1. Alternate energy sources
Chapter 4.2
Alternate energy sources

2. Fossil fuels are not going to last forever
Fossil fuels are not going to last forever. As the world’s population grows then more fossil fuels are being used at a faster rate.
Also the use of fossil fuels causes damage to the environment.
As a result we need to find alternate energy sources.

3. Solar energy This is the Earth’s most abundant energy resource.
Solar energy technologies use the sun’s rays to supply heat or electricity.
There are 2 advantages to solar energy: its fuel is free and it’s nonpolluting.
Passive solar collectors are objects that the sunlight passes through and object collect and then radiate heat.
Active solar collectors collect heat and pass that through air or liquids to move the heat.
Although it is free there are a few problems – necessary equipment and installation can be expensive. A supplemental heating system is needed for cloudy days.

4. Nuclear energy
The fuel for nuclear plants comes from radioactive materials that releases energy through nuclear fission.
Nuclear fission is the nuclei of heavy atoms, like uranium, are hit with neutrons and that splits the nuclei into smaller nuclei and gives off heat energy.
Problems with nuclear energy – the cost of facilities has increased, hazards with nuclear waste disposal, an accident could allow radioactive materials to escape.

5. Wind energy Wind power could possibly be harnessed for energy.
On the Altamont Pass (on the way to San Francisco) there are over 7000 wind turbines to harness wind power.
Problems with wind power – need for technical advances, noise pollution, and cost.

6. Hydroelectric power
Hydroelectric power is the power produced by falling water. This water drives turbines that produce electricity.
The purpose of reservoirs are to hold water that can move through a dam for hydroelectric power.
Problems with this: reservoirs can fill up with sand, also sites to make reservoirs are limited.

7. Geothermal energy
This is the energy harnessed by trapping natural underground reservoirs of steam and hot water.
The hot water is used for heating and to turn turbines to gain electricity. Geysers are a good source of hot water and steam.
The Geysers, near Oakland and San Francisco, is the first commercial geothermal power plant.
This power is clean (no pollution) but doesn’t last forever. The steam and hot water only usually last 10 to 15 years.

8. Tidal power
Tidal power is collected by making a dam across the mouth of a bay or an estuary in costal areas with drastic tide changes. The strong tides drive turbines and electric generators.