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.

Which renewable energy source contributed the most to the total energy consumed in the United States in 2014?

  • Sorry, that’s incorrect.

    Wood and waste biomass, along with biofuels, accounted for about 50% of the U.S. renewable energy supply in 2014, and more than 4% of all energy consumed. 

  • Sorry, that’s incorrect.

    Wood and waste biomass, along with biofuels, accounted for about 50% of the U.S. renewable energy supply in 2014, and more than 4% of all energy consumed. 

  • Correct!

    Wood and waste biomass, along with biofuels, accounted for about 50% of the U.S. renewable energy supply in 2014, and more than 4% of all energy consumed. 

  • Sorry, that’s incorrect.

    Wood and waste biomass, along with biofuels, accounted for about 50% of the U.S. renewable energy supply in 2014, and more than 4% of all energy consumed. 

Which residential usage consumes the largest amount of energy?

  • Sorry, that’s incorrect.

    Consuming the largest amount of energy, space heating accounts for 31% of all residential energy used. Space cooling accounts for an additional 12% of energy usage.

  • Sorry, that’s incorrect.

    Consuming the largest amount of energy, space heating accounts for 31% of all residential energy used. Space cooling accounts for an additional 12% of energy usage.

  • Correct!

    Consuming the largest amount of energy, space heating accounts for 31% of all residential energy used. Space cooling accounts for an additional 12% of energy usage.

  • Sorry, that’s incorrect.

    Consuming the largest amount of energy, space heating accounts for 31% of all residential energy used. Space cooling accounts for an additional 12% of energy usage.

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.

Energy intensity is a measure of:

  • Correct!

    Energy intensity is a measure of a nation's energy efficiency represented through energy use per unit of GDP (Gross Domestic Product).

  • Sorry, that’s incorrect.

    Energy intensity is a measure of a nation's energy efficiency represented through energy use per unit of GDP (Gross Domestic Product).

  • Sorry, that’s incorrect.

    Energy intensity is a measure of a nation's energy efficiency represented through energy use per unit of GDP (Gross Domestic Product).

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. 

True or false? Wind energy generation is increasing in the United States.

  • Correct!

    In the United States, the amount of electricity generated from wind doubled between 2009 and 2014, and now makes up 18% of all renewable energy consumed and almost 2% of total U.S. energy use. 

  • Sorry, that’s incorrect.

    In the United States, the amount of electricity generated from wind doubled between 2009 and 2014, and now makes up 18% of all renewable energy consumed and almost 2% of total U.S. energy use. 

The United States is home to how many of the world's automobiles?

  • Sorry, that’s incorrect.

    With less than 5% of the world's population, the United States is home to one-third of the world's automobiles.

  • Correct!

    With less than 5% of the world's population, the United States is home to one-third of the world's automobiles.

  • Sorry, that’s incorrect.

    With less than 5% of the world's population, the United States is home to one-third of the world's automobiles.

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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