Business Calculator Explained
Introduction
Calculating a business or organization’s impact on the climate is not an exact science. The calculations below, therefore, try to incorporate the most up-to-date references and data available. The most prudent assumptions have been made, and objective sources of information have been used for citation purposes. Where they are applicable, conservative estimates have been made.
The total amount of metric tons that appears on the second page of the calculator is arrived at by adding together the total emissions calculated in the Infrastructure, Transportation, and Shipping sections.
Infrastructure
The calculator determines the carbon footprint of the indirect emissions from the electricity and natural gas usage attributable to the organization using common conversion factors, if energy usage is known. If the amount of annual energy usage is not known, the carbon footprint is calculated one of two ways based on: 1) data specific to the building or complex hosting the event; or 2) regional data based on national energy surveys. In either case, the energy intensity of the building or complex hosting the organization is calculated.
Electricity
Option 1
If site specific data is available, the total kilowatt hours consumed annually by the building/complex
needs to be divided by the total amount of square feet of the building/complex. For example, if a building
uses six million kWhs in a year and the square footage of the building is 600,000 ft2, then the electricity
energy intensity of the building is 10 kWhs consumed per square foot per year.
Option 2
If site specific data is not available, regional data is used and energy intensity is calculated based
on the region where the building is located and its range of square footage. For example, if the building
hosting an event is located in the Midwest and falls within the range of 10,001 and 100,000 ft2, the
energy intensity of the building is 11.4 kWhs consumed per square foot per year. These figures are
taken from the U.S. Energy Information Administration’s 2003 Consumer Buildings Energy Consumption
Survey.i (Note the figures in the table have been discounted by 10% for calculation purposes to
account for more energy intensive activities that fall within the “commercial” category.)
The calculator then multiplies the energy intensity figure (calculated above) by the total amount of square feet used for the organization’s operations. The result is the estimated annual amount of electricity (kWhs) that will be consumed by the square footage dedicated to the organization.
To calculate carbon dioxide emissions associated with electricity consumption, the amount of electricity used (either known from utility bills, or calculated using one of the options above) is multiplied by the electricity grid emissions factor for the state of Colorado. Electricity grid emissions intensity is calculated by determining the amount of pounds of carbon dioxide that is emitted as a result of generating one kilowatt hour of electricity. This figure depends on the types of resources, e.g. coal, natural gas, wind, hydro, etc. that are used to generate the electricity consumed in Colorado. The Colorado-specific emission factor used in this calculator is based on the US Environmental Protection Agency’s Emissions & Generation Resource Integrated Database (eGRID).ii The factor for Colorado is 1986 pounds of CO2 per kWh.
Total electricity consumed (kWhs) multiplied by the emissions factor determines the amount of pounds of carbon dioxide that are attributable to the organization as a result of electricity consumption.
Natural Gas
If annual energy usage for natural gas is not known, calculating the building’s energy intensity for natural gas consumption must be determined, as above.
Option 1
If site specific data is available, the average total therms consumed annually by the building that hosts
the organization needs to be divided by the total amount of square feet of the building. For example, if
a building uses 200,000 therms annually and the square footage of the building is one million ft2, then
the natural gas energy intensity of the building is 0.2 therms consumed per square foot per year. To
determine the estimated amount of natural gas used, the calculator then multiplies the energy intensity
for natural gas by the amount of square footage used by the organization.
Option 2
If site specific data is not available, regional data is used and energy intensity is calculated based
on the region where the building is located and its range of square footage. For example, if the building
hosting the organization is located in the Midwest and falls within the range of 10,001 and 100,000 ft2,
the energy intensity of the building is 49.9 cubic feet of natural gas consumed per square foot per year.
(These figures are taken from the U.S. Energy Information Administration’s 2003 Consumer Buildings Energy
Consumption Survey.iii) This figure is then multiplied by the total square footage used by the
organization’s operations to arrive at the total number of cubic feet of natural gas that is
consumed. This figure is converted into therms by dividing by 100 (100 cubic feet = one therm).
To calculate the amount of pounds of carbon dioxide from natural gas consumption attributable to the organization, the calculator multiplies the number of therms used annually by 12.0593,iv the amount of pounds of CO2 that is emitted from burning one therm of natural gas.
Total for Infrastructure
To calculate the total CO2 emissions in metric tons, the calculator adds the total number of pounds of CO2 that are attributable to the organization’s electricity and natural gas usage, and then divides that total by 2,205, the amount of pounds in a metric ton.
Transportation
The business calculator determines total CO2 emissions from business-related automobile and airline travel.
Automobile
To calculate CO2 emissions associated with the organization’s annual automobile travel, the calculator divides the total amount of miles entered by the average fuel efficiency of the vehicles used to determine the amount of gallons used annually. The amount of gallons is then multiplied by 19.36, v the amount of pounds of CO2 that is emitted from burning one gallon of gasoline. To calculate the total CO2 emissions from automobile travel in metric tons, the calculator divides the total number of pounds by 2,205, the amount of pounds in a metric ton.
