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?

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? Carbon capture and storage would reduce energy efficiency of a coal plant?

  • Correct!

    Carbon capture and storage will reduce energy efficiency of a coal plant, though it will decrease carbon emissions.

  • Sorry, that’s incorrect.

    Carbon capture and storage will reduce energy efficiency of a coal plant, though it will decrease carbon emissions.

What type of transportation uses the most total energy?

  • Correct!

    By far the largest share of energy in transportation is consumed by cars, light trucks, and motorcycles—about 58% in 2012, followed by other trucks (21%), aircraft (9%), boats and ships (3%), and trains and buses (3%). Pipelines account for 3% and military uses for 2%.

  • Sorry, that’s incorrect.

    By far the largest share of energy in transportation is consumed by cars, light trucks, and motorcycles—about 58% in 2012, followed by other trucks (21%), aircraft (9%), boats and ships (3%), and trains and buses (3%). Pipelines account for 3% and military uses for 2%.

  • Sorry, that’s incorrect.

    By far the largest share of energy in transportation is consumed by cars, light trucks, and motorcycles—about 58% in 2012, followed by other trucks (21%), aircraft (9%), boats and ships (3%), and trains and buses (3%). Pipelines account for 3% and military uses for 2%.

  • Sorry, that’s incorrect.

    By far the largest share of energy in transportation is consumed by cars, light trucks, and motorcycles—about 58% in 2012, followed by other trucks (21%), aircraft (9%), boats and ships (3%), and trains and buses (3%). Pipelines account for 3% and military uses for 2%.

  • Sorry, that’s incorrect.

    By far the largest share of energy in transportation is consumed by cars, light trucks, and motorcycles—about 58% in 2012, followed by other trucks (21%), aircraft (9%), boats and ships (3%), and trains and buses (3%). Pipelines account for 3% and military uses for 2%.

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.

True or false? Fuel cells store energy.

  • Sorry, that’s incorrect.

    Fuel cells are an efficient way to convert hydrogen to electricity, but the energy is stored in the hydrogen.

  • Correct!

    Fuel cells are an efficient way to convert hydrogen to electricity, but the energy is stored in the hydrogen.

True or false? Wind energy generation is increasing in the United States.

  • Correct!

    In the United States, the amount of electricity generated from wind doubled between 2009 and 2014, and now makes up 18% of all renewable energy consumed and almost 2% of total U.S. energy use. 

  • Sorry, that’s incorrect.

    In the United States, the amount of electricity generated from wind doubled between 2009 and 2014, and now makes up 18% of all renewable energy consumed and almost 2% of total U.S. energy use. 

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.

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.

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 of the following is frequently used as a unit of measurement for the energy content of fuels?

  • Sorry, that’s incorrect.

    The British Thermal Unit, or Btu, is frequently used as a measure for energy content of fuels. One gallon of gasoline contains about 124,000 Btu.

  • Correct!

    The British Thermal Unit, or Btu, is frequently used as a measure for energy content of fuels. One gallon of gasoline contains about 124,000 Btu.

  • Sorry, that’s incorrect.

    The British Thermal Unit, or Btu, is frequently used as a measure for energy content of fuels. One gallon of gasoline contains about 124,000 Btu.

  • Sorry, that’s incorrect.

    The British Thermal Unit, or Btu, is frequently used as a measure for energy content of fuels. One gallon of gasoline contains about 124,000 Btu.

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