HomeMy WebLinkAboutItem 15 - COUNCIL READING FILE_e_CAP Appendix A - GHG Inventory and Forecast Climate Action Plan for Community Recovery
Appendix A - Community Greenhouse Gas Emissions Inventory and Forecast
CLIMATE ACTION PLAN
Appendix A: Greenhouse Gas Emissions
Inventory and Forecast
Climate Action Plan for Community Recovery
Appendix A - Community Greenhouse Gas Emissions Inventory and Forecast
City of San Luis Obispo
CONTENTS
1. Introduction .............................................................................................................................1
1.1 Community GHG Inventory Overview ................................................................................1
1.2 2005 Community GHG Inventory .......................................................................................2
1.3 2005 Updated Community GHG Inventory .........................................................................2
1.4 2016 Community GHG Inventory .......................................................................................3
1.5 Progress Toward 2020 Target ...........................................................................................4
1.6 Progress to State GHG Reduction Targets ........................................................................4
2. Community energy ..................................................................................................................6
2.1 Community Energy Sector Overview .................................................................................6
2.2 Updated Inventory Data and Methods ...............................................................................6
2.2.1 Electricity ....................................................................................................................6
2.2.2 Natural Gas – Direct Emissions .................................................................................10
2.2.3 Natural Gas – Fugitive Emissions .............................................................................12
2.3 Total Energy GHG Emissions ..........................................................................................12
3. Transportation .......................................................................................................................14
3.1 Transportation Sector Overview ......................................................................................14
3.2 Updated Inventory Data and Methods .............................................................................14
3.3 Total Transportation GHG Emissions ..............................................................................15
4. Solid waste............................................................................................................................16
4.1 Solid Waste Sector Overview ..........................................................................................16
4.2 Updated Inventory Data and Methods .............................................................................16
4.2.1 Green Waste .............................................................................................................17
4.2.2 Municipal Solid Waste GHG Emissions Conversion Factor .......................................17
4.3 Total Solid Waste GHG Emissions ..................................................................................21
5. Forecast .............................................................................................................................22
6. Areas for improvement .......................................................................................................24
List of Abbreviations ..............................................................................................................26
Climate Action Plan for Community Recovery
Appendix A - Community Greenhouse Gas Emissions Inventory and Forecast
City of San Luis Obispo
LIST OF TABLES
Table 1.1. San Luis Obispo Community GHG Emissions (2005) .................................................2
Table 1.2. 2005 update baseline GHG emissions. ......................................................................3
Table 1.3. 2016 GHG emissions. ................................................................................................4
Table 1.4. GHG emissions, 2005 -2016 (MTCO2e). .....................................................................4
Table 1.5. Progress to AB32 and SB 32 target (MTCO2e). .........................................................5
Table 2.1. Community electricity activity data, 2005 -2016 (kWh).................................................7
Table 2.2. Electricity conversion factor (MTCO 2e/kWh). ..............................................................8
Table 2.3. Community electricity GHG estimates, 2006 -2015 (MTCO2e).....................................9
Table 2.4. Community natural gas activity data, 2005-2016 (Therms). ......................................10
Table 2.5. Local Government Operations Protocol (LGOP) natural gas carbon dioxide equivalent.
.................................................................................................................................................11
Table 2.6. Community Natural Gas GHG estimates, 2005 -2016 (MTCO2e). .............................11
Table 2.7. Energy GHG emissions, 2005 -2016 (MTCO2e). .......................................................12
Table 3.1. 2005 and 2016 VMT estimates. ................................................................................14
Table 3.2. Total annual VMT emissions. ...................................................................................15
Table 4.1. City solid waste activity data, 2008 -2016 (Disposal Ton). .........................................16
Table 4.2. Total percent of waste degradable based on waste type. .........................................18
Table 4.3. Conversion to metric tons of methane. .....................................................................19
Table 4.4. Recorded methane capture rates from Cold Canyon Landfill. ...................................19
Table 4.5. Percent of emissions reaching the atmosphere. .......................................................20
Table 4.6. Disposed solid waste conversion factor with Fifth Assessment Report global warming
potential (MTCO2e/Disposal Ton). .............................................................................................20
Table 4.7. Total solid waste disposed emissions (MTCO 2e). .....................................................21
Table 5.1. Demographic projections (2005-2035). .....................................................................22
Table 5.2 Forecasted GHG emissions with state reductions, 2005 -2050 (MTCO2e). .................23
Climate Action Plan
Appendix A - Community Greenhouse Gas Emissions Inventory and Forecast
City of San Luis Obispo
LIST OF FIGURES
Figure 1.1 Progress to AB32, SB 32, and Carbon Neutrality target. ............................................5
Figure 2.1. Electricity emissions factor (MTCO2e/kWh). .............................................................8
Figure 2.2. Total community electricity activity data and GHG estimates, 2006 -2016. .................9
Figure 2.3. Energy GHG emissions, 2005 -2016. .......................................................................13
Figure 4.1. Total City solid waste (Disposal Ton). .....................................................................17
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Community Greenhouse Gas Emissions Inventory and Forecast
City of San Luis Obispo Page A-1
1. INTRODUCTION
A greenhouse gas (GHG) inventory is a comprehensive measure of GHG emissions that have
occurred as the result of activity in a jurisdiction or a geographic area in a calendar year. It is
common to prepare two separate GHG inventories, one for local government operations only and
the other for community-wide emissions. Though inventories are custom to their jurisdiction, local
government GHG inventories typically include the accounting of emissions from the buildings,
facilities, and vehicles operated by a local government, while community-wide inventories typically
include accounting of emissions from all businesses, residents, and transportation within the
jurisdictional boundary.
This report focuses on community-wide GHG emissions. Section 1 of this report provides an
overview of the community GHG emissions inventories and forecasts. Sections 2 -5 provide
detailed summaries of the inventoried GHG emissions sectors. Section 6 provides a detailed
description of the GHG forecasts and a discussion of the City’s progress toward its GHG reduction
targets. Section 7 concludes the report with a description of areas for improvement.
1.1 Community GHG Inventory Overview
In 2012, the City of San Luis Obispo (City) adopted the City of San Luis Obispo Climate Action
Plan (CAP) to achieve GHG emission reductions consistent with state law and City General Plan
policy. The foundation of the CAP is the 2005 baseline GHG inventory (completed in 2009), which
estimates the GHG emissions that occurred as the result of activity in the city.
In the 2017 California Climate Change Scoping Plan, the California Air Resources Board notes,
“In developing local plans, local governments should refer to ‘The U.S. Community Protocol for
Accounting and Reporting of Greenhouse Gas Emissions ’ (community protocol), which provides
detailed guidance on completing a GHG emissions inventory at the community scale in the United
States – including emissions from businesses, residents, and transportation .” The City prepared
a 2016 comprehensive community-wide and local government GHG emissions inventory update
compliant with all relevant protocols and guidance documents including the U.S. Community
Protocol, Local Government Operations Protocol (LGOP), the Global Protocol for Community
Scale GHG Emissions (GPC), and the Intergovernmental Panel on Climate Change (IPCC)
Guidelines for National GHG Inventories. The community-wide GHG inventory is the foundation
for the Climate Action Plan Update, which is expected to be adopted in 2020.
