within a particular scope.
3.3.1 Quantifying Emissions
Emissions for this study were quantified following the methods defined in the GRPv3 for GHG inventories.'
Methods are broken down into Calculation-Based Methods, Measurement-Based Methods, and Simplified
Estimation Methods(SEMs).
Calculation-Based methods use data which measure the level of a particular activity which results in
GHG emissions. Emissions factors are then applied to this data (e.g. GHG emissions per unit of activity)
to estimate overall GHG emissions associated with the activity levels recorded in the data. An example
of this would be using fuel purchase records to determine the amount of gasoline used over the course
of the reporting period and applying an appropriate emissions factor(units of COze per gallon of
gasoline burned in a combustion engine)to quantify the amount of CO2e emitted for the reporting
period.
Measurement-Based methods directly measure emissions at their sources using systems capable of
monitoring the concentration of reported GHGs and their outflow rates.This is particularly relevant for
agencies/facilities with large stationary combustion sources and stringent regulatory reporting
requirements.
Simplified Estimation methods use deemed emissions levels for various sources and thus don't require
the same level of data/rigor as applied in the other methods.And example of this is the fugitive
refrigerant emissions screening method outline in Section C of the GRPv3 and its assumed factors. Note
that emissions calculated using this method cannot exceed 10%of the organization's combined Scope 1
and Scope 2 emissions.
Most emissions reported in this study were quantified using the Calculation-Based Method. The SEM approach
was however leveraged to report fugitive refrigerant emissions under Scope 1.
All emissions are reported in units of Carbon Dioxide Equivalent(CO2e)which normalize the effects of different
greenhouse gas emissions based on their global warming potential(GWP)to the equivalent amount of carbon
dioxide with the same GWP.
3.3.2 Emissions Factors
Emissions factors for this study were sourced from industry standard, peer reviewed, and government sources.
These sources included:
■ National Renewable Energy Laboratory
■ Energy Information Administration (EIA)
■ Environmental Protection Agency(EPA)
■ California Air Resources Board
■ Intergovernmental Panel on Climate Change
5 Defined in Section C of the GRPv3
P a g e 17 Section 3:Approach(es) Used in GHG Inventory
Page 35 of 109
■ The Climate Registry6
Additional information on the emissions factors applied in this study is discussed under each emissions source
quantified in Section 4 (Study Findings: Organizational Emissions).
6 The organization which publishes and maintains the General Reporting Protocol and its supplementary materials.
8 Section 3:Approach(es) Used in GHG Inventory
Page 36 of 109
4 Study Findings: Organizational Emissions
This section of the report provides a detailed treatment of emissions findings for each scope. Emissions sources
and their magnitudes are discussed under each scope separately.
This inventory quantified overall emissions for TDPUD within each scope as shown in Table 4-1
Table 4-1 Aggregated Emissions Within Each Reporting Scope for CY2022
Scope Component Component Emissions Scope Emissions
[Tons COA [Tons COA
Transport 475
1 Building 155 9,394
Generation1 8,763
2 Electricity Consumed 235 239
Transmission Losses 3.50
Employee Commutes 337
3 Electricity Sold 32,701 33,516
Wastewater(water sold) 478
'Including District Equity Component
It is reiterated here that an 'overall' emissions value (for any organization) cannot be developed by aggregating
across Scopes. Each 'Scope' provides its own relevance to the organization's full value chain and must be
interpreted/understood on its own standing—especially when trying to compare or aggregate across multiple
organizations. For example, the emissions reported for electricity sales to any given entity under Scope 3 for this
inventory should be reported under Scope 2 for that particular entity. Similarly, the local wastewater treatment
facility would report the portion of emissions provided here under Scope 3 within Scope 1 of its own inventory.
While tempting to combine, the results for each scope must be interpreted independently and cannot be
combined without double counting the reported emissions.
4.1 Scope 1 Emissions: Direct Anthropogenic
This study found that TDPUD emitted 9,394 Tons of CO2e under its Scope 1 emissions sources for the 2022
Calendar Year. Emissions are broken down into each GRPv3 reporting category in Table 4-2. Most of the
reported emissions are derived from TDPUD's equity in serval generation resources (predominately the Nebo
power plant)—reported under stationary sources in Table 4-2.
Table 4-2 Summary of Scope 1 Emissions
for 2022 by Reporting Category Table 4-3 Scope 1 Emissions by location
Category Emissions Emissions
[Tons COZe] Location
[Tons COZe]
Stationary 8,908 Within TDPUD Service Territory 630
Mobile 475 Outside of Service Territory 1 8,763
Fugitive 9.8 Total 9,394
Total 9,394
9 Section 4: Study Findings: Organizational Emissions
Page 37 of 109
In Table 4-3 these same generation resources place the majority of TDPUD's Scope 1 GHG emissions outside of
its service territory.The largest contributor to emissions within TDPUD's service territory is its fleet operations
which amounted to about 475 Tons of CO2e in 2022 (or 74%of the local emissions).This can be seen
graphically in Figure 4-1 which isolates Scope 1 emissions for local operations only(e.g. minus emissions from
the production of electricity at facilities owned or controlled by the organization).
Total Operations Emissions
700 for CY 2022 [Tons CO2e]
600
500
400
■Fugitive
300 ❑Mobile
200 ■Stationary
100
C) L-iML
2022
Figure 4-1 Scope 1 Emissions Occurring from Local Operations Only
Individual Scope 1 emission sources which were considered in the 2022 Inventory are listed in Table 4-4. It
should also be noted that while TDPUD is a water utility, its operations do not include any Scope 1 or Scope 2
emissions sources called out in the WENRP—namely biogenic CO2 and CH4 from man-made reservoirs'or
process N20 from wastewater discharge.Therefore, all Water Utility emissions are covered under the GRPv3.
