Hydroelectric

Mona Zebarjadi,EE80j: Summer 2009

World Consumption

BP Statistical review, 2009

Million tones oil equivalent

Oil

Natural Gas

Nuclear energyHydroelectricity

Coal

2007

World Capacity and output

A.Shakouri, 19 Sept. 2008

Globally

Gross theoretical potential 4.6 TW

Technically feasible potential 1.5 TW

Economically feasible potential 0.9 TW

Installed capacity in 1997 0.6 TW

Production in 1997 0.3 TW

(can get to 80% capacity in some cases)

Source: WEA 2000

Hydroelectric Energy Potential

Nate Lewis, Caltech

Site types• 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. 2008

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;

http://zebu.uoregon.edu/2001/ph162/l1.html

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: 25-50 years for machinery and 50-100 years for external structure

• Capital cost: depends strongly on the site– some examples : Three Gorges, China 1993,

1200$/kW– Itaipu: 1984-91, 1600$/kW

• Maintenance cost : additional 1 to 2%• Largest plant and highest heads tend to have

lowest unit cost