The National Academies

The National Academies: What You Need To Know About Energy

What You Need To Know About Energy

What do you know about energy?

On average, which is most efficient in coverting heat into electic power?

  • Sorry, that’s incorrect.

    On average, a typical coal-burning power plant in 2013 was about 33% efficient in converting heat energy into electrical power. A gas-fired plant was about 42% efficient. And in natural gas combined-cycle power plants—in which waste heat from a natural gas turbine is used to power a steam turbine—generation may be as much as 60% efficient.

  • Sorry, that’s incorrect.

    On average, a typical coal-burning power plant in 2013 was about 33% efficient in converting heat energy into electrical power. A gas-fired plant was about 42% efficient. And in natural gas combined-cycle power plants—in which waste heat from a natural gas turbine is used to power a steam turbine—generation may be as much as 60% efficient.

  • Correct!

    On average, a typical coal-burning power plant in 2013 was about 33% efficient in converting heat energy into electrical power. A gas-fired plant was about 42% efficient. And in natural gas combined-cycle power plants—in which waste heat from a natural gas turbine is used to power a steam turbine—generation may be as much as 60% efficient.

In 2014, how much of the world's CO2 is released by the United States?

  • Sorry, that’s incorrect.

    The United States emits about 18% of the world’s greenhouse gases, behind only China, which accounts for approximately one-quarter of total global emissions. 

  • Correct!

    The United States emits about 18% of the world’s greenhouse gases, behind only China, which accounts for approximately one-quarter of total global emissions. 

  • Sorry, that’s incorrect.

    The United States emits about 18% of the world’s greenhouse gases, behind only China, which accounts for approximately one-quarter of total global emissions. 

  • Sorry, that’s incorrect.

    The United States emits about 18% of the world’s greenhouse gases, behind only China, which accounts for approximately one-quarter of total global emissions. 

How many gallons of water are required to hydraulically fracture a well, on average in the U.S.?

  • Sorry, that’s incorrect.

    The national average is around 1.5 million gallons per well , according to the EPA.

  • Sorry, that’s incorrect.

    The national average is around 1.5 million gallons per well , according to the EPA.

  • Sorry, that’s incorrect.

    The national average is around 1.5 million gallons per well , according to the EPA.

  • Correct!

    The national average is around 1.5 million gallons per well , according to the EPA.

True or False: Burning coal in electric power plants is a major source of CO2 and other emissions. However, its use doesn't have negative consequences beyond the emissions caused by combustion.

  • Sorry, that’s incorrect.

    Mining coal disturbs the land and modifies the chemistry of rainwater runoff, which in turn affects stream and river water quality.

  • Correct!

    Mining coal disturbs the land and modifies the chemistry of rainwater runoff, which in turn affects stream and river water quality.

If electricity production wastes between 40 and 65% of the primary energy source, why is it used?

  • Sorry, that’s incorrect.

    Most direct uses of primary energy are limited to generating heat and motion. Electricity, by contrast, is extremely versatile, with a wide range of complex applications. 

  • Sorry, that’s incorrect.

    Most direct uses of primary energy are limited to generating heat and motion. Electricity, by contrast, is extremely versatile, with a wide range of complex applications. 

  • Correct!

    Most direct uses of primary energy are limited to generating heat and motion. Electricity, by contrast, is extremely versatile, with a wide range of complex applications. 

Renewable energy (solar, wind, geothermal, hydroelectric, biofuels, waste, and wood) accounted for what percentage of the total energy supply in the United States in 2014?

  • Correct!

    In 2014, 10% of our total energy use came from renewable energy sources, such as biomass, wind, solar, and hydropower.

  • Sorry, that’s incorrect.

    In 2014, 10% of our total energy use came from renewable energy sources, such as biomass, wind, solar, and hydropower.

  • Sorry, that’s incorrect.

    In 2014, 10% of our total energy use came from renewable energy sources, such as biomass, wind, solar, and hydropower.

  • Sorry, that’s incorrect.

    In 2014, 10% of our total energy use came from renewable energy sources, such as biomass, wind, solar, and hydropower.

True or false? Carbon capture and storage would reduce energy efficiency of a coal plant?

  • Correct!

    Carbon capture and storage will reduce energy efficiency of a coal plant, though it will decrease carbon emissions.

  • Sorry, that’s incorrect.

    Carbon capture and storage will reduce energy efficiency of a coal plant, though it will decrease carbon emissions.

What is the largest reservoir of stored solar energy?

  • Sorry, that’s incorrect.

    Fossil fuels represent the largest source of stored solar energy, resulting from the transformation of biomass over millions of years into oil, natural gas and coal. 

  • Sorry, that’s incorrect.

    Fossil fuels represent the largest source of stored solar energy, resulting from the transformation of biomass over millions of years into oil, natural gas and coal. 

  • Correct!

    Fossil fuels represent the largest source of stored solar energy, resulting from the transformation of biomass over millions of years into oil, natural gas and coal. 

Which of the following is emitted by coal-fired power plants?

  • Sorry, that’s incorrect.

    All of the above are emitted from coal-fired power plants and can be harmful to our health and the environment.

  • Sorry, that’s incorrect.

    All of the above are emitted from coal-fired power plants and can be harmful to our health and the environment.

  • Sorry, that’s incorrect.

    All of the above are emitted from coal-fired power plants and can be harmful to our health and the environment.

  • Sorry, that’s incorrect.

    All of the above are emitted from coal-fired power plants and can be harmful to our health and the environment.

  • Correct!

    All of the above are emitted from coal-fired power plants and can be harmful to our health and the environment.

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