Table 4-4 List of Emissions Sources Included under Scope 1
Combustion of fossil fuels in stationary equipment. Common examples include space heating
equipment such as boilers and furnaces,though this can include incinerators, process
equipment, stationary generators, etc.The EPSP expands this to include emissions from the
Stationary production of electricity at facilities owned or controlled by the organization.
Combustion GRPv3 Sources EPSP Sources WENRP Sources
Emissions ■ Backup & Emergency Generators ■ Emissions from
■ District Headquarters Radiant Heaters electricity generators in
■ District Headquarters Boilers/Furnaces
which TDPUD has None
equity.
The WENRP specifies that"emissions associated with natural lakes converted to reservoirs without inducing significant
changes to water surface area should not be considered"(Pg.25 WENRP). Donner Lake is a natural lake with limited surface
area impact due to its dam.TDPUD only has rights to [980 acre-feet].
P a g e 1 10 Section 4: Study Findings: Organizational Emissions
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Combustion of fossil fuels occurring in non-stationary equipment such as transportation
vehicles and heavy machinery. Note that mobile/portable generators are reported here unless
the electricity is delivered to the grid in which case such emissions are reported with other
Mobile electric generation under stationary sources.
Combustion GRPv3 Sources EPSP Sources WENRP Sources
Emissions ■ Electric Dept.fleet vehicles
■ Water Dept. fleet vehicles
None None
■ Heavy equipment (including snow cat)
■ Pool vehicles
Intentional or unintentional emissions from production, processing,transportation, or storage
of substances not passed through a stack, chimney,vent, exhaust pipe, etc. Notable examples
Fugitive include refrigerant leakage in HVAC equipment and SF6 from high voltage equipment
Emissions GRPv3 Sources EPSP Sources WENRP Sources
■ HVAC refrigerant leakage ' SF6 emissions from high None
voltage equipment.
Non fuel-combustion emissions due to a physical or chemical process. Examples include
chemical manufacturing processes, acid gas (SO2) scrubbers, and gas releases in geothermal
Process facilities.
Emissions GRPv3 Sources EPSP Sources WENRP Sources
None ' Acid gas scrubber Nebo None
gas turbines
4.1.1 Stationary Combustion Emissions
Four specific stationary combustion emissions sources were identified and considered in this study as listed in
Table 4-4. Each source, its emissions factors, and overall emissions for 2022 are discussed below.
4.1.1.1 Backup and Emergency Generators
During the data collection phase, it was found that fuel purchases for the backup and emergency generators
could not be separated from fuel purchased for fleet vehicle operations. In discussions with District staff, it was
determined qualitatively that the fleet vehicle fuel use was much larger than that used for backup and
emergency generators. Furthermore, no data was available to estimate the proportion of fuel used by each with
any reasonable accuracy.Therefore, all emissions from fuel use (gasoline and diesel purchases) are reported
under Section 4.1.1.3
4.1.1.2 District Facility(buildings/structures)Space and Water Heating
Space heating for District facilities is predominately Natural Gas (with some electric resistance heating used by
the Water Department in pump houses).The heating is used in a variety of system types which include radiant
heaters, boilers, and furnaces. Insufficient trend data was available from each of these systems to do an in-
depth analysis of emissions by source. Instead, utility billing histories for natural gas for each of TDPUD's
facilities were aggregated to calculate a combined emissions for all systems using the following calculation:
P a g e 1 11 Section 4: Study Findings: Organizational Emissions
Page 39 of 109
EYear — Y, EI F* T hermsMonth
Month
Where:
Are the calculated GHG emissions (in units of COZe)for the facility space and water heating
£Year sources.
Is the emissions factor(in units of COze per Therm) used to estimate GHG emissions for space
EIF and water heating equipment derived from EPA GHG emissions factors database for
stationary sources.$k is equal to 0.00585 Tons COze per Therm.
ThermSMonth Is the monthly natural gas consumption by TDPUD facilities in units of Therms.
Natural gas bills from Southwest Gas provided monthly natural gas consumption data for District facilities. Note
that the billing periods do not neatly align within each calendar month.As such,the billing data was normalized
to Therms per billing day in the billing period and then interpolated across each month in 2022 to account for
overlap in the billing periods on each end of the year.These data were aggregated for 2022 for which The
District is estimated to have used 24,817 Therms and thereby emitted 145 Tons CO2e. Figure 4-2 shows the
monthly natural gas consumption for the District over CY 2022. It should be noted that natural gas consumption
is sensitive to outdoor temperature (lower temperatures equal higher consumption for heating) and will
therefore vary year to year depending on the severity of a given winter season.
Monthly Natural Gas Consumption for CY 2022
Sum of normTherms_MO Sum of GHG (Tons CO2e)_MO
6,000 30
c N
_o
5,000 25 0
a--+
Q LnN
4 000 ---- ---------------------------------------------- - ------- 20 —
N , w a
to o E
0
- ------------------------------------------------------- - ua, 3,000 15
N N
t v �
N
u 2,000 -------------------------------------- 10
z1,000 - - -- --- ---- ----------------------------- - -- 5 a�
0 0
1 2 3 4 5 6 7 8 9 10 11 12
MONTH OF THE YEAR
Figure 4-2 District Natural Gas Consumption by Month for Calendar Year 2022
$https://www.epa.gov/climateleadership/ghg-emission-factors-hub
P a g e 1 12 Section 4: Study Findings: Organizational Emissions
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Figure 4-2 also shows the monthly GHG emissions resulting from the stationary natural gas combustion. As
expected,the emissions are directly proportional to the natural gas consumption of a given month.
