Making a Decision

Should you invest in a wind turbine? The choice is ultimately yours and yours alone. A well informed decision will require much thought and personal research. From the preceding chapters we hope you have learned enough about wind energy to decide on your next step.

You should plan to review other literature and contact a number of wind turbine dealers or consultants to answer questions specific to your site and application. The Center maintains lists of wind turbine manufacturers, dealers and wind energy consultants to help you select the equipment best suited to your needs. You can find most of this information in the Resources Section. You will also find a bibliography of books, magazines and other literature in that section, as well as the names of trade organizations and government agencies dealing in renewable energy.

You also should plan to visit a few installed wind machines near you. This is a good way to become familiar with local wind turbine dealers and their performance with clients.

Following is a review of the major points involved in a wind energy decision, condensed into a series of nine steps.

1. Evaluating Energy Requirements

The easiest way to determine your present energy usage is to consult all your fuel bills for the previous year. Distinguish between your use of electricity, oil, natural gas and any other fuel that might be reduced or replaced by a wind system. Note how your consumption varies by the month or season so that your energy use pattern can be compared to the availability of winds in your area. Although the fuel bills will not indicate how your energy usage varies with time of day, you should determine this in at least a rough sense to compare with wind availability. When is it the greatest? When is it the least?

2. Evaluating Energy-Efficiency Measures and Other Energy Alternatives

Before considering a wind turbine, you should have already applied sound energy-efficiency measures to your home, farm or business. Doing this will provide a double benefit, because you may not need as large and expensive a wind turbine as you might have thought. You may even be happy enough with your fuel savings to dismiss any further thoughts of buying a wind turbine.

On the other hand, you already may have taken several steps toward energy-efficiency, and the results of your economic evaluation of a wind turbine may prompt you to consider alternative ways of cutting fuel costs. Potentially viable options include solar energy systems, wood stoves and ground source heat pumps. Remaining with your present energy supplier could even be the best buy. Whatever your final decision, it should be based on sound economic principles and be compatible with your energy needs and lifestyle.

3. Evaluating Legal, Social and Environmental Issues

A survey of these issues is crucial to your decision-making, because certain issues can alter or even end your plans for a wind turbine. In general, rural areas will be least affected by these issues.

Contact the local zoning board, town clerk, or building inspector to identify applicable zoning ordinances and building permit requirements. Liability coverage and insurance needs should be discussed with an insurance agent. To avoid unforeseen public objections to the sight of a wind turbine in the neighborhood, discuss your intentions with neighbors. Obtain a title search to determine if prior agreements or easements exist which would prevent a wind turbine from being installed on your property.

4. Evaluating Wind Resources

Taking wind measurements for at least three months, and preferably a year or longer, is the best way to determine your wind conditions, especially if the data is also compared with those collected at a nearby IEC wind monitoring station. The necessary instruments can be purchased, rented or provided as part of a site evaluation study performed by a hired consultant or wind turbine dealer. A wind turbine site should experience wind speeds averaging no less than 12 mph, for economic viability. This average wind speed is required for most applications.

Before investing in measurements, however, decide if your site has the potential for having sufficient winds. Consult the wind index and also evaluate your site’s elevation relative to the surrounding terrain and its access to the prevailing winds. Look at vegetative indicators. Remember that the power in the wind is a function of the cube of the speed. A 10% error in a wind speed estimate can mean a 33% error in a wind power calculation.

5. Determining Wind System Application

If you have already decided what a wind turbine will provide (electricity, for example), then you should next determine an appropriate machine size, or generating capacity. As a rule of thumb, a wind turbine should be sized to supply anywhere between 25 and 75% of your electrical demand. How much you are willing to spend on a system also will affect size selection.

If you have not yet decided what fuel source to displace, the previous steps should give you a clue. Try to match fuel consumption to wind availability. Seasonal winds are strongest in winter and early spring, and daily winds usually peak during the afternoon. If you are considering storing the electricity, as with batteries, then the daily variation in winds is less important.

Most people choose electricity as the wind turbine’s product. Interconnection of the wind system with the utility grid eliminates the need for separate storage and provides the convenience of unlimited back-up power from an existing energy source. If you are only looking for alternative energy sources for hot water or space heating, there are other alternatives that should be considered for their practicality and cost-effectiveness. Active and passive solar systems, and wood stoves or furnaces might be better suited for such heating needs.

6. Shopping for a Wind System

Once you have decided how wind energy will work for you, you should examine the wind turbine products and accessories available on the market. If you haven’t already, this is the time to contact one or more dealers to discuss your particular interests and get preliminary cost estimates. Choosing a good wind dealer is probably just as important as selecting a good wind system, because most dealers service what they sell. Dealers should provide you with references. Don’t hesitate to demand excellence. You should be as particular about service and maintenance of your wind machine as you are for your automobile.

Become familiar with manufacturer’s product literature, and read what you can about specific wind turbines in popular magazines, newspaper articles and elsewhere. Talk with local wind turbine owners, who can be your most reliable information source. Ask the owners about how they chose their wind systems and whether their expectations were realized. Find out what problems they have had with their machines’ performance, utility cooperation and so on. Ask how responsive the dealer has been to service calls since the installation.

As you narrow your choices to just a few machines, compare wind turbine warranties and note differences between those provided by the manufacturer and those offered by the dealer. Inquire whether the dealer’s warranty is transferable or assumable by the manufacturer should the dealer go out of business. Compare the maintenance requirements of machines. Higher maintenance means higher annual costs. You should compare the terms and prices of service contracts offered by different dealers.

7. Determine the Requirements for Utility Interconnection

If you plan to interconnect the wind system with the utility’s power lines, you must first contact the local utility office. The utility in turn should provide you with a written description of its costs and conditions involved with interconnection, such as double-metering. Determine the need for safety and power conditioning devices, additional monthly service and demand charges, buy-back rates and electrical inspection of the installation. Be prepared to submit a detailed schematic diagram (including electrical plans) of the planned wind system.

8. Evaluating Wind System Economics

This is the time to evaluate the financial consequences of your pending decision. The initial costs and annual expenses of wind turbine ownership must be weighed against the benefits of long-term fuel cost savings. discusses the variety of costs and savings pertinent to you. Most of them can be incorporated into the simple pay-back method of economic analysis to determine the pay-back period of your investment and the cost per kilowatt-hour of wind turbine-generated electricity. If you desire a more thorough approach that considers all the costs and savings on a yearly basis throughout a wind turbine’s projected lifetime, consult a reference on “life-cycle costing” in

Remember that wind energy systems qualify for a 1.5 cents per kWh energy production Federal tax credit for energy sold during the first 10 years of operation if the system is placed in service before December 2001. Additionally, the Iowa Energy Center’s Alternate Energy Revolving Loan Program may help to offset start-up costs.

9. Refine System Design

After having gone through the previous seven steps, you may want to make some final adjustments to your initial wind turbine design concept. If they will significantly affect system costs or performance, then you should retrace the appropriate steps.


You are now prepared to make a sound decision. The key to satisfaction with a wind system starts with understanding what any given machine can and cannot do. If you take the time and effort to plan an installation that will cost and perform as expected, a wind system should give you years of reliable service.