The growth in the size of wind turbines and their components have negatively affected America’s transportation industry. The wind industry has pushed high-load permits to high numbers. Four to five truck loads are needed for each turbine. By one count in 2009, 22,000 truck loads were needed to ship 5,000 wind turbines. Even a small turbine can require up to eight hauls (one nacelle, one hub, three blades, and three tower sections.

Tower sections are one example of problematic parts because they are tremendously heavy. Typical lengths run from 60 to 70 ft and more with 15-ft diameters, and weights of 100,000 to 150,000 lb. Such loads are transported on special equipment with many axles. Shippers need an approved route before getting a permit, and approved routes can change from day to day.

The message from the transport industry is that the current size and scale of wind-turbine components presents a considerable challenge to the trucking industry. The challenge is exasperated by a fragmented regulatory system under which the trucking industry operates. Each state determines the routes that large trailers must take and the condition of the roadways on which they travel.

Over the last few years, a 1.5-MW wind turbine has been a prevalent size on U.S. roads and wind farms. It is about the largest and heaviest that transports easily on most U.S. roads. But turbine design is trending to larger units, hence, 2.5 and 3-MW units will soon be more frequently encountered. These will be challenges for transport and construction companies because each state has different rules, and approved routes change as frequently as the wind. This is potentially bad news for wind-farm developers that expect to stay on construction schedules. Hence, wind project developers must consider transportation early in making wind farm siting decisions.