2012 Community Greenhouse Gas Inventory
Arlington County, Virginia
August 2013
Prepared by:
TableofContents
1 Executive Summary ............................................................................................................................... 1
2 Buildings Sector ..................................................................................................................................... 5
2.1 Buildings Sector Results ................................................................................................................ 5
2.2 Buildings Sector Methodology ...................................................................................................... 7
2.2.1 Stationary Combustion Methodology ................................................................................... 7
2.2.2 Electricity Methodology ...................................................................................................... 11
2.2.3 Buildings Sector Data Summary .......................................................................................... 11
2.2.4 Buildings Sector Emission Factors ....................................................................................... 13
3 Community Transportation Sector ..................................................................................................... 15
3.1 Community Transportation Sector Results ................................................................................. 15
3.2 Pass‐Through and County Origin/Destination Traffic ................................................................. 16
3.2.1 Pass‐Through and County Origin/Destination Traffic Methodology .................................. 16
3.3 WMATA – Metrobus and Metrorail ............................................................................................ 20
3.3.1 Metrobus and Metrorail Results ......................................................................................... 20
3.3.2 Metrobus and Metrorail Methodology ............................................................................... 20
3.4 Taxis ............................................................................................................................................ 23
3.4.1 Taxi Results.......................................................................................................................... 23
3.4.2 Taxi Methodology ............................................................................................................... 24
3.5 University Shuttles ...................................................................................................................... 25
3.5.1 University Shuttles Results .................................................................................................. 25
3.5.2 University Shuttles Methodology ....................................................................................... 25
4 Solid Waste Sector .............................................................................................................................. 27
4.1 Solid Waste Sector Results .......................................................................................................... 27
4.2 Solid Waste Sector Methodology ............................................................................................... 27
4.2.1 Landfill Process Methodology ............................................................................................. 27
4.2.2 Waste‐to‐Energy Methodology .......................................................................................... 28
4.2.3 Waste Collection and Transportation Methodology .......................................................... 28
4.2.4 Solid Waste Sector Data ...................................................................................................... 29
4.2.5 Solid Waste Sector Emission Factors .................................................................................. 30
4.2.6 Solid Waste Sector Assumptions ........................................................................................ 31
5 Non‐County Government Sector ........................................................................................................ 32
5.1 Non‐County Government Sector Results .................................................................................... 32
5.2 Non‐County Government Sector Methodology .......................................................................... 33
5.2.1 Non‐County Government Sector Data ................................................................................ 33
5.2.2 Non‐County Government Sector Assumptions ................................................................... 33
1
1 ExecutiveSummaryThis report contains the greenhouse gas (GHG) emissions for the Community of Arlington County for
calendar year (CY) 2012. The purposes of this report are to measure progress toward Arlington’s
recently established Community emissions target of 3.0 metric tons of carbon dioxide equivalent
(mtCO2e) per resident per year by CY 2050 as defined in the County’s Community Energy Plan1, and to
document the methodologies, assumptions and data sources used to calculate emissions. The Arlington
Initiative to Rethink Energy (AIRE) will use these and future greenhouse gas emissions inventories to
guide the specific programs and tools it offers to the community to lead the way to smart energy choices
that reduce emissions.
In 2012 Arlington Community emissions totaled 2,403,295 metric tons CO2e, of which 91,267 metric tons
CO2e were attributable to the County Government and 2,312,028 metric tons CO2e from other County
sources. This equates to a per capita emissions level of 11.3 metric tons CO2e, an achievement
representing a 13 percent decrease in per capita emissions relative to the CY 2007 baseline. On an
absolute basis, Community emissions improved by 10 percent relative to CY 2007 and 8 percent relative
to CY 2000 despite population growth. Arlington’s population reached 212,900 residents in 2012 which
represents growth of 3 and 12 percent relative to CY 2007 and CY 2000, respectively.
Table ES.1: Arlington County Total Community Emissions and Emissions Per Capita
Metric 2000
(reference) 2007
(baseline) 2012
% Change2007‐2012
Community Emissions (mtCO2e) 2,515,238 2,572,871 2,312,028 ‐10%
County Government Emissions* 95,383 96,120 91,267 ‐5%
Population (resident) 189,453 206,800 212,900 3%
Per Capita Emissions (mtCO2e/resident) 13.8 12.9 11.3 ‐13% *Emissions listed here are the total Government Operations inventory, including Arlington Schools, and are different from the net government operations emissions, which track achievement of the AIRE 2012 goal and are separate and additional to the gross inventory total compiled according to the LGOP.
Excluding the County Government emissions portion of the community, Commercial and Residential
buildings contributed more than 60 percent to Community emissions in CY 2012 at 1,436,567 metric
tons CO2e. The transportation sector contributed more than one‐third of Community emissions at
836,434 metric tons CO2e and the solid waste sector emitted 39,027 metric tons CO2e or about 2
percent. All three sectors reduced emissions relative to CY 2007. The largest percent reduction occurred
in the solid waste sector with a total reduction about 21 percent. The buildings sector reduced emission
by 15 percent and the transportation sector achieved a modest reduction of 1 percent.
1 http://freshaireva.us/2012/04/energyplan/
2
Figure ES.1: Total Community Emissions by Sector and Inventory Year
About half of Community emissions were the result of purchased electricity in commercial and
residential buildings and by Metrorail trains and infrastructure. Emissions from purchased electricity
totaled 1,206,608 metric tons CO2e in CY 2012, a 12 percent reduction from CY 2007. Slightly more than
one‐third of Community emissions were generated by mobile combustion of gasoline, diesel and
compressed natural gas (CNG) in private vehicles, heavy duty commercial vehicles, community transit
vehicles and waste haulers. Mobile combustion emissions were virtually unchanged between CY 2007
and CY 2012 at slightly more than 800,000 metric tons CO2e. The majority of remaining Community
emissions was the result of natural gas, fuel oil, kerosene and LPG consumption in the buildings sector.
This stationary combustion generated 263,060 metric tons CO2e in CY2012, a 24 percent reduction
relative to CY 2007. Landfill and waste‐to‐energy (WTE) plant emissions contributed marginally to
Community emissions in CY 2012, generating about 39,000 metric tons CO2e.
Table ES.2: Total Community Emissions by Sector, Source and Data Year
Sector Revised Values (mtCO2e)
Change 2007‐2012 (mtCO2e)
% Change 2007‐2012
2000 2007 2012
Buildings Sector 1,570,917 1,682,148 1,436,567 ‐245,581 ‐15%
Commercial Buildings 1,051,180 1,094,729 909,194 ‐185,535 ‐17%
Single‐family Residential Homes 337,397 360,869 320,737 ‐40,131 ‐11%
Multi‐family Residential Buildings 182,340 226,550 206,636 ‐19,914 ‐9%
Transportation Sector 884,571 841,599 836,434 ‐5,164 ‐1%
Passenger Cars/Motorcycles 427,198 421,184 408,752 ‐12,432 ‐3%
Light Trucks/SUVs 282,504 275,647 291,414 15,767 6%
Heavy Duty Trucks 104,369 71,318 68,490 ‐2,829 ‐4%
Metrorail 32,862 37,864 33,101 ‐4,763 ‐13%
Taxis 14,764 15,871 21,142 5,271 33%
Metrobus 22,660 19,500 13,273 ‐6,227 ‐32%
University Shuttles 215 215 263 48 22%
Solid Waste Sector 59,750 49,125 39,027 ‐10,098 ‐21%
WTE Plant 53,682 44,431 35,218 ‐9,214 ‐21%
2,515,238 2,572,871
2,312,028
0
500,000
1,000,000
1,500,000
2,000,000
2,500,000
3,000,000
2000 2007 2012
Emissions (m
t CO2e)
Solid Waste Sector
Transportation Sector
Buildings Sector
3
Landfill 4,818 3,536 2,807 ‐730 ‐21%
Collection and Transport Vehicles 1,249 1,157 1,002 ‐155 ‐13%
Community Emissions (non‐Government) 2,515,238 2,572,871 2,312,028 ‐203,210 ‐10%
County Government Emissions 95,383 96,120 91,267 ‐4,853 ‐5%
Total Community 2,610,621 2,668,991 2,403,295 265,696 ‐10%
Federal and other non‐County Government 3,303* 315,546 315,446 ‐100 ‐0.03%*2000 Federal and Other non‐County Government emissions only include Airport Service Equipment, other data not available.
Methodologies employed in this inventory comply with the Local Government Operations Protocol v1.1
(LGOP)2 and the ICLEI Community Protocol v1.0 (ICP)3 where applicable, and cases where methodologies
deviate from protocols are noted. The inventory includes all Scope 1 and Scope 2 sources as outlined by
the protocols and all emissions data shown are in units of metric tons of carbon dioxide, unless
otherwise noted. This inventory updates results and methodologies previously reported4 for 2000 and
2007 as new data and methodology refinements have emerged.
For the purposes of this report, the “Community” sources described below include commercial and
residential activities occurring within the geopolitical boundary of Arlington County, but do not include
any of the County government operations emissions reported separately. These activities generate
emissions as a result of purchased electricity, combustion of fossil fuels and generation of solid waste.
Emissions from the following specific activities and sources are estimated as part of the Community
inventory and include those sources which are required for compliance with the ICP5:
Buildings Sector
o Use of fuel in residential and commercial stationary combustion equipment
o Use of electricity by the community
Transportation Sector
o On‐road passenger vehicles operating within the community boundary
o On‐road freight and service vehicles operating within the community boundary
o On‐road transit vehicles operating within the community boundary
o Transit rail vehicles operating within the community boundary
Solid Waste Sector
o Generation, collection, transportation and disposal of solid waste by the community
The buildings sector (referred to as the “built environment” in the ICP) includes all commercial buildings,
single‐family homes and multi‐family residences that consume electricity and combust fossil fuels onsite
that are not operated by the County Government or school system. Federally controlled sites, including
Army National Guard Arlington Hall Station, Joint Base Myer‐Henderson Hall, National Foreign Affairs
Training Center and the Pentagon as well as the Reagan National Airport are included in a separate total
2 http://www.icleiusa.org/tools/ghg‐protocol/local‐government‐operations‐protocol‐1 3 http://www.icleiusa.org/tools/ghg‐protocol/community‐protocol 4 http://freshaireva.us/wp‐content/uploads/2012/04/Greenhouse‐Gas‐Emissions‐Inventory.pdf 5 Emissions from potable water and wastewater facilities are the only required source by the ICP not listed here, however, those facilities are operated by the County Government and emissions are thus captured in a separate report on the County’s Government Operations Inventory.
