Energy consumption is a hot topic in contemporary times due to its effect on the environment and most people's desire to save money through minimizing the amount of electricity and gas that they use and pay for. This concept of energy conservation includes decreasing energy consumption along with switching to renewable forms of energy such as solar energy or wind power.
During the early history of the United States, the primary source of energy came from burning wood. The Age of Industrialization, starting with the invention of the steam engine, caused the energy consumption of the world to triple by 1875. By around 1885, however, coal became a more popular energy source, due to its higher energy content. After World War II, petroleum and natural gas replaced coal in railroads and for heating purposes. Coal was still used to fire electrical power plants, though. Due to the Arab oil embargo of 1973–74, when oil prices soared fivefold in the space of a year, the manufacturing, transportation and utilities industries sought alternative energy sources, leading to the increased importance of hydroelectric and nuclear resources.
Until approximately 1958, the United States produced almost all the energy it needed to fuel its businesses and home life. Since 1958, however, the gap between how much the United States produces and how much it consumes has steadily widened, and the reliance on foreign energy sources often influences political decisions.
The top producers of oil in 2009 were Russia, with 9,934 barrels of oil produced every day, Saudi Arabia (9,760), the United States (9,141), Iran (4,177), China (3,996), Canada (3,315), Mexico (3,001), the United Arab Emirates (2,795), Brazil (2,577) and Kuwait (2,496). In contrast, the top consumers of oil in 2009 were the United States, which consumed 18.8 million barrels of oil daily, China, (8.3 million), Japan (4.4 million), India (3.1 million), Russia (2.7 million), Brazil and Germany (2.5 million each), Saudi Arabia (2.4 million) and Canada and Mexico (2.1 million each). In 2009, the worldwide consumption of energy dropped for the first time in 30 years as a result of the economic crisis.
The top world consumers of electricity are the United States, which used 21.7 percent of the world's electricity in 2008, followed by China (19.3 percent), Japan and Russia (4.8 percent each), India (3.2 percent), Germany (3.1 percent), Canada (3 percent), France (2.5 percent), South Korea (2.3 percent) and the United Kingdom, (1.9 percent).
In 2009, nuclear energy generated approximately 14 percent of the world's electricity, and 30 countries utilized nuclear energy to provide for part of their nation's energy needs. Since the 1950s, nuclear power plants have been operational, with 440 commercial nuclear power reactors functioning worldwide. In addition, 180 nuclear reactors provide power for 140 ships and submarines. While nuclear plants are expensive to build, they are often cheaper to run.
Solar energy has been used for thousands of years to grow crops, provide indoor illumination (just pull aside the curtains) and dry clothing. New advances in the field of solar energy enable homeowners to generate electricity through solar power, heat water in the home and swimming pool and heat the home through active solar heating systems. Wind energy provided humans with hundreds of years of windmill use to grind grain and pump water, and now it is used to run wind turbines to generate electricity. People who have naturally running water on their property can use a microhydropower system to generate their own electricity. Oceans are being explored as an energy resource, and many hope that ways will be found to harness the ocean's thermal energy, tides and waves.
The U.S. Department of Energy offers a plethora of tips to help consumers save energy and money: what to know when buying appliances and electronics, how to reduce electricity use, what to keep in mind when designing a new home or undertaking renovations, which types of heating and cooling systems are the most energy-efficient, which lighting choices are the most economical (and don't forget to turn off lights when no one will be using that particular room!), how to reduce one's water-heating bills and how to choose energy-efficient windows and cars that run on alternative fuels. The growth in population, along with expectations for a higher standard of living, likely will cause an increase in energy consumption.