"Kids and Cranez" Comes to Wind Farm

Monday, October 10, 2016

By Loren G. Flaugh

MidAmerican Energy, Mortenson Construction Company and Siemens Energy again combined to sponsor their popular “Kids and Cranez” open house at the 250 megawatt (MW) O'Brien Wind Energy Project currently under construction in Franklin, Lincoln and Center Townships in north central O'Brien County.

This MidAmerican Energy wind farm consists of 104 Siemens 2.34 MW wind turbines and it's their second O'Brien County wind farm. Numerous wind turbine sites across the north and west end of the wind farm are already generating voltage that's connected onto the high voltage grid at the new MidAmerican Energy O'Brien County substation located northeast of Sanborn.

Employees working for Mortenson Construction had numerous pieces of massive construction equipment positioned at wind turbine site #84 two miles east of Sanborn and one/half mile south of Highway 18. Assembly of this turbine site, with the 191,000 pound Siemens nacelle looming 260 feet high overhead, was completed the day before. Two other completed sites are located to the west.

Large equipment was almost within arm's reach for the many dozens of young children and adults that streamed into the site on a sunny, warm October afternoon. Children taking in this impressive display of massive equipment were given plastic hardhats and a t-shirt for attending this open house basically meant to attract the interest and curiosity of children.

Easily the piece of construction equipment that garnered the most attention among so many fascinated children was the giant Manitowoc 16,000 crane, with its massive crawler track system, and 300-foot tall boom towering above the scene. The giant lifting block and hook, where cables are attached that lift the massive turbine components high off the ground, was positioned just above the ground so that kids could have their photos taken standing next to it.

Mortenson's employees had two children's bicycles suspended from two hydraulic cranes that formed an impressive arch as the grandparents and parents led children in to view the heavy construction equipment on display. The bicycles were prizes for coloring a picture that they were given, along with the hardhat and t-shirt.

Curious children got and up close and personal look at the giant Manitowoc 16,000 crane and the two rubber-tired hydraulic cranes. Information posted on the equipment provided visitors and children that summarized the amount of weight the hydraulic crane or the giant crawler crane was capable of lifting, in terms that a child could grasp. For example, the giant crawler crane could lift many more fully loaded yellow school busses than what either hydraulic crane could lift.

Hot food, sandwiches and ice cream were also served to the fascinated crowd. Mortenson had posted signs in Primghar and Sanborn advertising the event.

While answering a few brief questions, a Mortenson crew foreman said that there were still 31 wind turbine sites that remained to be completed. Mortenson has four giant Manitowoc cranes working on the entire project. The last crane still northwest of Hartley was being readied to move to one of the 34 turbine sites located south of Highway 18.

At the O'Brien County Board of Supervisors meeting two days later, county engineer Tom Snyder reported that Mortenson crane crews and riggers were working earlier in the morning and later into the evenings in an effort to lift turbine components when the wind conditions are more favorable.

According to a recent Mortenson plan of the day, Mortenson currently has 156 construction workers with many different skill sets working on the project while another 17 Mortenson employees work in the construction office.

High-voltage electricians are in the process of completing the electrical installation to each turbine site as they are erected. The Siemens nacelle generates a 700 volt, three-phase AC output that is stepped up to 34,500 volts through a step-up transformer located at the base of each turbine. High voltage cables are pulled up through tube and terminated in the generator. Fiber optic communications cables are also pulled to the top for the data acquisition systems.

Trench Tech is the underground utility construction contractor that's laying in the extensive 34,500-volt collection system that gathers the output from each turbine site step-up transformer and routes it back to the wind farm substation northeast of Sanborn. Power from as many as 10 turbines are combined into one circuit that carries the voltage back to the substation.

Due to the large and lengthy wind turbine components that come into the project site, many of the wind farm's gravel road intersections required wide-radius turns built at specific intersections. Mortenson's heavy equipment operators' dumped loads of dirt in the ditches at specific intersections. That dirt was compacted, and then crushed rock was dumped for traction and stability. Many of these intersections in the areas north of Highway 18 are now being restored to their original condition.

Access roads and entrances into the turbine sites are also being returned to their 16-foot wide permanent width after turbine sites are assembled. During the construction phase, these entrances and access roads are much wider.

When Mortenson began wind farm construction, they were expecting to be largely finished in early November. MidAmerican Energy is to have all 204 wind turbines operational by the end of the year.

First published in the Cherokee Chronicle Times. CLICK HERE to read the article on their website.