4
that represents areas outside of Arlington County’s control, but within its jurisdictional boundary.
Federal facilities are not included as part of the County Community emissions target, and thus will be
tracked separately from the rest of the Community emissions. This is similar to Federal accounting
practices under Executive Order 13514, where certain sources are “goal subject” and certain sources are
“goal excluded”. For Arlington County accounting purposes, Federal buildings and National Airport are
considered goal excluded. Any government activities outside of the sites listed are included in the non‐
County government sector of this inventory, and are also goal excluded.
The transportation sector includes all electrically and fossil fuel‐powered passenger vehicles, heavy‐duty
commercial vehicles and Metrorail, Metrobus, university shuttles and taxis traveling within County
boundaries, excluding the County, School and Arlington Transit (ART) fleets. This includes trips
originating within the County as well as pass‐through trips. Similar to emissions from the federally
controlled buildings, airport emissions from service equipment are considered goal excluded and are
tracked separately under non‐County government.
Emissions from solid waste are generated at landfill and WTE facilities physically located outside the
County boundary, however, the Community’s share of emission from these sites are captured in this
inventory since the waste originated within the County boundary.
The figure below displays these inventory boundaries and the associated hierarchy for aggregating
emissions from Community sources.
Figure ES1: Hierarchy for Aggregating Emissions
Community Sources
Buildings
Non‐residential Buildings
(Commercial)
Residential Buildings
(Single‐family, Multi‐family)
Transportation
Private Passenger Vehicles
(Cars, Light Trucks, SUVs, Motorcyles)
Commercial Vehicles and Equipment
(Heavy Duty Trucks, Haulers, Service Equipment)
Community Transit
(Metrorail, Metrobus, University Shuttles, Taxis)
Solid Waste
Landfilled MSW
Combusted MSW
(Waste‐to‐Energy Plant)
5
2 BuildingsSectorArlington’s Community buildings sector generates emissions as a result of the purchase and
consumption of electricity and the combustion of fossil fuels such as natural gas, fuel oil, kerosene and
liquefied petroleum gas (LPG). Specific emission sources within the Community include commercial
buildings, single‐family homes and multi‐family residences. The buildings sector does not include water
delivery and wastewater buildings, infrastructure and processes; water delivery and wastewater
treatment emissions are captured separately in the Government Operations inventory. This is in
accordance with the LGOP and the ICP, which require energy from water delivery and waste water
facilities to be separated out to increase transparency on the impact of water use in the community.
Federal buildings and Reagan National Airport emissions are not included in any of the emission totals or
figures in this section. Those emissions are tracked separately and shown in below in section 5 which
summarizes the non‐County government sector.
2.1 BuildingsSectorResultsBuildings sector emissions totaled 1,436,567 metric tons CO2e during CY 2012, as displayed in Figure 2.1
and Table 2.1. This represents a decrease of 245,581 metric tons CO2e, or 15 percent, relative to CY
2007. The majority of this decrease occurred in the non‐residential buildings sector (17 percent),
whereas emissions from residential buildings decreased only 10 percent relative to 2007.
Figure 2.1: Buildings Sector Emissions by Building Type and Inventory Year
In CY 2012 non‐residential buildings generated the largest share (63 percent) of total buildings sector
emissions, followed by single‐family homes at 22 percent, and multi‐family residences around 15
percent. The pie chart and table below display the emissions breakdown from non‐residential and
33%35%
37%
67% 65%63%
0
200,000
400,000
600,000
800,000
1,000,000
1,200,000
1,400,000
1,600,000
1,800,000
2000 2007 2012
Emissions (m
tCO2e)
Non‐Residential Buildings Residential Buildings
1,570,9171,682,148
1,436,567
6
residential buildings. Consumption from 2000 and 2007 was not updated for this report for electricity.
For natural gas, County government consumption was removed from 2000 and 2007 due to new
information on the data used in the published report.
Figure 2.2: CY 2012 Emissions Breakdown for Non‐residential and Residential Buildings
Table 2.1: Buildings Sector Emissions by Source and Inventory Year
Source 2000 2007 2012 % Change2007‐2012
Non‐Residential Buildings 1,051,180 1,094,729 909,194 ‐17%
Residential Buildings 519,737 587,419 527,374 ‐10%
Single‐family Homes 337,397 360,869 320,737 ‐11%
Multi‐family Residences 182,340 226,550 206,636 ‐9%
Total Buildings Sector Emissions 1,570,917 1,682,148 1,436,567 ‐15%
Nearly three‐quarters of buildings sector emissions resulted from consumption of 2,483,502 megawatt
hours of electricity in CY 2012. The balance of emissions was almost entirely the result of combusting
4,714,221 million Btu of natural gas. Only about one percent of buildings sector emissions resulted from
combusting other fossil fuels including fuel oil, kerosene and LPG. Fugitive refrigerant emissions were
not estimated for Community buildings, in accordance with the ICP because they are assumed to be de
minimis and unlike County government refrigerant data, community data was unavailable.
63%
22%
15%
Non‐Residential Buildings
Single‐family Residential Homes
Multi‐family Residential Buildings
7
Figure 2.3: Buildings Sector Emissions by Fuel and Inventory Year
Table 1.2: Buildings Sector Emissions by Fuel and Inventory Year
Source 2000 2007 2012 % Change2007‐2012
Electricity 1,145,994 1,337,115 1,173,508 ‐12%
Natural Gas 355,612 314,336 250,589 ‐20%
Fuel Oil & Kerosene 66,531 27,919 10,584 ‐62%
LPG 2,780 2,778 1,886 ‐32%
Buildings Sector Emissions 1,570,917 1,682,148 1,436,567 ‐15%
2.2 BuildingsSectorMethodology
2.2.1 StationaryCombustionMethodologyEmissions from combustion of natural gas, fuel oil, kerosene and LPG within the buildings sector were
calculated based on fuel consumption of each Community source, in accordance with the LGOP and ICP.
To calculate CO2 emissions, consumption values for each fuel were multiplied by the corresponding
emission factor for each fuel type, with the resulting kilograms of CO2 emissions divided by 1,000 to get
metric tons CO2 emissions. CO2 emissions for each fuel type were then summed to arrive at total CO2
emissions in units of metric tons CO2.
Natural Gas CO2 Emissions (mtCO2) = Natural Gas Consumed (MMBtu) × Emission Factor (kgCO2/MMBtu) ÷ 1,000
Propane CO2 Emissions (mtCO2) = Propane Consumed (MMBtu) × Emission Factor (kgCO2/MMBtu) ÷ 1,000
Diesel CO2 Emissions (mtCO2) = Diesel Consumed (gallons) × Emission Factor (kgCO2/gallon) ÷ 1,000
Total CO2 Emissions (mtCO2) = CO2 from Natural Gas + CO2 from Propane + CO2 from Diesel
73%79%
82%
23%
19%
17%
4%
2%
1%
0
200,000
400,000
600,000
800,000
1,000,000
1,200,000
1,400,000
1,600,000
1,800,000
2000 2007 2012
Emissions (m
tCO2e)
Electricity Natural Gas Fuel Oil & Kerosene LPG
1,570,9171,682,148
1,436,567
Note: LPG emission not visible in the chart
8
The same general process and equations used to calculate CO2 emissions were then used to calculate
CH4 and N2O emissions with substitution of the appropriate emission factors.
To calculate a single total emissions value for stationary combustion, total CO2, CH4 and N2O emissions
were first converted into units of metric tons of carbon dioxide equivalent using global warming
potentials, then summed.
Total CO2 Emissions (mtCO2e) =Total CO2 Emissions (mtCO2) × GWPCO2
Total CH4 Emissions (mtCO2e) =Total CH4 Emissions (mtCH4) × GWPCH4
Total N2O Emissions (mtCO2e) =Total N2O Emissions (mtN2O) × GWPN2O
Total CO2e Emissions (mtCO2e) =Total CO2 Emissions + Total CH4 Emissions + Total N2O Emissions
2.2.1.1 FuelOilandKeroseneConsumptionforNon‐residentialBuildingsMethodology6The estimation methodology is based on the trend in commercial sector fuel oil consumption relative to
natural gas consumption for the District of Columbia per EIA’s State Energy Data System (SEDS) for
2000‐20107,8. The correlation exists between fuel oil and natural gas consumption because these fuels
are commonly used for the same purposes in non‐residential buildings (e.g. heating) and natural gas has
been consistently replacing fuel oil in recent years. The data used to establish the fuel ratio trend is
displayed in the table and graph below.
Table 2.3: SEDS Fuel Oil and Natural Gas Consumption Data and Ratio 2000‐2010
Year Fuel Oil
(trillion Btu) Natural Gas (trillion Btu)
FO/NG Ratio
2000 3.3 18.2 0.18
2001 3.2 17 0.19
2002 1.7 18.8 0.09
2003 2.2 17.6 0.13
2004 2.7 17.9 0.15
2005 2.4 18.6 0.13
2006 2.0 17.5 0.11
2007 1.8 19.8 0.09
2008 1.2 18.9 0.06
2009 1.8 19.4 0.09
2010 1.1 18.8 0.06
6 The methodology used to estimate fuel oil and kerosene consumption for non‐residential buildings has been updated compared to the methodology used in the 2000/2007 inventory report, to improve accuracy by using more recent data. See the 2000/2007 inventory report for details on the original methodology and data sources for non‐residential buildings. 7 Kerosene consumption was ignored since marginal relative to fuel oil consumption and, thus, not available in the SEDS dataset. 8http://www.eia.gov/state/seds/data.cfm?incfile=/state/seds/sep_use/com/use_com_DC.html&sid=District%20of%20Columbia
9
The fuel oil to natural gas ratios calculated for 2000 and 2007 for the District of Columbia were applied
directly to Arlington County (updating the published Community Inventory). The linear trend of ratios
observed 2000 to 2010 was extrapolated to estimate the ratio for 2012. Once ratios were calculated,
they were multiplied by the known commercial sector natural gas consumption for Arlington County in
each inventory year. Subsequently, fuel oil consumption from Government Operation was removed.
