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Renewable Sources of Energy
Renewable Energy Information
An Overview of Renewable Energy
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Overview of Renewable Energy
Renewable energy is energy from a non-nuclear source that is in constant supply over time. In contrast, the supply of fossil energy sources such as oil, natural gas or coal is limited.
In 2003, generation from all renewable sources combined supplied 47 percent of the electricity used in Oregon. According to data from the U.S. Department of Energy´s Energy Information Administration, renewable energy sources accounted for about six percent of total energy consumption in the United States in 2003. In contrast, fossil energy sources supplied 86 percent of all energy used in the United States, and nuclear electric power supplied eight percent.
There are five principal renewable sources of energy: the sun, the wind, flowing water, biomass and heat from within the earth.
Solar energy is energy that comes directly from the sun. The sun is a constant natural source of heat and light, and its radiation can be converted to electricity.
Natural conditions of climate and geography produce the winds that blow across the landscape. Historically, windmills were used to supply mechanical energy, for example to pump water or grind grain. Modern day wind turbines produce electricity.
Like the winds, flowing water is a product of the earth´s climate and geography. Snowmelt and runoff from precipitation at higher elevations flow toward sea level in streams and rivers. In an earlier era, water wheels used the power of flowing water to turn grinding stones and to run mechanical equipment. Modern hydro-turbines use water power to generate hydroelectricity.
"Biomass" describes, in one word, all plants, trees and organic matter on the earth. Biomass is a renewable source of energy because the natural process of photosynthesis constantly produces new organic matter in the growth of trees and plants. Photosynthesis stores the sun´s energy in organic matter. Biomass is used to make heat, electricity and liquid fuels.
Heat from deep within the earth is called "geothermal energy." In some locations, geothermal energy is close enough to the surface that, by drilling a well to reach the heat source, the energy can be extracted and used for heating buildings and other purposes. Where the temperatures are hot enough, geothermal energy can be used to generate electricity.
Heat, electricity and vehicle fuel are the main forms of energy that people use every day. All renewable energy sources can be used to produce electricity. Solar energy and geothermal energy can supply both electricity and heat. Biomass can supply all three forms of useful energy.
Uses for Renewable Sources of Energy
  Heat Electricity Vehicle Fuel
Water Power   yes  
Biomass Energy yes yes yes
Wind Power   yes  
Solar Energy yes yes  
Geothermal Energy yes yes  
More Information
Electricity from Renewable Sources
Oregon´s Renewable Resource Programs
Climate Change and Oregon
Energy Glossary 

Outside Links
USDOE Efficiency and Renewable Energy Network
Green Marketing Guidelines (PDF)