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

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

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

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

In 2008, industry used 31% of the total energy used; next was transportation at 28%, then residential at 22%, and commercial at 19%.

In 2008, industry used 31% of the total energy used; next was transportation at 28%, then residential at 22%, and commercial at 19%.

In 2008, industry used 31% of the total energy used; next was transportation at 28%, then residential at 22%, and commercial at 19%.

The average U.S. car gets 21.4 mpg. About 19 pounds of carbon dioxide are emitted for every gallon burned, or 0.9 lb/mile.

The average U.S. car gets 21.4 mpg. About 19 pounds of carbon dioxide are emitted for every gallon burned, or 0.9 lb/mile.

Consuming the largest amount of energy, space heating accounts for 31% of all residential energy used. Space cooling accounts for an additional 12% of energy usage.

Consuming the largest amount of energy, space heating accounts for 31% of all residential energy used. Space cooling accounts for an additional 12% of energy usage.

Consuming the largest amount of energy, space heating accounts for 31% of all residential energy used. Space cooling accounts for an additional 12% of energy usage.

More than a quarter of the world's coal reserves are located in the United States.

More than a quarter of the world's coal reserves are located in the United States.

A gallon of gasoline contains about the same energy as 1 kg of hydrogen. Although fuel cells are expected to be twice as efficient as gasoline vehicles, hydrogen is very diffuse and storing an ample supply on board represents an engineering challenge.

A gallon of gasoline contains about the same energy as 1 kg of hydrogen. Although fuel cells are expected to be twice as efficient as gasoline vehicles, hydrogen is very diffuse and storing an ample supply on board represents an engineering challenge.

90% of the coal mined in the United States was used to generate electricity in 2006.

90% of the coal mined in the United States was used to generate electricity in 2006.

Less than 2% of the U.S. supply of natural gas is imported from outside North America.

Less than 2% of the U.S. supply of natural gas is imported from outside North America.

Lighting accounts for 18% of the electricity used in the United States. A 12% decrease in overall electricity use in buildings could be realized if incandescent bulbs were replaced with CFL or LED bulbs.