Earth, Wind and Fire

Great name for your group. There is a lot of potential for the use of wind energy and many people are looking into it. As we go, I'll write my comments in red.

‍‍‍‍‍History ‍‍‍‍‍
-The history of wind as a source of energy began in 1000 B.C., to 1300 A.D. for the use of simple machines. The earliest known source of wind was for sailboats, which later led to the later sail-type windmills. The first windmills were invented to do the tasks of grain-grinding and water-pumping in Persia 500 - 900 A.D. Vertical-axis windmills were of the first windmills to be created which consisted to vertical sails connected to vertical shafts. The vertical-axis windmills were also used in China which some say is their origin because they appear and are documented as early as 1219 A.D.
Windmills began to appear in the western world in 1300 A.D., to 1875 A.D. howerer these windmills appeared on a horizontal axis because European water wheels were on a horizontal axis. The reason for the shift was unknown but the horizontal shift began to become more common. In 1270 A.D. the first illustration was drawn as a four blad mill mounted on a post, gain the name, "postmill" which for their time was technologically advanced. In 1390 A.D., the dutch refined the towermill which was essentially the postmill. the towermill was a multi-story windmill with multiple floors dedicated to grinding grain, storing grain and removing chaff. On the very bottom were living quaters for the windsmith and their family. These windmills gave room for improvemnt because they had to be managed manually, the windsmith's primary job. The European mills later became that improvent for the primary reason that the sails generated aerodynamic lift which improved the rotator efficiency. This feature allowed an increase in rotator speed which then allowed for a greater amount of grinding and pumping. Perfecting the windmill took place in increments over the duration of 500 years. When the process was finally complete the windmills had all of the major features to be recognized in the performance of modern wind turbine blades. These mills were the, "electrical motor" of pre-industrial Europe and had a diversity ranging from irrigation, grain-grinding, saw-milling of timber and the more common waterfall. They also processed spices, dyes, paint and cocoa. These large tower mills began to decline with the use and appearance of steam engines.
Over in the far west mills had be fufilling their standard job of mechanical water pumping with smaller systems and smaller rotor diameters. These systems were perfected in the United States during the 19th century which stated with the, "Halladay windmill" in 1854 then later leading to the Dempster design which is still commonly used in the United States. the most important refinement of the American fan-type windmill was the development of steel bladesin 1870. the steel could be used in more efficent shapes and was lighter. Between 1850 and 1970 more than 6 million were installed in the United States; ‍‍‍their primary use was for water pumping, stock watering and farm house needs. The larger windmills were used for pumping water for the steam railroad trains where there were no close rivers.‍‍‍
postmill.jpg dutch2.jpg
An early persian vertical A dutch windmill.
axis windmill.


  • Turbines on average have 200ft-long blades and are as tall as a 20 story building.The wind blows and the turbines turn a shaft that is attached to a generator and viola- ENERGY!
  • Alternator converts wind energy to electricity
    • All alternators work because of the effects of
      moving magnets past wire. When electrons flow through a wire a magnetic field is created around it
  • Types of turbines
    • HAWT
      • Must be pointed towards wind
    • VAWT
      • Main rotor shaft is arranged vertically
      • Pros
        • Doesn't need to be pointed in the direction of the wind (good where wind is variable), generator and gearbox are more accessible
      • Cons
        • Sometimes can produce pulsating torque, drag can be created
  • When the wind blows across teh rotor blades, the propeller shaft rotates the alternator and the alternator makes electricity
    • If wind speed is reduced by 1/2, power is reduced by 1/8 (Light wind = almost no power)
  • ‍‍Offshore wind power‍‍
  • Storage: To generate energy in times of little or no wind
    • Battery
    • Compressed Air
      • CAES
      • Energy is converted into compressed air & stored in large, above ground tanks or underground caverns
      • Hydrogen Fuel Cells
        • Generated electricity is used to split water into oxygen/hydrogen.

Pros and Cons

  • Pros
    • Does not pollute the environment
    • It's renewable! (the supply of wind is unlimited)
    • ‍‍‍‍Prices for harnessing energy has decreased by 60% since the 1960s ‍‍‍‍
    • Decent availability (some places are better suited than others)
  • Cons
    • ‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍Wind is unpredictable‍‍‍‍‍‍‍‍‍‍
    • ExpensesKills birds
      • Cost effectiveness
      • ‍Repair Costs

    • Noise and aesthetics


Wind power has low ongoing costs, but a moderate capital cost. The average cost per unit incorporates the cost of construction of the turbine and transmission facilities, borrowed funds, return to investors and estimated annual production, averaged over the projected life of the equipment, which may be in excess of twenty years. Energy cost estimates are very dependent on these assumptions so published cost figures can differ substantially.
In 2005 the cost was around 5-6 cents per kW-h and now is estimated to be but in 2006 it was estimated to be $55.80 per MW-h, coal at $53.10 per MW-h and natural gas at $52.50 MW-h making it the most expensive. ‍‍‍In 2011 wind has been determined to be one of the most effective and rewable resources but also by far the most expensive‍‍‍. People who produce or breed Wind energy in many jurisdictions receive financial or other support to encourage its development. Wind energy benefits from subsidies in many jurisdictions, either to increase its attractiveness, or to pay for subsidies received by other forms of production. In the US, wind power receives a tax credit for each kW·h produced; at 1.9 cents per kW·h in 2006, the credit has a yearly inflationary adjustment. Another tax benefit is accelerated depreciation. Many American states also provide incentives, such as exemption from property tax, mandated purchases, and additional markets for "green credits". Germany and Canada also provide incentives for wind turbine construction, such as tax credits or minimum purchase prices for wind generation, with assured grid access.
Secondary market forces also provide incentives for businesses to use wind-generated power, even if there is a premium price for electricity. Some manufactures for example pay utility companies a premium that goes to subsidize and build new wind power infrastructure. Companies use wind-generated power, and in return they can claim that they are undertaking strong "green" efforts. In the US the organization Green-e monitors business compliance with these renewable energy credits
‍Is Wind Energy Practical?

  • ‍‍‍Grid-connected systems‍‍‍

    • Connect smaller wind turbines
    • If not enough energy is produced, the utility makes up the difference
    • If more than enough energy is produced, one can sell it to the utility
    • Reduces energy dependence and carbon footprint
    • Still expensive
      • A 10 kilowatt machine (the size needed to power an average home) might cost $35,000-$50,000
      • ‍‍Commercial machines can cost up to $3.5 million‍‍
      • Then why?
        • Though it is not as effective as it could be right now, wind power is still an alternative energy source
        • With continuing research, wind power could potentially replace a great portion of energy used in the United States, especially when combined with solar and/or nuclear power
Drs. Rest, Donahue, and Sacks - you have a good beginning and foundation to the use of wind power as an energy source. Now we need to consider how it can be used for the general population including meeting the various needs of the consumers, the cost, and a plan for implementation in the future. Could this energy source be used with another - have you spoken with any of the other research groups?