energy ocean wind intro
Post on 10-Apr-2018
218 Views
Preview:
TRANSCRIPT
-
8/8/2019 Energy Ocean Wind Intro
1/23
An Introduction to Ocean
and Sea Breeze Wind Energy
Frank R. Leslie,
BSEE, MS Space Technology
5/25/2002, Rev. 1.7
f.leslie@ieee.org; (321) 768-6629
Renewable Energy from Ocean Winds
-
8/8/2019 Energy Ocean Wind Intro
2/23
Overview of Ocean Energy
Ocean energy is replenished by the sun and throughtidal influences of the moon and sun gravitational forces
Near-surface winds induce wave action and cause wind-
blown currents at about 3% of the wind speed Tides cause strong currents into and out of coastal
basins and rivers
Ocean surface heating by some 70% of the incomingsunlight adds to the surface water thermal energy,causing expansion and flow
Wind energy is stronger over the ocean due to less drag,although technically, only seabreezes are from oceanenergy
1.0 020402
-
8/8/2019 Energy Ocean Wind Intro
3/23
Whats renewable energy?
Renewable energy systems transform incoming solar energy and itsalternate forms (wind and river flow, etc.), usually without pollution-causing combustion
This energy is renewed by the sun and is sustainable
Renewable energy is sustainable indefinitely, unlike long-stored,depleting energy from fossil fuels
Renewable energy from wind, solar, and water power emits nopollution or carbon dioxide
Renewable energy is nonpolluting since no combustion occurs(although the building of the components does in making steel, etc.,for conversion machines does pollute during manufacture)
1.1 020302
-
8/8/2019 Energy Ocean Wind Intro
4/23
Renewable Energy (Continued)
Fuel combustion produces greenhouse gases that are believed tolead to climate change (global warming), thus combustion ofbiomass is not as desirable as other forms
Biomass combustion is also renewable, but emits CO2 andpollutants
Biomass can be heated with water under pressure to createsynthetic fuel gas; but burning biomass creates pollution andCO2
Nonrenewable energy comes from fossil fuels and nuclearradioactivity (process of fossilization still occurring but trivial)
Nuclear energy is not renewable, but sometimes is treated asthough it were because of the long depletion period
1.1 020402
-
8/8/2019 Energy Ocean Wind Intro
5/23
The eventual decline
of fossil fuels
Millions of years of incoming solar energy were capturedin the form of coal, oil, and natural gas; current usagethus exceeds the rate of original production
Coal may last 250 to 400 years; estimates vary greatly;not as useful for transportation due to losses inconverting to liquid synfuel
We can conserve energy by reducing loads and through
increased efficiency in generating, transmitting, andusing energy
Efficiency and conservation will delay an energy crisis,but will not prevent it
1.1 020402
-
8/8/2019 Energy Ocean Wind Intro
6/23
Available Energy
Potential Energy: PE = mh
Kinetic Energy: KE = mv2 or mu2
1.2 020412
-
8/8/2019 Energy Ocean Wind Intro
7/23
Economics
Cost of installation, operation, removal and restoration
Compare cost/watt & cost/watt-hour vs. other sources
Relative total costs compared to other sources
Externality costs arent included in most assessments
Cost of money (inflation) must be included (2 to 5%/year)
Life of energy plant varies and treated as linear depreciation to zero
Tax incentives or credits offset the hidden subsidies to fossil fuel
and nuclear industry Environmental Impact Statements (EIS) require early funding to
justify permitting
1.3 020402
-
8/8/2019 Energy Ocean Wind Intro
8/23
Ocean Wind Energy
Over or in proximity to the ocean surface, the windmoves at higher speeds over water than over landroughness
2.0 020525
-
8/8/2019 Energy Ocean Wind Intro
9/23
Ocean Wind Energy
Wind energy results from uneven heating of the atmosphere
Wind resources vary greatly worldwide; strong over oceans
Power is proportional to the cube of the wind speed
Ref.: www.freefoto.com/pictures/general/ windfarm/index.asp?i=2
6.0 020121
-
8/8/2019 Energy Ocean Wind Intro
10/23
Ocean Wind Energy (continued)
Long fetch (distance) of unhindered wind increasesspeed and available energy beyond land installations
Offshore wind turbines diminish public outcry againstwind turbines (low visibility, monopod supports)
Turbines are typically placed on concrete supports ingroups; rotors are often 80 m in diameter
Turbines are also placed along a coast on the foreshorearea to intercept the prevailing wind from over the ocean
Must avoid bird migration routes; turbine ~20 to 30 rpm
6.0 020402
-
8/8/2019 Energy Ocean Wind Intro
11/23
Ocean Wind Energy (continued)
Present and planned offshore wind energy plants willsupply significant consumer demand and reduce needfor coal- and oil-fired plants and resultant pollution
Middlegrunden near Denmark
Oil-drilling platforms
Small auxiliary turbine