Table 2.4: Fuel Oil Estimation Data by Inventory Year
Year Arlington Community Non‐residential NG
Consumption (MMBtu)
FO/NG Ratio
Total Estimated FO Consumption for
Arlington (gal)
FO Consumption from Government
Operations (gal)
FO Consumption from Non‐
residential Buildings(gal)
2000 2,870,702 0.181 3,771,825 47,871 3,723,954
2007 2,184,288 0.091 1,438,925 13,413 1,425,512
2012 1,542,514 0.042 465,149 42,606 422,543
2.2.1.2 FuelOil,KeroseneandLPGConsumptionforResidentialBuildingsMethodologyEstimates for residential fuel oil, kerosene and LPG consumption in the Community were made using
consumption data from the EIA’s Residential Energy Consumption Survey (RECS)9. Trend analysis was
performed for each fuel using filtered RECS Microdata data from 1993, 1997, 2001, 2005 and 2009 to
develop fuel consumption intensity factors for each inventory year on a per household (HH) basis.
Survey results with a heating degree day (HDD) value outside of 3,500 to 4,500 or a cooling degree day
(CDD) value outside of 1,000 to 2,000 were filtered out leaving only survey results with similar climates
and corresponding heating and cooling demands to Arlington (Arlington’s 30‐year climate normal are
4030 HDDs and 1,550 CDDs10). The consumption intensity factors were derived by dividing the total fuel
oil and kerosene or LPG consumption in each RECS data year by the number of households using each
fuel. The linear trend of resulting intensity factors was then used to interpolate and extrapolate intensity
factors for CY 2000, CY 2007 and CY 2012.11
9 http://www.eia.gov/consumption/residential/ 10 http://www1.ncdc.noaa.gov/pub/data/normals/1981‐2010/products/temperature/ 11 Note that the LPG intensity factor calculated for 2001 was thrown out as an outlier when performing trend analysis.
10
Table 2.5: Filtered RECS Fuel Consumption Intensity Factors (MMBtu/HH/yr)
Year FO KER FO+KER LPG
1993 87.1 12.3 99.4 59.8
1997 69.1 11.0 80.1 46.8
2001 71.6 15.8 87.4 Outlier*
2005 75.2 9.9 85.1 43.4
2009 60.8 7.2 68.0 39.6 * The calculated LPG intensity from filtered 2001 RECS
data was 28.1 MMBtu/HH/yr and was thrown out as
an outlier
The factors for each inventory year were multiplied by the number of households using each fuel per
Arlington housing profile data12 to determine residential consumption within the County. Because
housing statistics for fuel oil and kerosene use are lumped together in Census data and the housing
profile data, these fuels were combined throughout the calculations. This is an acceptable approach
because kerosene is often used in conjunction with fuel oil, makes up a much smaller portion of total
consumption, and the emission factors for both fuels are virtually identical for CO2 , CH4 and N2O.
Residential fuel oil and kerosene consumption estimates are shown in the table below.
Table 2.6: Estimated Residential Fuel Oil and Kerosene Consumption by Inventory Year
Year Fuel Oil/Kerosene Consumption Intensity Factor (MMBtu/HH/yr))
Number of Households Using Fuel Oil/Kerosene as Primary Heating Fuel (HH count)
Fuel Oil/Kerosene Consumption (MMBtu)
2000 85.4 4,446 379,865
2007 75.3 2,368 178,344
2012 68.1 1,232 83,877
Residential LPG consumption estimates are shown in the table below.
Table 2.7: Estimated Residential LPG Consumption by Inventory Year
Year LPG Consumption Intensity Factor
(MMBtu/HH/yr)) Number of Households Using LPG as Primary Heating Fuel (HH count)
LPG Consumption (MMBtu)
2000 48.5 903 43,774
2007 40.8 1,072 43,741
2012 35.3 841 29,707
In order to estimate the breakdown of single‐family household consumption versus multi‐family
household consumption in Arlington County for fuel oil/kerosene consumption (all LPG consumption is
assumed to occur at single‐family households), U.S. national averages were found for:
12 http://www.arlingtonva.us/departments/cphd/planning/data_maps/cphdplanningdataandmapsprofile.aspx
11
1. The percentage of total households using each fuel by housing type and 2. The consumption intensity of households using each fuel by housing type.
These national averages were combined with Arlington housing data to develop an estimated ratio of
consumption between single‐family and multi‐family households in Arlington County for each inventory
year. These ratios were then applied to the total fuel oil/kerosene consumption calculated previously.
The resulting breakdown of residential fuel oil/kerosene consumption estimates are displayed in the
table below. These data are provided in section 2.2.3.
Table 2.8: Estimated Fuel Oil and Kerosene Consumption for Single‐family and Multi‐family Households by Inventory Year
Year
Total Residential Fuel Oil + Kerosene
Consumption (MMBtu)
Household Type (type)
Estimated Share of
Consumption (%)
Estimated Consumption by Household
Type (MMBtu)
2000 379,865 Single‐family 57% 215,166
Multi‐family 43% 164,699
2007 178,344 Single‐family 52% 91,945
Multi‐family 48% 86,399
2012 83,877 Single‐family 49% 41,351
Multi‐family 51% 42,525
2.2.2 ElectricityMethodologyEmissions from purchased electricity within the building sector were calculated based on consumption
of each Community source, in accordance with the LGOP and ICP. The same general processes and
equations used to calculate emissions from stationary combustion were also used to calculate emissions
from purchased electricity. Note that the conversions from native gas units to units of carbon dioxide
equivalent using the global warming potential (GWP) for each GHG have been incorporated into the
equations below.
Electricity CO2 Emissions (mtCO2e) = Electricity Use (MWh) x Emission Factor (kgCO2/MWh) ÷ 1,000 × GWPCO2
Electricity CH4 Emissions (mtCO2e) = Electricity Use (MWh) x Emission Factor (kgCO2/MWh) ÷ 1,000 × GWPCH4
Electricity N2O Emissions (mtCO2e) = Electricity Use (MWh) x Emission Factor (kgCO2/MWh) ÷ 1,000 × GWPN2O
Total CO2e Emissions (mtCO2e) = Electricity CO2 Emissions + Electricity CH4 Emissions + Electricity N2O Emissions
2.2.3 BuildingsSectorDataSummaryArlington housing data was required by this analysis to estimate residential fuel oil/kerosene and LPG
consumption as well as to breakdown electricity and fuel oil/kerosene consumption between single‐
family and multi‐family households. These housing count and heating fuel data are presented in the
tables below. Data for federal sites and Reagan National Airport was compiled by Arlington County staff
through contact with each of the sites. Consumption for Arlington County Government and Schools was
removed from the commercial totals provided by the utilities.
12
Table 2.9: Arlington Household Count by Housing Type by Inventory Year
HH Type 2000a 2007b 2012c
Single‐family, detached 27,668 31% 27,947 27% 28,400 26.3%
Single‐family, attached 10,284 11% 10,719 10% 11,000 10.1%
Multi‐family 52,373 58% 63,385 62% 68,600 63.5%
Other 101 0.1% 101 0.1% 100 0.1%
Total 90,426 100.0% 102,152 100.0% 108,000 100.0% a 2000 Census
b 2008 Arlington Profile (1/1/2008 data) http://www.arlingtonva.us/departments/CPHD/planning/data_maps/profile/Profile%202008%20‐%20Full%20Profile.pdf c 2013 Arlington Profile (1/1/2013 data) http://www.arlingtonva.us/departments/CPHD/planning/data_maps/profile/file89033.pdf
Table 2.10: Arlington Primary Heating Fuel Breakdown by Inventory Year
Primary Heating Fuel 2000 2007 2012a
Electricity 35% 40% 44%
NG 57% 55% 52%
Fuel Oil/Kerosene 5% 3% 1%
LPG 1% 1% 1%
Other fuel 1% 0.1% 1%
None 0.4% 1% 0.1%a 2011 data used as proxy Sources: U.S. Census and American Housing Survey
Electricity and natural gas consumption data were compiled by Metropolitan Washington Council of
Governments (MWCOG) based on utility billing records for Arlington County and for each inventory
year. The MWCOG data was broken down by utility customer class for both fuels. To supplement this
data, County staff compiled electricity and natural gas data for federal facilities located in Arlington
including Reagan National Airport. Fuel oil/kerosene and LPG consumption data estimated using SEDS
data for non‐residential buildings and RECS data for residential buildings as described in sections 2.2.1.1
and 2.2.1.2 above. The tables below summarized buildings sector fuel consumption by source for each
inventory year.
Table 2.11: CY 2000 Buildings Sector Fuel Consumption
Source Electricity (MWh)
Natural Gas (MMBtu)
Fuel Oil & Kerosene
(gal)
LPG (gal)
Non‐residential 1,618,516 2,870,702 3,723,954 0
Residential 537,410 3,819,274 2,752,642 475,804
Single‐family 304,862 2,945,093 1,559,173 475,804
Multi‐family 232,548 874,181 1,193,468 0
Buildings Sector Total 2,155,926 6,689,976 6,476,596 475,804
13
Table 2.12: CY 2007 Buildings Sector Fuel Consumption
Source Electricity (MWh)
Natural Gas (MMBtu)
Fuel Oil & Kerosene
(gal)
LPG (gal)
Non‐residential 1,889,421 2,184,288 1,425,512 0
Residential 731,359 3,729,178 1,292,348 475,449
Single‐family 377,515 2,984,422 666,269 475,449
Multi‐family 353,845 744,756 626,079 0
Buildings Sector Total 2,620,781 5,193,466 2,717,860 475,449
Table 2.13: CY 2012 Buildings Sector Fuel Consumption
Source Electricity (MWh)
Natural Gas (MMBtu)
Fuel Oil & Kerosene
(gal)
LPG (gal)
Non‐residential 1,741,422 1,542,514 422,543 0
Residential 742,080 3,171,707 607,802 322,898
Single‐family 382,092 2,543,949 299,648 322,898
Multi‐family 359,987 627,758 308,154 0
Buildings Sector Total 2,483,502 4,714,221 1,030,345 322,898
2.2.4 BuildingsSectorEmissionFactorsThe methodologies used to calculate emissions required electricity emission factors, combustion
emission factors for natural gas, fuel oil, kerosene and LPG, and GWPs for all generated GHGs.
