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 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.

In 2014, of the four economic sectors, which used the most energy in the United States?

  • Sorry, that’s incorrect.

    In 2014, the industrial sector represented 32% of U.S. energy use, while transportation was 28%. Residential and commercial were 22% and 19% respectively.

  • Sorry, that’s incorrect.

    In 2014, the industrial sector represented 32% of U.S. energy use, while transportation was 28%. Residential and commercial were 22% and 19% respectively.

  • Correct!

    In 2014, the industrial sector represented 32% of U.S. energy use, while transportation was 28%. Residential and commercial were 22% and 19% respectively.

  • Sorry, that’s incorrect.

    In 2014, the industrial sector represented 32% of U.S. energy use, while transportation was 28%. Residential and commercial were 22% and 19% respectively.

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.

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.

Which of the following is considered an obstacle to cars running on hydrogen fuel cells?

  • Sorry, that’s incorrect.

    All of the reasons mentioned are considered obstacles to producing cars that run on hydrogen fuel cells.

  • Sorry, that’s incorrect.

    All of the reasons mentioned are considered obstacles to producing cars that run on hydrogen fuel cells.

  • Sorry, that’s incorrect.

    All of the reasons mentioned are considered obstacles to producing cars that run on hydrogen fuel cells.

  • Correct!

    All of the reasons mentioned are considered obstacles to producing cars that run on hydrogen fuel cells.

Refrigerators became 70% more efficient between 1972 and 2001, primarily due to regulation. What is a market response to increased efficiency of refrigerators?

  • Sorry, that’s incorrect.

    Refrigerators are not likely to be used more or less hours in the day, but people are more likely to have more of them if they cost less to operate.

  • Sorry, that’s incorrect.

    Refrigerators are not likely to be used more or less hours in the day, but people are more likely to have more of them if they cost less to operate.

  • Correct!

    Refrigerators are not likely to be used more or less hours in the day, but people are more likely to have more of them if they cost less to operate.

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.

A typical incandescent lamp (traditional light bulb) consumes 60 watts of power. How much do each of a compact fluorescent and LED lamp consume, in watts, to produce the same amount of light?

  • Sorry, that’s incorrect.

    A typical incandescent lamp (traditional light bulb) that consumes 60 watts of power produces around 800 lumens. A compact fluorescent lamp emits the same amount of light while using only 13 watts. And an LED lamp consumes only 10 watts to give off the same 800 lumens.

  • Sorry, that’s incorrect.

    A typical incandescent lamp (traditional light bulb) that consumes 60 watts of power produces around 800 lumens. A compact fluorescent lamp emits the same amount of light while using only 13 watts. And an LED lamp consumes only 10 watts to give off the same 800 lumens.

  • Sorry, that’s incorrect.

    A typical incandescent lamp (traditional light bulb) that consumes 60 watts of power produces around 800 lumens. A compact fluorescent lamp emits the same amount of light while using only 13 watts. And an LED lamp consumes only 10 watts to give off the same 800 lumens.

  • Correct!

    A typical incandescent lamp (traditional light bulb) that consumes 60 watts of power produces around 800 lumens. A compact fluorescent lamp emits the same amount of light while using only 13 watts. And an LED lamp consumes only 10 watts to give off the same 800 lumens.

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Carbon Dioxide (CO2)

A colorless, odorless, non-poisonous gas consisting of one carbon and two oxygen atoms. A by-product of fossil fuel combustion and other industrial processes, it is considered a greenhouse gas because it traps heat (infrared energy) radiated from Earth within the atmosphere. For this reason, CO2 is believed to be a major contributor to human-induced climate change.

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