Alternative Energy: Hydroelectric Power By Naina Gimadeyeva and Kalil Johnson

General Description Electricity is generated by hydropower Hydropower is the gravitational force of falling water The force of water drives the water turbine and generator to create electricity

Hydroelectric Power: How it Works Dam are built barrier constructed to control the flow of water Water flows into tunnels in the dam Gravity causes the water to flow down Which turns the turbines that drives the generators Electricity is made by the spinning turbines How it works video

Advantages Water provided is free No greenhouse gas emissions, minimal pollution Low maintenance costs and operations More reliable than solar, wind, or wave power Fuel is renewable Increases to full power very quickly Reservoirs offer a variety of recreational opportunities

Disadvantages of Hydropower Expensive to construct Flooding can disrupt the plant and animal life Effects fish population-reducing access to spawning grounds Dams causes soil erosion Hydrology is dependent on precipitation- can be effected by drought Water quality- low dissolved oxygen levels Power plants in tropical regions produce a high amount of methane and carbon dioxide due to decaying plant material

Extra Information Specifications Limited locations due to Swift flowing rivers or streams Mountainous regions Heavy rainfall Limited locations due to Space requirements Areas needed with heavy rainfall Need to displace the people Building costs Least common compared to others Supplies 9% of the United States’ electricity Accounts for 49% of all renewable energy used by the U.S.

Hydroelectric Power: Dams Two types of dams: Gravity dam- supported by a bedrock base Arch dam- form a convex arch, supported by lateral walls Used in narrow canyons with steep sidewalls Risk Factors to the design of a hydroelectric dam: Resistance of dams to earthquakes Permanent inspection Ecological impact – under-oxygenated waters Human impact – relocation of people Conditions for building a dam Topographical location – detailed features Geographical location – natural features, populations, industries and etc. Hydrological conditions - the science dealing with occurrence, circulation, distribution, and properties of water

Hydroelectric Energy: Dams Contd. Hoover Dam (Boulder Dam): built in the 1930s in the Black Canyons of the Colorado River Construction deaths of 112 workers were due to Rock slide Explosion Drowning Health Prostration Construction of the dam: Groundwork- construction of cofferdams were constructed to prevent flooding River diversion- built diver tunnels through canyon walls to reroute water in construction site Rock clearance- men suspended removed rock with dynamite and jackhammers Concrete- built in trapezoid columns to reduce stress and built cooling coils to cool the concrete Construction cost approximately $49 million ($736 million adjusted for 1936 to 2008) Hoover dam (google map)

Websites http://discoverer.prod.sirs.com/discoweb/disco/do/article?urn=urn%3Asirs%3AUS%3BARTICLE%3BART%3B0000133825 http://ga.water.usgs.gov/edu/hyhowworks.html http://www.enviroliteracy.org/article.php/59.html http://www.tvakids.com/electricity/hydro.htm http://home.clara.net/darvill/altenerg/hydro.htm http://www.epa.gov/solar/energy-and-you/affect/hydro.html http://www.energyrefuge.com/archives/hydro-electricity.htm http://ga.water.usgs.gov/edu/wuhy.html * http://www.eia.doe.gov/kids/energyfacts/sources/renewable/water.html http://www.beyondfossilfuel.com/hydroelectric/ http://www.promotega.org/AAU06004/Hydroelectricity.htm