Renewable Energy Non-Polluting Resources Mr. Matthew Rodman Science Patria Mirabal Middle School (MS 324) New York City, New York, USA

Focus What factors have led to the United States to using renewable energy resources? How will widespread use of renewable energy resources affect the environment and the economy?

Renewable Energy Resources that are constantly recycled by the environment are called renewable. Wind, water, biomass, sunlight, and geothermal energy are all renewable energy sources. Renewable energy are usually nonpolluting and do not contribute to the greenhouse effect.

Renewable Energy Renewable energy use resources in the environment that are always renewed or replaced. They all come from energy from the sun that is used directed (solar energy) or indirectly (water, wind, and biomass). Geothermal energy uses the heat from the center of the Earth. Renewable energy resources are usually clean, do not contribute to the greenhouse effect, and are unlimited (but they are sometimes expensive).

Solar Power Solar power uses sunlight to produce electricity. There are two main types of solar power plants. 1.Photovoltaic – uses sunlight to directly make electricity 2.Indirect Solar Energy – uses mirrors to concentrate sunlight to boil water in a power plant. Solar power is extremely expensive.

Wind Power Wind power plants use wind to turn windmills to generate electricity. Wind power is clean, safe, and cheap, but requires a lot of space because each windmill only produces a little electricity. Wind power can only be effectively built in areas with a lot of wind.

Hydroelectricity Hydroelectric power plants use falling or running water to turn turbines to produce electricity. Hydroelectricity is clean and reliable, but requires the building of dams which can cause flooding. Hydroelectricity can only be built near bodies of water like rivers. Hydroelectric dams can kill fish and destroy environments upstream of the power plant.

Biomass Electricity Oils from plants can be converted into fuels that work like petroleum. This is better for the environment because it does not burn fossil fuels, but uses plants that remove carbon dioxide from the environment. Biomass energy has never been used on the large scale, and still produces pollution. Since biomass energy uses foods as a source of electricity, it will cause food prices to rise.

Geothermal Electricity Geothermal energy uses heat from magma, volcanoes, or geysers to produce electricity. It can only be built on geologically active areas where there are volcanoes or earthquakes. It is clean, reliable, and renewable.

Benefits of Renewable Energy Clean Unlimited Supply Less expensive over long term Do not contribute to greenhouse effect

Environmental Impact of Renewable Energy Sources Even though they do not produce much pollution, they do change the natural environment (windmills, dams, etc.) Renewable energy sources are frequently very expensive over the short term (1-5 years) but become less expensive over the long term, mainly because fossil fuels are becoming rarer and rarer. Renewable electricity can be unreliable because the natural environment has rapid changes in weather. Renewable electricity typically produces less electricity than nonrenewable sources.