Platform design can be modified to support largewind turbine
6.0 020402
-
8/8/2019 Energy Ocean Wind Intro
12/23
Wind Energy Equations
(also applies to water turbines)
Assume a tube of air the diameter, D, of the rotor
A = D2/4
A length, L, of air moves through the turbine in t seconds L = ut, where u is the wind speed
The tube volume is V = AL = Aut
Air density, , is 1.225 kg/m3 (water density ~1000
kg/m3
) Mass, m = V = Aut, where V is volume
Kinetic energy = KE = mu2
6.1 020402
-
8/8/2019 Energy Ocean Wind Intro
13/23
Wind Energy Equations(continued)
Substituting Aut for mass, andA = D2/4 , KE = /4D2u3t
Theoretical power, Pt = /4D2u3t/t = 0.3927aD
2u3,
(rho) is the density, D is the diameter swept by the rotor blades, and u is the speedparallel to the rotor axis
Betz Law shows 59.3% of power can be extracted
Pe = Pt59.3%rtg, where Pe is the extracted power, r is rotorefficiency, t is transmission efficiency, and g is generatorefficiency
For example, 59.3%90%98%80% = 42% extraction of theoreticalpower
6.1 020402
-
8/8/2019 Energy Ocean Wind Intro
14/23
Generic Trades in Energy
Energy trade-offs required tomake rational decisions
PV is expensive ($4 to 5 perwatt for hardware + $5 per wattfor shipping and installation =$10 per watt)
compared to wind energy($1.5 per watt for hardware+ $5 per watt forinstallation = $6 per watt
total)
Are Compact FluorescentLamps (CFLs) always betterto use than incandescent?
Ref.: www.freefoto.com/pictures/general/windfarm/index.asp?i=2
Ref.:http://www.energy.ca.gov/
education/story/story-images/solar.jpeg
Photo ofFPLsCapeCanaveralPlant byF. Leslie,2001
7.1 020315
-
8/8/2019 Energy Ocean Wind Intro
15/23
Energy Storage
Renewable energy is often intermittent, and storageallows alignment with time of use.
Compressed air, flywheels, weight-shifting (pumped
water storage at Niagara Falls) Batteries are traditional for small systems and electric
vehicles; first cars (1908) were electric
www.strawbilt.org/systems/ details.solar_electric.html
7.2 020402
Hydrogen can be made by electrolysis
Energy is best stored as a financial credit throughnet metering
Net metering requires a utility to bill at thesame rate for buying or selling energy
-
8/8/2019 Energy Ocean Wind Intro
16/23
Energy
Transmission
Electricity and hydrogen are energy carriers, not natural fuels
Electric transmission lines lose energy in heat (~2% to 5%); tradesloss vs. cost
Line flow directional analysis can show where new energy plants arerequired to reduce energy transmission
Hydrogen is made by electrolysis of water, cracking of natural gas, orfrom bacterial action (lab experiment level)
Oil and gas pipelines carry storable energy
Pipelines (36 or larger) can transport hydrogen without appreciableenergy loss due to low density and viscosity
More efficient than 500 kV transmission line and is out of view
7.3 020402
-
8/8/2019 Energy Ocean Wind Intro
17/23
Legal aspects and other
complications
PURPA: Public Utility Regulatory Policy Act of 1978. Utilitypurchase from and sale of power to qualified facilities; avoidedcosts offsetting basis of purchases
Energy Policy Act of 1992 leads to deregulation
NIMBYs rally to shrilly insist Not In My Backyard!
Investment taxes and subsidies favor fossil and nuclear power
High initial cost dissuades potential users; future is uncertain
Lack of uniform state-level net metering hinders offsetting costs
Environmental Impact Statements (EIS) require extensive andexpensive research and trade studies
Numerous public interest advocacy groups are well-funded andready to sue to stop projects
7.4 020402
-
8/8/2019 Energy Ocean Wind Intro
18/23
Conclusion
Renewable energy offers along-term approach to theWorlds energy needs
Economics drives the energyselection process and short-term (first cost) thinking leadsto disregard of long-term,overall cost
Increasing oil, gas, and coalprices will ensure that thetransition to renewable energy
occurs Offshore and shoreline wind
energy plants offer a logicalapproach to part of futureenergy supplies
8.0 0201402
-
8/8/2019 Energy Ocean Wind Intro
19/23
References: Books, etc.
General: Srensen, Bent. Renewable Energy, Second Edition. San Diego: Academic Press, 2000, 911 pp. ISBN 0-
12-656152-4. Henry, J. Glenn and Gary W. Heinke. Environmental Science and Engineering. Englewood Cliffs: Prentice-
Hall, 728pp., 1989. 0-13-283177-5, TD146.H45, 620.8-dc19 Brower, Michael. Cool Energy. Cambridge MA: The MIT Press, 1992. 0-262-02349-0, TJ807.9.U6B76,
333.7940973. Di Lavore, Philip. Energy: Insights from Physics. NY: John Wiley & Sons, 414pp., 1984. 0-471-89683-7l,
TJ163.2.D54, 621.042. Bowditch, Nathaniel. American Practical Navigator. Washington:USGPO, H.O. Pub. No. 9. Harder, Edwin L. Fundamentals of Energy Production. NY: John Wiley & Sons, 368pp., 1982. 0-471-08356-
9, TJ163.9.H37, 333.79. Tidal Energy, pp. 111-129.
