Basic Units of Measurement and Conversions - Basic Mathematics for Water and Wastewater Operators - page 86

Calculation
Due to rounding, performing the calculations given in the equations below may not
return the exact results shown.
(18 lb propane per cylinder) × (0.817 lb C per lb propane) × (0.4536 kg/lb) × (44 kg
CO 2 per 12 kg C) × (1 metric ton/1000 kg) = 0.024 metric tons CO 2 per cylinder.
Railcars of Coal Burned
The average heat content of coal in 2009 was 27.56 mmBtu per metric ton. The aver-
age carbon coefficient of coal in 2009 was 25.34 kg carbon per mmBtu (USEPA,
2011). The fraction oxidized to CO 2 is 100% (IPCC, 2006). Carbon dioxide emis-
sions per ton of coal were determined by multiplying heat content times the carbon
coefficient times the fraction oxidized times the ratio of the molecular weight of car-
bon dioxide to that of carbon (44/12). The amount of coal in an average railcar was
assumed to be 100.19 short tons, or 90.89 metric tons (Hancock and Sreekanth, 2001).
Calculation
Due to rounding, performing the calculations given in the equations below may not
return the exact results shown.
(27.56 mmBtu/metric ton coal) × (25.34 kg C per mmBtu) × (44g CO 2 per 12g C)
× (90.89 metric tons coal per railcar) × (1 metric ton/1000 kg) = 232.74 metric tons
CO 2 per railcar.
Tons of Waste Recycled Instead of Landfilled
To develop the conversion factor for recycling rather than landfilling waste, emission
factors from the USEPA's Waste Reduction Model (WARM) were used (USEPA,
2012b). These emission factors were developed following a life-cycle assessment
methodology using estimation techniques developed for national inventories of
greenhouse gas emissions. According to WARM, the net emission reduction from
recycling mixed recyclables (e.g., paper, metals, plastics), compared with a baseline
in which the materials are landfilled, is 0.73 metric tons of carbon equivalent per
short ton. This factor was then converted to metric tons of carbon dioxide equivalent
by multiplying by 44/12, the molecular weight ratio of carbon dioxide to carbon.
Calculation
Due to rounding, performing the calculation given in the equation below may not
return the exact results show.
(0.73 metric tons of carbon equivalent per ton) × (44 g CO 2 per 12 g C) = 2.67 metric
tons CO 2 equivalent per ton of waste recycled instead of landfilled.
Coal-Fired Power Plant Emissions for One Year
In 2009, a total of 457 power plants used coal to generate at least 95% of their elec-
tricity (USEPA, 2012a). These plants emitted 1,614,625,638.1 metric tons of CO 2 in
2009. Carbon dioxide emissions per power plant were calculated by dividing the
total emissions from power plants whose primary source of fuel was coal by the
number of power plants.