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An Introduction to Wind Energy

An Introduction to Wind Energy. Frank R. Leslie, B. S. E. E., M. S. Space Technology 1/19/2002, Rev. 1.0 f.leslie@ieee.org; (321) 768-6629. Overview. Renewable energy is sustainable indefinitely, unlike long-stored energy from fossil fuels

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An Introduction to Wind Energy

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  1. An Introduction to Wind Energy Frank R. Leslie, B. S. E. E., M. S. Space Technology 1/19/2002, Rev. 1.0 f.leslie@ieee.org; (321) 768-6629

  2. Overview • Renewable energy is sustainable indefinitely, unlike long-stored energy from fossil fuels • Renewable energy from wind, solar, and hydroelectric power emits no pollution or carbon dioxide (although the building of the components does) • Biomass combustion is also renewable, but emits CO2 and pollutants • Nuclear energy is not renewable, but sometimes is treated as though it were because of the long depletion period • Sustainable energy comes from the sun or from tidal forces of the moon and sun Revised 020115

  3. Energy considerations for 2050 • Fossil-fuel energy will deplete in the future; took millions of years to create that much fuel • US oil production peaked about 1974; world energy will peak about 2004-9 or so • Renewable energy will eventually become mandatory, and our lifestyles may change • Transition to renewable energy must occur well before a crisis occurs Revised 020115

  4. The eventual declineof fossil fuels • Millions of years of incoming solar energy were captured in the form of coal, oil, and natural gas; current usage thus exceeds the rate of original production • Coal may last 250 years; estimates vary greatly; not as useful for transportation due to thermal losses in converting to convenient liquid “synfuel” • We can conserve energy by reducing loads and through increased efficiency in generating, transmitting, and using energy • Efficiency and conservation will delay an energy crisis, but will not prevent it Revised 020115

  5. The Hubbert Curve predicts fossil fuel decline • Dr. M. King Hubbert, geophysicist, published his prediction that the US oil peak would be reached in 1970. Later, others predicted the World oil peak would occur in the first decade of the 21st Century. • Past the production peak, oil prices will increase as extraction becomes more difficult and the price is bid up. www.hubbertpeak.com/midpoint.htm Revised 020115

  6. Where does our local electricity come from? • Our local utility, FPL, lists these for the 12 months ended May 2001: • Petroleum, 40% • Nuclear, 25.5% • Natural Gas, 20% • Purchased Power (various sources), 7.5% • Coal, 7% • Any renewables are in the Purchased Power category • Will we “export our pollution” to other states as California does? Cape Canaveral Plant, photo by F. Leslie, 2001 Revised 020115

  7. Solar Energy: Thermal • Low-temperature extraction of heat from ground; ~70° F to 80° F • Water heating for home and business; ~90° F to 120° F • High-temperature process-heating water for industry; ~200° F to 400° F • Solar thermal power plants; ~1000° F From www.energy.ca.gov/education/story/story-images/solar.jpeg Arizona has clearer skies than Florida. Ref.: Innovative Power Systems Revised 020115

  8. Wind Energy • Wind energy results from uneven heating of the atmosphere • Wind resources vary greatly worldwide, even within a few miles • Power is proportional to the wind speed cubed Ref.: www.freefoto.com/pictures/general/ windfarm/index.asp?i=2 Revised 020115

  9. Wind Energy in Practice • Favorable California tax incentives resulted in major U.S. wind farms • Altamonte Pass • Tehachapi • San Gorgonio Pass • Other turbines are located in Dakotas, Iowa, Texas, Minnesota, Wyoming, Iowa, Vermont, etc. • Early Twentieth Century saw wind-driven water-pumps commonly used in rural America, but the spread of electricity lines in 1930s (REA) caused their decline Revised 020115 www.nrel.gov/wind/usmaps.html

  10. Wind Energy is best suited to the Great Plains States • Coastal Florida has Class 2 wind energy (160 to 240 W/m^2) per the PNNL Wind Energy Atlas ― sufficient to investigate but marginal for major wind energy systems • High average wind speeds in the Rocky Mountain Region (300 to 1000 W/m^2) and the Great Plains States (200 to 250 W/m^2) Revised 020115

  11. Florida has marginal wind energy • These wind energy maps are available for each state and for the World • Coastal Florida is Class 2 with seabreeze and storm front passages • Summer ground heating results in ~10 mph seabreezes and storms • Winter is calmer, with frontal storm passages averaging every four days From the PNNL Wind Energy Atlas Revised 020115

  12. A sample day’s seabreeze wind profile from the FSEC MET system in Cocoa, FL Effective wind is from 9 a.m. to ~5 p.m. Ref.: FSEC Revised 020115

  13. Predominant wind energy direction determines the site selected N • The energy rose is the cube of the wind speed (flower-like) rose • In Palm Bay, Florida, this wind data sample shows the main wind direction at 150 degrees azimuth • Several years of data are averaged to get a useful sample; 30 years desirable • In obstructed areas, the site selection is critical to obtain the maximum wind energy S Revised 020115

  14. Energy is proportional to wind speed cubed • Recall that the average wind power is based upon the average of the speed cubed for each occurrence • The wind energy varies from trivial to disastrous! • Precautions are needed to protect the turbine Turbines must be turned automatically out of destructive winds to protect them. Some turn sideways, while others rotate vertically. Another way is to drag flaps from the tip of the blades. Most turbines reject power when the wind speed exceeds 30 mph. Ref.: Bergey Revised 020115

