Tower Kits

Several turbine manufacturers sell tilt-up tower kits designed and engineered for their wind machines. Because steel pipe is heavy and expensive to ship long distances, most kits include all of the materials you need except the pipe. You purchase pipe locally.

Wind turbines often require adaptors, known as stub towers, to fit onto commercially available towers. Stub towers consist of a short piece of pipe, with a flange that bolts onto the base of the turbine. Be sure to obtain an adaptor for your turbine. For best results, buy a hot-dipped galvanized adaptor. They last much longer than ungalvanized steel sub-towers.

When buying a tower, be sure you purchase a model that’s approved by the wind turbine manufacturer. When shopping for a wind generator tower kit, also be aware that some kits may not include anchors, because the type of anchor needed for a tower varies from one location to the next, depending on the soil type. In most cases, anchor foundations are constructed on site using concrete and rebar.

When mounting a wind turbine, be sure to avoid roof-top towers. Such installations are an unequivocally bad idea for several reasons. First, roof-mounted turbines in most locations are too close to the ground, where average annual wind speeds are much lower. Lower average annual wind speeds mean much lower output. A 2007 study of roof-mounted wind turbines by Encraft Ltd, a British consulting firm, showed that wind turbines mounted on homes and apartment buildings produced much less electricity than predicted by computer models. On residential structures, annual wind speeds were only about 5 to 7 miles per hour, well below the models’ predicted wind speeds of 10 to 12 miles per hour — and well below the speed at which the wind turbines produce electricity. (The models obviously didn’t account for ground drag and turbulence).

Meters were installed to monitor the output of the micro-turbines and small turbines in this study. The researchers compared energy generated by the urban turbines to the manufacturers’ performance predictions. The researchers found that on average, wind turbines exported less than 0.5 kilowatt-hours a day — that’s 5 cents worth of electricity per day. Some of the turbines generated less power than the inverters consumed and were negative energy producers at their low wind speed sites. That is, these systems consumed more electricity than they generated. Overall, the turbines produced only 50 to 60 kWh of electricity per year — that’s $5 to $6 per year!

Rooftop installations are not a good idea because they’re also exposed to turbulence created by ground clutter, trees and buildings. As noted in previous chapters, turbulence reduces the quality and quantity of wind. This reduces energy production and increases wear and tear on the turbine, resulting in shorter turbine life.

Buildings are also rarely designed and engineered to support the load and handle the vibrations produced by a wind turbine. These vibrations can cause structural damage to buildings and vibrations are conducted into the building, which can be annoying to occupants.