Renewable Energy Resources

Inexhaustible energy refers to energy resources that are constant and will never run out. Includes the Sun, wind, water, and geothermal energy Inexhaustible Energy Resources

Solar Energy The sun helps to cause global winds and currents in the ocean.

Global Wind Currents

Passive Solar Solar energy can be –Passive Example sun shining through a window or sky light

Active Solar Active solar collectors often convert the energy of sunlight into electricity –Example Solar panels Active solar collectors can also heat water that is then distributed through the house. –Example Tube collectors

Active solar collector that heats water

Solar Energy Benefits Solar energy is clean and inexhaustible (it will never run out). Passive solar energy is relatively inexpensive.

Disadvantages of Solar Energy Cloudy days means no energy collected. Solar energy doesn’t work at night. While the energy can be stored in batteries, it is difficult to store large amounts of the electrical energy created by solar energy. Old batteries must be discarded, which can pollute the environment.

Wind Energy Wind energy comes from solar energy since wind is caused by the sun heating the Earth unevenly. Windmills have been used throughout history to –grind corn and wheat into flour –pump water Windmills now are used mostly to generate electricity.

Historical Uses of Wind For grinding grain For pumping water

Hydroelectric energy is electricity produced by water power. Water in rivers is dammed. The water runs through turbines in the dam that turn generators that make electricity. Other ways to capture the power of water: –Tides moving in and out along ocean shores turn generators for electricity. –Waves cause generators to bob up and down, creating electricity. Energy from Water

Dams can stop migration of fish and other river species. Upstream lakes fill with sediment on dammed rivers. Downstream erosion increases in dammed rivers. Land is often flooded upstream from a dam. Wildlife habitats are damaged by damming. Problems with Using Water

Geothermal energy comes from the heat inside Earth. –Water is pumped down into Earth over hot rocks. The heated water turns to steam which turns a turbine that turns a generator to produce electricity. In some countries, natural groundwater is heated by magma and pumped directly to the consumer for use in the home. Energy from the Heat Within

Geothermal Energy in Iceland DduaU0http:// DduaU0

Renewable energy refers to energy resources that can be replaced in nature or by humans within a relatively short period of time. Includes biomass, such as trees and crops, and biomass transformed into fuels. Renewable Energy Resources

Biomass energy is derived (gotten) from burning organic material such as wood, grains, alcohol, and garbage. –Bio means life. –Mass refers to matter. Biomass

Wood, when burned, releases a lot of heat energy. Many countries still rely mostly on wood for heating and cooking. Wood smoke can pollute the air, and habitats are destroyed when trees are removed in large amounts from an area. Burning Wood

Grains and grasses can produce alcohol and oil which can be converted into fuels for transportation. –Ethanol –Biodiesel These fuels are considered more efficient than burning biomass directly (such as burning wood). Alcohol and Oil from Grains and Grasses

Burnable garbage is a resource that could be used to generate electricity. Using garbage to burn for energy would help keep landfills from filling up. However, some garbage is toxic when burned. Energy from Burning Garbage

Garbage, when it rots, produces a gas—METHANE. This is a renewable form of methane that does NOT come from fossil fuels. The methane is collected as it rises, and is burned for heat energy. Other Energy from Garbage

Homemade Methane