how we calculate

 

Carbonfund.org's Carbon Calculators use information from the U.S. Department of Energy's Energy Information Administration, the Environmental Protection Agency, and other leading sources to develop an accurate assessment of carbon dioxide emissions emitted per energy type or use. After you learn how we calculate, please calculate your own carbon footprint here.

Quick Links

Residential | Transportation | Total US CO2-equivalent Emissions | Business Calculator |Shipping Calculator | Conversions

 

Residential

Electricity
We calculate emissions from electricity generation based off figures from the EPA’s eGRID emission factors based on 2009 and 2012 data. On average, electricity sources emit 1.222lbs CO2 per kWh (0.0005925 metric tons CO2 per kWh). State CO2 emissions per kWh may vary greatly in accordance with the amount of clean energy in the energy supply (Vermont: 0.0055 lbs/kWh; North Dakota: 2.0685 lbs/kWh). (Source: EPA eGRID Summary Tables and Data Files)

Natural Gas
There are 0.005 metric tonnes of CO2 per 1 therm of natural gas. (Source: EPA Clean Energy)

US avg.: In 2010, 65.5 million households used natural gas. Collectively, they used 4,787 billion cubic feet of natural gas annually, or 730.84 CCF (approximately 748.38 therms) per household or 283.27 CCF (approximately 290.07 therms) per person per household using natural gas. (Source: Energy Information Agency, US Census Bureau. Berkshire Gas )

Heating Oil
There are 10.15 kg of CO2 per gallon of home heating oil. (Source: US DOE 1605(b) Voluntary Reporting of Greenhouse Gases Program.)

US average: In 2010, 3972.83 million gallons of heating oil were consumed by 7.7 million households resulting in an average of 515.95 gallons per household or 198.44 gallons per person per household using heating oil.VolumeHouseholds)

Transportation

Vehicles
Unleaded gasoline emits 8.91 kg of CO2 per gallon. (Source: US DOE 1605(b) Voluntary Reporting of Greenhouse Gases Program.)

Air Travel

CO2 emissions in air travel vary by length of flight, ranging from 0.277 kg CO2 per passenger mile to 0.185 kg CO2per passenger mile, depending on the flight distance. Our calculator allows the user to take the issue of radiative forcing into account. (Sources: EPA Climate Leaders, table 4, page 7; For more information on air travel-related radiative forcing, please see this IPCC document.)*Assumes Coach Class, please contact us directly for business and first class emissions.

Rail Travel

The CO2 emissions for rail travel vary by distance of the trip. On average, commuter rail emits 0.172 kgs CO2 per passenger mile and subway trains emit 0.163 kgs CO2 per passenger mile, and long distance trains (i.e., intercity rail) emit 0.185 kgs CO2 per passenger mile (Source: EPA Climate Leaders, table 2, page 5). For rail trips under 20 miles, we calculate your emissions at 0.172 kgs CO2per passenger mile, and over 20 miles we calculate at 0.185 kgs CO2 per passenger mile. To ensure that our rail calculator fully covers your trip, we add 10% to the total mileage of your trip to account for potential detours, stop-overs, and other issues that may arise on your trip.


Bus Travel 

On average, bus trips emit 0.107kgs CO2 per passenger mile (Source: EPA Climate Leaders table 3, page 5). Road and transportation conditions vary in real life beyond what can be estimated. To ensure that our bus calculator fully covers your trip, we add 10% to the total mileage of your trip to account for potential traffic jams, detours, and pit-stops that may arise on your trip.


Total US CO2-equivalent Emissions

In 2009, US emissions of 6,576 million metric tons CO2-equivalent, the figure is divided by the US population to yield CO2-equivalent per person. (Source: Energy Information Agency /US CensusBureau)

Hospitality

Meals 

The average person's diet contributes 2,545 kilograms CO2e to the atmosphere each year. By dividing by 365, it is deduced that a person emits, on average, 7 kg CO2e a day from their meals. This calculation is based on an average US, non-vegetarian diet. The emissions for food preparation are not included in this calculation. (Source: Johns Hopkins Bloomberg School of Public Health, Average of Table 3).

Hotel Rooms 

Emissions associated with a one night stay in a hotel room are calculated at 16.8 kg CO2 per room day for an average hotel (budget through mid-scale). For upscale hotels, that include restaurants, meal service and meeting space, emissions are calculated at 33.38 kg CO2 per room day. (Source: Environmental Protection Agency, CHP Potential in the Hotel and Casino Market Sectors, prepared by Energy and Environmental Analysis, Inc. for EPA.)