4.1.1.3 District Owned(Financial Equity)Stationary Generation Assets
The EPSP expands the General Reporting Protocol's definition of Scope One emissions sources to include
emissions from the production of electricity at facilities owned or controlled by the organization. It was
established in 3.2.4 Reporting Boundary that this inventory would be applying an equity approach in defining the
organizational boundary.This means that Scope One emissions for TDPUD must include emissions from any
electricity generation facilities in which The District has financial equity.9
The additional GHG emissions sources from which TDPUD has equity interests include:
■ Horse Butte Wind Farm (26%share),
■ Veyo Heat Recovery Project (23%share), and
■ Nebo Power Station (3%Share)
Data was collected on the hourly generation of each resource in TDPUD's resource portfolio and a full hourly
GHG emissions profile was derived according to The District's resource mix as discussed in 4.2.2.The subset of
emissions from electricity generation facilities in which TDPUD has financial equity was estimating using the
following formula:
EYear — EIFHorse Butte * Y EHorse Bute,Hr + EIFVeyo * EVeyo,Hr + EIFNebo * ENebo,Hr
Hours Hours Hours
Where:
Are the calculated GHG emissions (in units of COze)for the production of electricity at facilities
£Year owned or controlled by TDPUD proportional to its equity interest.
Is the emissions intensity factor(in units of COze per Megawatt-Hour) used to estimate GHG
EIFasser emissions for each generation asset.The specific values used for the EIF and their derivation are
explained in detail in 4.2.2.
Easset,Hr Is the equity owned portion of hourly electricity generation for each asset.
Emissions from the three electricity generation facilities in which TDPUD has financial equity totaled to 8,763
Tons of CO2e for calendar year 2022.The time-series distribution of these emissions (and the electricity
generation) can be seen plotted in Figure 4-3. Here it can be seen that while the emissions from Horse Butte and
Veyo are non-zero10,the major contributor to overall emissions comes from the Nebo power plant (shown in
yellow).
9 This does not include Power Purchase Agreements(PPAs). Emissions from purchased power are reported under Scope 2
for electricity consumed by TDPUD operations and under Scope 3 for electricity sold to customers.
10 While it may not be immediately intuitive that'renewable'generation resources have non-zero emissions,this subject is
discussed in detail in Section 4.2.1 and Section 4.2.2.
P a g e 1 13 Section 4: Study Findings: Organizational Emissions
Page 41 of 109
Scope One Emissions From Electricity Generation (Equity Assests)
N
C
N
50
N
E 07
W N
�0 40
N
a7 C
7�
0— 20
t
C
G1
41
L
04. Resource
ti� ti� ti� ti� titi ti� titi ti� ti� ti� ti� titi
Horse Butte
Oti 10 0�1 Ob, Oh Ofo O1 OV Odf 4a 11; Nl Nedo
Vey.
u_ 300
L
a.J
u r,
1L 200
41
+J u
L
C 100
V
0 '— -
,�O
Oa O" OJD� 01 00 OA 4 titi ti�
Date
Figure 4-3 Time Series Distribution of Stationary Generation Asset Emissions
4.1.2 Mobile Combustion Emissions
It was previously noted that fuel purchases for fleet vehicle operations could not be separated from fuel
purchased for the backup and emergency generators. Since fleet vehicle fuel use was estimated to be much
larger than that used for backup and emergency generators,the overall emissions for fuel purchases are
reported here as Mobile Combustion Emissions.
TDPUD maintains and operates a fleet of approximately fifty light, medium, and heavy duty vehicles to facilitate
its local operations. A majority of these fleet vehicles are diesel fueled,though the light duty vehicles use
gasoline. At the time of this inventory no telemetry data was available on vehicle operations and duty cycles to
facilitate a ground up estimate of vehicle fuel consumption for CY2022. Instead,this inventory relied on fuel
purchase records in CY2022 to estimate the amount of fuel consumed (combusted) in its fleet operations. In
additional to direct fuel combustion,the IPCC provides a simplified method of estimating emissions from non-
energy applications of petroleum products11 such as solvents and lubricants.
11 See Chapter 5 Non-Energy Products from Fuels&Solvent Use in the IPCC Guidelines for National Greenhouse Gas
Inventories
P a g e 1 14 Section 4: Study Findings: Organizational Emissions
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The general approach in estimating mobile combustion emissions applied the following equation:
EYear — EIFProductj * VolumeProductj
i
Where:
Are the calculated mobile GHG emissions (in units of COze) for each source/product for
EYear the reporting year summed across all purchases in the reporting year.
Is the emissions intensity factor(in units of COZe per volume of product) used to estimate
ElFp,duct,i GHG emissions for mobile combustion sources. Each EIF used in the calculations is
discussed below.
Volume Is the purchased volume of products contributing to mobile emissions tracked in this
Product, inventory.
Emissions Intensity factors were sourced from different datasets based on the emissions source. Sources were
classified as either being Gas/Oil/Lubricant, Diesel, or Unleaded Gasoline.The emissions intensity factors and
their sources are defined in Table 4-5.
Table 4-5 Mobile Combustion Emissions Sources and Intensities
Expense EIF Description
Description (Ton COZe Per Gallon)
DIESEL FUEL 0.0054 The value used in this study is sourced from CARB's Low Carbon Fuel
Standard reporting data for certified Renewable Diesel pathways.12
UNLEADED 0.0097 Standard unleaded fuel with an emissions factor defined by the EPA's
FUEL database for emissions factors (its GHG Emissions Factors Hub).13
GAS, OIL, Emissions from lubricants in combustion engines are reported here
LUBRICANTS 0.0083 using the IPCC approach defined in its Guidelines for National
Greenhouse Gas Inventories.
