17-05-2012, 04:07 PM
Hydroelectric Energy
Hydroelectric.ppt (Size: 8.14 MB / Downloads: 143)
Points to be covered
The water cycle
Flowing water as a source of power
Historic uses of hydro power
Types of hydroelectric generation
Benefits of hydroelectric power generation
Current levels of hydroelectrical generation capacity worldwide and in US
Issues regarding hydroelectric
Potential new sources of hydroelectricity
The WebQuest
Flowing water is a source of power
POWER (kW) = 5.9 x FLOW x HEAD
FLOW is measured in m3/sec
HEAD is measured in meters
Benefits of hydroelectric power
Economic benefits
No fuel costs
Low labor
Dams provide recreation and flood protection
Systems are long-lived (decades)
Provides relatively constant power
Conserves fossil fuels
Benefits local economies
Can be implemented remotely
Can prevent pollution caused by fossil fuels
Environmental problems?
Impacts to fish and birds
Upstream impacts
Wetlands are flooded
Humans often displaced
Siltation behind dams
Release of greenhouse gasses
Downstream effects
Scouring
Temperature impacts
Dam failures can flood downstream communities
Tide Power
Based on diurnal movements of water in oceans
Most effective in areas with pronounced tides
Include
Tidal stream systems (kinetic energy of flow)
Barrages (head energy of surface differences)
Tidal stream systems
Dominant technology is shrouded turbine
Prototypes have been tested in England, Australia, and Italy.
Outputs up to 1.2 MW are noted
Barrage systems
Depend upon impoundments built along coastlines
Developed in Canada, Russia, and France
Largest generates 240 MW.
Limited by geography, environmental considerations
Wave Power
Based on up-and-down motion of sea surface
Can be captured using devices that convert motion to electricity
Could yield more electricity than tidal
Recently deployed systems include
Portuguese project - 2.25 MW
Scotland project - 3.0 MW
Challenges include low speeds, corrosion, wind damage