PHYS 1110

Lecture 14

Professor Stephen Thornton

October 18, 2012

Reading Quiz

Which of the following global dams produces the greatest hydroelectric output?

A)North Anna.

B)Grand Coulee.

C)Hoover.

D)Niagara Falls.

E)Aswan.

Reading Quiz

Which of the following global dams produces the greatest hydroelectricity output?

A)North Anna.

B)Grand Coulee. See Table 7-1.

C)Hoover.

D)Niagara Falls – not a dam.

E)Aswan.

Table 6-1 Mass of CO2 Emitted for Various Fuels per Quantity of EnergyFuel CO2 Emitted Fuel CO2 Emitted Fuel CO2 Emitted

(g/MJ) (g/MJ) (g/MJ) Natural Gas 50 Kerosene 68 Coal (bituminous) 88 Propane 60 Fuel oil 69 Coal (lignite) 92Gasoline 67 Wood 84 Coal (anthracite) 98Source: http://en.wikipedia.org/wiki/Greenhouse_gas and http://www.eia.gov/oiaf/1605/coefficients.html

$3 billion. May never be built. Last company press release, Dec. 2010.

Cap and Trade

Vote failed in US Senate in 2009 but passed House by a vote of 219-212.

Successful in Northeast US and EU.

Advantages and Disadvantages of Fossil Fuels

Quiz

The terms peak coal, peak oil, etc refer to

A)How long until peak resource extraction occurs.

B)How long until the rate of production begins to decline.

C)The point in time when all the resource is gone.

D)The point in time when the maximum rate of a resource extraction is reached.

Quiz

The terms peak coal, peak oil, etc refer to

A)How long until peak resource extraction occurs.

B)How long until the rate of production begins to decline.

C)The point in time when all the resource is gone.

D)The point in time when the maximum rate of a resource extraction is reached.

Hydroelectric Power

Hydropower accounts for most of the 19% of global renewable energy.

Three Georges Dam in China – 200620,000 MW

Iguassu Falls area

Iguassu Falls

Hydroelectric CapacityProduction Installed

China 652 TWh 197 GWCanada 370 TWh 90 GWBrazil 364 TWh 69 GWUnited States 251 TWh 80 GWRussia 167 TWh 45 GWNorway 140 TWh 28 GWIndia 116 TWh 34 GWVenezuela 86 TWh 15 GWJapan 69 TWh 27 GWSweden 66 TWh 16 GW

Paraguay 100% (sell 90% to Brazil, Argentina)Ethiopia 88% Venezuela 68%

Several African and Small Asian countries also are virtually 100% hydropower:

BhutanCongoLesothoMozambiqueNepal

Table 7-1 Representative Global Hydropower SitesProject Location Type Power Capacity (annual energy)

HeightItaipu Dam Parana River, Impoundment, 14,000 MWe (91 x 106 kWh)

Brazil, Paraguay 196 m

Three Gorges Yangtze River, Impoundment, 20,300 MWe (80 x 106 kWh) Dam China 181 m

Guri Dam Caroni River, Impoundment, 10,235 MWe (47 x 106 kWh)Venezuela 162 m

Grand Coulee Columbia River, Impoundment, 6800 MWe (21 x 106 kWh) Dam Washington, USA168 m high

Niagara Falls Niagara River, Diversion, 2700 MWe (USA)New York, Canada run of river 2200 MWe (Canada)

Aswan Dam Nile River, Impoundment, 2100 MWeEgypt 111 m

Hoover Dam Colorado River, Impoundment, 2050 MWe (4.2 x 106 kWh)Nevada, Arizona 221 m

Fort Loudoun Tennessee River, Impoundment, 144 MWe Dam Tennessee, USA 37 m

Columbia River and its tributaries and dams (76).

Small circles 50 m or less dam height.

Medium circles 50 to 150 m dam height.

Large circles over 150 m height.

Grand Coulee is #4.

Power = (potential + kinetic energy) volumetric flowrate efficiency´ ´

2 2exit entrance

3

1

2

density

= height

=

water flow rate m / s

= efficiency

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= efficiency

= height

water flow rate m / s

P hQ

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Breastshot are more effective than overshoot.

Mill race

Overshot water wheels are most effective, then breastshot, and then overshot. Overshot 85% effective.

( )( )( ) ( )

3

3

33 2

20.5 m

0.7 m/s

= 0.4

1

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1000 kg/m

11000 kg/m 0.5 m 0.7 m/s 0.4

234 W

A

v

P Av

P

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r e

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Homeowner’s undershot water wheel is not very productive or useful:

Global pumped storage generating power capacity is over 100 GW, with about 22 GW in USA.

North Anna nuclear power plants are 1 GW each. Bath County pumped storage facility is 3 GW.

Let’s go through the list of disadvantages and advantages of hydropower. Which ones do you disagree with?

Take a few minutes to go over these on your computer. You can talk among yourselves.

Worst dam failures in history.Banqiao Dam, China, 1975; killed 175,000 during Typhoon Nina (26,000 flooding and 145,000 epidemics and famine. 62 dams failed.

Johnstown flood, 1889. Earthen dam broke and killed 2200.

Quiz

You own a 5000 acre parcel in the mountains of western Albemarle county. Which would you rather build on your property to generate income?

A)A 250 acre pumped storage facility.B)An overshoot water wheel on a creek.C)A pay parking lot for hikers.D)A 1500 acre lake behind a 50 m high dam.E)A coal burning plant.

Quiz

You own a 5000 acre parcel in the mountains of western Albemarle county. Which would you rather build on your property to generate income?

A)A 250 acre pumped storage facility.B)An overshoot water wheel on a creek.C)A pay parking lot for hikers.D)A 1500 acre lake behind a 50 m high dam.E)A coal burning plant.

Solar Energy

Burning a metric ton (1000 kg) of coal provides ~4x1010 J.

The time for sunlight on Earth to provide this energy is ~3x10-7 s.

Divide up into groups and discuss

•Passive solar heating and lighting for buildings.

•Solar water heaters

•Solar thermal collectors

Table 7-2 Specific Heats of Thermal Masses Material Density Specific Heat Energy Density (kg/m3) (kJ/kg 0C) (kJ/m3 0C)Brick 2400 1 2400Concrete 2400 0.96 2300Dry earth 1250 1.26 1580Dry sand 1600 0.80 1280Stone 2500 0.84 2100Oak wood 700 2 1400Water 1000 4.2 4200

Trombe wall

Glass X windows in 20-unit senior housing in Switzerland.