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.

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.

All of the reasons mentioned are considered obstacles to producing cars that run on hydrogen fuel cells.

All of the reasons mentioned are considered obstacles to producing cars that run on hydrogen fuel cells.

All of the reasons mentioned are considered obstacles to producing cars that run on hydrogen fuel cells.

The most recent federal efficiency standards, finalized by the U.S. National Highway Traffic Safety Administration (NHTSA) and the Environmental Protection Agency (EPA) in 2012, are projected to increase fuel economy to the equivalent of 54.5 mpg for cars and light-duty trucks by model year 2025, while also reducing CO2 emissions. 

The most recent federal efficiency standards, finalized by the U.S. National Highway Traffic Safety Administration (NHTSA) and the Environmental Protection Agency (EPA) in 2012, are projected to increase fuel economy to the equivalent of 54.5 mpg for cars and light-duty trucks by model year 2025, while also reducing CO2 emissions. 

The most recent federal efficiency standards, finalized by the U.S. National Highway Traffic Safety Administration (NHTSA) and the Environmental Protection Agency (EPA) in 2012, are projected to increase fuel economy to the equivalent of 54.5 mpg for cars and light-duty trucks by model year 2025, while also reducing CO2 emissions. 

The most recent federal efficiency standards, finalized by the U.S. National Highway Traffic Safety Administration (NHTSA) and the Environmental Protection Agency (EPA) in 2012, are projected to increase fuel economy to the equivalent of 54.5 mpg for cars and light-duty trucks by model year 2025, while also reducing CO2 emissions. 

School buildings represent 13% of commercial buildings energy use, or about 2.5% of total U.S. energy use (13% × 19%).

School buildings represent 13% of commercial buildings energy use, or about 2.5% of total U.S. energy use (13% × 19%).

School buildings represent 13% of commercial buildings energy use, or about 2.5% of total U.S. energy use (13% × 19%).

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.

Mining coal disturbs the land and modifies the chemistry of rainwater runoff, which in turn affects stream and river water quality.

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.

Gasoline, diesel fuel, and natural gas all release CO2 when burned.

Gasoline, diesel fuel, and natural gas all release CO2 when burned.

Gasoline, diesel fuel, and natural gas all release CO2 when burned.

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.