Two methods are used to generate 1 GWhe of electricity: (1)burning coal with a generation efficiency of 30% and (2) burningMSW with an efficiency of 25%. (The energy content of coal is 31MJ/kg.) For MSW generation, assume an energy content of 10 MJ/kgand a total net energy requirement of 5000 MJ/tonne for collectionand transportation, which is provided by burning fossil fuels at20% efficiency. The MSW consists of 50% carbon-neutral organicmaterial and 50% fossil fuel–derived material. (The energy contentand the density of petroleum is 35 MJ/kg and 0.72 kg/L,respectively.) Compare the relative contributions to greenhouse gasemissions for these two methods. Ignore any effects of possiblecarbon sequestration.
