Quiz: Coal vs. Natural Gas


Photograph by George Steinmetz, Corbis

There’s been a lot of public debate about the pros and cons of coal vs. natural gas. But how much do you know about these two fossil fuels?

Which of the following pairs correctly represents the contribution of coal and natural gas to current world production of electricity?

  • 9% coal, 20% natural gas
  • 20% coal, 9% natural gas
  • 21% coal, 40% natural gas
  • 40% coal, 21% natural gas

About 40% of the world’s electricity is generated by burning coal, while about 21% is generated by burning natural gas. Over the past few years, the percent of natural gas has increased thanks to falling prices and lower emissions.

Burning natural gas instead of coal at a power plant results in a reduction of which of the following harmful emissions?

  • Mercury
  • Carbon dioxide
  • Nitrogen oxides
  • All of the above

On average, power plants that run on natural gas emit half as much carbon dioxide, less than a third of the nitrogen oxides, one percent of the sulfur oxides, and much lower levels of mercury than plants that burn coal.

Which of the following is the largest contributor of toxic mercury to the environment in the U.S.?

  • Coal-burning power plants
  • Broken thermometers
  • Burning hazardous wastes
  • Producing chlorine

Coal-burning power plants are responsible for more than 50% of human-caused releases of mercury in the U.S. Smaller contributions are made by broken devices, burning hazardous waste, and industrial processes that produce chlorine.

Which countries produce the highest amounts of coal and natural gas, respectively?

  • Australia, Qatar
  • China, United States
  • Russia, Saudi Arabia
  • India, Iran

The top three coal producers are China, the United States, and India. The biggest natural gas producers are the United States, Russia, Canada, and Iran.

Which U.S. states produce the most coal and natural gas, respectively?

  • Wyoming, Texas
  • West Virginia, Louisiana
  • Pennsylvania, Oklahoma
  • Alaska, Colorado

The U.S. states that produce the most coal are Wyoming (41%), West Virginia (12%), and Kentucky (10%). The states that produce the most natural gas are Texas (7.1 Tcf), Louisiana (3 Tcf), and Wyoming (2.2 Tcf).

How much coal and natural gas remain in the ground?

  • 320 million short tons of coal and 112 billion cubic meters of natural gas
  • 7 billion short tons of coal and 2 trillion cubic meters of natural gas
  • 480 billion short tons of coal and 330 trillion cubic meters of natural gas
  • 948 billion short tons of coal and 850 trillion cubic meters of natural gas

The world has an estimated 948 billion short tons of coal in the ground and 850 trillion cubic meters of recoverable natural gas reserves.

Mountaintop removal is a process used to reveal deposits of what fuel?

  • Oil
  • Natural gas
  • Coal
  • Wind

To get at coal seams, miners may blast away entire mountains. This permanently alters the landscape and can choke up streams with sediments.

About how many Americans have died in coal mining accidents over the past century?

  • 1,000
  • 10,000
  • 100,000
  • 1,000,000

About 100,000 Americans have died in accidents in coal mines over the past hundred years. The deadliest year was 1907, when 3,242 deaths occurred. Thanks to safety improvements, the death toll has dropped steadily, but it remains higher in developing countries.

How much of current U.S. production of natural gas is due to hydraulic fracturing (fracking) of shale?

  • 25%
  • 35%
  • 45%
  • 55%

As of September 2012, about 35% of the "dry" natural gas (relatively pure) produced in the U.S. is shale gas. This is mostly liberated by fracking, in which a well is drilled into rock, then filled with water, sand, and chemicals at high pressure. This causes the rock to crack, and the gas seeps out.

Many developed countries have been switching from coal to natural gas for the following reason:

  • Natural gas produces less air pollution
  • Natural gas produces lower greenhouse gas emissions
  • Natural gas now costs less
  • All of the above

Burning coal produces more pollution and more greenhouse gases than burning natural gas. Prices for natural gas have also been low, making the shift more attractive.





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