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?

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. 

Which has been growing more, energy used by lighting and appliances or energy used for heating and cooling?

  • Correct!

    For decades, more than half of all residential energy use went  to space heating and cooling; in 1993, it accounted for nearly 60%. But EIA data show that by 2009, that share had dropped to 48%. And in the period 1993 to 2009, energy for appliances, electronics, and lighting rose from 24% to 35%, owing to the proliferation of appliances, as well as trends toward larger TVs and other devices.

  • Sorry, that’s incorrect.

    For decades, more than half of all residential energy use went  to space heating and cooling; in 1993, it accounted for nearly 60%. But EIA data show that by 2009, that share had dropped to 48%. And in the period 1993 to 2009, energy for appliances, electronics, and lighting rose from 24% to 35%, owing to the proliferation of appliances, as well as trends toward larger TVs and other devices.

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.

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.

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.

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 percentage of harvested corn was used to produce ethanol in the U.S. in 2014?

  • Sorry, that’s incorrect.

    In 2014, about 38% of harvested corn in the US went to make ethanol and its associated coproducts

  • Sorry, that’s incorrect.

    In 2014, about 38% of harvested corn in the US went to make ethanol and its associated coproducts

  • Correct!

    In 2014, about 38% of harvested corn in the US went to make ethanol and its associated coproducts

  • Sorry, that’s incorrect.

    In 2014, about 38% of harvested corn in the US went to make ethanol and its associated coproducts

  • Sorry, that’s incorrect.

    In 2014, about 38% of harvested corn in the US went to make ethanol and its associated coproducts

  • Sorry, that’s incorrect.

    In 2014, about 38% of harvested corn in the US went to make ethanol and its associated coproducts

Which of the following is not considered to be a drawback to wind energy?

  • Sorry, that’s incorrect.

    While wind energy has many benefits, all of the above are considered drawbacks to wind energy.

  • Sorry, that’s incorrect.

    While wind energy has many benefits, all of the above are considered drawbacks to wind energy.

  • Sorry, that’s incorrect.

    While wind energy has many benefits, all of the above are considered drawbacks to wind energy.

  • Correct!

    While wind energy has many benefits, all of the above are considered drawbacks to wind energy.

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