All diesel fuel purchased by The District is certified renewable diesel produced from non-petroleum renewable
sources. Its emissions intensity is therefore lower than standard diesel fuel and known data points of emissions
intensities for this fuel are documented by California Air Resources Board (CARB) in its Low Carbon Fuel
Standard (LCFS) carbon cap and trade program.The total mobile combustion emissions calculated for calendar
year 2022 for TDPUD is 475 Tons CO2e.
Note that since the available data only documented purchase date of the fuel (and not the date/time of actual
use), no additional time-series analysis was performed to review the distribution of mobile emissions
throughout the year. In 2023 TDPUD installed advanced telemetry data acquisition in its fleet vehicles which
should enable future inventories to do more detailed analysis on its mobile combustion emissions.
12 https://ww2.arb.ca.gov/resources/documents/Icfs-pathway-certified-carbon-intensities
11 https://www.epa.gov/climateleadership/ghg-emission-factors-hub
P a g e 1 15 Section 4: Study Findings: Organizational Emissions
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4.1.3 Fugitive Emissions
Fugitive emissions for TDPUD include HVAC refrigerant leakage and Sulfur Hexafluoride (SF6) emitted from
electrical transmission and distribution equipment.
TDPUD is subject to California regulation which requires annual reporting (and inventory tracking) of SF6 emitting
equipment(namely SF6 insulated switchgear).This inventory reviewed the annual reporting data and observed
that TDPUD does not own or operate any SF6 insulated switchgear and its annual SF6 emissions are zero.
Therefore,the only fugitive emissions to report are from HVAC refrigerant leakage.
Given the de minimis magnitude of fugitive emissions relative to the overall Scope 1 emissions, this inventory
applied a simplified estimation method to calculate fugitive refrigerant emissions.This inventory uses the
Screening Method defined in the GRPv3 for refrigeration and air conditioning systems as follows:
(CN * k) + (C* w* T) + [CD *y* (1 —z)](kg)
EYear = kg
1,000 (Mt)
Where:
Are the calculated mobile GHG emissions (in units of Metric Tons COZe)for each piece of
EYear refrigeration equipment for the reporting year summed across all pieces of equipment in the
organization.
CN Quantity of refrigerant charged into the new equipment
C Total full charge (capacity) of the equipment
T Fraction of year equipment was in use (e.g., 0.5 if used only during half the year and then
disposed)
CD Total full charge (capacity) of equipment being disposed of
k Installation emission factor=0.03
W Operating emission factor=0.15
Y Refrigerant remaining at disposal =0.80
z Recovery efficiency=0.70
The factors described in the above formula are defined in Table 4.1 in The Climate Registry's Default Emission
Factors (published for each year).The above formula reports emissions in units of Metric Tons of COze.These
results were converted to US Tons of COZe to be consistent with results reported in this inventory.The total
calculated fugitive emissions for CY 2022 were 9.8 Tons of CO2e which is less than 2%of local Scope 1 emissions
and approximately 0.1%of the total Scope 1 Emissions. In either case the emissions are significantly under the
10%threshold established in the GRPv3 and validates this inventory's application of the SEM approach.
4.1.4 Process Emissions
The EPSP identifies acid gas scrubbers for gas turbine power generator plants as a process emission source. Staff
reviewed available literature for the power plant through Utah Associated Municipal Power Systems (UAMPS)
and detailed information was not available on plant operations for the Nebo power plant or its GHG emissions
(beyond what could be found at the EIA). However; it is assumed that the emissions factor used in this study to
estimate the GHG emissions per Megawatt-hour of generated electricity(see Section 4.1.1 on Stationary
Combustion Emissions) includes this emissions component as it is applied to the whole plant and not simply the
16 Section 4: Study Findings: Organizational Emissions
Page 44 of 109
generator units.Therefore, while zero process emissions are being reported, the emissions from this source
should be understood to be included within the Stationary Combustion Emissions and not omitted from this
study.
4.2 Scope 2 Emissions: Indirect Direct Anthropogenic
This inventory found that total Scope 2 emissions attributable to TDPUD were 238.5 Tons CO2e for calendar year
2022.
Table 4-6 Scope 2 Emissions Summary for TDPUD(CY2022)
OIL__ Electric Dept Water Department Total Emissions
[Tons CO2e] [Tons CO2e] [Tons CO2e]
28.34 206.19 235.02
0.48 3.48 3.48
• - 28.82 209.68 :
Scope 2 emissions result from activities which take place within an organization's boundary, but actually occur
within the boundary of a different organization. Such emissions are reported using location-centric and market-
centric perspectives which give two understandings of an organization's GHG footprint.
The location-centric approach accounts for geographically proximate grid resources to estimate the
GHG content in regionally proximate electricity generation.This ignores power purchase contracts and
focusses on "cleanliness" of regional/local generation.This helps provide insight on the local/regional
impacts of energy conservation.
The market-centric perspective accounts for an organization's energy purchasing decisions. It allows an
organization to understand the impact that their energy supply(e.g.,financial and contracting) decisions
have on their GHG footprint.
In some cases,the two approaches may be identical,while for other organizations they can be quite different.
For TDPUD,these two will generate different results as all its electricity is sourced contractually from outside of
the region and across NV Energy transmission infrastructure.Therefore,TDPUD's location-centric emissions
factor will be closely aligned with NV Energy's fuel mix while its market-centric emissions factor will reflect its
resource procurement portfolio.This inventory reports Scope 2 emissions using a market-centric perspective
which is consistent with its intent in applying the Equity Share organizational boundary.
Individual Scope 2 emission sources which were considered in the 2022 Inventory are listed Table 4-7.
