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Wind Turbines System Sizing, Cost, and Benefit Background   arrow

Sizing a Wind Energy System

Most small wind turbines have a rating or size based on the maximum electricity they can generate such as 1.8kw or 5kw. But that is not a very useful number for most consumers, since power ratings are not an apples-to-apples comparison. It is better to use the certified ratings from the Small Wind Certification Council. The SWCC rating will show the kWh (kilowatt-hour) production of a turbine at an assumed wind speed of 11.2 mph and under other assumed conditions.

However, if 11.2 mph is not the average wind speed at your location (which it likely isn’t), use the energy curve supplied by the manufacturer. This energy curve should show how much annual electricity (kWh) the machine produces at the average wind speed you expect or measure at your site. Compare the manufacturer’s estimated annual energy production with the SWCC rating to ensure it is reasonable. Match this output with your annual energy consumption. To determine this number, check your monthly bills to come up with the annual total of kilowatt hours of electricity you use.

Once you have determined your annual electricity use, you can decide how much electricity you want to offset with a turbine, based on budget and other considerations. For example, if you want to offset nearly all your electricity use and have determined you have annual usage of 10,000 kWh, select a turbine that will produce that much power over the course of a year at your average wind speed. If your turbine will generate 10,000 kWh and you pay $0.12/kWh, you can expect to save about $1,200 per year before inflation and other factors are taken into account.

Wind Turbine Costs

The cost of small wind turbines varies depending on how much power they can produce and other factors. A rough range is $5,000 to $8,000 per rated kilowatt. A system that would offset most of an average home’s electricity use might cost $40,000 before incentives. A small wind turbine, like other capital investments, should increase the value of your property. If you can tell a prospective buyer that your electricity bills are almost nothing, the value of the installed turbine may be an attractive incentive.

Maintenance varies by system, so ask about requirements when you are considering which kind of turbine to buy and when you are reviewing literature from different manufacturers. Wind turbines require regular maintenance that generally consists of periodic inspections and adjustments; if performing this kind of maintenance, sometimes at the top of a tall tower, is not something you are either willing to do or to pay for, wind energy is not right for you. Representatives of manufacturers can give you an idea of the expected maintenance schedule and help you arrange maintenance. A rule of thumb is to allocate about 1 percent of the installed cost of the wind system for operation and maintenance expenses over the life of the system.

In addition to maintenance costs, you will want to insure your turbine against possible damage and liability claims, and some counties require insurance. Ask your property insurance company whether they will insure the turbine. Generally, the most cost-effective way to insure a wind system is under an existing homeowner’s insurance policy on your house; it is often insured as an “appurtenant structure” (an uninhabitable structure).

Last updated: February 15, 2018 at 13:11 pm