In the 2017 Scoping Plan, the California Air Resources Board directs local governments to the
U.S. Community Protocol for Accounting and Report ing of Greenhouse Gas Emissions. The
Community Protocol includes required emissions sectors that must be inventoried including use
of electricity, onsite fuel combustion (i.e., natural gas), energy used for water conveyance and
treatment, use of on -road vehicles, and generation of solid-waste.1 This report presents a
1 1 The electricity and natural gas sectors of the City’s GHG inventory include energy used to convey and
treat water.
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City of San Luis Obispo Page A-2
summary of the updated 2005 GHG emissions and details the 2016 community GHG inventory
completed in 2018 and revised in 2019 .2
Greenhouse gas emissions are not measured directly. They are modeled and estimated by
multiplying data about some activity (e.g., the amount of electricity consumed, the number of miles
travelled in fossil fuel powered vehicles, the tons of solid waste sent to the landfill, etc.) by the
greenhouse gas emission content of a typical unit of that activit y (e.g., the average greenhouse
gas emissions content per therm of combusted natural gas). This inventory accounts for three
common greenhouse gasses: carbon dioxide (CO 2), methane (CH4), and nitrous oxide (N20).
Since methane and nitrous oxide are substan tially more potent greenhouse gases than carbon
dioxide (86 and 265 times more potent, respectively), the emissions modeled from their release
into the atmosphere are multiplied by their respective potential to warm the atmosphere relative
to CO2. The common reporting unit for greenhouse gas emissions is “Metric Tons of Carbon
Dioxide Equivalence”, or MTCO2e.
1.2 2005 Community GHG Inventory
In 2009, the community’s total 2005 baseline GHG emissions were estimated to be 264,237
metric tons of carbon dioxide equivalent (MTCO2e). The inventory included energy (residential
and nonresidential), transportation, and waste sectors. Of the three sectors, transportation
contributed the largest amount of GHG emissions with estimated emissions of 132,142 MTCO 2e
or 50 percent of the total City emissions. The second largest sector was commercial and industrial
energy use with estimated emissions of 57,950 or 22 percent of the total City emissions. The
commercial and industrial energy and waste sectors made up the remain ing 28 percent of the
total city emissions. Table 1.1 presents the original estimated 2005 GHG emissions by sector and
their percent of total emissions.
Table 1.1. San Luis Obispo Community GHG Emissions (2005)
Community Sector MTCO2e Percent of Total
Transportation 132,142 50%
Nonresidential Energy 57,950 22%
Residential Energy 55,377 21%
Waste 18,768 7%
Total 264,237 100%
Source: City of San Luis Obispo Climate Action Plan (2009)
1.3 2005 Updated Community GHG Inventory
To assess climate action progress, the City updated the 2005 baseline inventory for consistency
with current protocols and best practices. This section provides updated GHG emissions data
estimates for the baseline year of 2005 to allow for an “apples to apples” comparison to the 2016
GHG inventory. The City updated the 2005 GHG inventory to reflect an updated s cientific
understanding of how different greenhouse gasses contribute to global warming , to include a
2 Due to lagging data availability, 2016 is the most recent year for complete GHG inventory data. Annual
inventory updates will occur beginning in 2020. Where more current information is available by sector, it is
provided in this report.
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City of San Luis Obispo Page A-3
more accurate assessment of transpo rtation related emissions, and to respond to changes to data
privacy rules and collection methods that affect how data is provided.
Table 1.2 provides the updated 2005 baseline GHG emissions inventory with updated total GHG
emissions of 386,630 MTCO2e. Similar to the original 2005 inventory, the largest sector
contributing to the City’s total GHG emissions was transportation with an estimated emissions
total of 225,390 MTCO2e or 58 percent of the City’s total.3 The commercial and industrial energy
sector was the second largest sector contributing a total of 58,050 MTCO 2e GHG emissions or
15 percent of the City’s total. The remaining sectors of residential energy and solid waste made
up the remaining 28 percent of the City’s total emissions in 2005.
Table 1.2. 2005 update baseline GHG emissions.
Sector Subsector Subsector
MTCO2e
Sector
MTCO2e
Sector Percent
of Total
Transportation On-Road Transportation 225,390 225,390 58%
Nonresidential
Energy
Commercial/Industrial electricity 35,510
58,050 15%
Commercial/Industrial natural gas 22,540
Residential
Energy
Residential electricity 20,870 55,450 14% Residential natural gas 34,580
Solid Waste Community-wide municipal solid
waste disposal tons 47,740 47,740 12%
Total 386,630 100%
1.4 2016 Community GHG Inventory
In 2018, the City prepared a community -wide inventory of GHG emissions for the 2016 calendar
year. Table 1.3 provides the 2016 GHG emissions inventory results. In 2016, San Luis Obispo’s
total GHG emissions were estimated to be 339,290 MTCO 2e. As in 2005, transportation was the
largest contributor to the City’s total GHG emissions with an estimated 212,980 MTCO 2e or 63
percent of the City’s total emissions. Commercial and Industrial energy was the second largest
sector with GHG emissions of 44,270 MTCO 2e or 13 percent of the City’s total emissions. The
sectors of residential energy and solid waste account for the remaining 26 percent of the City’s
total 2016 GHG emissions.
3 Section 3 provides an explanation for the significant increase in estimated transportation emissions in the
revised 2005 baseline over the original draft.
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Table 1.3. 2016 GHG emissions.
Sector Subsector Subsector
MTCO2e
Sector
MTCO2e
Sector Percent
of Total
Transportation On-Road Transportation 212,980 212,980 63%
Nonresidential
Energy
Commercial/Industrial electricity 22,050
44,270 13%
Commercial/Industrial natural gas 22,220
Residential
Energy
Residential electricity 10,320 39,410 11% Residential natural gas 29,090
Solid Waste
Community-wide municipal solid
waste disposal tons 42,630 42,630 13%
Total 339,290 100%
1.5 Progress Toward 2020 Target
Table 1.4 provides a comparison overview of emissions from baseline year 2005 to 2016 to show
the City’s progress toward its target to reduce GHG emissions 15 percent below 2005 emission
levels. Over the eleven-year period, emissions were estimated to have dropped by 13 percent.
The most significant changes occurred in the energy, solid waste, and off -road sectors.
• Energy emissions dropped by approximately 26 percent and reflects a significant change
in the carbon intensity of grid consumed electricity, a substantial increase in rooftop
renewable energy systems, and investment in energy efficiency.
• Solid waste emissions decreased by approximately 11 percent due to a decrease in the
amount of solid waste produced by San Luis Obispo residents and businesses.
