Thursday, June 3, 2010

Calculating Personal Energy Use And Carbon Equivalents

In the previous post I gave an example of energy use calculations for our residence and car.  When energy is produced, transported, and used, CO2 is produced.  CO2 is an important greenhouse gas and recent research suggests that monitoring and controlling its production and release is necessary for good policy formation.  We can begin this process by calculating our personal production associated with residence and car.  
Using the numbers for annual energy that I gave before and CO2 equivalents for fuels, our annual production of CO2 can be calculated.  
400 gal propane      =  36.64 Mbtu  x 139.2 = 5,100 lbs
120 gal gasoline      =  13.80 Mbtu  x 156.4 = 2,158 lbs 
3 cord firewood        =  72.00 Mbtu  x 195.0 = 14,040 lbs
550 Kwh electricity   =    1.87 Mbtu              =  0 lbs
Total residential        =  124.31 Mbtu            = 21,298 lbs 

Car gasoline            =  55.20 Mbtu  x 156.4   = 8,633 lbs 
Waste disposal        =  (EPA calculation)      = 1,493 lbs 
Total annual household CO2 production for 2 people = 31,424 lbs 

(Assumed 1 Mbtu propane = 139.2 lbs CO2; 1 Mbtu gasoline = 156.4 lbs CO2;  1 Mbtu firewood = 195.0 lbs CO2; electricity was solar generated with no CO2 production).

The EPA calculates that average U.S. annual residence and car CO2 production for a household of 2 people is 41,500 lbs CO2.  So Jackie and I are at 75.7% of the average.  Assuming that less CO2 is better, we can begin to contemplate ways to reduce our “carbon footprint”.  As pointed out in the previous post, these calculations only include energy and carbon used and released by annual use of the house and car and do not include carbon released from production, transport, and marketing of food, clothes, shelter, appliances, education, and cars.  These latter items need to be accounted for by life cycle calculations that are beyond the scope of this post.
So have some fun and do your own calculations for energy use and carbon release.  
See here and here for examples.  
Posted by michael

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