Energy Supply & Demand

Supply is the quantity of something that producers have available for sale. Demand is the quantity that people wish to consume and are able to buy. Geographers observe two important inequalities in the distribution of energy demand and supply:

• Demand. The heaviest consumers of energy are in developed countries, whereas most of the energy sources are currently found in developing countries.

• Supply. Some developing regions have abundant supply of energy resources, whereas others have little.

Given the centrality of energy in contemporary economy and culture, the unequal distribution in the demand and supply of energy has been a major challenge for industry and a source of instability between developed and developing countries.

Energy Supply

Historically, people relied primarily on animate power, which is power supplied by animals or by people themselves. Now five-sixths of the world’s energy is supplied by three fossil fuels. A fossil fuel is an energy source formed from the residue of plants and animals buried millions of years ago. As sediment accumulated over these remains, intense pressure and chemical reactions slowly converted them into the fossil fuels that are currently used. When these substances are burned, energy that was stored in plants and animals millions of years ago is released.

The three fossil fuels are coal, petroleum, and natural gas (Figure 11-26):

• Coal. As North America and Europe developed rapidly in the late 1800s, coal supplanted wood as the leading energy source in these regions.

• Petroleum. First pumped in 1859, petroleum did not become an important source of energy until the diffusion of motor vehicles in the twentieth century.

• Natural gas. Originally burned off as a waste product of petroleum drilling, natural gas is now used to heat homes and to produce electricity.

Energy Supply

Three fossil fuels—petroleum, coal, and natural gas—supply most of the world’s energy.

In Chapter 11, we distinguished between renewable resources (those produced in nature more rapidly than they are consumed by humans) and nonrenewable resources (those produced in nature more slowly than they are consumed by humans). The fossil fuels are nonrenewable energy resources that have finite supplies capable of being exhausted. Consequently, sustainable development will necessitate increased reliance in the future on renewable energy instead of fossil fuels (see Energy Alternatives in Chapter 1).

The United States is highly dependent on the three fossil fuels. Wood was the principal energy source in the nineteenth century. Coal became most important during the late nineteenth century, and petroleum and natural gas gained prominence during the second half of the twentieth century.

Changing U.S. Energy Supply

Petroleum, natural gas, and coal account for nearly 90 percent of all energy supplied in the United States. Petroleum and natural gas account for increasing shares and coal for a decreasing share.

Pause & Reflect 11.2.1

The use of one of the three fossil fuels is increasing in the United States in the twenty-first century. Which one is it? Why might that be the case?

Energy Demand

Demand for the world’s energy is currently divided about equally between developed and developing countries. However, consumption of fossil fuels has been increasing at a much faster rate in developing countries. As a result, developing countries are expected to demand 60 percent of the world’s energy in 2040. China has surpassed the United States as the country that uses the most energy. Still, the highest per capita consumption of energy remains in North America; the region contains one-twentieth of the world’s people but consumes one-fourth of the world’s energy.

Share of World Energy Demand by Country

Developed and developing countries each consume around one-half of the world’s energy.

Future Energy Demand

Developing countries will account for an increasing share of world energy demand in the years ahead.

Energy Demand

The highest per capita consumption is in China and the United States, and the lowest is in sub-Saharan Africa.

Demand for energy in the United States comes from four principal sources:

• Industry. Factories use roughly 40 percent natural gas and 30 percent each coal and petroleum. Most of the natural gas and petroleum is burned directly, whereas coal is consumed primarily through purchasing electricity.

• Transportation. Almost all transportation systems run on petroleum products.

• Homes. Natural gas and coal provide roughly equal shares of home needs. Natural gas is the principal source of home heating and air conditioning, whereas electricity generated primarily from coal is the principal source of electricity.

• Commercial. Stores and offices have uses and sources similar to those for homes.