Work, Energy, and Power in Humans

Read these texts to learn how energy is transferred and transformed in humans and in society.

World Energy Use

Energy is an important ingredient in all phases of society. We live in a very interdependent world, and access to adequate and reliable energy resources is crucial for economic growth and for maintaining the quality of our lives. But current levels of energy consumption and production are not sustainable. About 40% of the world's energy comes from oil, and much of that goes to transportation uses. Oil prices are dependent as much upon new (or foreseen) discoveries as they are upon political events and situations around the world. The U.S., with 4.5% of the world's population, consumes 24% of the world's oil production per year; 66% of that oil is imported!


Renewable and Nonrenewable Energy Sources

The principal energy resources used in the world are shown in Figure 7.28. The fuel mix has changed over the years but now is dominated by oil, although natural gas and solar contributions are increasing. Renewable forms of energy are those sources that cannot be used up, such as water, wind, solar, and biomass. About 85% of our energy comes from nonrenewable fossil fuels – oil, natural gas, coal. The likelihood of a link between global warming and fossil fuel use, with its production of carbon dioxide through combustion, has made, in the eyes of many scientists, a shift to non-fossil fuels of utmost importance – but it will not be easy.


A pie chart of the world’s energy consumption by source is shown. Thirty-five point four three percent is petroleum, twenty-eight point one five percent is coal, twenty-three point four six percent is dry natural gas, six point two seven percent is hydro-electricity, five point seven nine percent is nuclear electricity, point eight six percent is geothermal, wind, solar, biomass, and point zero five percent is geothermal, biomass, or solar energy not used for electricity.

Figure 7.28 World energy consumption by source, in billions of kilowatt-hours: 2006.

 

Source: Rice University, https://openstax.org/books/college-physics/pages/7-9-world-energy-use
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