For electricity, regional e‐GRID factors for the SRVC – SERC Virginia/Carolina were used for data years
2000, 2007 and 2009. Factors were not available for CY 2012, so factors based on 2009 data were used
as proxy.
Table 2.14: e‐GRID Emission Factors by Inventory Year
e‐GRID Data Year Inventory Year CO2
(kg/MWh) CH4
(kg/MWh) N2O
(kg/MWh) Data Sources
2000* 2000 528.07 0.0120 0.0104 eGRID2002
2007 2007 507.30 0.0101 0.0087 eGRID2010
2009 2012 469.86 0.0098 0.0079 eGRID2012* CH4 and N2O data not available in eGRID2002; values were extrapolated from GRID2006‐eGRID2012 data
14
Emission Factors used for combustion of natural gas, fuel oil, kerosene and LPG were pulled directly
from Tables G.1 and G.3 of the LGOP.
Table 2.15: CO2 Emission Factors for Natural Gas, Fuel Oil, Kerosene and LPG
Fuel Type Heat Content
Carbon Content (Per Unit Energy)
Fraction Oxidized
CO2 Emission Factor
(Per Unit Energy)
CO2 Emission Factor
(Per Unit Mass or Volume)
Btu/scf kgC/MMBtu kgCO2/MMBtu kgCO2/scf
Pipeline Natural Gas (US weighted average)
1,028 14.47 1 53.02 0.0545
MMBtu/gallon kgC/MMBtu kgCO2/MMBtu kgCO2/gallon
Distillate Fuel Oil No. 2 0.138 20.17 1 73.96 10.21
*Kerosene 0.135 20.51 1 75.20 10.15
LPG 0.092 17.18 1 62.98 5.79Source: LGOP v1.1, Table G.1
*Kerosene and Fuel Oil consumption data are lumped together, the majority of which is fuel oil, thus the kerosene factor is not used in the
emission calculations but is provided here as reference.
Table 2.16: CH4 and N2O Emission Factors for Natural Gas, Fuel Oil, Kerosene and LPG
Fuel Type / End‐Use Sector
Natural Gas Fuel Oil and Kerosene LPG
CH4 (kg/MMBtu)
N2O (kg/MMBtu)
CH4 (kg/gal)
N2O (kg/gal)
CH4
(kg/gal) N2O
(kg/gal)
Residential / Commercial
0.005 0.0001 0.0015 0.0001 .0010 .0001
Source: LGOP v1.1, Table G.3 and Table G.4
15
3 CommunityTransportationSectorGHG emissions from mobile combustion within the Arlington County Community are generated by a
variety of transportation sources and fuels within various sectors. This section will focus on the sources
not under operational control of the County government and include:
1. Pass‐Through Traffic (In‐County Vehicle Miles Traveled (VMT) from Vehicle Trips Originating and Ending Outside the County, with no In‐County stops)
2. County Origin/Destination Traffic (In‐County VMT from Vehicle Trips Originating or Ending in Arlington County)
3. Commercial sources such as taxicab companies, university shuttle services and the Metrorail and bus systems.
A wide range of fuels were consumed by these sources, including unleaded gasoline, diesel, biodiesel,
compressed natural gas (CNG) and electricity. Emissions from mobile combustion can be calculated
using fuel consumption, distanced traveled (referred to as vehicle miles traveled, or VMT) and specific
vehicle information (model type, model year, fuel economy). CO2 emissions account for the majority of
mobile emissions and are dependent on the amount of fuel consumed. CH4 and N2O emissions are
dependent on the distance traveled and the emission control technologies within each vehicle. In the
absence of fuel consumption data, specific vehicle information and VMT can be used to estimate the
quantity of fuel consumed. To calculate mobile combustion emissions, MWCOG model data was utilized
along with the protocols and factors provided by the ICP methodologies. Additional details on the
methodologies and assumptions used to calculate fuel consumption and GHG emissions for each mobile
combustion source are described below.
3.1 CommunityTransportationSectorResultsCommunity transportation related emissions in 2012 totaled 836,434 metric tons CO2e. Emissions
decreased by about 1 percent compared to the 2007 estimate for Arlington County of 841,599. This
slight decrease was due to a reduction in pass‐through traffic emissions, as emissions from County
origin/destination traffic increased by about 4 percent between 2007 and 2012. There was an overall
decrease of 8 percent in emissions from community transit sources, including Taxis, University Shuttles,
Metrorail and Metrobus services. However, there was a significant increase in emissions from taxis, due
to increased number of cabs and overall VMT. There was a reduction in electricity consumption from
Metrorail servicing Arlington County stations of 13 percent, but the largest source of emission
reductions was from Metrobus, a 32 percent decrease. However, the decrease from Metrobus is likely
due in large part to a change in estimation methodology rather than reductions in service or efficiency
improvements.13There was a 22 percent increase in emissions from university shuttles. Emissions for all
three inventory years, 2000, 2007 and 2012 are provided by specific source categories in Table 3.1.
13 Metro did increase the overall fuel efficiency of its bus fleet since 2007 by introducing diesel hybrid buses; however this alone does not account for the significant reductions. Section 3.3.2.1 provides additional detail.
16
Table 3.1: Comparison of Mobile Emissions from Community Transportation Sources by Inventory Year
Source 2000
Emissions (mtCO2e)
2007Emissions (mtCO2e)
2012 Emissions (mtCO2e)
% Change 2007‐2012
Community Mobile Emissions (Total) 884,571 841,599 836,434 ‐1%
Pass‐Through Traffic 539,273* 366,940 353,252 ‐4%
Passenger Cars/Motorcycles 239,383* 159,296 150,764 ‐5%
Light Duty Trucks/SUVs 199,355* 142,811 141,000 ‐1%
Heavy‐Duty Trucks 100,536* 64,833 61,488 ‐5%
Community Mobile Emissions (Excluding Pass‐Through Traffic)
345,298* 474,658 483,182 2%
County Origin/Destination Traffic 274,797* 401,209 415,404 4%
Passenger Cars/Motorcycles 187,815* 261,887 257,988 ‐1%
Light Duty Trucks/SUVs 83,150* 132,837 150,414 13%
Heavy‐Duty Trucks 3,833* 6,485 7,002 8%
Community Transit 70,501 73,449 67,778 ‐8%
Taxis 14,764 15,871 21,142 33%
University Shuttles 215 215 263 22%
Metrorail 32,862 37,864 33,101 ‐13%
Metrobus 22,660 19,500 13,273 ‐32%*Breakdown of 2000 data was by residential and commercial traffic, which is not directly comparable to the County origin/destination and pass‐
through traffic breakdown used in 2007 and 2012. The totals are directly comparable.
3.2 Pass‐ThroughandCountyOrigin/DestinationTrafficIn the Arlington County Inventory report published in 2010, community transportation was broken out
into residential and non‐residential emissions. In order to be compliant with the new ICP, this was
adjusted when calculating 2012 emissions and recalculating 2007 emissions. The protocol’s preferred
methodology called for the exclusion of all pass‐through traffic (trips that neither originated or ended in
the County and had no intermediate stops in the County) from being included. The alternative method
provided by the ICP is to use the same methodology Arlington County employed for their 2000 and 2007
inventory report, which includes the pass‐through traffic. In order to be internally consistent and
protocol compliant, emissions were calculated using both methods, from just County origin/destination
related VMT and total VMT including pass‐through traffic. This new disaggregation of VMT data (pass‐
through and origin/destination) is not directly comparable to the original breakdown of residential and
non‐residential. Moving forward the County will continue using the pass‐through and origin/destination
breakdown to be protocol compliant. This new disaggregated data was not available for 2000, so the
original data will be maintained. Because emissions were disaggregated in different ways, it is only
appropriate to compare total annual emissions, VMT, and fuel use across all three years; the lower
levels of aggregation are not comparable.
3.2.1 Pass‐ThroughandCountyOrigin/DestinationTrafficMethodology
Emissions of CO2 from vehicles in Arlington County for both pass‐through traffic and County
origin/destination traffic were calculated based on estimates of fuel consumption. To calculate CO2
emissions, gallons of fuel consumed were multiplied by the emission factor for that fuel type, with the
resulting kilograms of CO2 emissions divided by 1,000 to get metric tons CO2 emissions, as shown below:
17
CO2 Emissions (mt CO2) = [Gallons Fuel Consumed * Emission Factor (kg CO2/gallon)]/1,000
Fuel consumption data are not directly available, but were estimated using the following steps.
1. Fuel estimates were based on County VMT data provided by MWCOG and their Transportation
Demand Model, which provided estimates of Total VMT, both including and excluding pass‐
through traffic (Tables 3.3a and 3.3b below).
2. VMT data were allocated across vehicle types according to the percentages provided in Table 3.4.
3. VMT data, by vehicle type, were multiplied by the fuel efficiencies for each vehicle type (Table 3.5
below) weighted by model year counts from County registrations to estimate fuel consumption.
Emissions of CH4 and N2O were calculated using miles traveled by vehicle type, and applying a model
year weighted emission factor. To calculate CH4 and N2O emissions, miles traveled for each vehicle were
multiplied by the emission factor assigned to each vehicle type, resulting in grams of emissions. To
obtain total metric tons of native gas, the grams of emissions for each vehicle and gas were summed
and divided by 1,000,000. To obtain metric tons of CO2e, the metric tons of native gas totals were
multiplied by a GWP of 21 for CH4 and a GWP of 310 for N2O.