Table 4-7 List of Anticipated Scope 2 Emissions Covered by Inventory
A simple example of Scope 2 emissions are those associated with an organization's electricity
consumption. Electricity consumed by an organization must be generated elsewhere, and
Indirect generally by a separate organization. While the emissions occur directly within the generating
Emissions facility's boundary,they were indirectly generated by the consumer.They are therefore
(Energy) reported under Scope 2 for the consumer and Scope 1 for the generator.14
GRPv3 Sources EPSP Sources WENRP Sources
14 This is slightly modified for vertically integrated utilities and any organizations which consume power that is self-
produced since such emissions are reported as direct(Scope 1).
P a g e 1 17 Section 4: Study Findings: Organizational Emissions
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4r
■ Electricity consumed by District HQ ■ T&D Losses from self-
facility. consumed electricity
■ Electricity consumed by well houses. ■ SF6 emissions from None
■ Electricity consumed by electric transmission outside of
infrastructure. District boundary.
Similar to what was noted under Scope 1,the TDPUD Water Utility does not manage any water-specific
emissions sources which result in reportable Scope 2 emissions.
Under the market-centric perspective, Scope 2 emissions are heavily influenced by the generation resource mix
from which electricity is sourced.This inventory collected data on:
TDPUD's generation resources (hourly generation for each resource in TDPUD's portfolio),
■ Hourly electricity imports to each of TDPUD's substations (representing total imported electricity), and
■ Hourly electricity consumption across all TDPUD facilities
The above data were used to develop an hourly estimate of The District's resource mix(e.g. model the hourly
contribution of each of The District's resources to its total loads) and the subsequent hourly emissions intensity
for electricity imported by TDPUD into its service territory.The modeled emissions intensity was then used to
inform components within each scope of reported emissions.
The general form of the equation used to derive TDPUD's hourly resource mix emissions profile applies a
resource specific emissions intensity factor to the hourly generation of each resource in TDPUD's resource mix.
The resulting hourly emissions profile for each resource is summed within the hour to develop an overall hourly
emissions intensity for imported electricity.The hourly data is then summed to calculate overall annual
emissions.This is represented mathematically by the following:
EYear - Y [YresourceElFresource * Generatlonresource,hrhour
hour
Where:
Are the calculated GHG emissions (in units of CO2e) for the production of electricity at
Year facilities from which TDPUD sources its electricity.
Is the emissions intensity factor(in units of CO2e per Megawatt-Hour) used to
ElFresource estimate GHG emissions for each generation resource. The specific values used for
the EIF, and their derivation, are explained in detail in 4.2.2.
Generationresource,hr Electricity generation for each resource for each hour of the year.
The precise application of the above general approach for Scope 2 omitted emissions occurring from resources
in which The District owns financial equity(discussed in 4.1.1.3) as those emissions are reported under Scope 1
within this inventory's organizational boundary. Scope 2 emissions are those which occur from the remaining
resources not already reported in Scope 1 specifically resulting from TDPUD's own electricity use."
1s An important nuance to note here is that the Scope 1 emissions include emissions resulting from all electricity imported
from generation resources in which The District has equity(regardless of who ultimately consumes the electricity).Scope 2
P a g e 1 18 Section 4: Study Findings: Organizational Emissions
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4.2.1 Differences in Reported GHG Emissions
After data collection, this inventory established emissions intensity factors each generation resource as a first
critical step in deriving overall GHG emissions attributed to electricity generation.This process was navigated
with careful attention paid to the original objectives of the inventory. Namely,fundamental differences exist
between the objectives underlying the engineering assumptions and reporting standards established by
statewide programs (for example California's Renewable Portfolio Standard) and those applied in this GHG
inventory. A basic Venn diagram can be used to demonstrate this relationship as the two are not mutually
exclusive (see Figure 4-4).
CARB Mandatory GHG
Reporting Industry Standard GHG
Inventory Reporting
Renewable Portfolio
Standard
Figure 4-4 Statewide Program Reporting Vs. GHG Inventory Reporting
In particular,the emissions reported by this inventory are not the same as those reported under California's
Renewable Portfolio Standard (RPS).The RPS program levies a particular definition for what it considers to be a
'renewable' resource which is intentionally designed to achieve the objectives of the program.This definition,
and the resulting emissions assumptions, are therefore not purely derived using physical first principles and
necessarily includes both social and political dimensions.
This inventory endeavors to quantify emissions solely based on the physical first principals of the technologies
used to generate the electricity and the specific circumstances of the facility/locations where those activities
occur. This inevitably leads this inventory to recognize that all electricity generation technologies have some
level of GHG emissions in over the lifecycle of its facility—even resources deemed as 'renewable'have non-
zero emissions. The emissions intensities used by this inventory and how they were derived is discussed further
in the next section.
4.2.2 Emissions Intensities for Generation Resources
Consistent with the objectives discussed in the previous section,this inventory applies 'life-cycle emissions
factors'for each of the electricity generation technologies in TDPUD's resource portfolio. Life-cycle emissions
factors are used to account for the real-world impact that its resource procurement has on its organizational
emissions. Furthermore,this provides critical information for downstream users of electricity
procured/generated by TDPUD when assessing their own GHG impacts.
emissions are only concerned with the portion of electricity consumed by The District and not already reported under
Scope 1.
P a g e 1 19 Section 4: Study Findings: Organizational Emissions
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The National Renewable Energy Laboratory (NREL) has compiled research on over 3,000 published life cycle
assessments on utility scale electricity generation technologies.This research project was initially published in
2012 and has since been updated several times (with the most recent update published in 2021).This NREL
study provides lifecycle GHG emissions for common utility scale electricity generation technologies and was the
main reference point for emissions factors for this inventory.16 Emissions factors used for this inventory are
listed in Table 4-8.
