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, 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.

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%. 

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.

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.

Which of the following energy sources releases carbon dioxide when burned?

  • Sorry, that’s incorrect.

    Gasoline, diesel fuel, and natural gas all release CO2 when burned.

  • Sorry, that’s incorrect.

    Gasoline, diesel fuel, and natural gas all release CO2 when burned.

  • Sorry, that’s incorrect.

    Gasoline, diesel fuel, and natural gas all release CO2 when burned.

  • Correct!

    Gasoline, diesel fuel, and natural gas all release CO2 when burned.

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.

What technology was most responsible for increase in lighting efficiency from 45 Im/W in 2001 to 58 Im/W in 2010?

  • Sorry, that’s incorrect.

    Increasing market share of compact fluorescents was primarily responsible for the increased lighting efficiency between 2001 and 2010.

  • Sorry, that’s incorrect.

    Increasing market share of compact fluorescents was primarily responsible for the increased lighting efficiency between 2001 and 2010.

  • Correct!

    Increasing market share of compact fluorescents was primarily responsible for the increased lighting efficiency between 2001 and 2010.

  • Sorry, that’s incorrect.

    Increasing market share of compact fluorescents was primarily responsible for the increased lighting efficiency between 2001 and 2010.

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.

The consumption of energy in the United States is projected to rise by how much between 2013 and 2040?

  • Sorry, that’s incorrect.

    U.S. energy consumption is projected to rise 9% by 2040, or 0.3% per year, while global consumption will increase about 50% over the same period

  • Sorry, that’s incorrect.

    U.S. energy consumption is projected to rise 9% by 2040, or 0.3% per year, while global consumption will increase about 50% over the same period

  • Correct!

    U.S. energy consumption is projected to rise 9% by 2040, or 0.3% per year, while global consumption will increase about 50% over the same period

  • Sorry, that’s incorrect.

    U.S. energy consumption is projected to rise 9% by 2040, or 0.3% per year, while global consumption will increase about 50% over the same period

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Primary Energy

Energy that has not undergone transformation to another form. This may include fuels like natural gas or oil, or may include other forms of energy, such as solar or wind energy.

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