Section 2 provides a detailed report for each GHG emissions sector and the changes in emissions
from each sector from 2005 to 2016.
Table 1.4. GHG emissions, 2005-2016 (MTCO2e).
Sector 2005 2016 Percent Change
Transportation 225,390 212,980 -6%
Nonresidential Energy 58,050 44,270 -24%
Residential Energy 55,450 39,410 -29%
Solid Waste 47,740 42,630 -11%
Total 386,630 339,290 -12%
1.6 Progress to State GHG Reduction Targets
The key drivers for updating the community GHG inventory are 1) to assess progress toward the
City’s GHG emissions reduction target, and 2) to establish the foundation for the Climate Action
Plan update. Consistent with Assembly Bill (AB) 32, the City’s cu rrent adopted target is to achieve
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Community Greenhouse Gas Emissions Inventory and Forecast
City of San Luis Obispo Page A-5
a 15 percent reduction below baseline emissions by 2020. Since the baseline inventory was
updated through this inventory process, resulting in a slightly increased baseline, a new target
must be calculated.
As noted in Table 1.5 and Figure 1.2, a 15 percent reduction in baseline emissions is 328,640
MTCO2e from the updated baseline year emissions of 386,630 MTCO 2e. The 2016 emissions
estimate of 339,290 MTCO2e represents a 12 percent reduction in GHG emissions, notable
progress toward the 2020 target.
Since adoption of the City’s CAP in 2012, the state adopted a 2030 target through Senate Bill
(SB) 32. If the City adopts a 2030 goal that matches the state target of reducing GHG emissions
40 percent below the 2020 target levels, the target for San Luis Obispo would be 197,180
MTCO2e. In September of 2018, Council directed staff to develop a climate action plan with a
reduction target of carbon neutrality by 2035. A carbon neutrality by 2035 target would require
achieving a far greater reduction than the SB32 requirements by 2030.
Table 1.5. Progress to AB32 and SB 32 target (MTCO2e).
Year Emissions
2005 (Updated) 386,630
2016 339,290
2020 Target (Updated) 328,640
2030 Target (40% below 1990) 197,180
2035 Target (Carbon Neutral) 0
Figure 1.1 Progress to AB32, SB 32, and Carbon Neutrality target.
386,630
339,290
328,640
197,180
00
50,000
100,000
150,000
200,000
250,000
300,000
350,000
400,000
450,000
2005 2016 2020 Target
(Updated)
2030 Target (40%
below 1990)
2035 Target
(Carbon Neutral)
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Community Greenhouse Gas Emissions Inventory and Forecast
City of San Luis Obispo Page A-6
2. COMMUNITY
ENERGY
2.1 Community Energy Sector Overview
This section presents the GHG emissions for the energy sector, specifically emissions generated
from residential and non -residential energy use that has occurred within City limits. This section
presents the updated 2005 GHG emissions along with updated em issions for 2016.
2.2 Updated Inventory Data and Methods
The update to the 2005 inventory for the energy sector incorporates changes in scientific
understanding of how different greenhouse gasses contribute to global warming and changes to
data privacy rules that affect how energy data is retained and provided. This section provides
updated electricity and natural gas activity data and emissions estimates for the baseline year of
2005, as well as electricity and natural gas activity data and GHG emissions estimates for years
2005 through 2016.
2.2.1 Electricity
Pacific Gas & Electric (PG&E) Company provides electric service to the community and offers
community electricity data to local agencies through the PG&E Green Community Portal. The
electricity data (presented in kilowatt-hours, or kWh) in Table 2.1 is separated between residential
and non-residential uses, which is the finest resolution possible to prevent data from being
removed for privacy purposes.
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City of San Luis Obispo Page A-7
Table 2.1. Community electricity activity data, 2005-2016 (kWh).
Year Residential Nonresidential Total
2005 93,045,220 158,267,695 251,312,915
2006 94,844,802 165,562,683 260,407,485
2007 92,479,221 170,259,426 262,738,647
2008 91,007,229 176,783,866 267,791,095
2009 89,252,248 183,654,370 272,906,618
2010 87,910,124 218,185,988 306,096,112
2011 86,239,267 172,742,643 258,981,910
2012 85,773,964 172,045,211 257,819,175
2013 84,492,752 171,842,797 256,335,549
2014 78,932,662 171,846,749 250,779,411
2015 78,069,529 170,606,678 248,676,207
2016 76,376,280 163,204,691 239,580,971
2017 76,543,278 165,277,531 241,820,809
2018 74,076,694 159,958,964 234,035,658
Nonresidential electricity use includes commercial, governmental, agricultural, and industrial
usage. From 2005 to 2016, residential electricity usage decreased by 1 8 percent and non-
residential electricity consumption increased approximately 3 percent. Between 2005 and 2016,
total electricity use decreased by 5 percent. Table 2.1 includes activity data for 2017 and 2018 for
informational purposes. Data for both years indicate a continuing downward trend.
The 18 percent decrease in residential electricity usage may be due to low residential growth, a
significant increase in residential renewable energy installations, increases in energy efficiency
investments, and overall trends toward conservation.
To calculate GHG emissions, an emissions factor is applied to the activity data. Table 2.2 shows
the electricity emissions factors for the three major greenhouse gasses occurring as the result of
electricity use in the city. PG&E staff provided CO2 emissions factors via the Green Community
Portal data request in 2018 and 2019. In addition to carbon dioxide (CO2), small amounts of
methane (CH4) and nitrous oxide (N2O) are released in the electricity generation process. CH4
and N2O emissions factors are provided by PG&E’s third-party-verified GHG inventory. Variability
of the emissions factors occur primarily due to two factors: 1 ) fluctuations in hydro power
production as the result of precipitation variability , and 2) increasing renewable energy sources in
PG&E’s power portfolio. CO2 is the most commonly referenced GHG, however, numerous gasses
have greenhouse characteristics. Methane and nitrous oxide are commonly accounted for in GHG
inventories. These gasses have a greater global warming potential; CH 4 traps approximately 86
times as much heat as CO2 over a 20-year period and N2O traps approximately 265 times as
much heat. To account for these differences, a factor is applied to the gasses emissions to
calculate aCO 2 equivalence. Table 2.2 provides the emissions factors for 2005 through 2018. Due
to changes in PG&E’s energy portfolio (and particularly an increase in renewable energy
supplies), the 2016 emissions factor is approximately 40 percent lower than the 2005 factor.
Figure 2.1 illustrates the changes in MTCO2e/kWh factors from 2005 to 2016.
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Table 2.2. Electricity conversion factor (MTCO2e/kWh).
Year kWh/MTCO2e
2005 0.000224
2006 0.000208
2007 0.000290
2008 0.000292
2009 0.000262
2010 0.000203
2011 0.000179
2012 0.000203
2013 0.000195
2014 0.000198
2015 0.000185
2016 0.000135
2017 0.000097
2018 0.000134
Figure 2.1. Electricity emissions factor (MTCO2e/kWh).