Table 4-8 Life-Cycle Emission Factors for Utility Scale Generation(note values are in units of g CO2e/kWh generated17)
Generation Technology Upstream On-Going Downstream Total
Combustion non-combustion
Photovoltaic' 28.0 0 10.0 5.0 43.4
Concentrating Solar Power 19.7 0 10.0 0.5 28.0
Geothermal' 15.3 0 6.9 0.1 36.7
Hydropower' 6.2 0 1.9 0.0 20.5
Wind' 11.8 0 0.7 0.3 13.0
Landfill Natural Gas NR NR NR NR 298
Nuclear- Light Water Reactor 2.0 0 11.7 0.7 13.0
ZNatural Gas-Conventional Gas 0.8 389 71.0 0.0 486.0
Coal' 2.5 1,010 10.0 2.5 1,001.0
Pumped-Storage Hydropower 3.0 0 1.8 0.1 7.4
n�o
c Li-Ion Battery Storage 31.5 0 NR 3.4 32.9
v' Hydrogen Storage 26.7 0 2.5 1.9 37.9
1 All Technologies
z Trough and Tower
One notable omission in the set of technologies reviewed in the NREL study is landfill natural gas (electricity
from which TDPUD purchases from the City of Murray). Establishing an emissions factor for landfill natural gas
was difficult as not much research is available on the subject. On the one hand the electricity is generated by
burning natural gas (methane released by landfills) and therefore not physically any different than a natural gas
plant. However, it is also true that the methane would have likely been released regardless, and in a form that
has a much higher global warming potential than the CO2 resulting from its combustion.This inventory opted to
take a middle ground approach which acknowledged that while the emissions are clearly non-zero,they are
much better than the assumed alternative of allowing the methane to simply emit untreated from the landfil1.18
This is a potentially important point of continued research in future inventories.
The values listed in in Table 4-8 are broken down into three components: "upstream", "on-going", and
"downstream".These each correspond to the portions of a generation asset's lifecycle where:
16 The NREL study results can be found here:https://www.nrel.gov/analysis/life-cycle-assessment.html
17 These units are a departure from those reported everywhere else in this study.The values in this table were kept in these
units as this is how they were reported in the original NREL study cited.
18 The specific value was generated by taking a weighted average of all resources NREL reviewed with weights determined
by the technology's representation in the overall grid (highly weighted towards natural gas).
P a g e 120 Section 4: Study Findings: Organizational Emissions
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■ Upstream—includes activities such as mineral extraction, component/material manufacturing, and
asset construction.This includes both the facility itself and the fuels used in for generation.
■ On-Going—refers to an asset's operation and maintenance activities while used to generate electricity.
This includes any emission in the fuel-to-electricity conversion process (for example combustion in a
natural gas turbine) as well as emissions resulting from facility maintenance and day-to-day operations.
■ Downstream—includes the remaining life-cycle emissions occurring due to decommissioning, disposal,
and recycling of the asset and any remnant fuel.
For fossil fuel generation technologies, most emissions occur during operation of the facility when it is actively
generating electricity. On the other hand, most emissions from resources classified as 'renewable' occur during
the upstream portion of its lifecycle.This difference in when the emissions occur is important to capture to
appropriately compare emissions across multiple generation technologies.19
This inventory used the emissions factors listed in the "Total" column of Table 4-8 which accounts for emissions
released in each stage of the generation asset's lifecycle.
4.2.3 Indirect Emissions (Scope 2) Analysis Results
The Scope 2 emissions calculated for TDPUD in calendar year 2022 were shown in Table 4-6 where it can be seen
that the bulk of emissions come from electricity consumed by the Water Department (-88%). Total Scope 2
emissions for The District in calendar year 2022 were 238.5 Tons COZe. Note that the emissions reported under
Scope 2 do not include emissions from the Nebo, Horse Butte, or Veyo generation resources as those were
already reported under Scope 1 as discussed in Sections4.1.1.3.
The same above is shown graphically along with an hourly(time-series) plot of scope 2 emissions for the Electric
and Water Departments in Figure 4-5. Note that Figure 4-5 not only shows the relative proportion of emissions
for each of TDPUD's utilities, but it also shows when in time those emissions occurred in calendar year 2022. It
can be seen that the most while the Water Department's peak emissions occur during the summer months
(coincident with the highest customer water demands)the Electric Utility's emissions peak over the winter and
are instead driven by heating demands for buildings and equipment.
19 Consider too that emissions occur in different geographic locations based on when in the lifecycle the emissions are
released. Emissions resulting from industrial activities, most of which occur in the upstream and downstream periods,tend
to disproportionally impact regions with lower socio-economic means.While a particular technology might release far
fewer emissions on-site(while operating), it may be the case that its overall emissions are simply displaced in time and
location and not immediately observable during the ongoing/operations phase of its lifecycle.
P a g e 121 Section 4: Study Findings: Organizational Emissions
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Hourly Scope 2 Emissions For TDPUD - CY 2022 Annual Emissions
250
Emissions Source Electric — water
0.100
200
al
0.075 N
rV 0 150
O
U
V) H
0
Ln p 100
C U1
o in
E w
w a.a2s
sa
a.aaa o
Jan 2022 Apr 2022 Jul 2022 Oct 2022 Jan 2023 2022
Date-Time Date-Time
Figure 4-5 Overview of Scope 2 Emissions for Calendar Year 2022
4.3 Scope 3 Emissions: Indirect Emissions Outside of Organization Value Chain
The final category of reportable emissions captures all remaining indirect emissions outside of consumed
energy.This category is clearly broad and provides an organization the opportunity to capture/report emissions
both upstream and downstream within its value chain.
Given the broad nature of potential Scope 3 emissions sources, the extent and rigor with which they are
reported will necessarily be limited by the resources and strategic objectives of the organization performing the
inventory. Specific Scope 3 emissions which this study quantified are listed in Table 4-9.
