Andrew Oliphant Department of Geography & Environment

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Individual Carbon Emissions Calculator

This carbon emissions calculator was produced by a student group in Geography at San Francisco State University for Focus The Nation @ SFSU, January 2008


Format: Excel spreadsheet, Version: 2.1, July 2008

Download here: CarbonCalc


Authors: Andrew Oliphant, David Toy, Genevieve Munsey, Erica Yelensky, David Friedman, Sam Oakley

Disclaimers..
This calculator is based on a large number of simplifications and assumptions and is most accurate for people living in California. The calculations should be seen in absolute terms as approximations only and are most useful for investigating the role that lifestyle changes can play in reducing your carbon footprint (or greenhouse gas equivalent). Explanation of calculations and assumptions employed are provided in notes below and in the spreadsheet

Questions, comments welcomed. Contact Andrew Oliphant, Department of Geography, SFSU, <andrewo@sfsu.edu>



 

Explanation of calculations and assumptions made in this calculator

1. Energy usage

Electricity
Calculated from mass of CO2 = monthly electricity bill/price per kWh * CO2 conversion (depends on how electricity was generated) * 12 months
Electricity CO2 emissions conversion is 1.37 pounds per MWh for the USA and 0.61 for California. Average US electricity use is 4400 MWh per person. (EPA 2007)
Source: US EPA http://www.epa.gov/climatechange/emissions/ind_assumptions.html

Natural gas
Pounds carbon per year (nat gas) = monthly gas bill /13.83*120.61*12
Emissions = (average monthly gas bill / price per thousand cubic feet) natural gas emission factor * months in a year. Price per thousand cubic feet = $13.83, emission factor (natural gas/thousand cubic feet) = 120.61, months in a year = 12.
Source: US EPA http://www.epa.gov/climatechange/emissions/ind_assumptions.html

Oil
Pounds carbon per year (oil) = (average monthly fuel oil bill / price per gallon)* fuel oil emission factor * months in a year. Price per gallon = $2.37, emission factor (fuel oil/gallon) = 22.28, months in a year = 12
Source: US EPA http://www.epa.gov/climatechange/emissions/ind_assumptions.html

2. Waste Assumptions:
Average American emits 2.1 ton CO2eq/year by throwing away trash.
Recycling can reduce waste by up to 42%
Composting can reduce waste by up to 24%
Source: Nature Conservancy CO2 Calculator

3. Food
Average American consumes 4.1 ton CO2eq/year of food.
Vegan and vegetarian diets emit 72% and 42% less than the typical American diet, respectively. A heavy meat diet emits 24% more than the average.
Re. organic food responses, "Most of the time" reduces your emissions by 29%, "Sometimes" reduces emissions by 15%, and "Never or rarely" is the average emissions
Source: Nature Conservancy CO2 Calculator

Transport
4. Vehicular travel
Emissions = (number of miles driven per week * weeks in a year) / average household fuel efficiency * pounds of CO2 emitted per gallon * emissions of greenhouse gases other than CO2. Pounds of CO2 emitted per gallon = 19.4, emissions of greenhouse gases other than CO2 = 100/95. We also include adjustments for the number of people traveling in the car and separate the freeway and around town driving as per their respective fuel usages (miles per gallon) accessed from <https://www.fueleconomy.gov/feg/findacar.htm>
Source: US EPA http://www.epa.gov/climatechange/emissions/ind_assumptions.html

5. Airline travel
Emissions based on distance traveled (assumed to be 1000 miles for each short haul leg, 3000 miles for medium haul and 8000 miles for long haul). The average weight CO2 equivalent emitted per mile per passenger is 0.59, 0.40 and 0.42 lbs for short medium and long haul flights respectively (assuming plane is full). Note, radiative warming effect of airline emissions including ozone production, water vapor and contrails is about 2.7 times greater than just the CO2 emissions alone. Hence we use a CO2 equivalent here.
Sort haul flights have higher emissions due to the large emissions during the landing/take off Cycle, while longer haul flights have slightly higher emissions than medium haul flights due to the additional weight of fuel required for the longer journey.
Note premium economy = 1.3 times this amount, business = 2.1 times, first class = 3.4 times
Note, these approximations are based on industry averages. The actual amount of fuel burned per passenger per mile depends on the type of plane, the number of people flying, the weight of the cargo and the configuration of seating.
Source: Ross, D. 2007: GHG emissions by airline travel, Carbon Planet http://www.carbonplanet.com/downloads/ghg_emission_factors_for_flights.pdf

 

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