Comparison of Wind Power Technologies

Item Horizontal (Airplane propeller type) (HAWT) Old Vertical Turbines(VAWT) Mass Megawatts NEW VAWT ( Vertical Axis Turbine)
Description Over 95% of wind turbines currently in use Various designs ; largely experimental Utilizes the positive technological aspects of both horizontal (HAWT) and vertical (VAWT)
Definition HAWT (Horizontal axis wind turbine) VAWT (Vertical axis wind turbine) Mass Megawatts NEW VAWT (Vertical Axis Turbine)
Cost per kWh in 16 MPH average wind 4 to 5 cents per kWh 7 cents per kWh Less than 3 cents per kWh
Advantages
  • No cyclical stress unlike vertical axis.
  • Ability to place high above the ground to avoid turbulence.
  • Components on ground level for simplified installation and easier maintenance.
  • Manufacturing backlog avoided through limited use of custom made components.
  • 35% to 60% less expensive per kWh than HAWT or VAWT depending on local labor cost and local access to components.
  • Smaller blades use a fraction of the material per rated kilowatt.
  • Modular and scalable
  • Inxpensive to repair, high maintenance components such as gearboxes and generators are at ground level , isolated from problem causing vibrations. This dramatically reduces premature failure.
  • Use of local vendors and workforce
  • Reduced stress on bearings.
  • Extremely quiet-no noise.
  • NO Bird Kill.
  • Stiffer blades and higher efficiency ( cannot have both with vertical axis turbines
  • Easy start in lower wind speed
  • Ability to place high above the ground to avoid turbulence.
  • Component failures are isolated, preventing a complete shutdown of a MAT.
  • Lower capital expenditures and maintenance costs enables profitability at twenty times more locations than HAWTs and VAWTs with lower cost.
Disadvantages
  • Blades on top of tower,
    difficult to Maintain and repair.
    Expensive to Manufacture.
    Expensive to repair-all components on top of tower.
    Extreme stress on bearings.
    Avian mortality issues.
  • Long periods of downtime for repairs; necessitates the use of a crane.
  • Blades have problematic cyclical stress unlike horizontal.
    More stress on bearings than horizontal
    Lower efficiency per swept area
    Higher efficient version is

    A) difficult to start,

    B)more prone to shaft problem with larger blades
    Difficult to mount on higher tower
    Bearing replacement requires tower to be taken down.
  • Control difficulties
  • Takes more swept blade area to produce same amount of power as Horizontal turbine.(Moot point due to lower blade cost per kilowatt/hour produced.)
  • Possible perceived aesthetics issues