Table 4-9 List of Anticipated Scope 3 Emissions Covered by Inventory
GHG accounting for scope 3 must balance an emission's relevance to the organization,
comprehensive reporting within the boundary, consistency&transparency in methodology,
and finally the accuracy(or rigor)with which emissions are quantified.
Indirect GRPv3 Sources EPSP Sources WENRP Sources
Emissions
(Other) ■ Electricity delivered to
■ Fuel combustion from employee customers. ■ Waste-Water
commuting ■ T&D Losses from electricity treatment
delivered to customers
As noted for Scope 2, Scope 3 emissions sources all fall outside of The District's organizational boundary.
However,they are indirectly linked to District activities due to purchasing decisions, policy decisions, or through
the use of District products (e.g., electricity and water).
The total Scope 3 emissions reported for the 2022 calendar year are 33,516 Tons CO2e as summarized in Table
4-10
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Table 4-10 Aggregated Scope 3 Emissions for CY2022
Emissions [Tons
Emission Source COA
Employee Commutes 337
Electricity Sold 32,701
Wastewater(water sold) 478
Total 33,516
It can be seen in the above table that the vast majority of reported Scope 3 emissions are attributed to
electricity sales and, more fundamentally,to TDPUD's resource portfolio. However, most of those emissions
physically occur outside of the Truckee/Tahoe region. Employee commuting and wastewater treatment
emissions instead all directly occur within the Truckee/Tahoe region20.
4.3.1 Fuel Combustion from Employee Commuting
Emissions occur from employees commuting between their homes and their worksites. Such emissions may
arise from several sources including:
■ Personal Automobiles
■ Bus Travel
■ Rail Travel
■ Air Travel
As previously stated,these emissions technically fall outside of the District's organizational boundary and are
directly attributed to the individuals commuting to and from their worksites.21 However,the District is indirectly
linked as an employer with some ability to affect its employee's commuting patterns through policy decisions
and/or incentive structures.As such,these emissions are reported under Scope 3 for The District.
Several methods are available to calculate emissions from employee commuting.This inventory has opted to
use a distance-based method which applies data from employee commuting patterns (e.g. distances and
number of commutes) with appropriate emissions factors for each mode utilized. Note that the magnitude of
emissions in this category are minor relative to the other Scope 3 emissions reported here,though they are
similar in magnitude to the mobile emissions reported under Scope 1 for The District. Emissions were calculated
using the following approach:
G annual — Dannual,Mode *EIFMode
Commute Modes
Where:
Are the calculated GHG emissions (in units of CO2e) attributed to employee
EYear commuting activity for the reporting year.
The annual distance traveled by commuters using a given mode (e.g. personal auto,
annual,Mode bike, bus, etc.).
20 Broadly speaking as employees commute from Reno and other regions outside of Truckee and Tahoe specifically.
21 It is assumed individuals have personal agency over their purchasing decisions and location.
P a g e 123 Section 4: Study Findings: Organizational Emissions
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Is the emissions intensity factor(in units of CO2e per mile traveled) used to estimate
Effmode GHG emissions for each mode of commute transportation.The specific values used
for the EIF and their derivation are explained below.
Distances for employee commutes were derived using data on city of residence for employees and a sample of
employees were interviewed regarding their commuting patterns to estimate frequency of commutes. Similarly,
a sample of vehicles were surveyed for specific characteristics (e.g. Body type,fuel type, etc.)to estimate their
emissions factors.
Except for occasional circumstances, most employees were found to commute using personal automobiles with
some occasions of carpooling and few instance of regularly walking or riding bikes for employees living relatively
closer to their worksites.The predominate mode was personal automobile transportation for which two
volumetric emissions factors were used (CO2e per gallon of fuel burned), one for gasoline vehicles and another
for diesel, which were multiplied by an estimated `typical'fuel economy for each mode of transportation to
derive the final EIF for each mode.
Table 4-11 Volumetric Emissions for Vehicle Fuel Types Table 4-12 Summary of Employee Commuting Emissions
Employee Distanceofeway DistanceA,,,,,,ai Emissions
Diesel Gasoline Count [Mi.h] [MirotaJ (CO2e]
0.0113[Tons CO2e/Gal] 0.0097[Tons CO2e/Gal] 77 22 9,397 337
The average commuting distance traveled (one way)for employees at The District is approximately 22 miles
with a total of 9,397 miles traveled annually by District employees for commuting. The resulting emissions for
employee commuting are estimated to be 337 Tons of CO2e annually.
4.3.2 Electricity Delivered to Customers
While The District has no direct control over how much electricity its customers utilize (or when it is used),
TDPUD still retains some indirect influence on each through policies, programs, and incentives. Furthermore,
TDPUD has agency over its resource portfolio (e.g.,The mix of resource types and emissions discussed under
Scope 2).22
Consistent with the above,the ESPS defines electricity sold to customers (including the associated transmission
and distribution losses) as Scope 3 reportable emissions for electric utilities. Furthermore,these emissions are
reported without consideration of the equity boundaries applied in Scopes 1 and 2.The emissions reported here
for electricity sold to customers cannot therefore be added to either the Scope 1 or Scope 2 emissions
previously reported in this inventory without the risk of double-counting emissions activities.23 Rather,the
emissions reported in this section are informational and should be used to understand the relative impacts that
electricity use within TDPUD territory have on GHG emissions at a grid level.
22 Note that while TDPUD has agency over its resource mix, it is also subject to a number of constraints that must be
balanced for it to meet its missional objectives. Namely that the purchased power must be costed appropriately for
TDPUD's customers,and it must be reliably delivered at the time(s) required by the community.
