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.

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.

What is the primary energy user in the industrial sector?

  • Sorry, that’s incorrect.

    A few industries use a very large share of energy in the industrial sector. Petroleum refining is the principal consumer, with the chemical industry a close second. Those users, plus the paper and metal industries, account for 78% of total industrial energy use.

  • Sorry, that’s incorrect.

    A few industries use a very large share of energy in the industrial sector. Petroleum refining is the principal consumer, with the chemical industry a close second. Those users, plus the paper and metal industries, account for 78% of total industrial energy use.

  • Sorry, that’s incorrect.

    A few industries use a very large share of energy in the industrial sector. Petroleum refining is the principal consumer, with the chemical industry a close second. Those users, plus the paper and metal industries, account for 78% of total industrial energy use.

  • Sorry, that’s incorrect.

    A few industries use a very large share of energy in the industrial sector. Petroleum refining is the principal consumer, with the chemical industry a close second. Those users, plus the paper and metal industries, account for 78% of total industrial energy use.

  • Correct!

    A few industries use a very large share of energy in the industrial sector. Petroleum refining is the principal consumer, with the chemical industry a close second. Those users, plus the paper and metal industries, account for 78% of total industrial energy use.

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. 

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%. 

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.

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.

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.

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Compact Fluorescent Lamp (CFL)

A device that emits light due to electronic excitation of mercury atoms within a lamp. The mercury atoms lose their excitation energy by emitting an ultraviolet photon, which is converted to visible light in the fluorescent coating of the bulb. CFLs are much more efficient in converting electrical energy to light energy than incandescent bulbs.

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