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?

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: Burning biofuels does not release carbon dioxide.

  • Sorry, that’s incorrect.

    Biofuels contain carbon and although they may burn “cleaner” than oil-derived fuels, they do not avoid generating carbon dioxide emissions.

  • Correct!

    Biofuels contain carbon and although they may burn “cleaner” than oil-derived fuels, they do not avoid generating carbon dioxide emissions.

How are battery electric vehicles and hybrid vehicles different?

  • Sorry, that’s incorrect.

    Battery electric vehicles have only a motor and battery, they recharge from the grid and their carbon emissions depend on the energy used to generate the electricity they use. Hybrid vehicles have both a gasoline engine and an electric motor, and use petroleum onboard when their batteries are exhausted. Some hybrid vehicles can charge from the grid and others cannot. 

  • Sorry, that’s incorrect.

    Battery electric vehicles have only a motor and battery, they recharge from the grid and their carbon emissions depend on the energy used to generate the electricity they use. Hybrid vehicles have both a gasoline engine and an electric motor, and use petroleum onboard when their batteries are exhausted. Some hybrid vehicles can charge from the grid and others cannot. 

  • Sorry, that’s incorrect.

    Battery electric vehicles have only a motor and battery, they recharge from the grid and their carbon emissions depend on the energy used to generate the electricity they use. Hybrid vehicles have both a gasoline engine and an electric motor, and use petroleum onboard when their batteries are exhausted. Some hybrid vehicles can charge from the grid and others cannot. 

  • Sorry, that’s incorrect.

    Battery electric vehicles have only a motor and battery, they recharge from the grid and their carbon emissions depend on the energy used to generate the electricity they use. Hybrid vehicles have both a gasoline engine and an electric motor, and use petroleum onboard when their batteries are exhausted. Some hybrid vehicles can charge from the grid and others cannot. 

  • Correct!

    Battery electric vehicles have only a motor and battery, they recharge from the grid and their carbon emissions depend on the energy used to generate the electricity they use. Hybrid vehicles have both a gasoline engine and an electric motor, and use petroleum onboard when their batteries are exhausted. Some hybrid vehicles can charge from the grid and others cannot. 

On average, how much solar radiation reaches each square meter of earth?

  • Sorry, that’s incorrect.

    On average, even after passing through hundreds of kilometers of air on a clear day, solar radiation reaches Earth with enough energy in a single square meter to run a mid-size desktop computer-if all the sunlight could be captured and converted to electricity.

  • Correct!

    On average, even after passing through hundreds of kilometers of air on a clear day, solar radiation reaches Earth with enough energy in a single square meter to run a mid-size desktop computer-if all the sunlight could be captured and converted to electricity.

  • Sorry, that’s incorrect.

    On average, even after passing through hundreds of kilometers of air on a clear day, solar radiation reaches Earth with enough energy in a single square meter to run a mid-size desktop computer-if all the sunlight could be captured and converted to electricity.

In 2014, approximately how much energy did the United States use, in quadrillion BTUs?

  • Sorry, that’s incorrect.

    U.S. energy consumption was about 98 quads in 2014.

  • Sorry, that’s incorrect.

    U.S. energy consumption was about 98 quads in 2014.

  • Sorry, that’s incorrect.

    U.S. energy consumption was about 98 quads in 2014.

  • Correct!

    U.S. energy consumption was about 98 quads in 2014.

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.

What type of transportation uses the most total energy?

  • Correct!

    By far the largest share of energy in transportation is consumed by cars, light trucks, and motorcycles—about 58% in 2012, followed by other trucks (21%), aircraft (9%), boats and ships (3%), and trains and buses (3%). Pipelines account for 3% and military uses for 2%.

  • Sorry, that’s incorrect.

    By far the largest share of energy in transportation is consumed by cars, light trucks, and motorcycles—about 58% in 2012, followed by other trucks (21%), aircraft (9%), boats and ships (3%), and trains and buses (3%). Pipelines account for 3% and military uses for 2%.

  • Sorry, that’s incorrect.

    By far the largest share of energy in transportation is consumed by cars, light trucks, and motorcycles—about 58% in 2012, followed by other trucks (21%), aircraft (9%), boats and ships (3%), and trains and buses (3%). Pipelines account for 3% and military uses for 2%.

  • Sorry, that’s incorrect.

    By far the largest share of energy in transportation is consumed by cars, light trucks, and motorcycles—about 58% in 2012, followed by other trucks (21%), aircraft (9%), boats and ships (3%), and trains and buses (3%). Pipelines account for 3% and military uses for 2%.

  • Sorry, that’s incorrect.

    By far the largest share of energy in transportation is consumed by cars, light trucks, and motorcycles—about 58% in 2012, followed by other trucks (21%), aircraft (9%), boats and ships (3%), and trains and buses (3%). Pipelines account for 3% and military uses for 2%.

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. 

True or false? Fuel cells store energy.

  • Sorry, that’s incorrect.

    Fuel cells are an efficient way to convert hydrogen to electricity, but the energy is stored in the hydrogen.

  • Correct!

    Fuel cells are an efficient way to convert hydrogen to electricity, but the energy is stored in the hydrogen.

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