23 It is critical to remember that emissions cannot be aggregated across Scopes.
P a g e 124 Section 4: Study Findings: Organizational Emissions
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Hourly Scope 3 Emissions For TDPUD - CY 2022
10.0
7.5 a
O
N
5.0 n
O
N
A
2.5
0.0
30
3
20
x
10
Jan 2022 Apr 2022 Jul 2022 Oct 2022 Jan 2023
Date-Time
Figure 4-6 Hourly Electricity Use and Emissions for Electricity Sold to Customers
Figure 4-6 illustrates the hourly profile for both the electricity used by TDPUD customers (bottom) and their
subsequent GHG emissions (top). It can be seen at a general level that the emissions are proportional to
electricity use which reaches its peak in the winter months. However, it is also sensitive to the specific mix of
generation resources at a given moment—something that is not directly evident in the plots above.
Hourly Energy Use by Resource
2020 2021 2022
30
25
SOURCE
0
= Stampede
`m 20 TCIb
Q_ Scheduled Load Exchange
3 ` City of Murray
215 Unspecified Power
N _ Horse Butte
cc � Plesant Valley
d
Red Mesa
>,10
■ Veyo
N Nebo
W Unplanned Pool
5
0
0 7 12 19 23 0 7 12 19 23 0 7 12 19 23
Hour of Day
Figure 4-7 Mean Hourly Resource Stack By Year
The precise mix of electric resources (and therefore their emissions)varies on an hourly basis throughout the
year due to the realities of how individual generation resources are managed by the independent system
operator(ISO) and due to the intermittent nature of'renewable' resources. This is demonstrated in Figure 4-7
where TDPUD's mean hourly resource mix can be seen for calendar years 2020 through 2022. Here it can be
P a g e 125 Section 4: Study Findings: Organizational Emissions
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seen how the contribution of each generation resource varies by the hour of the day and from year to year-
though the overall shape of the profile(s)tends to remain similar.
Finally, Figure 4-8 shows the hourly changes in TDPUD's portfolio emissions intensity resulting from the factors
discussed above. It can be seen in Figure 4-8 that the overall emissions intensity has remained similar across the
last three years despite some variation from year to year.The emissions generally increase in the evening hours
where a larger percentage of the power is derived from Nebo and other unspecified (e.g. Natural Gas
dominated) resources.The dip in emissions intensity in the middle of the day is expected to become more
exaggerated with the addition of the Red Mesa solar project which came on-line in quarter one of 2023.
Typical Hourly Emissions Intensity
Profiles by Quarter
500
=400 - - - - � - - _ _ _ - N
I O
300 __ �� o
200
0 _
V 5o0 ----
______ -- Quarter
400
' N
300 L _t'�yi + r -- 2
3
q�j 200 - 4
4-
C
c 500
0400 _ _ :��_ ��� �� - - - -
200
0 5 10 15 20
Date Time
Figure 4-8 Mean Hourly Portfolio Emissions Intensities by Quarter
Table 4-13 Summary of Scope 3 Emissions from Electricity Sales
Electricity Sold 174,887 MWH
GHG Emissions 32,701 Tons CO2e
The total estimated Scope 3 emissions resulting from electricity sales to TDPUD customers is 32,701 Tons CO2e
from 174,887 mega-watthours of electricity sold.
4.3.3 Wastewater Treatment
The main greenhouse gasses produced by the wastewater treatment process are methane (CH4) and nitrous
oxide (N20). While TDPUD does not have any wastewater treatment facilities, much of the water that it
produces for customers eventually flows to the Truckee Tahoe Sanitation Agency(TTSA) where it is treated.The
WENRP recommends therefore that emissions from wastewater treatment for water produced by a water utility
be reported under its Scope 3 emissions.
As these are not direct emissions within TDPUD's organizational boundary and reported for informational
purposes,this inventory did not apply the same level of rigor as employed for emissions reported under Scopes
P a g e 126 Section 4: Study Findings: Organizational Emissions
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1 and 2. Furthermore, limited data/literature are publicly available from local agencies which would enable a
more rigorous analysis.The Tahoe Regional Planning Agency published a Greenhouse Gas Inventory in 2021
which included emissions from wastewater for the Tahoe Basin (treated at TTSA). However, only total emissions
were reported and no intermediate calculations or normalized results24 were published.The best available
research at the time of this inventory on emissions for wastewater treatment was found in the US GHG
inventory published in 201925 in which the EPA establishes a top-down approach for estimating national level
emissions for domestic wastewater treatment.
The EPA reports estimates that 9.4 million Tons of CO2 equivalent26 were generated by wastewater treatment in
2017. It also considers emissions proportional to the daily production of wastewater by the population (per
person) determined by the US Census. This inventory estimates that the wastewater emissions produced due
to domestic water produced by TDPUD to be 478 Tons in calendar year 2022. This was estimated by scaling the
EPA reported estimates by the US census population in 2017 (330 million)27 to the census population of Truckee
in 2022 of 16,850.
PUPTruckee
E Annual — E EPA
POP�US 2017
Where:
Are the calculated GHG emissions (in units of CO2e) attributed to wastewater
E/anuai processed by TTSA for domestic water produced by TDPUD.
The population of the Town of Truckee in 2022 as determined by the US Census.This
POpTruckee value is 16,850 persons.
The US census population used in the EPA GHG inventory. This value is 330 million
POPus2os� persons.
24 For example,emissions per million gallons of water treated.
26 https://www.epa.gov/sites/default/files/2019-04/documents/us-ghg-inventory-2019-chapter-7-waste.pdf
26 See Table 7-10 in 2019 US GHG inventory(Chapter 7)
27 Also reported in Table 7-9 in 2019 US GHG inventory(Chapter 7)
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