"Different fuels emit different amounts of carbon dioxide (CO2) in relation to the energy they produce when burned. To analyze emissions across fuels, compare the amount of CO2 emitted per unit of energy output or heat content.
Pounds of CO2 emitted per million British thermal units (Btu) of energy for various fuels:
"In 2016, about 728 billion short tons of coal were produced in 25 U.S. states. Surface mines were the source of 65% of total U.S. coal production and accounted for 62% of the total number of mines. About 0.9 million tons, or about 0.1% of total coal production, was refuse recovery coal.
The United States is a net exporter of coal. However, some coal is still imported, mostly for power plants on the eastern and southern coasts of the country, where it is cheaper to ship in coal by sea from South America than transport it from mines in the northern and western United States.1
Hydraulic fracturing, or "fracking," has changed the energy landscape. We can now affordably produce natural gas from previously inaccessible rock formations, which has led to increasing natural gas consumption. Thanks to its low prices and abundant domestic supply, natural gas may have a chance to overtake coal as the primary energy source for electricity in the United States.
America has made great strides in recent years to reduce carbon emissions by increasing efficiency and turning to other, low or non-carbon energy sources. Meanwhile, carbon emissions in China have grown dramatically during that same time. EARTH looks at this disparity and asks the difficult questions about who is to blame when the coal China is burning is imported from "cleaner" countries and the emissions are produced to manufacture goods exported back to places with lower emissions.