CH4 Emissions (mtCO2e) = ∑(all vehicles) [(miles traveledvehicle * CH4 EFvehicle)/1,000,000]*21
N2O Emissions (mtCO2e) = ∑(all vehicles) [(miles traveledvehicle * N2O EFvehicle)/1,000,000]*310
3.2.1.1 Pass‐ThroughandCountyOrigin/DestinationTrafficDataTable 3.3a: 2012 and 2007 VMT Provided by MWCOG for Origin/Destination and Pass‐Through Traffic
2012 Origin / Destination
2012 Pass‐Through
2007 Origin / Destination
2007 Pass‐Through Data Source
Average Weekday VMT 2,875,557 1,960,178 2,745,066 2,032,859
MWCOG Transportation Demand Model
Weekday VMT Adj. Factor 0.95 0.95 0.95 0.95 2006 MWCOG Memo
Average Daily VMT
2,731,779 1,862,169 2,607,813 1,931,216 Calculated
Days 365 365 365 365 n/a
Annual VMT 997,099,390 679,691,722 951,851,636 704,893,858 Calculated
Table 3.3b: 2000 VMT Provided by MWCOG, Disaggregated by Residential and Non‐residential
VMT Data Element 2000
(non‐residents) 2000
(residents) Data Source
Average Weekday VMT 2,937,137 1,911,095 MWCOG Transportation Demand Model
Weekday VMT Adj. Factor 0.95 0.95 2006 MWCOG Memo
Average Daily VMT 2,790,280 1,815,540 Calculated
Number of Days 365 365 n/a
Annual VMT 1,018,452,118 662,672,215 Calculated *County 0rigin/destination and pass‐through distinction was not available for 2000 data. The data from the original 2000 inventory was maintained for this calculation, broken down by the County into residential and non‐residential using MWCOG’s household transportation survey results. See the original published inventory report for details on this data. This breakdown is not directly comparable to the breakdown used for 2007 and 2012.
18
Table 3.4: Arlington County and Regional VMT by Vehicle Type and Inventory Year
VMT by Vehicle Type
2000 2007 2012
County (residents trips)
Region (non‐residents trips)
County (Origin/ Destination trips)
Region (Pass‐Through trips)
County (Origin / Destination trips)
Region (Pass‐Through trips)
Passenger Cars 76% 59% 73% 57% 70% 56%
Light Trucks 23% 36% 26% 38% 28% 38%
Motorcycles 0.21% 0.21% 0.21% 0.21% 1.3% 0.21%
Heavy Duty Trucks 0.30% 5.1% 0.40% 5.4% 0.40% 5.1% Source: 2000 non‐resident trips from COG. 2007 and 2012 pass‐through trips use COG vehicle regional data for 2008 and 2011. County
breakdown based on County registration data and trends in Washington DC fleet provided by COG. Table 3.5: Arlington County Weighted Fuel Efficiency by Vehicle Type and Inventory Year (miles per gallon)
Vehicle Type 2000 2007 2012
Passenger Car 23.00 23.02 23.17
Light Duty Truck/SUV 16.97 17.01 17.05
Heavy Duty Truck 5.30 6.00 5.80
Bus 6.80 7.20 7.10
Motorcycle 50.00 45.10 43.50 Source: Personal Cars and Light Duty Trucks use Arlington registration data and Adj Comp MPG from Table 1 in EPA Light Duty Auto Technology book. Heavy Duty Trucks and Buses use rita.dot.gov Table 4‐14. Motorcycles use rita.dot.gov estimates Table 4‐11.
Table 3.6: Calculated Fuel Consumption for Community Transportation Sources by Inventory Year
Source
2000 2007 2012
Gasoline
(gallons)
Diesel
(gallons)
Gasoline
(gallons)
Diesel
(gallons) Gasoline (gallons)
Diesel (gallons)
*County Origin/ Destination Traffic
29,387,329 419,176 43,152,030 649,057 44,225,018 1,084,668
*Passenger Cars/Motorcycles
20,404,034 44,078 28,677,228 0 27,920,927 317,610
Light Duty Trucks/SUVs
8,983,295 0 14,474,802 14,489 16,304,091 81,930
Heavy‐Duty Trucks 0 375,097 0 634,568 0 685,129
Pass‐Through Traffic
47,562,595 9,890,698 33,011,330 6,359,622 31,605,476 6,266,554
Passenger Cars/Motorcycles
26,024,756 52,066 17,449,696 0 16,321,892 172,844
Light Duty Trucks/SUVs
21,537,839 0 15,561,634 15,577 15,283,584 76,802
Heavy‐Duty Trucks 0 9,838,632 0 6,344,045 0 6,016,908 *Notethattaxicabfuelconsumptionisremovedfromthesetotalsandprovidedseparately
3.2.1.2 Pass‐ThroughandCountyOrigin/DestinationTrafficEmissionFactorsEmission factors used for the calculation of CO2 emissions are from the LGOP, version 1.1, and are
detailed in Table , below.
19
Table 3.7: CO2 Emission Factors for Mobile Combustion
Fuel Factor
(kg CO2/gallon) Source
Motor Gasoline 8.78 LGOP, version 1.1 (May 2010) Table G.11 Default CO2 Emission Factors for Transport Fuels Diesel Fuel No. 1 and 2 10.21
Emission factors for CH4 and N2O are provided in the ICP by model year. As pollution control technology
has improved, newer model year vehicles emit less. Arlington County vehicle registrations for
2002/2003 and 2012 were used to develop vehicle counts by model year for each vehicle type for the
years 2000, 2007 and 2012. These vehicle counts were then used to weight and average the ICLEI
provided factors to ensure the factors used were representative of the fleet age in Arlington County.
Table 3.8: Weighted CH4 and N2O Emission Factors for Arlington County by Inventory Year (grams per mile)
Vehicle Type Fuel Type 2000 2007 2012
CH4 N2O CH4 N2O CH4 N2O
Passenger Car Gasoline 0.048 0.053 0.042 0.046 0.042 0.046
Light Duty Truck/SUV Gasoline 0.058 0.087 0.048 0.070 0.048 0.071
Heavy Duty Truck Gasoline 0.033 0.013 0.033 0.013 0.033 0.013
Bus Gasoline 0.033 0.013 0.033 0.013 0.033 0.013
Motorcycle Gasoline 0.010 0.010 0.010 0.010 0.010 0.010
Passenger Car Diesel 0.001 0.001 0.001 0.001 0.001 0.001
Light Duty Truck/SUV Diesel 0.001 0.001 0.001 0.001 0.001 0.001
Heavy Duty Truck Diesel 0.0051 0.0048 0.0051 0.0048 0.0051 0.0048
Bus Diesel 0.0051 0.0048 0.0051 0.0048 0.0051 0.0048
Source: ICP TR.1.4 – weighted by counts of vehicle types by model year from Arlington County registration data.
3.2.1.3 Pass‐ThroughandCountyOrigin/DestinationTrafficAssumptionsData on VMT allocation by vehicle type was initially provided by COG for 2007 and 2012, however the
data was inconsistent and derived from two different models that used conflicting vehicle type
definitions. Instead of using the modeled data, the allocation of VMT was based on the same
assumption used in Arlington County’s original 2000 and 2007 report, that the percent VMT by each
vehicle type roughly matches the overall fleet breakdown by vehicle type. If 70 percent of Arlington
County’s registered vehicles were passenger cars, then it was assumed 70 percent of the VMT in
Arlington County would have been driven by passenger cars. For Pass‐through traffic only, a regional
fleet breakdown performed by COG was used instead of the Arlington County specific registration data,
as it was assumed the pass‐through traffic vehicle mix would mirror that of the entire region instead of
just Arlington County.
MWCOG aggregated vehicle registrations for the vehicle fleet in the Metropolitan DC region,
including parts of Maryland, Virginia and Washington DC for 2005, 2008 and 201114. This was
used to allocate VMT by vehicle type for pass‐through traffic.
14 MWCOG, The Composition of the Vehicle Fleet in the Metropolitan Washington Region. (2009), and http://www.mwcog.org/uploads/committee‐documents/Zl1fWFlW20111110130359.pdf
20
It was assumed that Arlington County and D.C. see similar vehicle trends, as specific Arlington
County registration data available for 2002/2003 was very similar to the breakdown of vehicle
types within Washington, D.C in 2005. Additionally, COG includes Arlington County, Washington
D.C. and Alexandria together in a “Central Jurisdiction” region for some studies.15 The percent
change in the number of vehicles in each vehicle class between 2005 and 2008, and 2008 and
2011 for Washington DC was applied to each vehicle class percentage from the 2002/2003
Arlington County Registration to estimate vehicle type mix in 2007 and 2012.
The VMT data provided by MWCOG was for 2007 and 2013. The 2013 data was used as a proxy for 2012,
as MWCOG indicated they would be very similar.
3.3 WMATA–MetrobusandMetrorailThe Washington Metropolitan Area Transit Authority (WMATA) operates public transit throughout
Arlington County to service area residents. Energy consumption data used to estimate emissions are
apportioned to Arlington County for both rail service and bus service as described below.
3.3.1 MetrobusandMetrorailResultsTable 3.9: Metrobus and Metrorail Emissions Summary Data by Inventory Year
Source 2000
Emissions (mtCO2e)
2007Emissions (mtCO2e)
2012 Emissions (mtCO2e)
% Change 2007‐2012
Metrorail 32,862 37,864 33,101 ‐13%
Metrobus 22,660 19,500 13,273 ‐32%
3.3.2 MetrobusandMetrorailMethodology
3.3.2.1 MetrobusMethodologyMetrobuses for Arlington County‐specific routes in 2012 were based out of three different garages: Four
Mile Run Division, Royal Division and West Ox Division. WMATA provided the following bus data:16
2012 Bus Assignments – Number of buses by bus route for each garage.
2012 Bus Route Distance – Daily VMT per route, both for in service revenue miles and out of service non‐revenue miles.
Bus Fuel Type – Bus fuel type by garage. Four Mile Run contains all CNG buses, Royal houses diesel buses, and West Ox holds diesel‐hybrid buses.
