Wind Turbines
 

Wind Energy Systems

Benefits of Wind Energy:

  • Turbines generally require the least amount of footprint per kWh produced.
  • Modern designs have made most turbines aesthetically appealing.
  • Operate 24 hrs a day as long as the wind speed is sufficient.
  • Generally are more cost effective when comparing $ per kWh produced.
  • Can be emplaced with minimal interference to ground activities or access to other activities on the property.
  • Slight additions to tower height can make dramatic improvements in production results rather than a larger or more expensive turbine.
  • Can be a better choice for larger power demands and where the owner wants the least amount of property disturbance.
  • Can be a better option or the only option for property with roof, property, or tree/shading obstacles.

Wind turbines are not noisy, as myths suggest. Most quality, low rotor speed turbines can barely be heard over a normal everyday conversation and are usually masked further by surrounding ambient noise produced from other activities.

 

Shortfalls:

  • Higher initial installation cost.
  • Highly topography reliant, meaning surrounding geography and ground obstacles dictate installation possibilities and locations.
  • Exaggerations and myths about turbine effects may cause initial objection to their installation but are easily put to rest with the proper education.
  • Due to height and certain tower structures, installation locations may be restricted by legal ordinances.

Wind resources (speeds, consistency), unlike solar, vary widely over relatively smaller areas, resulting in optimum areas and prohibitive areas. A proper site assessment prior to design or installation is essential and sometimes required for financial assistance and incentive applications.

Diagram showing how a wind turbine works

Wind energy systems tend to be more complex than others due to the myriad of factors and components that can affect its performance. most of that complexity is within the generator, the tower, and the siting of the tower itself. The actual conversion and use of the electricity is very similar to a PV system from the inverter on. The turbine uses engineered airfoils which actually pull themselves through the wind much like airplane wings and are not a drag-type profile like on an old farm type water pumping windmill, or cupped/spiral shaped anemometer. They combine the highest efficiency of one blade and the balance of multiple blades together. 3 blades have proven over time to be the magic number. The size of the blades and the resulting diameter of the area they cover is called the swept area and is essentially the “collection” area. This is best matched to the size of the alternator which produces the electricity by the manufacturer and the produced electricity is then transmitted down the tower by cable to the “balance of system”.

All tower mounted turbines collect wind from any direction using a tail or the rotor itself in downwind types to direct the rotor into the wind. In extremely high wind situations, most turbines have rotor speed governing devices or complete shutdown mechanisms applied automatically or manually to prevent “over speed” and damage to the turbine.

In wind energy, the performance of the turbine takes into account many factors to calculate the production of a turbine and is addressed in your initial site assessment. This includes the turbine alternator size and the rotor swept area. But this is only the beginning. Wind near the ground is slower than wind higher up due to ground drag from obstacles nearby and is filled with turbulence. Think of a towel you are holding upright being dragged across the ground, the bottom will bow further from your hands as obstacles catch the end of the towel. This shape is called wind sheer, created by trees, houses, hills and the like. Wind sheer is critical in determining the height of the tower to get your turbine up into the highest wind speed and avoid damage to your machine for a long life. Wind near the ground is filled with turbulence which causes destructive vibrations to turbines and also poor performance from the turbine, shortening it’s life, causing continual maintenance problems, and loss of maximum energy production. Roof mounted, short “flagpole” mounted, and vertical axis (straight up and down) turbines are to be avoided at all costs due to the above factors and more! So what d0 you look for? That’s our specialty. Once a site assessment has been completed, our staff will match the appropriately sized turbine, manufacturer, and tower type/size to your needs to maximize your peak energy generation given your average wind speeds, tower height, and production capabilities of your turbine components.

Wind towerA wind generator tower is very often more expensive than the turbine. The tower puts the turbine up in the “fuel” -the smooth strong winds that give the most energy. Wind turbines should be sited at least 30 feet higher or more than anything within 500 feet. Three common types of towers are tilt-up, fixed-guyed, and freestanding and the area of your property will dictate which will be the best fit for you. Towers must be specifically engineered for the lateral thrust and weight of the turbine, and should be adequately grounded to protect your equipment against lightning damage if ever struck. The plus side is that the taller the tower, the more energy can be produced! A 10% increase in wind speed by adding tower height can result in a 30% increase in the power available in the wind. Our experience in the tower construction industry is one of the factors that make us your go-to source for wind energy!

Learn more about how URE can help you harness Wind Energy.