Air Travel
If the estimated number of hours flown by the organization’s employees is entered, the calculator multiplies this figure by 414.65,vi the average number of miles flown per hour of air travel. The product is multiplied by 1.3068,vii which is the total climate impact of one air-passenger mile, expressed in pounds of carbon dioxide. The result is then divided by 2,205, the number of pounds in a metric ton.
If the estimated number of miles flown by the organization’s employees is entered, the calculator multiplies this figure by 1.3068, which is the total climate impact of one air passenger mile, expressed in pounds of carbon dioxide. The result is then divided by 2,205, the number of pounds in a metric ton.
Total for Transportation
To calculate the total amount of metric tons associated with transportation, the calculator adds together the total tons from automobile and air travel.
Shipping
The business calculator determines CO2 emissions from business related shipping activities use air, maritime, and truck modes of transportation.
Air Shipping
To determine the amount of CO2 emitted as a result of air shipping, the calculator multiplies the amount shipped (metric tons) by the number of miles it was shipped. It then multiplies the product by the emissions factor for air shipping, 0.0009 metric tons CO2 per metric ton-mile transported. This emissions factor was calculated as follows:
- According to the U.S. Department of Transportation’s Federal Highway Administration, the amount of CO2 emitted in 2003 as a result of air shipping was 12.4 teragrams of CO2, or 12,400,000 metric tons of CO2. viii
- According to the U.S. Department of Transportation’s Bureau of Transportation Statistics, that amount was transported by air shipping a total of 15.1 billion short ton-miles in 2003.ix To convert this figure into metric ton-miles, multiply it by 0.907 (1 short ton = 0.907 metric tons), which equals 13.7 billion metric ton-miles.
Finally, to determine the emissions factor perform the following calculation:
- 12,400,000 metric tons CO2 / 13,700,000,000 metric ton-miles = 0.0009 metric tons of CO2 per metric ton-mile.
Maritime Shipping
To determine the amount of CO2 emitted as a result of maritime shipping, the calculator multiplies the amount shipped (metric tons) by the number of miles it was shipped. It then multiplies the product by the emissions factor for maritime shipping, 0.000088 metric tons CO2 per metric ton-mile transported. This emissions factor was calculated as follows:
- According to the U.S. Environmental Protection Agency, the amount of CO2 emitted in 2005x as a result of maritime shipping was 49.9 teragrams of CO2,or 49,900,000 metric tons of CO2.
- According to the U.S. Department of Transportation’s Bureau of Transportation Statistics, that amount was transported by maritime shipping a total of 591.3 billion short ton-miles in 2005.xi To convert this figure into metric ton-miles, multiply it by 0.907 (1 short ton = 0.907 metric tons), which equals 536.3 billion metric ton-miles.
Finally, to determine the emissions factor perform the following calculation:
- A ton-mile is defined as one ton of freight shipped one mile and, therefore, reflects both the volume shipped (tons) and the distance shipped (miles). 49,900,000 metric tons CO2/ 563,300,000,000 metric ton-miles = 0.000088 metric tons of CO2 per metric ton-mile. Note that this calculation is based only on U.S. domestic freight data, not international. If international maritime shipping data were also considered, this emissions factor would likely be less due to large tankers being able to transport a significant amount of freight with comparably less fossil fuel input.
Heavy-duty Truck
To determine the amount of CO2 emitted as a result of shipping by heavy-duty truck, the calculator multiplies the amount shipped (metric tons) by the number of miles it was shipped. It then multiplies the product by the emissions factor for heavy-duty truck shipping, 0.00033 metric tons CO2 per metric ton-mile transported. This emissions factor was calculated as follows:
- According to the U.S. EPA, the amount of CO2 emitted in 2005 as a result of heavy-duty trucking was 385.8 teragrams of CO2, or 385,800,000 metric tons of CO2.xii
- According to the U.S. Department of Transportation’s Bureau of Transportation Statistics, that amount was transported by heavy-duty truck a total of 1,293.3 billion short ton-miles in 2005.xiii To convert this figure into metric ton-miles, multiply it by 0.907 (1 short ton = 0.907 metric tons), which equals 1,173.02 billion metric ton-miles.
Finally, to determine the emissions factor perform the following calculation:
- 385,800,000 metric tons CO2 / 1,173,020,000,000 metric ton-miles = 0.00033 metric tons of CO2 per metric ton-mile.
Total for Shipping
To calculate the total amount of metric tons associated with shipping, the calculator adds together the total tons from air, maritime and heavy-duty truck shipping.