In ArcGIS software, WMATA geospatial route data from the General Transit Feed Specification (GTFS)
data exchange17 were clipped to Arlington County and analyzed to calculate the proportion of each
route within the County. In conjunction with these geospatial route results, bus assignments and route
distance data were used to calculate the VMT per year within the County for each route. There were a
few cases where the same bus route ran from multiple garages, raising the issue of how to properly
15 Griffiths (2009). 16 All 2012 WMATA data gathered and compiled by J. Altavilla (2013). 17 Found through the WMATA Developer Tools at: http://www.wmata.com/rider_tools/developer_resources.cfm
21
apportion fuel consumption per route based on the fuel type at each garage. In these cases, the 2012
Bus Assignments data were assessed to find the percentage of buses at each garage for each of these
routes. This “Garage Factor” (GF) was applied to the following equation to estimate annual VMT per bus
route:
Annual VMT per bus route (miles) = {GF (%) x Number of Days per Week18 x Number of Weeks per Year19 x [Revenue
Distance (miles)* Proportion of Route in Arlington (%) + Non‐revenue Distance (miles)]}20
The following equation was used to calculate fuel consumption:
Total Fuel Consumption (gallons) = VMT (miles) ÷ Fuel Economy (miles/gallon)
The following equations outline how emissions were calculated from fuel consumption:
CO2 Emissions (mtCO2e) = Total Fuel Consumption (gal) x CO2 Emission Factor (kg CO2/gal) ÷ 1,000 kg CO2/mtCO2
CH4 Emissions (mtCO2e) = Total VMT (miles) x CH4 Emission Factor (g CH4/mile) ÷ 1,000,000 g CH4/mtCH4 * 21 (CH4
GWP)
N2O Emissions (mtCO2e) = Total Fuel Consumption (gal) x N2O Emission Factor (g N2O/mile) ÷ 1,000,000 g
N2O/mtN2O * 310 (N2O GWP)
A change in the available data for 2012 led to the use of different calculation methods than those from
the previous inventory. Measured fuel consumption data by Metrobus garages were used for the 2000
and 2007 calculations while VMT was utilized in 2012. The 2012 WMATA bus data coupled with the
geospatial route analysis provides accurate VMT, but still relies on assumed MPG values that could
cause an underestimation of fuel consumption. Alternatively, the methods used for 2000 and 2007 may
have overestimated total fuel consumption for the buses within Arlington County because of the
assumption that routes serving the County were 100 percent within the County boundaries. As our
Geographic Information System (GIS) analysis shows, the majority of routes servicing the County are not
100 percent in the County, indicating an overestimation in the previous inventory the amount fuel
consumption that was allocated to the County. It is expected that a large portion of the decrease in
annual emissions from 2000 and 2007 to 2012 is attributable to the improved methodology rather than
actual reductions in emissions. However, the spatial data for routes is not available for previous years so
the same methodology cannot be retroactively applied to 2000 or 2007.
18 Number of days per week depends on the days of the week the bus ran. For example, some bus routes only ran on the weekend or had special schedules during holidays. This was outlined in the WMATA data. 19 Number of weeks per year depends on the days of the week the bus ran. For example, some bus routes ran each week while others only ran a few times per year on holiday weekends. 20 Note that non‐revenue distance is only added for the Four Mile Run Division as that garage is based in Arlington County. The assumption is that all non‐revenue miles (i.e., the bus is out of service) occur in Arlington as the bus travels to its route before service and back to the garage at the end of service. Since the Royal and West Ox garages are not located in Arlington County, it was assumed that non‐revenue miles fell outside of the county.
22
3.3.2.2 MetrorailMethodologyElectricity consumption associated with accounts and substations for Metrorail stations and rail lines
within Arlington County was provided by WMATA for 2012. With the exception of two accounts, all were
associated with stations and train lines entirely within Arlington County. The two other accounts
included electricity consumption from the yellow and blue lines from Pentagon City station to the
Huntington Station in Fairfax, VA. To estimate the electricity consumed within Arlington County, the
length of track located in Arlington County was separated from the total track length between the
Pentagon City station in Arlington County and the Huntington Station in Fairfax County, and this
proportion was applied to the total electricity consumed along these lines. Activity data (kWh
consumed) were used to calculate GHG emissions. The following equations provided in the LGOP were
used to calculate the GHG emissions generated from electricity consumption:
Electricity CO2 Emissions (mtCO2e) = Electricity Use (MWh) x Emission Factor (kgCO2/MWh) ÷ 1,000 × GWPCO2
Electricity CH4 Emissions (mtCO2e) = Electricity Use (MWh) x Emission Factor (kgCO2/MWh) ÷ 1,000 × GWPCH4
Electricity N2O Emissions (mtCO2e) = Electricity Use (MWh) x Emission Factor (kgCO2/MWh) ÷ 1,000 × GWPN2O
Total CO2e Emissions (mtCO2e) = Electricity CO2 Emissions + Electricity CH4 Emissions + Electricity N2O Emissions
3.3.2.3 DataforMetrobusandMetrorail
Table 3.10: Metrobus and Metrorail Fleet Activity Data, VMT and Electricity Consumption by Inventory Year
Category 2000 2007 2012 % Change 2007‐
2012
Metrobus
Emissions (mtCO2e) 22,660 19,500 13,273 ‐32%
CNG Consumption (gge) 0 1,715,719 1,300,450 ‐24%
Diesel Consumption (gallons) 2,231,566 636,980 231,652 ‐64%
Total Fuel Consumption (gge) 2,463,649 2,418,944 1,556,194 ‐36%
Metrorail
Emissions (mtCO2e) 32,862 37,864 33,101 ‐13%
Electricity Consumption (kWh) 61,822,481 74,214,230 70,051,519 ‐6%
3.3.2.4 MetrobusandMetrorailEmissionFactorsEmission factors used for the calculation of CO2, CH4 and N2O emissions are from the ICP, and are
detailed in Table .11. Electricity factors are the same as those used for the buildings sector.
Table 3.11: Emission Factor Ranges for Metrobus (Mobile Combustion)
Bus Fuel Type C02 EF (kg/gal)a CH4 EF (g/mile)b N2O EF (g/mile)b
CNG 6.55 0.175 1.966
Diesel/Diesel Hybrid 10.21 0.0051 0.0048aCNG CO2 factor from LGOP Table G.11 converted to kg/gal using Arlington billing information, Diesel/Diesel Hybrid factor from LGOP Table G.11
bCNG CH4 and N2O factors from LGOP Table G.13. Diesel/Hybrid Diesel CH4 and N2O factors from LGOP Table G.12
23
Table 3.12: Purchased Electricity Emission Factors for SRVC eGRID Subregion
eGRID Data Year Inventory Year CO2
(kg/MWh) CH4
(kg/MWh) N2O
(kg/MWh) Sources
2000 2000 528.07 0.0120 0.0104 eGRID 2002
2007 2007 507.30 0.0101 0.0087 eGRID 2010
2009 2012 469.86 0.0098 0.0079 eGRID 2012 Note: CH4 and N2O data not available in eGRID2002; values were extrapolated from eGRID2006‐eGRID2012 data
3.3.2.5 MetrobusandMetrorailFor Metrobuses, average fuel economy in buses was found to be approximately 3 MPG for CNG, 3.5
MPG for diesel and 4.5 MPG for diesel hybrids21,22.
The gasoline gallon equivalent for CNG buses was derived using the Washington Gas reported heating
value of natural gas provided to Arlington County based on the first and last billing periods of 2012.
For Metrorail, the 2400 Huntington Ave and S. Fern & S. 18th Street accounts both serve all facilities
along Blue/Yellow line from Pentagon City Station to Huntington Station, 5.68 total miles, 1.97 in
Arlington County (34.68%).
3.4 TaxisTaxicab companies are regulated in Arlington County, so data on vehicle activity is available. In 2012
Arlington County had seven taxicab companies in operation, accounting for 775 vehicles. Emissions
result from the combustion of fuel in each vehicle and can be estimated based on total fuel use and
VMT.
3.4.1 TaxiResultsTaxicabs accounted for 21,142 metric tons CO2e in 2012. This was increase of about 33 percent from
2007 and about 43 percent from 2000. The increase was the result of large increase in total VMT by taxis
in the County, going from 1,748,750 in 2007 to 2,305,849 in 2012. This was offset somewhat by an
increase in vehicle efficiency of 32 percent from 2000/2007 to 2012 due to an increase in the number of
hybrid taxicabs now in use.
Table 3.13: Comparison of Taxi Emissions by Inventory Year
Source 2000
Emissions (mtCO2e)
2007Emissions (mtCO2e)
2012Emissions (mtCO2e)
Change 2007‐2012 (mtCO2e)
% Change 2007‐2012
Taxis 14,764 15,871 21,142 5,271 33%
21 Greater Greater Washington. February 28, 2012. Metro switching most buses to alternative fuels. Online at: http://greatergreaterwashington.org/post/13656/metro‐switching‐most‐buses‐to‐alternative‐fuel/ 22 PlanItMetro: Metro’s Planning Blog. September 27, 2012. Metrobus fuel efficiency on the rise. Online at: http://planitmetro.com/2012/09/27/metrobus‐fuel‐efficiency‐on‐the‐rise/
24
3.4.2 TaxiMethodologySimilar to community traffic, emissions from taxis are calculated based off estimates of VMT and fuel
consumption. 2000 and 2007 estimates for VMT and fuel consumption were taking directly from the
published inventory report23, but emissions were recalculated using updated emission factors. Each of
the taxicab companies provided vehicle counts and average fuel efficiency for their fleet, including their
hybrid vehicles. Five of the seven companies also provided VMT estimates for their fleets, representing
about 92 percent of the entire taxi fleet in the County. VMT for the remaining 8 percent was estimated
based on these data. Fuel consumption was estimated based on the VMT and fuel efficiency for each
vehicle and then multiplied using the equations provided above in sections 3.2.1.1 and 3.2.1.2.
3.4.2.1 TaxiDataTable 3.14: Taxi Activity Data, VMT and Fuel Consumption by Inventory Year
Year Total Cabs Total VMT Gasoline Consumption (gallons)
2000 701 31,544,784 1,619,373
2007 757 34,065,000 1,748,750
2012 775 59,500,978 2,305,849
3.4.2.2 TaxiEmissionFactorsEmission factors used for the calculation of CO2 emissions are the same as those used for County
origin/destination traffic for passenger cars, as provided in section 3.2.3 above.
