Alternative Energy Sources

Renewable Energy Sources Energy sources that are replaced almost as fast as they are used: Water power Wind power Solar energy Geothermal energy Each of these is limited in some way

Water Power Water power is the most efficient way to produce electricity: hydroelectric power The turbine blades are turned directly by the moving water Only rivers suitable for damming can produce hydroelectric power New technologies may harness tidal power to produce electricity Revelstoke Dam (BC)

Wind Power Wind power depends on the force of moving air against a windmill Windmill farms can produce significant amounts of electrical energy Wind power is most useful in coastal areas, or other areas with consistently strong winds

Solar Energy Uses the limitless energy of the sun for heat and electricity Passive solar heating traps heat; such as through special windows Active solar heating collects the heat, transfers it to a storage area, and then moves it through a building Active Solar Heating Passive Solar Heating

Solar Cells Photovoltaic cells convert sunlight into electricity Simple explanation Photons in sunlight hit the solar panel and are absorbed by semiconducting materials, such as silicon. Electrons (negatively charged) are knocked loose from their atoms, allowing them to flow through the material to produce electricity. Due to the special composition of solar cells, the electrons are only allowed to move in a single direction. The complementary positive charges that are also created (like bubbles) are called holes and flow in the direction opposite of the electrons in a silicon solar panel. An array of solar cells converts solar energy into a usable amount of direct current (DC) electricity.

Photovoltaic Cells

Geothermal Energy Heat from the interior of the Earth Brought to the surface by steam or hot water, where it can run a generator or heat homes Geothermal energy needs no fuel and gives off no pollution Superheated steam is difficult and expensive to move around