Part 2 Renewable Resources

• Wind energy results from uneven solar heating of the atmosphere, resulting in broad circulation areas

• Wind resources vary greatly worldwide, even over a few miles

• Wind power is proportional to the wind speed cubed

Wind Energy

Ref.: www.freefoto.com/pictures/general/ windfarm/index.asp?i=2

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Wind Energy in Practice

• California 50% tax incentives resulted in major U.S. wind farms– Altamonte Pass– Tehachapi– San Gorgonio Pass

• Other turbines are located in Dakotas, Iowa, Texas, MA, ME, NY, OR, PA, WA, WY, IA, VT, WV etc.

• Early Twentieth Century saw wind-driven water-pumps commonly used in rural America, but the spread of electricity lines in 1930s caused their decline.

www.nrel.gov/wind/usmaps.html

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Energy Is Proportional to Wind Speed Cubed

• Recall that the average wind power is based upon the average of the speed cubed for each time

• The wind energy varies from trivial to disastrous!

• Precautions are needed to protect the turbine

Ref.: Bergey

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A 1000 W, 10-ft diameter wind turbine:

•Wind energy at 103 ft above ground greatly exceeds that at ground level

Wind and Solar Facility

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Geothermal Energy

• First electricity from geothermal produced in Laredello, Italy in 1903

• Active geysers supply steam or hot water for heating in The Geysers, California (824 MWe)

• “Hot, dry rock” (HDR) offers potential for deep-injecting water and using the resultant steam to spin a turbine

• At a lower (~75F) geothermal temperature, an air conditioner can extract heat from the ground for winter heating or insert energy into the ground to gain a more efficient cooling sink in summer

www.eren.doe.gov/geothermal/ geysers20.html

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Bioenergy (From Biomass)

• Direct firing, cofiring, and gasification are forms of biopower

• Ethanol can be made from grain, diesel from soybeans, and ethanol/methanol can be made from cellulose

• May be intentionally grown (coppicing; cut by “lawnmower on steroids”) such as poplar trees or might use waste byproducts

• Biomass satisfied 4% of energy demand in 1990

• Biomass can serve as a bridge from fossil fuels, although it is an inefficient producer of energy

• Liquid fuels are essential for transportation vehicles due to high energy density

www.seco.cpa.state.tx.us/.../ re_renew_maps_bio_poten.htm

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Hydroelectric Energy Use

• Hydro installed on most useful rivers years ago• Dams are under attack by some environmentalists who want

water unhindered for fish passage, recreation, and for endangered species -- “So fish can swim free” (Piscean justice campaign?)

• Impounded waters hold back ocean rise somewhat• Stable output although seasonal variations

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Tidal Energy

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Tides are produced by gravitational forces of the moon and sun and the Earth’s rotation (24 hour, 50 minute period)

Existing and possible sites:

France: Rance River estuary 240 MW station

England: Severn River (proposed)

Canada: Passamaquoddy in the Bay of Fundy (1935 attempt failed; not economically practical)

California: high potential along the northern coast; NIMBYs would block it

Environmental, economic, and esthetic aspects plus limited resources have delayed implementation

Salter “ducks” rock up and down as the wave passes, oscillating to convert rotary motion to electrical energyA Wavegen, wave-driven, air compressor or oscillating water column spins a Wells turbine to produce electricity regardless of air flow direction

Source: Wave Energy paper. IMechE, 1991 and European Directory of Renewable Energy (Suppliers and Services) 1991

Wave Energy

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Ref.: www.fujita.com/archive-frr/ TidalPower.html©1996 Ramage

Ocean Thermal Electric Conversion(OTEC)

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Hawaii has the research OTEC laboratory; funding ended in 1998; used for chilled water office cooling now

OTEC requires some 40°F temperature difference between the surface and deep waters to economically extract energy

Open-cycle plants vaporize warm water and condense it using the cold sea water, yielding potable water and electricity from turbine-driven alternators

Closed-cycle units evaporate ammonia at 78°F to drive a turbine and an alternator

Ref.: www.nrel.gov/otec/achievements.html

Subsurface Gulf Stream currents of 4 to 5 knots can drive turbines to generate electricityThe equivalent of a waterproof wind turbine can be placed underwater to extract energyBlue Energy of Canada planned a prototype demonstration in the Second Quarter of 2004

Ocean Current Energy

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www.bluenergy.com/technology/ turbine.html

Florida Atlantic Univ. starting Ocean Energy Center 2007 for Gulf Stream energy

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Questions? ? ?

This diamond mine is in Eastern Siberia in Mirny. Its 1722 feet deep and ¾ mile wide.

The truck “Belaz” is one of the largest in the world

On next slide it’s like a tiny dot

The hole is so large that its airspace is closed to aircraft as the wind causes unpredictable

vortex

The hole is so large that its airspace is closed to aircraft as the wind causes unpredictable

vortex

View from spaceView from space