People living in industrialized countries make up a relatively small percentage of the world’s population but consume a disproportionate share of the total energy consumed in the world. For example, the United States, with only 5% of the world’s population, uses approximately 20% of the total energy consumed in the world.


There is a direct relation-ship between a country’s standard of living as measured by gross national product and energy consumption per capita. After the peak in oil production, expected in 2020–2050, oil and gasoline will be in shorter supply and more expensive. Before then, use of these fuels may be curtailed in an effort to lessen global climate change. As a result, within the next 30 years both developed and developing countries will need to find innovative ways to obtain energy.


In the future, affluence may be related as closely to more efficient use of a wider variety of energy sources as it is now to total energy consumption. The appliances that use most of the electrical energy are water heaters, refrigerators, clothes driers, and washing machines. Regional variations in energy consumption are significant. However, in California, where people often commute long distances to work, about one-half of the energy is used for transportation, more than double the national average.