1. Renewable Energy
Chapter 18

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

3. 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

4. Lesson 18.1- Biomass and Geothermal Energy4

5. 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.

6. 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.

7. 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 - (Creative Commons licensed)
Geyser info source - National Park Service:
Deforestation can be seen at the border between the Dominican Republic (right) and Haiti (left). 7

8. 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

9. 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.

10. 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 - (Creative Commons licensed)
Geyser info source - National Park Service: 10