Table 2.3 provides the GHG emissions from electricity use in the city by residential and
nonresidential subsectors from 2005 to 2016. During this time, electricity related residential GHG
emissions decreased by approximately 50 percent, while nonresidential electricity emissions
decreased by approximately 38 percent. Overall emissions decreased approximately 43 percent
over the same period.
0.000000
0.000050
0.000100
0.000150
0.000200
0.000250
0.000300
0.000350
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016MTCO2e/kWhYear
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City of San Luis Obispo Page A-9
Table 2.3. Community electricity GHG estimates, 2005-2018 (MTCO2e).
Year Residential Nonresidential Total
2005 20,870 35,510 56,380
2006 19,840 34,620 54,460
2007 26,880 49,490 76,370
2008 26,650 51,770 78,420
2009 23,450 48,240 71,690
2010 17,910 44,440 62,350
2011 15,530 31,120 46,650
2012 17,480 35,050 52,530
2013 16,520 33,600 50,120
2014 15,710 34,210 49,920
2015 14,480 31,640 46,120
2016 10,320 22,050 32,370
2017 7,430 16,040 23,470
2018 9,940 21,470 31,410
Figure 2.2 illustrates GHG and kWh activity data trends between 2005 and 2016 on the same
chart. It is important to note that while overall electricity use has been steadily decreasing, GHG
emissions have been more variable due to changes in PG&E’s power portfolio and the related
carbon intensity of the electricity it supplies.
Figure 2.2. Total community electricity activity data and GHG estimates, 2006 -2016.
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
0
50,000,000
100,000,000
150,000,000
200,000,000
250,000,000
300,000,000
350,000,000
2005 2007 2009 2011 2013 2015
kWh MTCO2e
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City of San Luis Obispo Page A-10
2.2.2 Natural Gas – Direct Emissions
Natural gas is primarily composed of methane and includes very small amounts of ethane,
propane, butane, pentane, nitrogen, and carbon dioxide. When natural gas is combusted, most
of the methane becomes carbon dioxide and water. Traditionally, greenhouse gas emissions
inventories account for the emissions that occur as the result of the onsite combust ion of natural
gas. Southern California Gas Company (SoCalGas) provides natural gas utility services in the
city. Table 2.4 provides the natural gas activity data in therms from 2005 -2016 separated by
residential and nonresidential uses. Non -residential use combines commercial and industrial use.
Table 2.4. Community natural gas activity data, 2005-2018 (Therms).
Year Residential Nonresidential Total
2005 6,460,870 4,211,790 10,672,660
2006 6,643,410 4,501,180 11,144,590
2007 6,702,810 4,532,760 11,235,570
2008 -- -- --
2009 -- -- --
2010 -- -- --
2011 -- -- --
2012 -- -- --
2013 -- -- --
2014 5,275,340 3,987,264 9,262,604
2015 5,068,160 3,952,562 9,020,722
2016 5,435,586 4,151,275 9,586,861
2017 5,667,638 4,289,700 9,957,338
2018 5,621,586 4,227,571 9,849,157
Note: 2008-2013 data is not available.
As a company policy, SoCalGas only retains community natural gas data through 2014, which
means the data in the original 2005 baseline inventory must be used in conjunction with the data
provided via an Energy Data Request Portal request submitted by City staff in 2017. Since
SoCalGas cannot confirm the 2005 inventory data, the comparison in natural gas consumption in
the baseline year and years 2014 -2017 should be observed with caution. The natural gas data
provided in Table 2.4 shows a 16 percent decrease in residential therms and a 1 percent increase
in non-residential usage between 2005 and 2016. Combined, the natural gas sector has a net
decrease of 10 percent. Table 2.4 also includes 2017 and 2018 data for informational purposes
and to illustrate a slight increase in natural gas use.
Just as with electricity, GHG emissions are estimated from act ivity data by applying an emission
coefficient to the activity data . Table 2.5 shows the emission coefficient for converting therms of
natural gas combusted on-site to MTCO2e. Unlike electricity, the inventory assumes no changes
in the carbon intensity of combusting natural gas in any given year , as the chemical composition
of combusted natural gas does not substantially vary from year to year .
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Table 2.5. Local Government Operations Protocol (LGOP) natural gas carbon dioxide
equivalent.
Greenhouse Gas MTCO2e/Therm
CO21 0.005310
CH41 0.000043
N2O1 0.000003
CO2e2 0.005320
Table 2.6 provides GHG emissions estimates in MTCO2e for natural gas consumption in the city
from 2005-2016. As noted in the natural gas activity data, there was a 16 percent decrease in
MTCO2e for residential and a 1 percent decrease for non-residential sectors with a total decrease
in natural gas-related emissions of 10 percent.
Table 2.6. Community Natural Gas GHG estimates, 2005-2016 (MTCO2e).
Year Residential Nonresidential Total
2005 34,580 22,540 57,120
2006 35,550 24,090 59,640
2007 35,870 24,260 60,130
2008 -- -- --
2009 -- -- --
2010 -- -- --
2011 -- -- --
2012 -- -- --
2013 -- -- --
2014 28,230 21,340 49,570
2015 27,120 21,150 48,270
2016 29,090 22,220 51,310
2017 30,330 22,960 53,290
2018 30,080 22,620 52,700
Note: 2008-2013 data is not available.
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2.2.3 Natural Gas – Fugitive Emissions
Methane is a powerful greenhouse gas and 86 times stronger than carbon dioxide over a 20 -year
time period in the atmosphere. As more is learned about the total natural gas system leakage rate
from well head, through the transmission system, to the distributions system, and at the end use,
it is becoming clear that fugitive methane emissions from the usage of natural gas is a critical
component of the climate crisis. Staff is currently working with technical experts to identify a
defensible method for estimating these emissions. Although not included in this report, they will
likely be included prior to the Climate Action Plan update that will be adopted in 2020.
2.3 Total Energy GHG Emissions
Table 2.7 and Figure 2.3 show the total energy-related GHG emissions separated by energy type
and subsector. The residential energy subsector saw a 2 9 percent decrease in emissions
between 2005 and 2016. The nonresidential subsector emissions decreased by 24 percent.
Overall, energy GHG emissions dropped by 26 percent over the 11 -year period. Note that Figure
2.3 provides total energy sector emissions with a dark line; the dashed line indicates a total
emissions estimate necessitated by SoCalGas’s inability to provide historical data.
Table 2.7. Energy GHG emissions, 2005-2016 (MTCO2e).
