Hydroelectric Mona Zebarjadi, EE80j: Summer 2009
World Consumption BP Statistical review, 2009 Million tones oil equivalent Oil Natural Gas Nuclear energy Hydroelectricity Coal
2007
World Capacity and output
A.Shakouri, 19 Sept Globally Gross theoretical potential 4.6 TW Technically feasible potential 1.5 TW Economically feasible potential 0.9 TW Installed capacity in TW Production in TW (can get to 80% capacity in some cases) Source: WEA 2000 Hydroelectric Energy Potential Nate Lewis, Caltech
Site types – Low (effective head <10m) – High (effective head>100m) Small-Scale Hydro (micro-, mini, pico) – Capacity <30MW US, capacity <5MW UK
Turbine types Reaction turbines: are acted on by water, which changes pressure as it moves through the turbine and gives up its energy. Francis Kaplan, Propeller, Bulb, Tube, Straflo Tyson Water Wheel Archimedean screw turbine Impulse turbines: change the velocity of a water jet. The jet impinges on the turbine's curved blades which change the direction of the flow. The resulting change in momentum causes a force on the turbine blades. Pelton Turgo Michell-Banki (also known as the Crossflow or Ossberger turbine)
Francis (radial- flow) Most common
Propeller (Axial-flow) Kaplan
Impulse turbines Great for high heads Low specific speed Pelton, Turgo, Cross-flow
Ranges of application
A.Shakouri, 19 Sept Hydro Power Advantages: No pollution (Co2 or So2 No2) flood control, Very high efficiency (80%); little waste heat; low cost per KWh; Can adjust KWh output to peak loads;
Disadvantages: Fish are endangered species; Produce methane, Sediment buildup and dam failure (250,000 killed China, 1975); changes watershed characteristics; alters hydrological cycle (affects the agriculture), Social effect
Economy Expected life time: years for machinery and years for external structure Capital cost: depends strongly on the site – some examples : Three Gorges, China 1993, 1200$/kW – Itaipu: , 1600$/kW Maintenance cost : additional 1 to 2% Largest plant and highest heads tend to have lowest unit cost