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Conservation Of Energy

EPA

ENERGY CONSERVATION
POLLUTION PREVENTION (P2) EDUCATION TOOLBOX Tools for Helping Teachers Integrate P2 Concepts in the Classroom United States Environmental Protection Agency EPA-905-F-97-011 August 1997

WHAT ARE THE USES OF ENERGY? Energy is defined as "the ability to do work." In this sense, examples of work include moving something, lifting something, warming something, or lighting something. The following is an example of the transformation of different types of energy into heat and power. Oil burns to make heat --> Heat boils water --> Water turns to steam --> Steam pressure turns a turbine --> Turbine turns an electric generator --> Generator produces electricity --> Electricity powers light bulbs --> Light bulbs give off light and heat

It is difficult to imagine spending an entire day without using energy. We use energy to light our cities and homes, to power machinery in factories, cook our food, play music, and operate televisions. In a home where electricity supplies all of the energy requirements, the average energy consumption is shown below: Air conditioner and heater Water heater Lighting and small appliances Refrigerator Other Ovens and stoves Clothes dryer = 20% = 8% 5% = 3% 50% 10%

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4%

Electricity is generated from both renewable and nonrenewable energy sources. These sources are defined below. Renewable energy sources: These sources are constantly renewed or restored and include wind (wind power), water (hydropower), sun (solar), vegetation (biomass), and internal heat of the earth (geothermal). About 9.0 percent of electricity in the U.S. is generated from renewable sources. Nonrenewable energy sources: These are natural resources that cannot be replenished (fossil fuels such as oil, gas, and coal). About 71.5 percent of electricity in the U.S. is generated from nonrenewable sources. In addition to renewable and nonrenewable energy sources, about 19.5 percent of electric power in the U.S. is generated by nuclear...