Year Residential Nonresidential Total
Electricity Natural Gas Electricity Natural Gas Res. Nonres. Total
2005 20,870 34,580 35,510 22,540 55,450 58,050 113,500
2006 19,840 35,550 34,620 24,090 55,390 58,710 114,100
2007 26,880 35,870 49,490 24,260 62,750 73,750 136,500
2008 26,650 -- 51,770 -- -- -- --
2009 23,450 -- 48,240 -- -- -- --
2010 17,910 -- 44,440 -- -- -- --
2011 15,530 -- 31,120 -- -- -- --
2012 17,480 -- 35,050 -- -- -- --
2013 16,520 -- 33,600 -- -- -- --
2014 15,710 28,230 34,210 21,340 43,940 55,550 99,490
2015 14,480 27,120 31,640 21,150 41,600 52,790 94,390
2016 10,320 29,090 22,050 22,220 39,410 44,270 83,680
2017 7,430 30,330 16,040 22,960 37,760 39,000 76,760
2018 9,940 30,080 21,470 22,620 40,020 44,090 84,110
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Figure 2.3. Energy GHG emissions, 2005-2016 (MTCO2e).
113,500
83,680
0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
160,000
2005 2007 2009 2011 2013 2015 2017
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City of San Luis Obispo Page A-14
3. TRANSPORTATION
3.1 Transportation Sector Overview
This section presents the GHG emissions for the transportation sector and includes emissions
from all on-road trips (including cars, trucks, buses, etc.) that have occurred within City limits. This
section presents the updated 2005 GHG emissions along with updated emissions for 2016.
3.2 Updated Inventory Data and Methods
This section provides updated activity data and emissions estimates for baseline year 2005 and
activity data and emissions estimates for 2016. Since the 2005 baseline inventory was completed
in 2009, the state has updated emissions factors and legislation on fuel economy standards.
Additionally, the City has adopted a transportation model that more accurately models the vehicle
miles travelled in, to, and from city boundaries.
The original 2005 inventory used the “geographic system boundary” method which considers
transportation activity occurring solely within city boundaries, regardless of where a trip’s
destination begins or ends. This method included emissions from vehicles that were travelling
through city boundaries but did not account for any of “outside of city boundary” miles that
occurred from trips that originated or ended in the city.
In 2019, the City was able to use its own “origin -destination” transportation model to estimate the
vehicle miles for trips that began and ended in the city, trips that began outside the city and ended
in the city, trips that began in the city and ended outside the city, and trips that passed through
the city without stopping. Consistent with the preferred GPC accounting method, the updated
inventory includes 100 percent of internal trip miles, 50 percent of the miles for trips that start or
end in the city, and zero percent of the miles that are from vehicles passing through the city.
The updated transportation model currently only estimates vehicle miles travelled for calendar
year 2016. To estimate baseline 20 05 emissions, the City replicated the 2005 “geographic system
boundary” model with 2016 data and found a 3 percent increase in vehicles miles travelled.
Assuming the two methods would capture the same scale and direction of change between 2005
and 2016, 2005 origin-destination VMT was estimated by reducing the 2016 VMT by 3 percent.
Table 3.1 reports the 2005 and 2016 VMT estimates.
Table 3.1. 2005 and 2016 VMT estimates.
Measure 2005 2016
Annual VMT 461,452,450 475,634,980
Source: City of San Luis Obispo, Public Works Department.
The origin destination model is preferred to the geographic model because it allows the City to
understand where trips are occurring. The new method identifies a key finding: over 80 percent
of community VMT occurred as the result of regional trips (e.g., trips to the city from outside the
city or trips from the city to areas outside the city).
Vehicle miles traveled estimates for both years were converted to GHG emissions using the 2014
Emissions Factor (EMFAC) model. EMFAC represents the state’s current understanding of motor
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vehicle travel activities and their associated emission levels. EMFAC 2014 is the latest U.S.
Environmental Protection Agency (EPA) approved motor vehicle emission model that assesses
emissions from on-road vehicles including cars, trucks, and buses in California. The City used
EMFAC 2014 to estimate emissions factors for this updated report.
Table 3.2 provides the VMT and associated GHG emissions for each vehicle class in San Luis
Obispo County for 2005 and 2016. GHG emissions were estimated using the California Air
Resources Board (CARB) EMFAC 2014 tool. Using VMT as inputs, EMFAC 2014 generated VMT
and CO2 emission results for both 2005 and 2016 for each type of vehicle common in San Luis
Obispo County. The City used this information to generate a CO2/VMT emissions factor specific
to San Luis Obispo County, reflecting the unique balance of different vehicle types, vehicle ages,
and vehicle fuels used county-wide.
EMFAC 2014 does not model CH4 and N2O emissions. The standard practice is to multiply CO2
emissions factors by 100/95 (approximately 1.05) to convert CO 2 emissions to CO2e. As the
emissions factor generated by EMFAC is in tons of CO 2/VMT, the City also converted the units of
this factor to metric tons. The City then applied this converted emissions factor to the total City
VMT given in Table 3.1. This resulted in the total annual greenhouse gas emissions.
3.3 Total Transportation GHG Emissions
Table 3.2 shows that as VMT was modelled to increase from 2005 to 2016 by 3 percent, the total
GHG emissions from on-road transportation decreased by approximately 6 percent. The decrease
in GHG emissions is attributed to state and federal fuel efficiency standards, low carbon fuel
standards, and an increasingly efficient overall fleet of vehicles (including an increased uptake of
electric, hybrid, and high efficiency vehicles) within the city that is resulting in the emissions
decline, despite an increase in miles driven.
Table 3.2. Total annual VMT emissions.
2005 2016
Total VMT MTCO2e/
VMT
Total
Emissions
Total VMT MTCO2e/
VMT
Total
Emissions
All vehicles 461,452,446 0.000488 225,390 475,634,980 0.000448 212,980
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4. SOLID WASTE
4.1 Solid Waste Sector Overview
This section presents the GHG emissions for the solid waste sector, specifically emissions from
the disposal of solid waste produced within City limits into a landfill. This section presents the
updated 2005 GHG emissions along with updated emissions for 2016.
4.2 Updated Inventory Data and Methods
This section provides updated solid waste activity data for the baseline year of 2005, as well as
activity emissions estimates for years 2005 through 2016 to estimate the City’s total greenhouse
gas emissions. The City of San Luis Obispo deposits all waste generated within city limits into the
Cold Canyon Landfill. Cold Canyon Landfill provided solid waste disposal data. Table 4.1 and
Figure 4.1 provide the City’s solid waste disposal tonnage for 2005 to 2016. Dat a for 2005 to 2007
was not able to be collected; therefore 2008 data was used as a proxy.
Table 4.1. City solid waste activity data, 2008-2016 (Disposal Ton).
Year Total Waste
(Disposal Ton)
2008 53,010
2009 47,483
2010 44,836
2011 39,497
2012 40,469
2013 42,094
2014 40,200
2015 44,530
2016 46,860
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Figure 4.1. Total City solid waste (Disposal Ton).
