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.

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%. 

Energy intensity is a measure of:

  • Correct!

    Energy intensity is a measure of a nation's energy efficiency represented through energy use per unit of GDP (Gross Domestic Product).

  • Sorry, that’s incorrect.

    Energy intensity is a measure of a nation's energy efficiency represented through energy use per unit of GDP (Gross Domestic Product).

  • Sorry, that’s incorrect.

    Energy intensity is a measure of a nation's energy efficiency represented through energy use per unit of GDP (Gross Domestic Product).

What are ways that electricity system operators match power needs to generation on a day-to-day basis?

  • Sorry, that’s incorrect.

    Load-following and peaker plants, demand-response and energy storage are all ways that grid operators can adjust generation to meet demand.

  • Sorry, that’s incorrect.

    Load-following and peaker plants, demand-response and energy storage are all ways that grid operators can adjust generation to meet demand.

  • Sorry, that’s incorrect.

    Load-following and peaker plants, demand-response and energy storage are all ways that grid operators can adjust generation to meet demand.

  • Sorry, that’s incorrect.

    Load-following and peaker plants, demand-response and energy storage are all ways that grid operators can adjust generation to meet demand.

  • Correct!

     

    Load-following and peaker plants, demand-response and energy storage are all ways that grid operators can adjust generation to meet demand.

In 2014, approximately how much energy did the United States use, in quadrillion BTUs?

  • Sorry, that’s incorrect.

    U.S. energy consumption was about 98 quads in 2014.

  • Sorry, that’s incorrect.

    U.S. energy consumption was about 98 quads in 2014.

  • Sorry, that’s incorrect.

    U.S. energy consumption was about 98 quads in 2014.

  • Correct!

    U.S. energy consumption was about 98 quads in 2014.

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 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.

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

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.

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Explore Other Topics

Energy Hands-on

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Integrated Gasification Combined Cycle (IGCC)

A technology that converts coal into synthetic gas, or “syngas.” See Coal Gasification.

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