The world’s projected natural gas supplies jumped 40 percent last year. How is such a thing possible? Until a decade ago, experts believed that it would be technically infeasible to exploit the potential resource base of natural gas locked in 48 shale basins in 32 countries around the world. Then horizontal drilling combined with hydraulic fracturing, also known as fracking, was perfected. The shale gas rush was on, and last year the U.S. Energy Information Administration (EIA) issued an analysis revising its estimates of available natural gas dramatically upward.
The ability to produce clean burning natural gas from shale could transform the global energy economy. Right now we burn about 7 trillion cubic feet (tcf) of natural gas to generate about 24 percent of the electricity used in the United States. The U.S. burns a total of 23 tcf annually to heat homes and supply industrial processes as well as produce electricity. Burning coal produces about 45 percent of U.S. electricity.
A rough calculation suggests that 100 percent of coal-powered electricity generation could be replaced by burning an additional 14 tcf of natural gas, boosting overall consumption to 37 tcf per year. The EIA estimates total U.S. natural gas reserves at 2,543 tcf. This suggests that the U.S. has enough natural gas to last about 70 years if it entirely replaced the current level of coal-powered electricity generation.
Similarly, it would be notionally possible to replace all current U.S. gasoline consumption with about 17 tcf of natural gas per year. So replacing coal and gasoline immediately would require burning 54 tcf annually, implying a nearly 50-year supply of natural gas.
What about the greenhouse gas implications? The EIA estimates that the U.S. emitted 5.2 billion tons of carbon dioxide in 2009 (the last year for which figures are available). Burning coal emitted 1.75 billion metric tons of carbon dioxide into the atmosphere. Similarly, burning petroleum in the transportation sector emitted 1.7 billion metric tons of CO2, of which about two-thirds came from consuming gasoline. By comparison, the natural gas burned to generate electricity emitted 373 million metric tons of CO2. A rough calculation suggests that replacing coal and gasoline with natural gas would reduce overall U.S. carbon dioxide emissions by about 25 percent.