4.2.1 Green Waste
Green waste data was provided by the City of San Luis Obispo Utilities Department for years
2006 through 2016. Green waste is a part of the diverted waste stream to the Cold Canyon
Landfill, which means that it is not buried at the plant. Traditionally, green waste was either used
as alternative daily cover a t the Cold Canyon Landfill or hauled to a windrow composting facility
near Santa Maria. There is no standard protocol for estimating the emissions from windrow
composting and therefore no emissions are estimated in this inventory. However, given the
importance of diverting organic materials, the subsequent construction and operation of an
anerobic digester to process organic green waste in 2018, and legislation requiring substantial
increases in organic waste diversion, staff will continue to monitor the av ailability of a standard
method and will include this information in future greenhouse gas and Climate Action Plan
updates.
4.2.2 Municipal Solid Waste GHG Emissions Conversion Factor
This inventory follows the “methane commitment method” to account for t he future emissions
produced from annually deposited solid waste. This method requires the following steps:
1. Estimate the percent of degradable organic materials in landfilled waste.
2. Identify the conversion factor to translate tons of carbon dioxide to metr ic tons of methane.
3. Estimate the amount of methane per ton of landfilled waste that will enter the atmosphere.
4. Convert the estimate of methane to carbon dioxide equivalence.
1. Estimate the percent of degradable organic materials in landfilled waste .
The CARB Municipal Solid Waste Characterization Landfill Tool v. 1.3 provides landfill waste
characterization estimates for waste by type sent to California landfills. The waste types identified
in the waste characterization studies are listed in Table 4.2. For each of these waste types, the
0
10,000
20,000
30,000
40,000
50,000
60,000
2008 2009 2010 2011 2012 2013 2014 2015 2016 2017Tonnage
Landfilled Waste
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tool includes California average estimates of the fraction of waste -in-place (WIPFRAC), total
degradable organic carbon (TDOC), and the decomposable anaerobic fraction (DANF) of the
waste type.4 There are two relevant waste characterization studies for this inventory: one from
2003 to 2006 and the other from 2007 to the present. Table 4.2 provides information about waste
characterization estimates used in this inventory, as well as the degradable organic content
(DOC) percent per ton of solid waste, which is calculated by multiplying WIPFRAC, TDOC, and
DANF for each waste type.
Table 4.2. Total percent of waste degradable based on waste type.
2003-2006 2007-Present
Waste Type WIPFRAC TDOC DANF DOC WIPFRAC TDOC DANF DOC
Newspaper 2.20% 47.09% 15.05% 0.16% 1.65% 47.09% 15.05% 0.12%
Office Paper 1.95% 38.54% 87.03% 0.65% 1.84% 38.54% 87.03% 0.62%
Corrugated Boxes 5.75% 44.84% 44.25% 1.14% 4.80% 44.84% 44.25% 0.95%
Coated Paper 11.09% 33.03% 24.31% 0.89% 8.98% 33.03% 24.31% 0.72%
Food 14.55% 14.83% 86.52% 1.87% 15.50% 14.83% 86.52% 1.99%
Grass 2.81% 13.30% 47.36% 0.18% 1.90% 13.30% 47.36% 0.12%
Leaves 1.41% 29.13% 7.30% 0.03% 3.24% 29.13% 7.30% 0.07%
Branches 2.59% 44.24% 23.14% 0.26% 1.95% 44.24% 23.14% 0.20%
Lumber 9.65% 43.00% 23.26% 0.96% 14.51% 43.00% 23.26% 1.45%
Textiles 4.44% 24.00% 50.00% 0.53% 5.47% 24.00% 50.00% 0.66%
Diapers 4.36% 24.00% 50.00% 0.52% 4.33% 24.00% 50.00% 0.52%
Construction/
Demolition 12.06% 4.00% 50.00% 0.24% 5.48% 4.00% 50.00% 0.11%
Medical Waste 0.04% 15.00% 50.00% 0.00% 0.00% 15.00% 50.00% 0.00%
Sludge/Manure 0.09% 5.00% 50.00% 0.00% 0.05% 5.00% 50.00% 0.00%
Source: CARB Municipal Solid Waste Characterization Landfill Tool v. 1.3
2. Identify the conversion factor to translate tons of carbon dioxide to metric tons of methane .
The next step in calculating the emissions factor is estimating the metric tons of methane to be
generated from the organic content in the landfilled waste. Solid waste activity data is reported in
tons, while the standard unit for GHG reporting is metric tons. Table 4.3 presents the conversion
factors to metric tons. As the decomposing organic content in landfilled sol id waste transitions
from carbon to methane, the atomic mass changes as well. Since the CO 2e in this inventory is
presented as mass (metric tons), this change in mass is accounted for with the stoichiometric
ratio between CH4 and carbon.
Finally, of the total landfill gas generated from decomposing waste, approximately half is methane;
a methane gas fraction is applied to remove other gasses from the total. The remainder is biogenic
4 For more information, visit
https://ww3.arb.ca.gov/cc/protocols/localgov/pubs/landfill_emissions_tool_v1_3_2011-11-14.xls
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CO2 from vegetation from natural areas, crops, and urban vegetation and de minimus amounts of
N2O. The GPC advises against accounting for either of these gases in a community inventory.
Table 4.3. Conversion to metric tons of methane.
lbs/ton1 MT/lbs 1 Stoichiometric ratio
between CH4 and carbon2
Fraction of CH4 Gas in
Landfill Gas 3
Metric Tons of Methane
2000 0.000454 1.333333 0.5 0.604796
1 Standard conversion factor.
2 16/12, provided by the Global Protocol for Community-Scale Greenhouse Gas Emission Inventories.
3 IPCC Good Practices Guidance and Uncertainty Management in National Greenhouse Gas Inventories
(2000) default range.
3. Estimate the amount of methane per ton of landfilled waste that will enter the atmosphere.
The next factor in the solid waste emissions coefficient is the amount of landfill gas that is collected
by landfill gas capture systems. The San Luis Obispo County Air Pollution Control D istrict (APCD)
provides landfill capture rates for Cold Canyon Landfill, as provided in Table 4.4 for the years
2008 – 2013. The landfill capture rate for 2006 is sourced from the County of San Luis Obispo
EnergyWise Plan Appendix A. Given the lack of data availability for several years, including 2005,
2007, 2014, 2015, and 2016 and the significant variability across years, this inventory relied on
the EPA’s standard landfill methane capture rate of 75 percent.
Table 4.4. Recorded methane capture rates from Cold Canyon Landfill.
Year Cold Canyon
2005 Not Available
2006 60%
2007 Not Available
2008 70%
2009 99%
2010 85%
2011 85%
2012 85%
2013 75%
The next phase of the equation considers the amount of methane that is oxidized in the soil. As
reported in Table 4.5, only 25 percent of landfill gas enters the atmosphere. Of that 25 percent,
10 percent is oxidized on site in the soil of the land fill cover. Of the 75 percent of the methane
that is captured, approximately 9 9 percent enters the atmosphere as CO2 due to the methane
being combusted as part of the flaring process. Approximately 23 percent of the total methane
emitted enters the atmosphere. Table 4.5 shows the factors used in this calculation.
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Table 4.5. Percent of emissions reaching the atmosphere.