  15. Vertical Axis Wind Turbines (VAWT) Panemone, 1000 B.C. Savonius Darrieuswith Savonius Giromill Revised 020115

  16. Horizontal Axis Wind Turbines (HAWT) American Farm, 1854 Experimental Wind farm Sailwing,1300 A.D. Dutch with fantail 1.8 m Modern Turbines Dutch post mill 75 m Middelgrunden Ref.: WTC Revised 020115

  17. EnergyTransmission • Electricity and hydrogen are energy carriers, not natural fuels • Electric transmission lines lose energy in heat (~2 to 5% as design parameter) • Line energy flow directional analysis can show where new energy plants are required • Hydrogen is made by electrolysis of water, cracking of natural gas, or from bacterial action (lab experiment level) • Pipelines can transport hydrogen without appreciable energy loss Revised 020115

  18. Energy Storage • Renewable energy is often intermittent, and storage allows alignment with time of use. • Compressed air, flywheels, weight-shifting (pumped water storage) are developing • Batteries are traditional for small systems and electric vehicles; grid storage alternative • Energy may be stored financially as credits in the electrical “grid” • “Net metering” provides the same cost as sale dollars to the supplier; 37 states’ law; needed in Florida www.strawbilt.org/systems/ details.solar_electric.html Revised 020115

  19. Distributed Generation (DG) • Distributed generation occurs when power is generated (converted) locally and might be shared with or sold to neighbors through the electrical grid • Distributed generation avoids the losses that occur in transmission over long distances; energy used nearby • Varying wind and sunshine averages across several houses, blocks, cities, or states • Supply is robust, but precautions are required to protect electricity workers when main base-load power is out and system may feed back into powerlines Revised 020115

  20. Generic Trades in Energy • Energy trade-offs are required to make rational decisions • PV is expensive ($5 per watt for hardware + $5 per watt for shipping and installation = $10 per watt) compared to wind energy ($1.5 per watt for hardware + $5 per watt for installation = $6 per watt total) • Are Compact Fluorescent Lamps (CFLs) better to use? Ref.: www.freefoto.com/pictures/general/ windfarm/index.asp?i=2 Ref.: www.energy.ca.gov/education/story/story-images/solar.jpeg Photo of FPL’s Cape Canaveral Plant by F. Leslie, 2001 Revised 020115

  21. Legal aspects and other complications • PURPA: Public Utility Regulatory Policy Act of 1978. Utility purchase from and sale of power to qualified facilities; avoided costs • Power Plant Siting Act provides regulation by FERC • Energy Policy Act of 1992 leads to deregulation • Investment taxes favor conventional power • High initial cost dissuades potential renewable energy users • Lack of state-level net metering hinders offsetting costs • Renewable energy credits needed to offset unlikely carbon tax on fossil fuels and “externalities” (pollution, health, etc.) • “NIMBYs” rally to insist “Not In My Backyard”! • Need to consider beyond the first action; the results, and then what? Revised 020115

  22. Conclusion • Renewable energy offers a long-term approach to the World’s energy needs • Economics drives the selection process and short-term (first cost) thinking leads to disregard of long-term, overall cost • Increasing oil, gas, and coal prices will ensure that the transition to renewable energy will occur ― How will we choose to do it? Revised 020115

  23. References: Books • Gipe, Paul. Wind Energy for Home & Business. White River Junction, VT: Chelsea Green Pub. Co., 1993. 0-930031-64-4, TJ820.G57, 621.4’5 • Patel, Mukund R. Wind and Solar Power Systems. Boca Raton: CRC Press, 1999, 351 pp. ISBN 0-8493-1605-7, TK1541.P38 1999, 621.31’2136 • Brower, Michael. Cool Energy. Cambridge MA: The MIT Press, 1992. 0-262-02349-0, TJ807.9.U6B76, 333.79’4’0973. • Sørensen, Bent. Renewable Energy, Second Edition. San Diego: Academic Press, 2000, 911 pp. ISBN 0-12-656152-4. • Duffie, John and William A. Beckman. Solar Engineering of Thermal Processes. NY: John Wiley & Sons, Inc., 920 pp., 1991 Revised 020115

  24. References: Websites, etc. awea-windnet@yahoogroups.com. Wind Energy elist awea-wind-home@yahoogroups.com. Wind energy home powersite elist geothermal.marin.org/ on geothermal energy mailto:energyresources@egroups.com rredc.nrel.gov/wind/pubs/atlas/maps/chap2/2-01m.html PNNL wind energy map of CONUS windenergyexperimenter@yahoogroups.com. Elist for wind energy experimenters www.dieoff.org. Site devoted to the decline of energy and effects upon population www.ferc.gov/ Federal Energy Regulatory Commission www.hawaii.gov/dbedt/ert/otec_hi.html#anchor349152 on OTEC systems telosnet.com/wind/20th.html www.google.com/search?q=%22renewable+energy+course%22 solstice.crest.org/ dataweb.usbr.gov/html/powerplant_selection.html www.zetatalk.com/energy/tengx092.htm www.wind.enron.com/ Revised 020115

  25. Notes

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