A composite image of the Earth at night makes the world's biggest power consumers stand out.

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How much power does the world consume?

­­Consumer culture is spreading from affluent countries in North America, Europe and Asia to developing nations around the world, bringing with it the voracious appetite for goods, services and energy.

Energy consumption is reportedly higher in countries where less than 5 percent of the population lives below the poverty line than it is in countries where most people live in poverty -- four times higher. For example, Americans make up­ less than 5 percent of the world’s population yet consume 26 percent of the world’s energy [source: Worldwatch Institute]. Together, the United States and Canada account for 50 percent of energy consumed by the world’s richest industrialized countries; Europe, 33 percent. But the power landscape is changing. In the first half of 2003, auto sales in China grew 80 percent, and 4 million new privately owned cars hit the roads -- cars that will consume fossil-fuel energy [source: Worldwatch Institute].

When we talk about energy consumption, we’re talking about the sources of energy that generate our power: oil, coal, natural gas and alternatives like solar, wind, hydropower and biofuels. (Brazil, for example, generates electricity by burning sugarcane waste.) Currently, the world’s population consumes 15 terawatts of power from a combination of these energy sources [source: The Economist]. Just how much power is 15 terawatts? Let's think of it in smaller and more familiar terms: watts. Many of the lightbulbs in our homes consume 100 watts of energy. One terawatt could power about 10 billion 100-watt lightbulbs at the same time [source: Steacie Institute for Molecular Sciences].Collectively, developing countries use 30 percent of the world's energy, but with projected population and economic growth in those markets, energy demands are expected to rise 95 percent. Overall global consumption is expected to rise 50 percent from 2005 to 2030, primarily in the fossil-fuel sector [source: United States Energy Information Agency].

Let’s look at the primary types of energy sources the world consumes while adding up those 15 terawatts. We'll also explore some of the alternative, renewable opportunities that are gaining popularity.­

Petroleum products help make crayons, like these pictured at a Pennsylvania Crayola plant.

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World Energy Consumption

­­­Most people around the world -- 43 percent of the global population -- use oil as their primary power generator. Natural gas follows at 15 percent; combustible renewables and waste are next at 13 percent, followed by coal at 8 percent and alternative sources (geothermal, hydro and solar) at 3.5 percent [source: IEA].

Petroleum-based fossil fuels, such as gasoline, heating oil and diesel fuel, are commonly consumed for energy, but petroleum products aren’t used only as power sources. They're also used to create items like crayons, plastics, tires and even heart valves [source: Energy Information Administration]. This is where energy consumption gets tricky: The energy a person consumes isn't just represented by the gas for the car or the electricity bill. When we buy a box of crayons we’re also buying all the energy that was consumed to make the product, package it and truck it to our local store.

Despite the consequences of fossil fuels -- which most famously include global warming -- the world is hungry for them and consumes them at a rate 100,000 times that at which  they're formed [source: Solar Energy International]. The use of fossil fuels in developing countries has quadrupled since 1970. China, for example, consumes the most coal in the world and is the third largest consumer of oil. According to the Worldwatch Institute, if a Chinese citizen consumed oil in amounts equal to an average American citizen, China would use 90 million barrels of oil per day to sustain its needs. That’s 11 million more barrels than the world produced in one day in 2001 [source: Worldwatch Institute]. This is a projection that has unsustainable implications -- what if a nation, China or otherwise, were to develop a 90-million-barrel-per-day oil habit?

Some groups propose fees to reduce consumption while others emphasize the adoption of cleaner power-generating methods. The Intergovernmental Panel on Climate Change (IPCC) proposes a fossil-fuel tax: $20 to $50 for every metric ton of CO­2­­ a country generates to pay for the environmental damages of burning them. The link between global warming and energy demands has many experts not only encouraging rich, industrialized countries to cut back demand and change methods of production and delivery, but also encouraging developing nations to adopt sustainable, renewable sources of power and efficient technologies.

Converting to renewable sources of energy could have an immediate impact on the environment. Let’s look at some of the types of renewable energy sources available and the potential impact they could have.

Wind power is the fastest growing renewable energy source. Replacing one month’s use of fossil fuels with 100 kWhs of wind power is comparable to keeping your car off the road for 2,400 miles (3,862 km). A 1 kWh photovoltaic (solar electricity) system would prevent the mining of 150 pounds (60 kg) of coal, prevent 300 pounds (136 kg) of CO2 (as well as NO and SO2) from escaping into the environment, and save 105 gallons (397 liters) of water from consumption [source: Solar Energy International].

Some forms of alternative energy can be expensive to implement and out-of-range for the average homeowner. Solar water heaters, however, give average consumers the opportunity to reduce their carbon footprint. By replacing an electric water heater with a solar one, the long-term electricity savings spare the environment from more than 50 tons of CO2­ emissions [source: Solar Energy International].

­There are clean and efficient ways to generate energy at individual, national and glob­al levels, but such a change requires both desire and funds.

Lots More Information

Related HowStuffWorks ArticlesMore Great LinksSources

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