CoolClimate Calculator

 Calculations and Data sources

Default expenditure values
 - California Average
 - Income Classes
Transportation
 - Driving Emissions
 - Public Transportation Emissions
 - Air Travel Emissions
Housing
Food, Goods & Services
 - Cost of Living Adjustments

Default expenditure values

Default expenditure values are either chosen based on your city's average, or an average based on the combination of your household size and income.  This data is available from the Bureau of Labor Statistics based on the Consumer Expenditure Survey (CES) ¹, which can be found at: http://www.bls.gov/cex/.  Data is provided for several metropolitan areas throughout the United States, as well as based on household size and income. 

California Average

The California average default values are based on the average for the West, adjusted with an index calculated using the weighted average of the populations and incomes for the states in the West.

California average default values = Default values for the West * Index_{CA Avg}

Index_{CA Avg} = California average income / Weighted average of incomes in the West

Weighted average of incomes in the west = Sum for all states(Income_state * Population_state) / Sum for all states (Population_state)

Once you enter a value in the calculator, the default value gets replaced with your personal value when calculating your emissions.  If you do not enter a number, however, the default value will remain. 

Income Classes

Expenditure data based on household size is available for the following income classes:

1. Less than $5,000
2. $5,000-$9,999
3. $10,000-$14,999
4. $15,000-$19,999
5. $20,000-$29,999
6. $30,000-$39,999
7. $40,000-$49,999
8. $50,000-$69,999
9. $70,000 or more

However, because these income categories have been the same in the Consumer Expenditure Survey since 1991, we do not feel that they suffice as income categories for users today.  CES data for higher income categories is not available based on household size.  Therefore, to make our calculator more useful and user-friendly the income categories have been redefined as:

1. Less than $10,000
2. $10,000-$19,999
3. $20,000-$29,999
4. $30,000-$39,999
5. $40,000-$49,999
6. $50,000-$59,999
7. $60,000-$79,999
8. $80,000-$99,999
9. $100,000-$119,999
10. $120,000 or more

Default values based on these income categories were calculated using two methods.  For "Less than $10,000", and "$10,000-$19,999", averages of the two included categories were taken.  For the categories "$50,000-$59,999" and "$60,000-$79,999", and categories beyond $70,000 linear interpolation or extrapolation was used, using the expenditures and average incomes of the "$50,000-$69,999" and "$70,000 or more" categories. as reference points.

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Transportation

Driving emissions

Data and sources

Calculations

GHGs/mile [gCO₂/mi] = Vehicle manufacturing emissions [gCO₂/vehicle] / Vehicle lifetime [mi/vehicle]

Miles driven [mi/yr] / Miles per gallon [mi/gal] = Fuel used [gal/yr]

Fuel used [gal/yr] * (direct + indirect fuel emissions [gCO₂/gal]) = Fuel emissions [gCO₂/yr]

Miles driven [mi/yr] * (Vehicle manufacturing emissions [gCO₂/ton] * Vehicle size [ton] / Vehicle lifetime [mi]) = Vehicle manufacturing emissions [gCO₂/yr]

Total driving emissions = Fuel emissions [gCO₂/yr] + Vehicle manufacturing emissions [gCO₂/yr]

Public Transportation emissions

Data and sources

Calculations

Public transportation emissions [gCO2/yr] = Miles traveled [mi/yr] * (Public transportation emissions (direct) [gCO₂/mi] + Public transportation emissions (direct) * Indirect emissions multiplication factor [%])

Air Travel Emissions

Data and sources

Calculations

Based on total air miles

Air Travel emissions [gCO₂/yr] = Total air miles [mi/yr] * (Average emissions per air mile (direct) [gCO₂/mi] * Indirect well-to-pump factor (1.2) * indirect atmospheric radiative forcing factor (1.9)

Based on number of trips

Air Travel emissions [gCO2/yr] = ((Number of short trips [trip] * Emissions per short trip [gCO2/trip]) + (Number of medium trips [trip] * Emissions per medium trip [gCO2/trip]) + (Number of long trips [trip] * Emissions per long trip [gCO2/trip]) + (Number of extended trips [trip] * Emissions per extended trip [gCO2/trip])) * Indirect well-to-pump multiplication factor (1.2) * indirect atmospheric radiative forcing multiplication factor (1.9)

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Housing

Electricity and natural gas prices are based on state averages.  Data is from the Energy Information Administration.  Electricity data can be found at http://www.eia.doe.gov/fuelelectric.html, and natural gas data can be found at http://www.eia.doe.gov/oil_gas/natural_gas/info_glance/natural_gas.html.  The emissions for natural gas are based on data from http://www.eia.doe.gov/oiaf/1605/coefficients.html and it is the same for every state.  Electricity emissions are based on eGrid subregions (http://www.epa.gov/cleanenergy/energy-resources/egrid/index.html) corresponding to each U.S. state. 

Emissions data for fuel oil, other fuels, and water and sewage are based on EIO-LCA data.  More information about EIO-LCA can be found under Food, Goods and Services.

