Great Rock Windpower

Frequently Asked Questions

• How do residential wind turbines work?
• Will a small wind turbine save me money?
• What size turbine would I need for my home?
• Who should consider buying a wind turbine?
• Will it help the environment if I install a wind turbine at my home?
• Don't I have to take wind measurements for a year or more?
• Do wind turbines make noise or interfere with TV reception?
• Will my utility allow me to hook up a wind generator?
• Will I have to change any of the wiring in my house?
• What about towers?
• How much does a wind system cost?
• How reliable are wind turbines? Will I have to perform much maintenance?
• How do wind turbines perform as an investment?
• How would I have a wind turbine installed at my home?
   
   
  How do residential wind turbines work?
  A wind turbine, which is installed on top of a tall tower, collects kinetic energy from the wind and converts it to electricity that is compatible with a home's electrical system. In a normal residential application, a home is served simultaneously by the wind turbine and a local utility. If the wind speeds are below cut-in speed (7-10 mph) there will be no output from the turbine and all of the needed power is purchased from the utility. As wind speeds increase, turbine output increases and the amount of power purchased from the utility is proportionately decreased. When the turbine produces more power than the house needs, the extra electricity is sold to the utility. All of this is done automatically. There are no batteries in a modern residential wind system. Small wind systems for remote applications operate somewhat differently.
   
  Will a small wind turbine save me money?
  Yes, as a long term investment. Over its life a small wind system can produce electricity for as little as half the cost of electricity today and that cost will remain the same for aproximately 20 years. I can only guess what electricity from NSTAR will cost in 20 years. The amount of money a small wind turbine saves you in the long run will depend upon its cost, the amount of electricity you use, the average wind speed at your site, and other factors.
   
  What size turbine would I need for my home?
  Homes use approximately 9,400 kilowatt-hours (kWh) of electricity per year (about 780 kWh per month). Depending upon the average wind speed in the area, a wind turbine with rotor diameter of about 18 feet would be required to make a significant contribution to meet this demand. On the Island a windturbine will make more electricity through the winter months and less in the summer. Solar is complimentary to a small wind system because Solar PV panels produce more in the summer than in winter months.
   
  

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  Who should consider buying a wind turbine?
  A residential wind turbine can be a relatively large device and is not suitable for urban or small-lot suburban homes. Except for very small wind turbines on very small towers, a property size of one acre or more is desirable. As a general rule of thumb, if economics are a concern, a turbine owner should have at least a 10 mph average annual wind speed and be paying at least 10 cents/kWh for electricity.
   
  Will it help the environment if I install a wind turbine at my home?
  Yes. Wind turbines produce no pollution and by using wind power you will be offsetting pollution that would have been generated by your utility company. Over its life, a small residential wind turbine can offset approximately 1.2 tons of air pollutants and 200 tons of greenhouse gases (carbon dioxide and other gases which cause climate change).
   
  Don't I have to take wind measurements for a year or more?
  For most residential systems the cost of taking wind measurements is not justified. Wind resource data published by the U.S. Department of Energy is sufficient for an experienced evaluator to predict wind turbine performance. On the Vineyard we have been collectiong data and gaining knowledge enough to forgo wind measuring for turbines smaller than 100kW.  
   
  

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  Do wind turbines make noise or interfere with TV reception?
  Small wind turbines do make some sound, but not enough to be found objectionable by most people. A
  typical residential wind system makes less noise than the average washing machine or air conditioner. Wind turbines do not interfere with TV reception.
   
  Will my utility allow me to hook up a wind generator?
  YES. Federal regulations (specifically, the Public Utility Regulatory Policies Act of 1978, or PURPA) require utilities to connect with and purchase power from small (less than 80 MW) wind energy systems. Great Rock Windpower will help arrange the required utility company approvals. The wind turbines we reccomend have aready been approved by the utility.
   
  Will I have to change any of the wiring in my house?
  No. A wind turbine is easily connected to virtually any home without the need to change any wiring or appliances. The turbine will need two open spaces on the circuit breaker panel to be connected. If none are available an electrician can easily make the necessary changes.
   

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  What about towers?
  An 80- to 120-foot tower is usually supplied along with the wind turbine. Towers this tall are necessary to raise the wind turbine above turbulence generated by obstacles on the ground and trees. Wind velocity and, therefore wind turbine performance, increases with altitude. Several different types of towers are available, depending upon which manufacturer you select. Each type has its advantages; the most practical type of tower is the tilt-up guyed pipe tower.
  
  How much does a wind system cost?
  A small turbine can cost anywhere from $10,000 to $75,000 installed, depending upon size, application
  and service agreements with the manufacturer.
   
  How reliable are wind turbines? Will I have to perform much maintenance?
  Most small turbines have very few moving parts and do not require much maintenance. Some machines may require annual lubrication all require annual inspection. Modern wind Turbines are designed for a long life of 20-30 years and operate completely automatically.
   

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  How do wind turbines perform as an investment?
  The wind system will usually recoup its investment through utility savings within 5 to 15 years and after that the electricity it produces will be virtually free. Over its life a small wind system can produce electricity for as little as half the cost of electricity today and that cost will remain the same for aproximately 20 years. Many people buy wind systems in preparation for their retirement because they don't want to be subject to unpredictable increases in utility rates.
   
  How would I have a wind turbine installed at my home?
  Great Rock Windpower offers site assessment which includes a system reccomendation and an estimate. We also provided guidance for permitting as well as sales, installation and service. Call us to arrange you site assessment. 508-693-7414

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