Tidal energy is gravitational in origin. Solar energy comes from nuclear reactions in the sun.

Tidal energy is gravitational in origin. Geothermal energy comes from radioactive decay inside the earth.

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.

The United States imported approximately 27% of its oil. More than one-third of that came from Canada.

The United States imported approximately 27% of its oil. More than one-third of that came from Canada.

The United States imported approximately 27% of its oil. More than one-third of that came from Canada.

Electricity is a secondary energy source because it can only be produced from the use of primary energy sources such as coal, natural gas, or nuclear reactions.

Electricity is a secondary energy source because it can only be produced from the use of primary energy sources such as coal, natural gas, or nuclear reactions.

Electricity is a secondary energy source because it can only be produced from the use of primary energy sources such as coal, natural gas, or nuclear reactions.

Electricity is a secondary energy source because it can only be produced from the use of primary energy sources such as coal, natural gas, or nuclear reactions.

Extraction of "tight" oil—light crude oil contained in geological formations of shale or sandstone—accounted for only 12% of total U.S. oil production in 2008. By 2012, it made up 35%, and is predicted to rise to 50% in the near term.

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

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

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

As of 2014, total world consumption was approximately 92 million barrels per day, about 19 million or 21% of which were used by the United States.

As of 2014, total world consumption was approximately 92 million barrels per day, about 19 million or 21% of which were used by the United States.

As of 2014, total world consumption was approximately 92 million barrels per day, about 19 million or 21% of which were used by the United States.

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

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

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

New technologies for drilling have led to increases in supply of oil in the U.S. in the decade up to 2014.

New technologies for drilling have led to increases in supply of oil in the U.S. in the decade up to 2014.

New technologies for drilling have led to increases in supply of oil in the U.S. in the decade up to 2014.

New technologies for drilling have led to increases in supply of oil in the U.S. in the decade up to 2014.