Release Date: October 1, 2009

Wind Farms: Complex Projects in Rural Places Putting up tall turbine towers in windy countryside raises unique challenges

Midwest Construction

Windswept rural fields and hilltops across the country have begun sprouting a new crop: the tall, graceful turbine towers of rapidly growing wind farms that produce clean electricity. Like all types of specialized construction, building the power-producing turbines in rustic rural areas carries its own set of challenges. Constructing a wind farm wouldn�t be quite as challenging if the sites weren�t so, well, windy. Not to mention out in the middle of nowhere, often with inadequate roads, or no roads at all, and frequently far from such necessities as concrete plants and adequate lodging for traveling laborers. It�s a business that�s challenging but booming. According to the American Wind Energy Association, the industry built enough wind farms in 2008 to increase U.S. electric generating capacity by 50% , to more than 25,000 MW. That�s enough to power seven million households and push America past Germany as the world�s biggest harvester of wind energy. The growth pumped $17 billion into the economy, through wind farm projects with multiple turbines and construction contracts of $30 million or more per farm. Midwest states including Indiana, Michigan and Wisconsin were among the fastest-growing in the wind business in 2008, according to the association. Illinois solidified its place among the nation�s top 10 wind power states, and Iowa vaulted past California to become the No. 2 producer. It has been a great time to be in the business of constructing wind farms, a time to build on the knowledge base required to thrive in this unusual field. As Gerald Schulz, vice president of Michels Corp., Brownsville, Wis., notes, wind farm construction comes with a unique set of requirements and challenges, beginning with the location: "We�re building out in the middle of a field, generally, or it could even be on top of a mountain." "These are typically in rural areas, in some cases near a town, or it may be 30 miles away," agrees Jerry Grundtner, vice president of project development for M.A. Mortenson Co., Minneapolis. That remoteness presents a wide range of logistical challenges. "In our, case we port most of our skill sets to the site," says Schulz. That means finding a place to live for a large pool of workers, perhaps 300 at the peak of construction. "It�s a big impact for a community when we move in." "You can�t build a significant infrastructure of housing because you�re not there long enough," Grundtner says, noting that a typical wind farm project takes between six and 11 months to complete. "People rent out rooms from local residents, you find some houses you can rent, some people stay in motels." Then there is the matter of locating materials and supplies. For example, each turbine is constructed on a concrete foundation that requires 200 to 400 cu yd of concrete. Among the questions, Schulz says: "Is concrete available, is aggregate available?" Frequently, the answer is no. There may be a need to open a mobile batching plant to provide the concrete, and bring in a fleet of dedicated trucks to handle deliveries. That leads to the next challenge, getting to the turbine construction sites. A project that includes multiple turbines may spread across 40 to 80 sq mi of rural landscape. "It�s not uncommon for it to be a half-hour drive from the office to where you�re working that day," Grundtner says. Typically, the turbines are planted in the middle of agricultural fields, which means installation frequently is preceded by the construction of temporary or permanent roads across the fields. Schulz adds that the rural, public roadways leading up to the edge of the fields may not be up to the task of handling heavy construction traffic. "We improve them or end up fixing them when the job is done," he says. This includes pavement improvements and widening tight turning radii as necessary. Making it all the more complicated is the fact that concrete trucks aren�t the biggest wheels that need to navigate onto the remote worksites. The blades on today�s turbines are attached to towers that may be 300 or more ft tall. "Typically they�re installed with very large crawler cranes, 440-ton to 600-ton crawler cranes, and a significant amount of other support equipment," Grundtner says. "We could have two to five of these large crawler cranes on site." Getting the cranes to the concrete foundations where the turbines are to be erected means temporarily widening the access roads or crawling cross-country. It�s a challenge that arises frequently because the cranes may spend as little as one day at each turbine before moving to the next. Contractors try as much as possible to avoid taking the cranes apart, which is costly and time consuming. If the crane is to walk across a farm field, workers must be aware of barriers such as ditches, fences and railroad tracks. They also must make sure the ground will support the weight of the crane. "In some cases we have to lay down cribbing or bedding or mats to get them from place to place," Schulz says. Winter is ideal for moving the big cranes around, because the ground is harder and there are no crops to damage. Once the concrete foundation is prepared and the crane and turbine components are delivered to the site, there�s one more challenge, says Paul Coenen, vice president of wind construction for Boldt Construction Co., Appleton, Wis., which specializes in construction and installation requiring highly coordinated lifts of very heavy equipment. "It�s extremely weather-sensitive because of the high picking and heavy weights, particularly the upper sections of the tower, the hub and blades," he says. Rain, hail and ice can make the job tricky and dangerous - and so can wind. "The fact that we want a windy spot for these turbines creates a potential challenge in getting them erected. Cranes can sit idle on days when you get wind." Construction companies must, therefore, factor in the weather when they�re bidding on wind farm projects. They�ll want to study the same wind charts that developers use to pick sufficiently windy sites, trying to determine how many idle days to plan for, and even what time of year is best for building. "The timing of the year is a huge difference with respect to wind," Coenen says. Of course, the developer has the final say about the timing of a project, but it helps construction companies to know what they�ll be facing. It�s all part of the complicated logistics. Coenen says it�s often possible to use windy days for work that�s a little closer to the ground, but that requires paying close attention to the forecast. "It�s a constant balance between trying to do your plan of the day and looking ahead a few days," he says.