It's an increasingly common sight in Central Minnesota: an oversized semitrailer-load of wind turbine parts rumbling down the highway, drawing the attention and sometimes the frustration of other drivers.

St. Cloud is on a main route for wind turbine components traveling from the port of Duluth to destinations across the Midwest, where the demand for wind energy is soaring.

While the focus on renewable energy may be good for the environment and the local economy, the turbines themselves can be a traffic nightmare for those who must figure out how to move the massive parts across the country. Some also say they pose a safety risk.

In the past year or two, the frequency of those caravans has increased. From June through September, the Minnesota Department of Transportation issued more than 2,400 permits for oversized wind loads, including 332 in a single week in mid-October, said Ted Coulianos, MnDOT permit supervisor.

"They have become consistently the biggest of the superloads in significant volumes where people are noticing them," Coulianos said. "People aren't sure how to act around them, and that's the dangerous part."

In September, an 85-year-old South Haven woman was killed in a collision in St. Cloud with a truck carrying wind turbine parts. In other states, oversized wind loads have caused major traffic snarls and damaged infrastructure.

However, with the demand for wind energy continuing to grow, there's no sign of the trend slowing.

"It's not really going to die for another two to four years," Coulianos said. "Clearly, wind energy is here to stay, whether you agree with it or not."

Flow of parts

The turbine components generally arrive via ship at the port of Duluth and head to destinations in Iowa and other Upper Midwest states. Many of the parts are manufactured overseas, in places such as Germany, Spain and the Netherlands, by companies that include General Electric and Siemens.

Last summer, the port got busier after a semitrailer carrying wind parts dropped its cargo in Wisconsin, creating a traffic back-up and a public affairs mess, Coulianos said. As a result, Wisconsin toughened its permit requirements for the oversized loads, so GE rerouted its shipments to Duluth, he said.

In addition, Siemens had wind equipment arriving in Duluth and bound for Iowa, but flooding in Iowa caused delays, Coulianos said.

That meant late in the summer, there was a big rush to move those components across Minnesota.

The number of loads should drop in late November and increase again next spring, he said.

Not all of the loads are headed the same direction. There also are facilities making turbine parts in Fargo and northern Iowa that are sent in different directions, Coulianos said.

The loads can be massive, each weighing 232,000 pounds.

The turbine blades are each typically 125-155 feet long. The turbine tower typically is transported in three pieces, each about 80 feet long. The nacelle, which houses the generator, is the size of a city bus.

MnDOT would prefer that the loads stay on interstate highways. But that's not possible due to their height and the number of overpasses that are too low, Coulianos said.

That's caused the trucking companies to zigzag across Minnesota on state highways and even county roads, taking them through small towns and even metro areas such as St. Cloud.

"We've seen some very, very strange ... routings this summer, which caused a lot of head-shaking, I suppose, and problems," Coulianos said.

In many areas, people aren't familiar with traveling around oversized semitrailers, said John Dunlop, safety liaison with the 1,600-member American Wind Energy Association.

"Not only is the wind energy industry expanding rapidly, but the products are headed to areas of the country that have never, never had major components shipped to them before," Dunlop said.

Tragic crash

On Sept. 17, Shirlee Nelson of South Haven was killed and her husband, Millard, was injured when the minivan they were in was struck by a truck carrying wind turbine parts. The midday crash occurred at Minnesota Highway 15 and Second Street South in St. Cloud.

The Nelsons were married 67 years and very active with many friends, said their son, Terry. He described Shirlee as a caring, stay-at-home mother who drove her children to sporting events and "took good care of all of us." Millard Nelson is still sore but recovering, his son said.

The State Patrol is still investigating the cause of the crash. Terry Nelson said he doesn't want to comment further until the investigation is complete.

Coulianos called Nelson's death "our worst nightmare." It was the first fatal crash in Minnesota involving a wind load.

As a result, MnDOT is working to keep the wind loads out of metro areas such as St. Cloud as much as possible - even if that means the drivers must take a circuitous route, he said.

"We can't continue to have an exposure to that kind of risk," Coulianos said.

After the fatal crash, MnDOT began to route the oversized wind-turbine loads west to Sauk Centre instead of through the St. Cloud area. However, that route is temporarily unavailable due to road construction, Coulianos said.

Safety concerns

One group that opposes industrial wind development argues that wind turbine loads can pose a safety hazard because drivers sometimes go faster than they should and deviate from designated routes.

Lisa Linowes, executive director of the Industrial Wind Action Group, cited problems caused by large wind loads, including an incident in June in Texas when a truck hit a bridge abutment and caused irreparable damage.

Dropped loads or miscalculated turns also have caused serious traffic tie-ups in New York, California and Wisconsin, she noted.

"Under the pressure to get construction done, corners get cut," Linowes said.

The American Wind Energy Association encourages its members to work closely with transportation and state patrol agencies to provide safe transportation of wind components, Dunlop said.

Companies are looking at other ways of transporting components, such as barge and rail, he said. His organization also is working to make regulations more uniform from state to state, which would increase safety, Dunlop said.

Warning

In Minnesota, all oversized and overweight loads are required to have a permit. The carrier must provide specific information about the vehicle and load, its weight, size and proposed route, Coulianos said.

For very large loads, the carrier must survey the route ahead of time, hiring a pilot car with a height pole to make sure the route is clear of obstructions, he said.

MnDOT also can set conditions on the permit, such as requiring a State Patrol or civilian escort and restricting the hours of movement, Coulianos said.

Outside of the Twin Cities, the loads generally are required to move from 2 a.m.-10 p.m. because visibility is poor at night.

State officials don't notify the public in advance when the wind turbine shipments are moving through an area.

Exactly when the truck moves can depend upon traffic flow, State Patrol spokesman Lt. Mark Peterson said.

The flashing red or yellow lights on the escort cars are meant to warn motorists to pay attention, Peterson said.

"This obviously is meant to alert people to the presence of the wide load and to exercise caution when approaching ... and when passing," Peterson said.