Business Calculator

Office Emissions
All emissions factors in the “Office Emissions” category are based on annual (12 month) emissions. Emissions factors for energy (kWh) are based on state-based figures from the EPA eGRID

Natural Gas

There are 0.005 metric tonnes of CO2 per 1 therm of natural gas. (Source: Greenhouse Gas Equivalencies Calculator)

Electricity

Emissions factors for electricity by your monthly bill are based on state based figures from the EPA eGRID to get the state-by-state prices for energy, and the emissions factors are generated from the Department of Energy’s Energy Information Administration. On average, electricity sources emit 1.222 lbs CO2 per kWh. State CO2 emissions per kWh may vary greatly in accordance with the amount of clean energy in the energy supply (Vermont: 0.0055 lbs/kWh; North Dakota: 2.0685 lbs/kWh). (Source: (Source: EPA eGRID Summary Tables and Data Files)

Heating Oil

There are 10.15 kg of CO2 per gallon of home heating oil (diesel fuel). (Source: US DOE 1605(b) Voluntary Reporting of Greenhouse Gases Program.)

Propane

We calculate the emissions of propane to be 5.74 kg CO2 per gallon (source DOE EIA).

Building Type

Emissions factors by building type are calculated using assumptions from the EIA DOE. The figures provide the kWh used per sq foot of building type, then we multiply the energy needed for a particular space by state based emissions factors

Number of Employees

Emissions factors calculated by number of employees is calculated with the average sqft needed per employees, 225 sqft (based on industry assumptions that a typical office will require between 175 – 250 sq ft per employee). We then calculate the total sqft by average emissions for office buildings by sqft (Source: Energy Star). Then we multiply the energy needed for the total space by state based emissions factors

Servers

Server emissions are calculated assuming an average 251 watt server (source: Vertatique) with 95% up time. The energy usage of each server is then multiplied by state based emissions factors

Fleet

Fleet emission calculations assume the national average of 25.2 mpg and the emissions factor of 19.4 lbs CO2 per gallon of gasoline consumed. Fleet emissions for delivery vans and trucks assume an average of 8.5 mpg. and the emissions factor of 22.2 lbs CO2 per gallon of diesel consumed. Fleet emissions big rigs assume an average of 5.4 mpg and the emissions factor of 22.2 lbs CO2 per gallon of diesel consumed. (Source: Transportation Data Energy Book 2011)

Employee Travel 
All travel emissions factors sourced from EPA Climate Leaders.

  • Short flights are calculated to be under 300 miles round-trip with emissions of 0.277kg CO2 per passenger mile
  • Medium flights are calculated to be 1,500 miles round-trip with emissions of 0.185kg CO2 per passenger mile
  • Long flights are calculated to be 3,000 miles round-trip with emissions of 0.185kg CO2 per passenger mile
  • Train trips are calculated 0.172 kg CO2 per passenger mile
  • Bus trips are calculated at 0.107 kg CO2 per passenger mile

Employee Commute 
All emissions figures from EPA Climate Leaders.

  • Commute by Car – assumes 0.364 kg CO2 of gas consumed per mile and a two way commute 245 days a year. (The kg CO2/vehicle mile average of both passenger car and light-duty truck.)
  • Commute by Intercity Rail (Amtrak) – assumes a two way commute 245 days a year, with 0.185 kg CO2 emitted per mile.
  • Commuter Rail - Assomes a two way commute 245 days a year, with 0.172 kg of CO2 emitted per mile.
  • Commute by Transit (tram, subway) - assumes a two way commute 245 days a year, with 0.163 kg  of CO2 emitted per mile.

Shipping Calculator

Carbonfund.org’s shipping calculator utilizes three user generated inputs to determine a unit called a ‘ton-mile’ (e.g. a ton of freight traveling 1 mile, or a half ton of freight traveling two miles, or 1/1000th of a ton traveling 1,000 miles… you get the point):

  • Total number of shipments
  • Avg Weight of Shipment (lbs)
  • Avg Shipping Distance (mi)

Shipping Emissions Factors:

  • Air cargo – 1.527 kg CO2 per Ton-Mile
  • Truck - 0.297 kg CO2 per Ton-Mile
  • Train - 0.0252 kg CO2 per Ton-Mile
  • Sea freight - 0.048 kg CO2 per Ton-Mile

(Source: EPA Climate Leaders)

Conversions

  • 1 Renewable Energy Certificate = 1 Megawatt Hour (MWh) = 1,000 Kilowatt Hours (KWh)
  • 1 Kilowatt Hour = 3,413 British Thermal Units (BTUs)
  • 1 Metric Tonne = 2,204.6 Pounds
  • 1 Pound = 0.00045 Metric Tons
  • 1 Short Ton = 2,000 Pounds
  • 1 Short Ton = 0.90719 Metric Tons
  • 1 Therm = 100 Cubic Feet
  • 1 CCF = Abbreviation for 100 Cubic Feet
  • 1 CCF = 1.024 Therms


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