Wind: Patel, Mukund R. Wind and Solar Power Systems. Boca Raton: CRC Press, 1999, 351 pp. ISBN 0-8493-
1605-7, TK1541.P38 1999, 621.312136 Gipe, Paul. Wind Energy for Home & Business. White River Junction, VT: Chelsea Green Pub. Co., 1993.
0-930031-64-4, TJ820.G57, 621.45 Johnson, Gary L, Wind Energy Systems. Englewood Cliffs NJ: Prentice-Hall, Inc. TK 1541.J64 1985.
621.45; 0-13-957754-8. Waves:
Smith, Douglas J. Big Plans for Ocean PowerHinges on Funding and Additional R&D. Power Engineering, Nov.2001, p. 91.
Kotch, William J., RearAdmiral, USN, Retired. Weather for the Mariner. Annapolis: Naval Institute Press, 1983.551.5, QC994.K64, Chap. 11, Wind, Waves, and Swell.
Solar: Duffie, John and William A. Beckman. Solar Engineering of Thermal Processes. NY: John Wiley & Sons,
Inc., 920 pp., 1991.
9.1 020402
-
8/8/2019 Energy Ocean Wind Intro
20/23
References: Internet
General: http://www.google.com/search?q=%22renewable+energy+course%22
http://www.ferc.gov/ Federal Energy Regulatory Commission
http://solstice.crest.org/
http://dataweb.usbr.gov/html/powerplant_selection.html
http://mailto:energyresources@egroups.com
http://www.dieoff.org. Site devoted to the decline of energy and effects upon population
Tidal: http://www.unep.or.kr/energy/ocean/oc_intro.htm
http://www.bluenergy.com/technology/prototypes.html
http://www.iclei.org/efacts/tidal.htm
http://zebu.uoregon.edu/1996/ph162/l17b.html
Waves: http://www.env.qld.gov.au/sustainable_energy/publicat/ocean.htm http://www.bfi.org/Trimtab/summer01/oceanWave.htm
http://www.oceanpd.com/ http://www.newenergy.org.cn/english/ocean/overview/status.htm
http://www.energy.org.uk/E FWave.htm
http://www.earthsci.org/esa/energy/wavpwr/wavepwr.html
9.2 020329
-
8/8/2019 Energy Ocean Wind Intro
21/23
References: Internet
Thermal: http://www.nrel.gov/otec/what.html
http://www.hawaii.gov/dbedt/ert/otec_hi.html#anchor349152 on OTEC systems
Wind: http://awea-windnet@yahoogroups.com. Wind Energy elist
http://awea-wind-home@yahoogroups.com. Wind energy home powersite elist
http://telosnet.com/wind/20th.html
9.2 020329
-
8/8/2019 Energy Ocean Wind Intro
22/23
Units and Constants
Units: Power in watts (joules/second) Energy (power x time) in watt-hours
Constants: 1 m = 0.3048 ft exactly by definition
1 mile = 1.609 km; 1m/s = 2.204 mi/h (mph) 1 mile2 = 27878400 ft2 = 2589988.11 m2
1 ft2 = 0.09290304 m2; 1 m2 = 10.76391042 ft2
1 ft3 = 28.32 L = 7.34 gallon = 0.02832 m3; 1 m3 = 264.17 US gallons 1 m3/s = 15850.32 US gallons/minute g = 32.2 ft/s2 = 9.81 m/s2; 1 kg = 2.2 pounds Air density, (rho), is 1.225 kg/m3 or 0.0158 pounds/ft3 at 20C at sea level
Solar Constant: 1368 W/m2 exoatmospheric or 342 W/m2 surface (80 to 240W/m2)
1 HP = 550 ft-lbs/s = 42.42 BTU/min = = 746 W (J/s) 1 BTU = 252 cal = 0.293 Wh = 1.055 kJ 1 atmosphere = 14.696 psi = 33.9 ft water = 101.325 kPa = 76 cm Hg =1013.25
mbar 1 boe (42- gallon barrel of oil equivalent) = 1700 kWh
9.3 020402
-
8/8/2019 Energy Ocean Wind Intro
23/23
Energy Equations
Electricity: E=IR; P=I2 R; P=E2/R, where R is resistance in ohms, E is volts,
I is current in amperes, and P is power in watts Energy = P t, where t is time in hours
Turbines: Pa = A
2 u3, where (rho) is the fluid density, A = rotor areain m2, and u is wind speed in m/s
P = R T, where P = pressure (Nm-2 = Pascal) Torque, T = P/, in Nm/rad, where P = mechanical power in
watts, is angular velocity in rad/sec Pumps:
Pm = gQmh/p W, where g=9.81 N/kg, Qm is mass capacity inkg/s, h is head in m, and p is pump mechanical efficiency
9.4 020402
top related