Part 2 - Calculating your Carbon Footprint

1. If you live in southeastern Wisconsin, it is likely that most of your electrical energy currently comes from coal. The thermal energy content of coal is about 6 kW-h/kg. That means each kilogram of coal has roughly 6 kiloWatt-hours of energy in it. If the coal portion of your energy sources was perfectly efficient, i.e. 100% of the energy in the coal can be extracted and put to useful work (which is impossible according to the Second Law of Thermodynamics), how much burned coal does your total annual appliance use represent? Show your work.

2. Now consider that coal power plants are typically 35% efficient in extracting usable energy from coal. Now how much coal have you burned in a year using your appliances? Show your work.

3. Interestingly, the carbon dioxide "footprint" of your appliances is 4x as large as the mass of burned coal you computed above. How can the CO2 impact be so much larger than the actual mass of the coal burned? (Suggestion: try doing a web search to investigate this question.)