Table 3.15: Emission Factors for Taxi Estimate by Inventory Year
Year
Emission Factors
CO2 (kg/gal) CH4 (g/mile) N2O (g/mile)
2000 8.78 0.048 0.053
2007 8.78 0.042 0.046
2012 8.78 0.042 0.046
3.4.2.3 TaxiAssumptionsThe following assumptions were made when calculating emissions for taxicabs in Arlington County.
1. All taxicabs were assumed to be passenger vehicles for emission factor purposes
2. For the two taxicab companies that provided no VMT data, it was assumed that the average
daily VMT equaled that of the weighted average of the other taxis for which data was provided.
That came out to 44,755 miles per year.
3. It was assumed that the VMT data provided by MWCOG for non pass‐through traffic included
VMT from County taxis. In order to not double count emissions from taxis, they were subtracted
from the passenger car emissions from County origin/destination emissions.
23 http://freshaireva.us/wp‐content/uploads/2013/08/Greenhouse‐Gas‐Emissions‐Inventory‐2000‐2007.pdf
25
3.5 UniversityShuttlesGeorgetown University and Marymount University provide shuttle service in Arlington County.
Emissions from these shuttles are calculated similar to the other bus fleet emissions for Arlington
County, including Metrobuses and ART Buses.
3.5.1 UniversityShuttlesResultsEmissions from these sources increased slightly as the routes and schedules were expanded since 2007.
Total VMT increased from 104,972 to 134,181. The biggest change was the incorporation of biodiesel
blends into the fuel mix, as Georgetown University switched from diesel to B10 or B20, depending on
the time of year. This fuel change kept Georgetown’s emissions increase to around 10 percent from
2007 to 2012, when their total VMT increased by over that same time increased by about 35 percent.
2012 emissions totaled 263 metric tons, 51.4 from Georgetown University and 211.2 from Marymount
University.
Table 3.16: University Shuttles Emissions Summary Data by Inventory Year
Source 2000
Emissions (mtCO2e)
2007Emissions (mtCO2e)
2012 Emissions (mtCO2e)
% Change2007‐2012
University Shuttles Emissions (mtCO2e) 215 215 263 22%
Marymount 168 168 211 26%
Georgetown 47 47 51 10%
University Shuttles Biogenic Emissions (mtCO2) 0 0 11 N/A
Marymount 0 0 0 N/A
Georgetown 0 0 11 N/A
3.5.2 UniversityShuttlesMethodologyFuel consumption or VMT data were not directly available for either shuttle fleet. Each university does
provide route maps and shuttle schedules online. From this information, total trip length and number of
trips per route were calculated. The Georgetown University Fleet Manager estimates that the bus fleet
achieved approximately 5 MPG and used diesel fuel in 2000 and 2007, and a mix of B10 and B20
biodiesel in 2012.
The following equation was used to calculate total fuel consumption:
Total Fuel Consumption (gal) = VMT (miles) ÷ Fuel Economy (miles/gal)
Emissions of CO2 were calculated using total fuel consumption by the shuttle fleet, and applying a
vehicle type (bus) and fuel specific (diesel or biodiesel) emission factor. The following equation was used
to calculate CO2 emissions based on the estimated fuel consumption.
CO2 Emissions (mtCO2e) = Total Fuel Consumption (gal) x CO2 Emission Factor (kg CO2/gal) ÷ 1,000 kg CO2/mtCO2
To calculate CH4 and N2O emissions, total miles traveled were multiplied by the emission factor assigned
to each fuel type resulting in grams of emissions. To obtain total metric tons of native gas, the grams of
emissions for each gas were divided by 1,000,000. To obtain metric tons of CO2e, the metric tons of
26
native gas totals were multiplied by a GWP of 21 for CH4 and a GWP of 310 for N2O. This is shown in the
equations below:
CH4 Emissions (mtCO2e) = ∑(all vehicles) [(miles traveledvehicle * CH4 EFfuel)/1,000,000]*21
N2O Emissions (mtCO2e) = ∑(all vehicles) [(miles traveledvehicle * N2O EFfuel)/1,000,000]*310
3.5.2.1 UniversityShuttlesDataTable 3.17: University Shuttles VMT by Inventory Year
Annual VMT 2000 2007 2012 % Change 2007 ‐ 2012
University Shuttles 104,972 104,972 134,181 28%
Marymount 82,156 82,156 103,365 26%
Georgetown 22,816 22,816 30,816 35%
Table 3.18: University Shuttles Fuel Consumption by Inventory Year
Fuel Type 2000 2007 2012
B100 Consumption (gal) 0 0 1,130
Marymount 0 0 0
Georgetown 0 0 1,130
Diesel Consumption (gal) 20,994 20,994 25,706
Marymount 16,431 16,431 20,673
Georgetown 4,563 4,563 5,033
3.5.2.2 UniversityShuttlesEmissionFactorsEmission factors used for the calculation of CO2 emissions are from the LGOP, and are detailed in 3.19,
below.
Table 3.19: University Shuttles Emission Factors
Fuel (Unit) Factor Source
Diesel Fuel No. 1 and 2 (kg CO2/gallon)
10.21
ICP, Table TR.1.6 CO2 Emission Factors by Transportation fuel, Table TR.2.2 Heavy Duty Vehicle Emission Factors
Biodiesel (B100)+ (kg CO2/gallon)
9.45
CH4 Diesel EF (g/mile) 0.0051
N2O Diesel EF (g/mile) 0.0048
3.5.2.3 UniversityShuttlesAssumptionsThere was no direct contact or input from Marymount University, so the following assumptions were
used based on the information provided by Georgetown University.
Assumed that Marymount University shuttles have the same average fuel efficiency (5 MPG) as
the Georgetown University shuttles.
Assumed that all fuel used by Marymount University shuttles was diesel.
27
4 SolidWasteSectorGHG emissions from waste production come from the collection and disposal of residential and
commercial solid waste. Solid waste is either landfilled, which produces methane, or sent to waste‐to‐
energy (WTE) plants and combusted, producing CO2, N2O and CH4. All of Arlington County’s non‐recycled
residential waste is sent to the Covanta WTE plant in Alexandria, VA. The majority of the commercial
(including multi‐family and institutional) waste is also sent to the same WTE plant, however a small
portion is disposed of at various area landfills. Waste collection and transportation of residential waste
is performed a by a few contracted haulers, while collection and transportation of commercial waste is
done by a much larger number of private haulers. Emissions from waste collection and transportation
was previously captured in the Community transportation sector of the inventory, however to be
compliant with the ICP, these sources were moved to the waste sector. Process emissions and emissions
from purchased electricity from recycling facilities are not included in this report. There are no facilities
within the jurisdiction of Arlington County, and sufficient data are not available to calculate related
emissions.
4.1 SolidWasteSectorResultsTotal emissions from solid waste declined 18 percent between 2000 and 2007, and continued that trend
with a 20 percent decline from 2007 to 2012. The decline of emissions from solid waste is largely
attributable to changes in recycling behavior in the County. The recycling rate, as reported to and
confirmed by the Virginia Department of Environmental Quality, improved from 37.8 percent in 2000 to
40.3 percent in 2007 to 51.1 percent in 2012. 24
Table 4.1: Solid Waste Emissions Summary by Inventory Year
Sector Revised Values (mtCO2e) Change 2007‐
2012 (mtCO2e)
% Change 2007‐2012
2000 2007 2012
Solid Waste Sector 59,750 49,125 39,027 ‐10,098 ‐21%
WTE Plant 53,682 44,431 35,218 ‐9,214 ‐21%
Landfill 4,818 3,536 2,807 ‐730 ‐21%
Collection and Transport Vehicles 1,249 1,157 1,002 ‐155 ‐13%
4.2 SolidWasteSectorMethodology
4.2.1 LandfillProcessMethodologyThe waste produced in Arlington County in 2012 and sent to a landfill will emit CH4 over the course of
many years; however, without a detailed understanding of the landfill characteristics and the current
waste in place, it is impossible to accurately estimate the emissions in any single year. The total
emissions for all years, from the waste disposed of in 2012, will be accounted for in this data year. This
eliminates the need to track waste over multiple years and aggregating single year emissions from each.
24 Recycling rates from Arlington County Department of Environmental Services Solid Waste Bureau.
28
Emissions from waste sent out of the County to landfill disposal sites are calculated using Equation
SW.4.1 from the ICP.
∗ 1 ∗ 1 ∗ ∗ ∗
Where
CE = the landfill gas (LFG) collection efficiency (assumed to be 75%)
OX = the oxidation rate of methane in the LFG as it is released through the soil (assumed to be 0.1)
M = Total mass of waste entering the landfill (tons)
Pi = fraction of waste component i
EFi = Emissions factor for waste component i
4.2.2 Waste‐to‐EnergyMethodologyEmissions from the combustion of waste are estimated using the ICP. This requires the estimation of CO2
emissions from the combustion of the fossil fuel based components of MSW, including plastics, rubber,
textiles, waste oils and solvents. The biogenic CO2 emissions from the combustion of non‐fossil fuel
based components, such as food waste and paper, are estimated and tracked but not included as
emissions in the final inventory. This distinction does not apply to CH4 and N2O emissions from
combustion, which are included for 100 percent of the waste stream.
CO2 Emissions were calculated using formula SW 2.2.a. from the ICP:
CO2 emissions = Mass of Community MSW combusted * MSW Higher Heating Value*Emission Factor*(1‐Biologic
Fraction)*(2*10‐6)
CH4 and N2O Emissions were calculated using formula SW 2.2.b. from the ICP:
CH4 Emissions = Mass of Community MSW* MSW Higher Heating Value*Emission FactorCH4*(2*10‐6)*GWPCH4
N2O Emissions = Mass of Community MSW* MSW Higher Heating Value*Emission FactorN2O*(2*10‐6)*GWPN2O
Table 4.2: WTE Plant Emissions from Arlington County Generated Waste by Inventory Year
Equation Variables 2000 2007 2012
Total Non‐biogenic Emissions (mtCO2e) 53,682 44,431 35,218
Fossil CO2 Emissions (mt) 50,252 41,568 33,195
CH4 Emissions (mtCO2e) 1,156 965 681
N2O Emissions (mtCO2e) 2,275 1,898 1,341
4.2.3 WasteCollectionandTransportationMethodologyEmissions from the collection of solid waste and recyclables are estimated using 2007 reported fuel
consumption data and route information from the contracted residential waste and recyclables
collection fleet. This same data was not available in 2012, however the contracted waste and recycling
29
fleet for residential collection is largely the same. An emission factor on a per ton of waste basis was
calculated using the 2007 emissions estimate and the total mass of solid waste and recyclables that
were collected. The Arlington County specific emission factor as then multiplied by the mass of solid
waste and recyclables collected in 2012 to estimate emissions.
