* Three hours of labor: The U.S. coal mining industry directly employs over 80,000 people. The production rate for each employee is a little over six tons per labor hour, so 16 tons represents less than three hours of labor.
* 37 tons of carbon dioxide: Carbon dioxide emissions average about 2.3 pounds per kWh delivered. For 16 tons of coal representing 32,000 kWh of electricity delivered, that's 74,000 pounds (or 37 tons) of carbon dioxide produced. Note that there will be variation in this number depending on the carbon content of coal and electric losses assumed from the generator to delivery. The reason a ton of coal produces multiple tons of carbon dioxide is because during combustion the carbon atom (with an atomic weight of 12) unites with two oxygen atoms (with an atomic weight of 16) to form carbon dioxide, having an atomic weight of 44. To give you perspective on volume, 5 tons of carbon dioxide would occupy an Olympic size swimming pool. Despite such voluminous emissions, the carbon dioxide content in air near the earth's surface is less than 0.04 percent.
* Two tons of fly ash. U.S. coal fired power plants produce about 120 million tons of ash, while burning just over one billion tons of coal annually, or roughly 1.2 tons of fly ash is produced per 10 tons of coal. Over 40 percent of resulting fly ash is put to a beneficial use such as concrete applications, and the fly ash consists largely of aluminum, silicon, iron, and carbonate oxides.
* 0.002 pounds of mercury. U.S. coal power plants emit about 50 tons of mercury per year compared to over a billion tons of coal consumed.
