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.

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. 

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 efficient are ordinary commercial solar cell units?

  • Sorry, that’s incorrect.

    As of 2014, the very best experimental units could convert more than 40% of light energy to electricity; ordinary commercial units are in the range of 5% to 20%. 

  • Sorry, that’s incorrect.

    As of 2014, the very best experimental units could convert more than 40% of light energy to electricity; ordinary commercial units are in the range of 5% to 20%. 

  • Correct!

    As of 2014, the very best experimental units could convert more than 40% of light energy to electricity; ordinary commercial units are in the range of 5% to 20%. 

  • Sorry, that’s incorrect.

    As of 2014, the very best experimental units could convert more than 40% of light energy to electricity; ordinary commercial units are in the range of 5% to 20%. 

Which source(s) of energy are not nuclear in origin?

  • Sorry, that’s incorrect.

    Tidal energy is gravitational in origin. Solar energy comes from nuclear reactions in the sun.

  • Sorry, that’s incorrect.

    Tidal energy is gravitational in origin. Geothermal energy comes from radioactive decay inside the earth.

  • Correct!

    Tidal energy is gravitational in origin. Solar energy comes from nuclear reactions in the sun, and geothermal energy comes from radioactive decay inside the earth.

  • Sorry, that’s incorrect.

    Tidal energy is gravitational in origin. Solar energy comes from nuclear reactions in the sun, and geothermal energy comes from radioactive decay inside the earth.

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. 

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.

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.

Which of the following sources do experts expect will provide us with the “silver bullet” solution to our energy needs?

  • Sorry, that’s incorrect.

    There is no silver bullet. Tomorrow’s energy, like today’s, will come from a variety of sources.

  • Sorry, that’s incorrect.

    There is no silver bullet. Tomorrow’s energy, like today’s, will come from a variety of sources.

  • Sorry, that’s incorrect.

    There is no silver bullet. Tomorrow’s energy, like today’s, will come from a variety of sources.

  • Correct!

    There is no silver bullet. Tomorrow’s energy, like today’s, will come from a variety of sources.

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Secondary Energy Resource (or Source)

A source of energy that is dependent on a primary source of energy for its power. Since the production of electricity, for example, is dependent on the use of fossil fuels, nuclear power, or renewable sources, it is referred to as a secondary energy source.

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