Introduction: A Global Perspective

Using data from 2005, the United States was the largest energy consumer worldwide.

• The USA used a total of 100 quadrillion BTUs of energy.
• The world used a total of 472 quadrillion BTUs of energy.

That means, in 2005, the United States used over 20% of the total energy used by the entire world though the U.S. contains only 5% of the world’s population.
Most of the world’s energy—about 80 to 90 percent—is currently derived from fossil fuels. Looking ahead at worldwide energy consumption projections, the predictions show a steady increase upwards. In the United States and around the world, it is essential to start reducing our reliance on fossil fuels and producing more energy from sustainable sources.