Data and Sources

Calculations

Household emissions [gCO₂/yr] = Electricity emissions [gCO₂/yr] + Natural gas emissions [gCO₂/yr] + Other fuel emissions [gCO₂/yr] + Water and sewage emissions [gCO₂/yr] + Housing construction emissions [gCO₂/yr]

Electricity emissions [gCO₂/yr] = Electricity costs [$/mo] * 12 mo/yr * Electricity price [$/kWh] * Electricity emissions [gCO₂/kWh]

Natural gas emissions [gCO₂/yr] = Natural gas costs [$/mo] * 12 mo/yr * Natural gas price [$/kWh] * Natural gas emissions [gCO₂/kWh]

Other fuel emissions [gCO₂/yr] = Other fuel costs [$/mo] * 12 mo/yr * Other fuel emissions [gCO₂/$]

Water and sewage emissions [gCO₂/yr] = Water and sewage costs [$/mo] * 12 mo/yr * Water and sewage emissions [gCO₂/$]

Housing construction emissions [gCO₂/yr] = Square feet of household [sqft] * Housing emissions [gCO₂/(sqft*yr)]

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Food, Goods & Services

We use Economic Input-Output Life Cycle Assessment -  EIO-LCA,¹⁰ created by the Green Design Institute at Carnegie Mellon University, to calculate emissions from food, goods and services. EIO-LCA is a widely used life cycle assessment model of cradle-to-gate emissions of all major greenhouse gases per dollar of industry output for each of roughly 500 sectors of the U.S. economy.

We modify EIO-LCA emission factors to account for: 1) differences in consumer prices vs. producer prices ^{9 16}; 2) emissions from transport to market, wholesale trade and retail trade ^{11 16}; 3) inflation (using the Producer Price Index ¹² from 1997 to 2008); 4) changes in greenhouse gas intensity (emissions per unit of production) from 1997 to 2008, estimated at 1.9% per year ¹³; and 5) changes in industrial output for each sector ¹⁷. Next we aggregate all 280 consumer product categories in EIO-LCA into 6 categories of food, 3 categories of goods, and a single category of services, using averages weighted by consumer spending ¹⁷ from products in each sector.

Finally, we account for differences between the Consumer Expenditure Survey, produced by the Bureau of Labor Statistics, and the 1997 US Benchmark Input-Output Accounts produced by the Bureau of Economic Analysis using conversion factors provided by Garner et al.¹⁴.

Data and Sources

Calculations

Food emissions [gCO₂/yr] = Sum of food categories (Dollars spent on each category [$/mo] * Emissions for each category [gCO2/$]*12 [mo/yr])

Goods and Services emissions [gCO₂/yr] = Sum of goods and services categories (Dollars spent on each category [$/mo] * Emissions for each category [gCO2/$]*12 [mo/yr])

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Cost of Living adjustments

When you enter the city you live in, cost of living adjustments are made based on data available from the American Chamber of Commerce Research Association (ACCRA)'s Cost of Living Index (COLI) ¹⁵.

The data for individual items were categorized into groups, including food, goods and services.  Indices were made for each item, comparing them to the national average.  For example, the national average cost of toothpaste was cited as $2.40, and in Los Angeles it was cited as $2.86.  The index was calculated by dividing the city by the national average, so for LA, the index for toothpaste would be 1.19.  Then the items were grouped into categories, including food, goods and services. 

For each category, the average index of all items was taken to create a group index that is used to adjust your expenditures on items in these three categories.  If data for your city was not available, your prices were not adjusted for cost of living differences.  If you use a state average, the cost of living adjustment is based on an average of all cities in that state for which data is available.

References

1. Bureau of Labor Statistics based on the Consumer Expenditure Survey, which can be found at: http://www.bls.gov/cex/
2. WRI Mobile Combustion CO2 Emissions Calculation Tool, Version 1.2 (June 2003).  Visit the GHG Protocol Initiative (http://www.ghgprotocol.org) for more information and other GHG calculator tools
3. GREET. The Center for Transportation Research, Energy Systems Division at Argonne National Laboratory.  This model can be found at: http://www.transportation.anl.gov/software/GREET/
4. Energy Information Administration
   http://www.eia.doe.gov/fuelelectric.html
5. eGrid.
   http://www.epa.gov/cleanenergy/energy-resources/egrid/index.html
6. Energy Information Administration
   http://www.eia.doe.gov/oil_gas/natural_gas/info_glance/natural_gas.html
7. Energy Information Administration
   http://www.eia.doe.gov/oiaf/1605/coefficients.html
8. Quantifying CO2 Emissions of the Typical U.S.A. house, Unpublished study by Roxana, Hernandez, et al.
9. Hendrickson, C. T.; Lave, L.B.; Matthews, H.S. Environmental Life Cycle Assessment of Goods and Services: An Input-Output Approach. Resources for the Future Press: Washington, D.C., 2006. Page 51.
10. Green Design Institute, Carnegie Mellon University, Economic Input-Output Life Cycle Assessment -  EIO-LCA (www.eiolca.net). Accessed May 2007.
11. Norris, G., Croce, F.D., Jolliet, O. Energy Burdens of Wholesale and Retail Portions of Product Life Cycles. Journal of Industrial Ecology. 2006, 6(2), 59-69.
12. Burea of Labor Statistics, Producer Price Index. http://www.bls.gov/ppi
13. Energy Information Agency. Trends in U.S. Carbon Intensity and Total Greenhouse Gas Intensity, in Emissions of Greenhouse Gases in the United States 2003. http://www.eia.doe.gov/oiaf/1605/archive/gg04rpt/trends.html (Accessed January 18, 2008)
14. Garner, T. I., Janini, W.P., Paskiewicz, L, and Vendernia, M.. The CE and PCE: a comparison. Monthly Labor Review. 2006, 129(9), 20-46.
15. American Chamber of Commerce Research Association (ACCRA)'s Cost of Living Index (COLI).  This data can be found on their website at http://www.coli.org/.
16. Webber, C. L., and Matthews, H. S.. Food-Miles and the Relative Climate Impacts of Food Choices in the
    United States. Environmental Science & Technology. 2008, 42, 3508–3513
17. Bureau of Economic Analysis. 1997 Benchmark Input-Output
    Accounts; Bureau of Economic Analysis, Department of Commerce:
    Washington, DC, 2002.