Wind energy has become very popular but that is mostly because huge wind farms have been installed. Does it make sense for homeowners to set up a small scale wind turbine? Well, it very much depends on your location.
First be aware that small scale wind turbines, for example 50W nominal power, produce more costly electricity than large and medium-scale wind turbines. In the US, one of the easiest ways to assess the wind resources in a region is to consult a state wind map. Unfortunately, wind speed estimates on the maps are reported at 165 or 195 feet (50 or 60 meters) above the surface of the ground. Small scale wind turbines are typically installed much further down. Wind maps are also of limited value since wind speeds can vary considerably even over short distances.
Hills, cliffs, forests and buildings typically reduce wind speed but in some special cases they can actually magnify winds. As a rule of thumb, placing a wind turbine at the base of a hill significantly reduces the output. The best place for a wind turbine is generally on top of a hill. If you are seriously thinking about setting up wind turbine, consulting a professional wind site assessor may be the best solution. Professional wind site assessors can analyze your site and make recommendations for tower/turbine placement, minimum acceptable tower height etc.
In the UK, the recommendation is to only consider installing a wind turbine if the annual average wind speed for your site is 5 meters per second (11 mph) or more. If you think that your site is suitable for a wind turbine, you can install an anemometer (wind speed measuring device) to measure the wind speed for three months or longer.
Be aware that many manufacturers of wind turbines tend to overstate the electric production of their turbines. You may want to deduct 20% if you are trying to estimate if a wind turbine makes sense financially. You also need to decide if you are going to use batteries, it will be cheaper to connect a wind turbine to the grid without using batteries. Batteries also require some ongoing maintenance.
Also the turbine will require maintenance and repairs over the years. On the other hand, the cost of electricity from the utility is likely to increase. It’s been rising, nationwide, at a rate just under 4.5 percent annually for the last 35 years. When you are calculating the cost of electricity from a wind system, don’t forget to subtract financial incentives from federal, state and local governments and local utilities. The federal incentive for wind, for example, is currently 30% of the system cost.
A simple way of calculating the return on investment (ROI) is done by dividing the annual value of electricity generated by a wind system by the cost of the system. This is a very crude way of estimating the economic performance of an investment which will most likely overestimate the ROI.