Page 36 - North American Clean Energy July August 2015

wind power

Next-Generation Wind Turbines

Transportation and Logistical Hurdles
by U.S. Department of Energy Wind Program

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Tower diameters are limited by transportation constraints such as bridge height
Example of wind turbine blade transportation obstacles

IN MAY, THE ENERGY DEPARTMENT RELEASED Enabling Wind Power Nationwide, a report simultaneously performing all of the rolling and welding operations needed to produce
showing how the United States can unlock the vast potential for wind energy deployment tubular steel towers on-site or near-site at the wind plant. Unlike conventional spiral

in all 50 states, made possible through the next-generation of larger wind turbines and mills, this proposition can achieve the variable diameter and wall thickness required for
continued responsible siting. Enabling Wind Power Nationwide highlights the potential
towers. Another approach is being developed that combines high-strength concrete with
for taller wind turbine towers and larger rotors to access wind resources in regions with pre-stressing steel reinforcement to build tower modules that are composed of easily
limited or no wind deployments today, such as the Southeast. hese new regions represent transportable columns and wall panels.

an additional 700,000 square miles—or about one-ifth of the United States—bringing the
total area of technical wind potential to 1.8 million square miles.
Crane Availability and Requirements
he wind industry has already showed it can scale up wind turbine technology, both in Once the components arrive to their destination, large, often specialized cranes are needed
terms of the size of turbines and components, and in terms of manufacturing capacity. to assemble the turbines. Hoisting wind turbine nacelles onto taller towers requires the

he industry currently faces transportation and logistical constraints that make it diicult largest commercially available cranes due to the lift height onto the tower and mass of the
and costly to transport and install very large components. Technological advancements nacelle. Additional issues associated with hoisting heavier tower components are expected
will produce taller wind turbine towers of 110 meters and 140 meters that more eiciently to become increasingly important to overcome as these systems continue to grow.
capture the stronger and more consistent wind resources typically found at greater heights he availability, scheduling, and logistics of the larger crane classes required to lift

above ground level, compared with the average 80 meter wind turbine towers installed in progressively larger wind turbine nacelles onto taller towers are becoming increasingly
39 states today.
challenging. Crane availability decreases substantially above the 600-ton crane class, which
Over-the-road transportation limitations are based on the length, width, height, makes it more diicult to ensure that a large crane will be available for the installations.
and weight of loads, and these limits vary across the United States. Each state along a Crane builders in the United States are helping to address a shortage of large cranes

transportation route has diferent permit requirements and, as additional burdens are capable of handling larger wind energy components. For example, a new 650-ton crane
placed on the wind industry for increased shipment volumes, the permitting process has been developed which is expected to be able to install and service a 3-MW class wind
becomes more complex.
turbine nacelle at a 140 meter hub height.
Because tower components have increased in size and mass, large components like

tower segments trucked over land need to clear bridge heights, and long components like Responsible Siting
blades need to be able to safely clear turns along the road. Although alternate roads can In addition to technical challenges, wind plants must continue to be sited responsibly
sometimes be used, road weight limits on side roads more often restrict their accessibility. by understanding potential impacts on wildlife. As wind power moves into new areas,

his challenge generally limits the length of blades that can be transported over roadways more consideration on bird and bat species interactions is needed. Greater rotor heights
to between 53 meters and 62 meters, depending on the design characteristics of the may increase the potential for interaction between bats, birds, and turbines. he Energy
blade—such as the amount of pre-curve.
Department is working with a variety of governmental, industry, and academic partners to
Heavy components such as wind turbine nacelle assemblies—which house the gearbox address wildlife impacts. For example, wind energy bat impact minimization technologies

and other equipment on top of the tower— are typically shipped on common 13-axle are being developed to help address environmental siting and permitting challenges
trailers, which have a load constraint of about 165,000 pounds. As weights surpass this associated with responsibly developing and operating wind energy facilities in locations
limit, the number of available trailers drops dramatically, and the use of dual-lane or line with sensitive bat species.
trailers is required. For example, the capacity of a 19-axle trailer (the largest conventional Continuing technology development and overcoming transportation and logistical

trailer) is approximately 225,000 pounds, which is roughly the weight of a 4-megawatt hurdles is essential to expanding this clean energy source to every state across the nation.
(MW) wind turbine nacelle with the drivetrain removed.
By increasing the amount of land suited to commercial wind development with taller
towers, wind power can also provide local economic development opportunities, including
Department of Energy Investments
jobs for installers, engineers and other support personnel, in new communities and whole

Additional transportation constraints can be addressed through on-site or near-site regions with currently untapped resources.
construction. he Energy Department is currently exploring a couple of pathways to
address these constraints through public-private partnerships. One approach looks at
U.S. Department of Energy Wind Program | www.wind.energy.gov

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