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Explore the utilization of wind and water energy sources through windmills and hydroelectric systems, their impact on the environment, and the economics of wind energy. Discover the benefits, drawbacks, and solutions to NIMBY issues associated with windmills. Gain insights into the efficiency and storage of wind energy systems, with a focus on the top wind-energy markets worldwide. Delve into the workings of hydropower systems, their advantages, drawbacks, and role in global energy production. Learn about the different types of water turbines and the importance of harnessing natural resources for sustainable energy generation.
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Energy & Its Impact on Global Society Jerome K. Williams, Ph.D. Saint Leo University Dept. Mathematics & Sciences
Chapter 12: Wind and Water • Harnessing the Wind • Windmills: NIMBY • Wind Energy Systems • Wind Energy Storage & Econmomics • Hydropower: Using Water for Energy • Hydroelectric Energy Systems
Harnessing the Wind • One of first natural energy sources used: windmills used to pump water, grind grain • Extraction of energy from wind is enjoying a renewal in interest • Fastest growing form of energy today (30-40% in many areas)
Harnessing the Wind • Advantages • Non-polluting • Short construction times • Small, easily scaled to specific needs & locations • Very good complement to solar energy
Harnessing the Wind • Top Wind-Energy Markets (Table 12.2) • China • US • Germany • Spain • India
Windmills: NIMBY • Drawbacks? • Visual Pollution (Lower Property Values) • Noise, Communication Interference • Bird Fatalities • NIMBY = Not in My Back Yard
Windmills: NIMBY • Solution to NIMBY Faction? • Wind farms where population density very low • Offshore Wind Farms • Higher costs (construction & maintenance) • More energy harvested (higher wind speed over open water and less turbulence)
Wind Energy System • Power extracted from wind is proportional to the cube of wind’s velocity and area swept out by blades • Power = 2.36 x 10-6 x D2 x v3 (Units: kW) • Equation allows calculation max. power output • Blade diameter (D) in feet • Wind velocity (v) in miles per hour (mph)
Wind Energy System • Support Tower for turbine must be as high as possible since wind speed increases with distance from ground • Generators with fewer blades more efficient than mutivane rotors which function better at low wind speeds
Wind Energy System • Wind Turbine classified by orientation of rotor shaft and are of two varieties: • Horizontal axis (vertical blades): most common • Vertical axis (horizontal blades):
Wind Energy Storage & Economics • Present cost for at home wind generator system: around $4000 for 100 kWh monthly output • Still less expensive to buy electricity from local utility
Wind Energy Storage & Economics • Large wind-farm units are where demand lies • 36 states have “large wind-farms” (Table 12.4) • Incentives reduce installed costs to $1000 kWh • Electricity costs: 4 – 6 cents/kWh; dirt cheap • Landowners paid royalty by Uncle Sam to use land (up to $6000 /yr/turbine). PIMBY PLEASE !!!
Hydropower: Using Water for Energy • Hydropower used for many centuries to control water to do useful work (e.g., grind grain, saw lumber) • Water & wind: Only sources of mechanical energy until steam engine (19th century)
Hydropower: Using Water for Energy • How does hydropower work? • Recall from chapter three that one can convert potential energy to kinetic energy by changing elevation of water • Electricity Production (water) is not expensive; construction of new dams is very costly
Hydropower: Using Water for Energy • Table 12.5 lists hydropower output by country (China, US, Brazil, Canada, Russia, India) • 7% electricity in US is from hydropower • 21% world’s electricity comes from water
Hydropower: Using Water for Energy • Advantages • Plentiful supply of water • Non-polluting, renewable energy source • Economic potential for developing world (Africa) • Drawback • Affect environment (flooding large land area) • Trapping pollutants in water from human activity
Hydroelectric Energy Systems • Water flow to power plant from dam is through large pipe (penstock), where it drives a reaction or impulse turbine. • Output is function of both “head” and rate of water flow. The “head” is vertical distance from highest water level in dam and turbine.
Hydroelectric Energy Systems • Kinds of Waterwheels • Undershot wheel • Breast wheel • Overshoot wheel • Water Turbines (Two Kinds) • Impulse or Pelton Turbine • Reaction or Francis Turbine
Hydroelectric Energy Systems Breast Wheel Overshoot Wheel
Hydroelectric Energy Systems Pelton Turbine Francis Turbine
Problems • 11, 15, 19