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?

What is the largest reservoir of stored solar energy?

  • Sorry, that’s incorrect.

    Fossil fuels represent the largest source of stored solar energy, resulting from the transformation of biomass over millions of years into oil, natural gas and coal. 

  • Sorry, that’s incorrect.

    Fossil fuels represent the largest source of stored solar energy, resulting from the transformation of biomass over millions of years into oil, natural gas and coal. 

  • Correct!

    Fossil fuels represent the largest source of stored solar energy, resulting from the transformation of biomass over millions of years into oil, natural gas and coal. 

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. 

In 2014, how much of the world's CO2 is released by the United States?

  • Sorry, that’s incorrect.

    The United States emits about 18% of the world’s greenhouse gases, behind only China, which accounts for approximately one-quarter of total global emissions. 

  • Correct!

    The United States emits about 18% of the world’s greenhouse gases, behind only China, which accounts for approximately one-quarter of total global emissions. 

  • Sorry, that’s incorrect.

    The United States emits about 18% of the world’s greenhouse gases, behind only China, which accounts for approximately one-quarter of total global emissions. 

  • Sorry, that’s incorrect.

    The United States emits about 18% of the world’s greenhouse gases, behind only China, which accounts for approximately one-quarter of total global emissions. 

Combustion of gasoline and diesel fuel emits which of the following?

  • Sorry, that’s incorrect.

    All of the above are emitted by vehicles running on gasoline and diesel fuel.

  • Sorry, that’s incorrect.

    All of the above are emitted by vehicles running on gasoline and diesel fuel.

  • Sorry, that’s incorrect.

    All of the above are emitted by vehicles running on gasoline and diesel fuel.

  • Sorry, that’s incorrect.

    All of the above are emitted by vehicles running on gasoline and diesel fuel.

  • Correct!

    All of the above are emitted by vehicles running on gasoline and diesel fuel.

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 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.

The United States is home to how many of the world's automobiles?

  • Sorry, that’s incorrect.

    With less than 5% of the world's population, the United States is home to one-third of the world's automobiles.

  • Correct!

    With less than 5% of the world's population, the United States is home to one-third of the world's automobiles.

  • Sorry, that’s incorrect.

    With less than 5% of the world's population, the United States is home to one-third of the world's automobiles.

Which has been growing more, energy to heat homes or energy to cool homes?

  • Sorry, that’s incorrect.

    Current trends indicate that by 2040 residential buildings will consume up to 28% less energy for heating but about 50% more for cooling. 

  • Correct!

    Current trends indicate that by 2040 residential buildings will consume up to 28% less energy for heating but about 50% more for cooling. 

  • Sorry, that’s incorrect.

    Current trends indicate that by 2040 residential buildings will consume up to 28% less energy for heating but about 50% more for cooling. 

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.

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