Fraction of methane
recovered (frec) 1
Oxidation factor (OX)
2
Methane correction
factor (MCF) 3
Percent of Emissions
Reaching Atmosphere
75% 10% 99% 23.3%
1 Landfill gas capture rate, as provided by the Environmental Protection Agency
2 IPCC Good Practices Guidance and Uncertainty Management in National Greenhouse Gas Inventories
(2000) well-managed landfills factor.
3 IPCC Good Practices Guidance and Uncertainty Management in National Greenhouse Gas Inventories
(2000) managed landfill factor.
4. Convert the estimate of methane to carbon dioxide equivalence .
The solid waste CO2e conversion factor was calculated by multiplying the total degradable content
of each weight type (DOC), metric ton conversion factor, methane generation, and the IPCC Fifth
Assessment Report methane 20 -year global warming potential (Table 4.6). The facto rs for each
waste type are then weighted by the waste composition data to obtain a single emissions factor
for a ton of mixed waste. In 2005 to 2006, each ton of solid waste deposited in a landfill is
estimated to produce approximately 0.901 MTCO 2e per ton as it degrades over time. For 2007 to
2016, the conversion factor is 0.910 MTCO 2e per ton of solid waste.
Table 4.6. Disposed solid waste conversion factor with Fifth Assessment Report global
warming potential (MTCO2e/Disposal Ton).
Waste Type 2003-
2006
DOC1
2007-
Presen
t
DOC1
Metric Ton
(MT)
CH4
emissio
ns
CH4
GWP
2
2003-
2006
MTCO2e/
Ton
2007-
Present
MTCO2e/
Ton
Newspaper 0.16% 0.12% 0.604796033 0.2325 86 0.018893 0.014147
Office Paper 0.65% 0.62% 0.604796033 0.2325 86 0.079150 0.074673
Corrugated Boxes 1.14% 0.95% 0.604796033 0.2325 86 0.137882 0.115122
Coated Paper 0.89% 0.72% 0.604796033 0.2325 86 0.107692 0.087188
Food 1.87% 1.99% 0.604796033 0.2325 86 0.225818 0.240600
Grass 0.18% 0.12% 0.604796033 0.2325 86 0.021405 0.014505
Leaves 0.03% 0.07% 0.604796033 0.2325 86 0.003612 0.008322
Branches 0.26% 0.20% 0.604796033 0.2325 86 0.031997 0.024157
Lumber 0.96% 1.45% 0.604796033 0.2325 86 0.116652 0.175520
Textiles 0.53% 0.66% 0.604796033 0.2325 86 0.064439 0.079358
Diapers 0.52% 0.52% 0.604796033 0.2325 86 0.063217 0.062825
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Waste Type 2003-
2006
DOC1
2007-
Presen
t
DOC1
Metric Ton
(MT)
CH4
emissio
ns
CH4
GWP
2
2003-
2006
MTCO2e/
Ton
2007-
Present
MTCO2e/
Ton
Construction/
Demolition 0.24% 0.11% 0.604796033 0.2325 86 0.029159 0.013245
Medical Waste 0.00% 0.00% 0.604796033 0.2325 86 0.000346 0.000000
Sludge/Manure 0.00% 0.00% 0.604796033 0.2325 86 0.000274 0.000155
Total -- -- -- -- -- 0.901 0.910
Note: Values are rounded causing final values to be inconsistent with calculations.
1 Source: CARB Municipal Solid Waste Characterization Landfill Tool v. 1.3.
2 IPCC Fifth Assessment Report
4.3 Total Solid Waste GHG Emissions
To estimate the solid waste GHG emissions, the carbon dioxide equivalency conversion factor
was multiplied by the disposal ton activity data. Once these were applied, the annual solid waste
disposal ton emissions were calculated. As shown in Table 4.7, from 2005 to 2016, the solid waste
sector experienced a decrease in emissions by nearly 11 percent.
Table 4.7. Total solid waste disposed emissions (MTCO2e).
Year Total Waste
(Disposal Ton)
MTCO2e Conversion
Factor
Solid Waste Disposed
MTCO2e
2005 53,011 0.901 47,740
2006 53,011 0.901 47,740
2007 53,011 0.910 48,230
2008 53,011 0.910 48,230
2009 47,483 0.910 43,200
2010 44,836 0.910 40,790
2011 39,497 0.910 35,930
2012 40,469 0.910 36,820
2013 42,094 0.910 38,300
2014 40,200 0.910 36,570
2015 44,530 0.910 40,510
2016 46,857 0.910 42,630
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5. FORECAST
The GHG emissions forecast estimates how San Luis Obispo’s emissions would change over
time if no action were taken to reduce emissions. The forecast is based on changes to the number
of people who live and work in San Luis Obispo. As the population grows and more people work
in the community, there will be an increase (absent state or local action) in the amount of energy
used, vehicle miles traveled, trash thrown away, and other activities that generate GHG
emissions.
The demographic projections used in the forecast come from the Land Use and Circulation
Element of the City’s General Plan, which guides long -term growth and development in the
community. These proje ctions assume that the development anticipated in the Land Use and
Circulation is fully implemented by 2035. It is assumed that jobs in San Luis Obispo County
increase at a rate of 1.1 percent, as forecasted in the Land Use and Circulation Element, startin g
from the number of jobs in the community in 2015 as reported by the US Census. Table 6.1 shows
the demographic changes assumed in the forecast and their applicable subsectors.
Table 5.1. Demographic projections (2005-2035).
Demographic
Indicator Applicable Subsectors 2005 2016 2020 2030 2035
Population None 44,519 46,117 48,826 53,934 56,686
Housing units Residential electricity, residential
natural gas 20,391 21,155 22,190 24,512 25,762
Jobs 1 Commercial/industrial electricity,
commercial/industrial natural gas 43,847 50,985 53,153 59,723 63,199
Service
population 2
On-road transportation, community-
wide MSW disposal 66,443 71,610 74,403 83,796 88,286
1 Future job numbers assume a 1.1 percent increase in the number of jobs relative to 2015 levels.
2 Per the method used by the San Luis Obispo Community Development Department, service
population is equal to the residential population plus ½ the number of jobs.
Sources: City of San Luis Obispo Land Use and Circulation Element, City of San Luis Obispo
Community Development Department, Economics & Planning Systems, US Census Bureau.
The forecasts also consider known relevant actions that will continue to reduce greenhouse gas
emissions. There are three major policies that the City and the State have adopted to reduce
GHG emissions at the local level:
• Renewables Portfolio Standard (RPS) and Community Choice Energy (CCE)
participation: RPS requires that electrical providers supply an increased amount of their
electricity from eligible renewable sources. At time of writing, a bill to revise the RPS (SB
100), has been passed by the California Legislature and signed by Governor Brown
requiring that 33% of the electricity sold by a provider by 2020 be renewable, that 60% of
electricity be renewable by 2030, and that 100% of all electricity must be carbon -free
(although not necessarily renewable) by 2045. This analysis assumes that SB 100 fully
implemented. Additionally, in December of 2018, the City of San Luis Obispo joined
Monterey Bay Community Power (MBCP), a community choice energy program.
