Biofuels contain carbon and although they may burn “cleaner” than oil-derived fuels, they do not avoid generating carbon dioxide emissions.

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.

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.

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.

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.

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.

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

U.S. energy consumption is projected to rise 9% by 2040, or 0.3% per  year, while global consumption will increase about 50% over the same period 

U.S. energy consumption is projected to rise 9% by 2040, or 0.3% per  year, while global consumption will increase about 50% over the same period 

U.S. energy consumption is projected to rise 9% by 2040, or 0.3% per  year, while global consumption will increase about 50% over the same period 

U.S. energy consumption is projected to rise 9% by 2040, or 0.3% per  year, while global consumption will increase about 50% over the same period 

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.

In 2014, the United States got 35% of its energy from petroleum, and experts project that demand for this fuel will rise at least through 2020. 

In 2014, the United States got 35% of its energy from petroleum, and experts project that demand for this fuel will rise at least through 2020. 

In 2014, the United States got 35% of its energy from petroleum, and experts project that demand for this fuel will rise at least through 2020.