In 2005, a million Btu of energy from coal cost approximately $2, versus $5 for natural gas and $10 for oil. However, prices can fluctuate due to changes in the economy and new government policies.

In 2005, a million Btu of energy from coal cost approximately $2, versus $5 for natural gas and $10 for oil. However, prices can fluctuate due to changes in the economy and new government policies.

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.

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.

In 2008, the United States depended most on coal to generate electricity. Coal provided approximately 49% of the electricity generated by the United States that year.

In 2008, the United States depended most on coal to generate electricity. Coal provided approximately 49% of the electricity generated by the United States that year.

In 2008, the United States depended most on coal to generate electricity. Coal provided approximately 49% of the electricity generated by the United States that year.

There is no silver bullet. Tomorrow’s energy, like today’s, will come from a variety of sources.

There is no silver bullet. Tomorrow’s energy, like today’s, will come from a variety of sources.

There is no silver bullet. Tomorrow’s energy, like today’s, will come from a variety of sources.

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.

U.S. domestic production of crude oil peaked around 1970 at about 9.5 million barrels per day (MBD) and declined to about 5.1 MBD by 2006.

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.

Reducing demand through the improved efficiency of devices and procedures is another way to improve our energy situation.