Beginning in January of 2020, MBCP will be providing carbon free electricity to the
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community. This forecast assumes that 2 percent of electrical load will opt to remain with
PG&E.
• Title 24: This set of standards governs how new buildings must be constructed, including
specifying minimum energy efficiency requirements. The standards are updated every
three years to be more stringent. California’s zero net energy (ZNE) standards are
included in Title 24. The included forecast also assumes that the City’s Clean Energy
Choice Program has been implemented and that all new construction is either electric and
carbon free or has offset its emissions in the existing built environment.
• Clean Car Standards: These standards require that cars sold in California meet minimum
fuel efficiency requirements, and that vehicle and equipment fuel sold in the state emit
less GHGs during production and use. The City used the 2035 emissions coefficient
included in the EMFAC2014 modelling software, which includes assumptions about
ongoing fuel efficiency and fuel carbon content improvements.
The City has calculated the effect of these three policies on San Luis Obispo’s emissions and w ith
these three policies in place, San Luis Obispo’s future GHG emissions are expected to continue
to decrease. As shown in Table 6.2, emissions in 2020 are projected to be 306,600 MTCO2e (21
percent below 2005 levels), and in 2030 are expected to be at 275,730 MTCO2e (29 percent
below 2005 levels). In 2035, emissions with state policies in place are expected to be at 260,160
MTCO2e, or 32 percent below 2005 levels.
Table 5.2 Forecasted GHG emissions with state reductions, 2005 -2050 (MTCO2e).
Sector 2005 2016 2020 2030 2035 Percent Change
(2005-2035)
Transportation 225,390 212,980 198,210 161,290 142,830 -37%
Nonresidential Energy 58,050 44,270 30,430 33,690 27,720 -47%
Residential Energy 55,450 39,410 33,760 35,660 33,180 -39%
Solid Waste 47,740 42,630 44,890 49,880 52,560 10%
Total 386,630 339,290 307,290 280,520 256,290 -33%
Change from 2005 -12% -21% -29% -33%
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6. AREAS FOR
IMPROVEMENT
A greenhouse gas emissions inventory is only a partial snapshot of the total emissions occurring
in a community. The report as presented includes emissions sectors and categories as required
by global accounting protocol and represent those sectors that have defensible and transparent
methods and data. As the City continues its path of climate action toward carbon neutrality, the
following areas for improvement will be closely monitored:
• Energy in Water – The inventory presented in this report includes the energy required to
move and treat water in the city. However, it does not estimate emissions from the
conveyance of water from outside city limits to the city. Future inventories should identify
a defensible method to account for these emissions.
• Green Waste – All of the organic waste that is collected in the city is processed by an
anerobic digester that yields clean electricity and compost. Previously, the community’s
green waste was trucked to a wind row composting facility in Santa Maria, CA or landfilled
at Cold Canyon Landfill. The new approach is certainly reducing community emissions.
However, there are no available defensible methods for estimating emissions from wind
row composting, and therefore, no way to establish a baseline emissions level. The C ity
will continue to monitor GPC work on composting methods and will include as a sector
when available.
• Wastewater - The GPC requires local governments to account for direct process
emissions that occur from the treatment of wastewater. It is known that the treatment of
wastewater can release Nitrous Oxide and Methane, both of which are powerful
greenhouse gases. Although the GPC provides accounting methods for estimating the
direct release of emissions, an accounting protocol does not exist for the spec ific treatment
type that occurs at the San Luis Obispo Water Resource Recovery Facility (nitrification,
but no denitrification). Using an unvetted method, the City estimates these direct
emissions to be approximately 200 MTCO2e per year. Given the small si ze, this sector is
not critical for planning purposes, but will be included when future updates to the GPC
provide a defensible accounting method.
• Carbon Stocks and Sequestration – Greenhouse gas inventories do not need to evaluate
existing carbon stocks or potential for sequestration, but these analysis can help the City
understand how to better account for the existing value of these stocks and credit actions
in the future that either preserve or enhance the amount of sequestered carbon.
Sequestration, if included at all, is typically included in greenhouse gas inventories as an
Given the amount of land area in the General Plan Conservation/Open Space, estimating
the forestry and carbon stocks will be a meaningful part of a future inventory. As with the
wastewater issue mentioned above, the City will monitor GPC updates for defensible
accounting methods. Beyond that, the City is working with the cities of Vancouver B.C.,
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San Francisco, and Boulder, CO to develop a tool for estimating emissions from carbon
stocks and sequestration potential.
• Fugitive Methane – From the well head to the appliance, methane leaks directly into the
atmosphere as the result of natural gas development and transmission. Some estimates
of total system leakage are high enough to ma ke natural gas consumption as bad a climate
polluter as coal. A common protocol for amending the natural gas emissions coefficient to
account for this leakage is not available. The City will consider updating the coefficient in
future years when such information is vetted and available.
• Consumption - The inventory does not include the emissions that result from community
consumption (e.g., consumption of food, clothing, packaging, etc.). Given the City’s intent
to work closely with the community in develo ping and implementing the climate action
plan, it is important to recognize the greenhouse gas impacts created by the purchase and
disposal of products and materials. Global climate action leadership cities are working on
developing a standard protocol for inventorying consumption-based emissions. As with
the other items in this section, the City will seek to include the sector when such a protocol
is available. It should be noted that emissions from consumption may be significant, some
cities estimate that consumption emissions increase their total inventoried emissions by
more than 40 percent.
• Off-road equipment – Practices exist to account for emissions from lawn and garden and
construction equipment. Using the Air Resources Board “OFFROAD” model, staff could
estimate emissions from this voluntary sector in order lay a foundation for policy to reduce
emissions from construction equipment and to reduce emissions from fossil fueled lawn
and garden equipment.
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List of Abbreviations
AB: Assembly Bill
ADT: Average daily trips
APCD: Air Pollution Control District
Caltrans: California Department of Transportation
CAP: Climate Action Plan
CARB: California Air Resources Board
CH4: Methane
CO2: Carbon dioxide
CO2e: Carbon dioxide equivalent
DANF: Decomposable anaerobic fraction
DOC: Degradable organic content
EPA: US Environmental Protection Agency
GHG: Greenhouse gas
IPCC: Intergovernmental Panel on Climate Change
kW: Kilowatt
kWh: Kilowatt-hour
LGOP: Local Government Operations Protocol
MSW: Municipal solid waste
MTCO2e: Metric tons of carbon dioxide equivalent
N2O: Nitrous oxide
PG&E: Pacific Gas & Electric Company
RPS: Renewables Portfolio Standard
SB: Senate Bill
TDOC: Total degradable organic carbon
VMT: Vehicle miles traveled
WIPFRAC: Fraction of waste in place
WRRF: Water Resource Recovery Facility
ZNE: Zero net energy