Emissions from the transport of waste out of the County to the disposal sites are calculated using the
ICP method and the following equation.
Metric Tons CO2 equivalent emissions = Mass of waste*Miles Traveled*0.00014
4.2.4 SolidWasteSectorDataArlington County Solid Waste Division provided total tons of trash and recycling for the residential and
commercial sectors, as well as the composition of that waste.
Table 4.3: Landfill Emissions Data by Inventory Year
Material Type (Waste Components per ICP Table SW.5)
10% of Non‐residential MSW Sent to Landfill (tons)
Mass Fraction of Waste Type
2012 Total 7,424 100%
Paper (Newspaper, Office paper, Corrugated Containers, Magazines/Third‐class Mail) 1,879 25%
Food (Food Scraps) 186 3%
Plant debris (Grass, Leaves) 1,619 22%
Wood/textiles (Branches, Lumber) 461 6%
Other (Mixed MSW) 3,280 44%
2007 Total 7,783 100%
Paper (Newspaper, Office paper, Corrugated Containers,
Magazines/Third‐class Mail) 2,701 35%
Food (Food Scraps) 934 12%
Plant debris (Grass, Leaves) 249 3%
Wood/textiles (Branches, Lumber) 1,564 20%
Other (Mixed MSW) 2,335 30%
2000 Total 10,603 100%
Paper (Newspaper, Office paper, Corrugated Containers,
Magazines/Third‐class Mail) 3,679 35%
Food (Food Scraps) 1,272 12%
Plant debris (Grass, Leaves) 339 3%
Wood/textiles (Branches, Lumber) 2,131 20%
Other (Mixed MSW) 3,181 30%
Table 4.4: WTE Emissions Data by Inventory Year
Equation Variables 2000 2007 2012
Mass of Community MSW (short tons) 173,884 145,142 102,512
MSW Higher Heating Value (HHV) (MMBtu) 5,000 5,000 5,000
Biologic Fraction 0.669 0.669 0.646
Aggregated Unit Conversion Factor 2.00E‐06 2.00E‐06 2.00E‐06 Source: MSW HHV and Aggregated Unit Conversion Factor from ICP. Biologic fraction from GHGRP reporting for Covanta WTE Plant.
30
Table 4.5: Waste Collection Emissions Data by Inventory Year
MSW Source
Mass MSW (tons) Fuel Consumption ‐ Waste Collection (gal)
2000 2007 2012 2000 2007 2012
Residential 78,454 75,095 35,686 24,429 23,383 11,112
Residential (Recycle) 56,871 83,525 94,631 21,637 31,778 36,003
Commercial 106,033 77,830 74,250 N/A N/A N/A
Table 4.6: Waste Transportation Emissions Data by Inventory Year
Waste Destination
Mass MSW (tons) Distance Traveled (miles) 2000 2007 2012
Landfilled 10,603 7,783 7,424 125
WTE Plant 173,884 145,142 102,512 9
4.2.5 SolidWasteSectorEmissionFactorsEmission factors for collection, transportation and disposal process emissions can be found in the
equations above and are also included in Table 4.7 below.
Table 4.7: Emission Factors for Landfill Emissions by Inventory Year
Material Type
Emission Factor(mtCH4/wet short
ton waste)
*Paper (Newspaper, Office paper, Corrugated Containers, Magazines/Third‐class Mail) 0.1592
Food (Food Scraps) 0.0780
*Plant debris (Grass, Leaves) 0.0340
Wood/textiles (Branches, Lumber) 0.0620
Other (Mixed MSW) 0.0600
Source: Emission factors derived from EPA’s WARM model and provided by the ICP in Table SW.5.
*To obtain overall material type factors, the separate factors for the components of each material type (i.e. newspaper, office paper, magazines
for the paper material type) were weighted based on their relative share of default U.S. Waste Characterization as provided in ICP Table SW.2.
Table 4.8: Emission Factors for WTE Emissions by Inventory Year
Emission Factors 2000 2007 2012
CO2 Emission Factor (kg/MMBtu) 87.26 86.47 91.57
CH4 Emission Factor (kg/MMBtu) 0.0317 0.0317 0.0317
N2O Emission Factor (kg/MMBtu) 0.00422 0.00422 0.00422
*Emission factors calculated on GHGRP & eGRID data using 2005 for 2000, 2007 for 2007 and 2009 for 2012.
Table 4.9: Emission Factors for Collection of Solid Waste
Source
Emission Factor (mt CO2e per Ton of Waste)
Waste Collection
Residential Collection 0.0032
Residential (Recycle) Collection 0.0039
*Commercial Collection 0.0035 *Commerical Collection was based on an Average of Waste and Recycling Collection Factors from 2007 data
31
Table 4.9: Emission Factors for Transport of Solid Waste
Source
Emission Factor (mtCO2e per Ton of Waste per VMT)
Waste Collection
Transport of Solid Waste for Disposal 0.00014 Source: ICP Equation SW.6
4.2.6 SolidWasteSectorAssumptionsAssumed landfills where Arlington County waste was disposed have landfill gas collection systems, and
match the default efficiency of 75 percent for those systems provided by ICP.
Detailed data from 2007 showed that 10 percent of non‐residential waste was sent out of the County to
be landfilled. It was assumed that this held true in 2000 and 2012 as the same detailed data was not
available for those years.
It was assumed for Collection and Transport Vehicle emissions that the emissions rate per ton of MSW
and recyclable material collected from the collection vehicle fleet in 2007 was the same as in 2000 and
2012.
The exact location of the landfills that the private waste haulers transport 10 percent of Arlington
County’s waste to is unknown; therefore a conservative estimate of 125 miles was assumed to be the
average distance of these landfills from the County to calculate emissions from waste transportation.
This assumption likely overestimates emissions from this source.
32
5 Non‐CountyGovernmentSector
Emissions from Electricity use and stationary combustion of fossil fuels occur in federal facilities and
other non‐County government buildings (i.e. state government and Reagan National Airport). These
emissions are tracked separately from the County Government facilities and the other community
sources because the County has no operational control or influence over these facilities and their
emissions are not included in the community reduction goals. These sources do fall in the geopolitical
boundary of the County and therefore are tracked and estimated, but not included in the totals to
ensure clear delineation of accountability.
Emissions from non‐County government sources were not estimated previously because of the lack of
specific data. Electricity data for non‐County government sources are not available, nor included, for the
year 2000, however natural gas data is included as part of the commercial sector for 2000. There is
currently no way to disaggregate this from the commercial sector in the County, because no facility
specific data is available for 2000. The utility provided electricity data for 2007 and 2012 disaggregates
consumption data by sector, including the government sector. This sector includes consumption of the
County government, public schools, federal facilities, the airport and other non‐County government
including Metrorail. The non‐County government sector electricity consumption is estimated by
subtracting the independently estimated County Government, school and Metrorail consumption from
the utility government sector total. The non‐County government natural gas consumption is estimated
by summing the specific facility provided consumption data; no government sector consumption is
provided by Washington Gas. This is subtracted from the commercial sector consumption data provided
by Washington Gas to get the community consumption value.
5.1 Non‐CountyGovernmentSectorResultsEmissions from non‐County government sources totaled 315,446 metric tons CO2e in 2012. Of this,
about 82 percent of those emissions were from identified federal facilities, including Army National
Guard Arlington Hall Station, Joint Base Myer‐Henderson Hall, National Foreign Affairs Training Center
and the Pentagon as well as the Reagan National Airport.
Overall emissions from this sector remained roughly the same in 2012 compared to 2007 emissions of
315,546 metric tons CO2e.
Table 5.2: CY 2012 Non‐County Government Emissions
Source Electricity(mtCO2e)
Natural Gas(mtCO2e)
Fuel Oil &Kerosene (mtCO2e)
Gasoline (mtCO2)
Diesel (mtCO2)
Total (mtCO2e)
*Non‐County Government Buildings 258,080 54,670 0 0 0 312,750
Airport Service Equipment 0 0 0 1,087 1,609 2,696
Total 315,446
*Includes Federal Buildings, Regan National Airport and other non‐County Government Facilities
33
5.2 Non‐CountyGovernmentSectorMethodologyEmissions from non‐County government buildings are estimated using the same methodologies and
emission factors as described in the buildings sector above. The only non‐buildings sector emission
source included in this sector are emissions from Airport Service Equipment at National Airport. This
falls under the transportation source category and emissions are estimated based on fuel use and a fuel
specific emission factor. Only CO2 emissions are estimated from Airport Service equipment because no
specific vehicle information is available nor VMT data are available to calculate CH4 or N2O emissions.
The non‐CO2 emissions would be de minimis and are therefore excluded.
5.2.1 Non‐CountyGovernmentSectorData Table 5.2: Non‐County Government Sector Fuel Consumption by Type and Inventory Year
Source 2000* 2007 2012
Electricity (MWh) NA 522,590 546,176
Natural Gas (MMBtu) NA 841,811 1,028,486
Fuel Oil & Kerosene (gal) NA 70,808 0
Gasoline (gal) 132,000 131,000 123,799
Diesel (gal) 210,000 225,000 157,583 *Stationary Combustion data not available for 2000.
5.2.2 Non‐CountyGovernmentSectorAssumptionsIt is assumed that the 2000 electricity data provided by Dominion Virginia Power does not include
consumption for federal facilities.
It is assumed that the 2000 natural gas data provided by Washington Gas does include consumption for
federal facilities, and is included in the commercial sector estimate as no method was available to
disaggregate it.
It is assumed that the 2007 and 2012 utility data provided by Dominion Virginia Power and Washington
Gas both include consumption by federal and non‐County Government facilities, as well as County
Government, County Public Schools and Metrorail.