Renewable Energy Chapter 18

What is Renewable Energy? Forms of energy that are constantly being formed Includes solar, wind, biomass, geothermal, and hydropower

Why We Need Alternative Energy Sources Economic reasons: Fossil fuels won’t last forever. Renewable sources provide new jobs. Our country will be less dependent on others for fuel. Environmental reasons: Renewable sources will decrease air pollution and greenhouse gas emissions. Did You Know? Fossil fuels currently supply 80% of the world’s energy, but renewable energy use is rapidly growing. 3

Lesson 18.1- Biomass and Geothermal Energy 4

Biomass Plant material (wood), manure, and other organic matter is used as energy. The organic material is burned to produce energy. Major source of energy used in developing countries. Used as fuel for heating and cooking, lighting, vehicle fuel, or electricity generation.

Being used in developed countries to generate electricity: Great Britain- has manure powered stations U.S.- uses methane gas from the decomposition of trash In the U.S., corn is used to make ethanol a component in “gasahol”= a fuel source that causes less air pollution than the burning of fossil fuels.

Benefits and Costs of Biomass Energy No net change in atmospheric carbon dioxide Can be produced by all nations Costs: Takes away land from food crops or natural habitats Deforestation, soil erosion, and desertification can result if plant biomass is harvested too rapidly. Large energy input is needed. Burning biomass indoors can lead to indoor air pollution. Image - http://www.flickr.com/photos/carolynconner/4264882098/ (Creative Commons licensed) Geyser info source - National Park Service: http://www.nps.gov/yell/planyourvisit/noldfaith.htm Deforestation can be seen at the border between the Dominican Republic (right) and Haiti (left). 7

Geothermal Energy The energy comes from heat in the earth’s crust Heat is used to generate electricity Heated water or steam is pumped to a turbine that activates a generator to produce electricity Water is returned to the earth’s crust where it is heated and used again

U.S.= world’s largest producer of geothermal energy The Geysers in CA produce electricity for 1.7 million households Geothermal Heat Pumps are used to regulate temperatures to warm and cool homes. They consist of piping, that circulates fluid underground.

Benefits and Costs of Geothermal Energy Causes much less air pollution than fossil fuels Low greenhouse gas emissions Costs: Not sustainable if hot groundwater is used faster than it is naturally replenished Hot groundwater can contain pollutants that damage machines or add to pollution. Some geothermal energy projects can trigger earthquakes. Geothermal power plants can only be built in places with easy access to geothermal energy. Image - http://www.flickr.com/photos/carolynconner/4264882098/ (Creative Commons licensed) Geyser info source - National Park Service: http://www.nps.gov/yell/planyourvisit/noldfaith.htm 10