Endnotes
i US Department of Energy, Energy Information Administration, 2003 Commercial Buildings Energy Consumption Survey: Consumption and Expenditures Tables, Table C21, “Electricity Consumption and Conditional Energy Intensity by Building Size for Non-Mall Buildings, 2003,” http://www.eia.doe.gov/emeu/cbecs/cbecs2003/detailed_tables_2003/2003set10/2003pdf/c21.pdf
ii See US Environmental Protection Agency, “eGRID2006 Version 2.1: Year 2004 Summary Tables (State Emissions),” April 2007, http://www.epa.gov/cleanenergy/energy-resources/egrid/index.html
iii US Department of Energy, Energy Information Administration, 2003 Commercial Buildings Energy Consumption Survey: Consumption and Expenditures Tables, Table C31, “Natural Gas Consumption and Conditional Energy Intensity by Building Size for Non-Mall Buildings, 2003,” http://www.eia.doe.gov/emeu/cbecs/cbecs2003/detailed_tables_2003/2003set16/2003pdf/c31a.pdf
iv US Department of Energy, Energy Information Administration, Voluntary Reporting of Greenhouse Gases Program (Emission Coefficients), “Fuel and Energy Source Codes and Emission Coefficients,” http://www.eia.doe.gov/oiaf/1605/factors.html
v US Department of Energy, Office of Policy and International Affairs, “Technical Guidelines: Voluntary Reporting of Greenhouse Gases (1605(b)) Program,” March 2006, Table 1.D.1, p. 64, http://www.eia.doe.gov/oiaf/1605/TechnicalGuidelines_March2006.pdf
vi US Department of Transportation, Bureau of Transportation Statistics, “U.S. Air Carrier Traffic Statistics,” http://www.bts.gov/xml/air_traffic/src/datadisp.xml; table generated on 8/18/2006, figure was calculated by dividing the total number of scheduled System Revenue Aircraft Miles Flown in 2005, 7,915,129,000 miles, by the total number of scheduled System Revenue Aircraft Hours (Airborne) in 2005, 19,088,831 hours
vii In 2005, total Revenue Passenger Miles flown (scheduled flights only for domestic and international flights of US certificated airlines) was 779,004,706,880 miles (source: US Department of Transportation, Bureau of Transportation Statistics; TranStats, Air Carrier Summary: Schedule T-1, http://www.transtats.bts.gov/Fields.asp?Table_ID=264 ; table generated 8/18/2006). Total jet fuel consumed (scheduled flights only for domestic and international flights) in 2005 was 18,062,449,227 gallons (source: US Department of Transportation, Bureau of Transportation Statistics, “Airline Fuel Cost and Consumption – 2005,” http://www.bts.gov/xml/fuel/report/src/monthrep.xml?styyyy=2005; table accessed 8/18/2006). Divide these two numbers to get 43.13 Revenue Passenger Miles per gallon of jet fuel burned. This figure is then divided into 20.88, the amount of pounds of carbon dioxide that is emitted when one gallon of jet fuel is burned (see US DOE “Technical Guidelines” : above), to get 0.484 lbs. of CO2 per Revenue Passenger Mile. A conservative RFI (radiative forcing index) of 2.7 was then applied to account for the more accurate global warming impact of air travel, which includes the impact of greenhouse gases in addition to CO2, such as nitrous oxide, and contrails; see http://www.grida.no/climate/ipcc/aviation/064.htm. Thus, 2.7 multiplied by 0.484 equals 1.3068 lbs of CO2 equivalent emitted for each Revenue Passenger mile traveled.
viii Emissions factors calculated from data in: (1) Energy Information Administration, Documentation for Emissions of Greenhouse Gases in the U.S. 2005, DOE/EIA-0638 (2005), October 2007, Tables 6-1, 6-4, and 6-5. (Non-biogenic carbon content and gross heat of combustion for motor gasoline and diesel (distillate fuel)). (2) U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Alternative Fuels & Advanced Vehicles Data Center, Fuel Properties web page (http://www.eere.energy.gov/afdc/fuels/properties.html). (Biodiesel gross heat of combustion). (3) Energy Information Administration, Annual Energy Review 2006, DOE/EIA-0384(2006), June 2007, Table A3, p. 361. (Gross heat of combustion for ethanol). (4) Stacy C. Davis and Susan W. Diegel, Transportation Energy Data Book, Edition 26, Oak Ridge National Laboratory, ORNL-6978, 2007, Table B.7 Tables 6.7 and B.4. (Density and gross heat of combustion of methanol.)
ix US Department of Transportation, Bureau of Transportation Statistics, BTS Special Reports, “A Decade of Growth in Domestic Freight - July 2007,” Table 1, http://www.bts.gov/publications/bts_special_report/2007_07_27/html/table_01.html
x US Environmental Protection Agency, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 – 2005, April 2007, Table A-111, page A-129, http://www.epa.gov/climatechange/emissions/usinventoryreport.html
xi US Department of Transportation, Bureau of Transportation Statistics, BTS Special Reports, “A Decade of Growth in Domestic Freight - July 2007,” Table 1, http://www.bts.gov/publications/bts_special_report/2007_07_27/html/table_01.html
xii US Environmental Protection Agency, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 – 2005, April 2007, Table A-111, page A-129, http://www.epa.gov/climatechange/emissions/usinventoryreport.html
xiii US Department of Transportation, Bureau of Transportation Statistics, BTS Special Reports, “A Decade of Growth in Domestic Freight - July 2007,” Table 1, http://www.bts.gov/publications/bts_special_report/2007_07_27/html/table_01.html