Where the Wind Comes Sweepin’ Down the Plain

by Kristen Wright, associate editor

Richard Rodgers and Oscar Hammerstein II knew the power of Oklahoma’s wind in 1947 when they wrote of it “sweepin’ down the plain” in the show tune “Oklahoma!” The lyrics resonated so well with Okies that the Legislature declared it the official state song in 1953. More than half a century later, wind’s still sweepin’ down the plain, and it has joined “the wavin’ wheat” as an Oklahoma cash crop.

The state hosts 13 wind projects with more than 700 MW of generation, according to the American Wind Energy Association (AWEA). The National Renewable Energy Laboratory projects that by 2030, Oklahoma will be the nation’s second-largest wind power generator. Currently it ranks ninth.

“You can find wind in a lot of places, but Oklahoma is great because of the oil and gas industry,” said Aaron Weippert, O&M site manager of Acciona Energy North America’s Red Hills Wind Project LLC near Elk City. “The transmission is already installed.”

Construction on Red Hills began in April 2008, and the farm’s Acciona Windpower 1.5-MW turbines were operational by June 1, 2009, Weippert said.

Acciona built about 4.5 miles of transmission lines, he said, to connect to those owned by Western Farmers Electric Cooperative.

The co-op agreed to purchase all of the energy generated at Red Hills in a 20-year power purchase agreement. The 19-member generation and transmission cooperative serves two-thirds of rural Oklahoma.

To generate 123 MW, 82 turbines span 5,000 acres owned by 12 landowners in two counties. Seventy turbines are in Roger Mills County, which borders Texas on the west, and 12 are one county east in Custer County.

The turbines generate enough power for more than 40,000 homes, according to Acciona.

As of the 2000 U.S. census, Elk City had 4,159 households. There aren’t a lot of people in western Oklahoma, and there aren’t a lot of trees, either. About 35 miles east of Texas along Interstate 40, trees have long given way to low-lying cockleburs and other wicked scrub that pepper rolling, red dirt hills.

Electric Light & Power and Oklahoma Department of Commerce representatives toured Red Hills on Nov. 4. As the group stepped from the Acciona truck, the Spanish company’s steel-toe boots rule made sense. It’s nearly impossible to avoid shin-biting shrubbery while talking, walking and gawking at 80-meter-tall turbines.

And Acciona wants to plant more. In a dry, windy environment not conducive to growing much of anything without irrigation, it takes three to five years for shrub restoration, Weippert said. That involves planting native grasses from the Oklahoma Cooperative Extension Service, fertilization and erosion control.

“Soil has been our biggest challenge,” Weippert said. “We restore it to the way it was before.”

Acciona tries to blend in and keep the environmental impact to a minimum. The goal includes placing all distribution underground and looking like the neighbors. In other words, Acciona is abiding by another of the state song’s lyrics: “We know we belong to the land, and the land we belong to is grand!”

Tubines at Red Hills Wind Project are 80-meters-tall with blade diameters of 77 meters.
“Our office is a steel shed because that’s what you see around here,” Weippert said.

Acciona used about 33 loads of concrete to erect each turbine roughly an acre from the next. Topography, wind studies and sometimes landowners’ input determined their placement, Weippert said. Every foundation is 4-feet-deep, 20-feet-wide, and the black bolts into the foundation are 8-feet-long. On warm days, it’s common to find snakes as long as 6 feet sunning themselves around the bolt heads, Weippert said.

He warned his visitors not to stray from the 14 miles of gravel roads at Red Hills. Aside from the landowners’ cattle, he said, our most likely encounters would be with tarantulas, copperheads and rattlesnakes. Instead we saw wasps, a few of us spotted a fox and a single skunk lay stiff in the road. Weippert said that he saw a mountain lion in the area once. The most contentious critter–the lesser prairie chicken–tends to live a little farther northwest, he said.

“I haven’t seen a single prairie chicken,” Weippert said.

Nor has he seen protestors on behalf of the birds or any other cause, he said.

“I got here midconstruction,” Weippert said. “I haven’t heard a single complaint.”

Most residents realize Red Hills drops dollars into the local economy, so they’ve embraced it, he said. Its construction required about 350 workers, and 60 to 70 percent were Oklahomans, Weippert said. Acciona’s 25-year lease agreements with the landowners–three of whom live on-site–will provide increased revenues for Roger Mills and Custer counties through local infrastructure investments and property taxes during the project’s lifetime. Wind power is so new that the projected lifetime is 25 years, but at that time the project will be reassessed and either retooled with the newest technology or decommissioned, Weippert said.

Acciona built the wind farm’s on-site substation then turned it over to Western Farmers Electric Cooperative as part of a 20-year power purchase agreement.

Post-construction, the wind farm employs 11 maintenance technicians, one technical manufacturing advisor and another for maintenance. Three of the technicians are degreed engineers. Technicians receive at least six to eight weeks of training beyond manufacturing training. System operations, includ-ing the main control room, are in Chicago, but the farm also can be managed on-site by Weippert via two SCADA systems and remotely from Acciona’s headquarters near Pamplona, Spain, Weippert said.

Fourteen miles of gravel roads meander through 5,000 acres on Red Hills Wind Project near Elk City, Okla.

The farm includes seven circuits, with 10 to 14 turbines per circuit, an on-site substation Acciona built then turned over to Western Farmers Electric Cooperative, and a trasformer for every turbine to prevent line loss, Weippert said.

The turbines at Wind Hills are different than those at most wind farms in that they are 690-kV input and 12,000-kV output. They require multiple safety precautions–more than typical turbines, Weippert said.

As a result, all of the Red Hills technicians will be certified first responders within the next year, Weippert said. Safety protocol at Red Hills requires that if anyone gets injured, a direct call to the municipal fire department must be made because 911 doesn’t work as quickly, Weippert said. The fire department also has a GPS locator on every tower, and each door is numbered, he said.

Weippert conducts regular meetings with the fire department to keep them familiar with the site. He also schedules all work at Red Hills.

“I manage the work, not the workers,” he said.

His typical workday runs from 5:30 a.m. to 7 or 8 p.m., and much of it is “reporting, reporting, reporting,” he said.

The turbines are on 6-month maintenance schedules, and it takes a two-man crew one day to perform the work. The towers, made by DMI Industries in Tulsa, come with emergency ladders and service lifts large enough to accommodate two people. In addition, each turbine goes through a yearly maintenance check that takes a crew two or three days to perform.

The 37.5-meter-long blades from Brazilian manufacturer Tecsis make for a 77-meter diameter. The nacells and internal components, made by Acciona, came from Spain and Iowa, Weippert said.

The day we toured Red Hills, the wind whipped hard by Tulsa standards. It left a red veil of dirt on nearly everything. Weippert said it was a below-average wind day, however, with winds blowing at about 10 mph and generating about 30 MW. The windy season at Red Hills is from October to early May. Optimum wind speed is 20 to 25 mph; anything over that prompts the blades to pitch so they don’t pick up too much wind.

“Once you’re at 20 miles per hour wind, more wind is not creating more energy,” Weippert said.

When wind tops 56 mph, the turbines automatically shut down. The Red Hills team has meaured speeds topping 100 mph, Weippert said.

The turbines can create invisible wind wakes, too, so the team uses wake sector management to avoid turbulence, Weippert said. The turbines shut down automatically when the wind blows from due east or west. They also shut down when ice forms on the blades, but that’s occurred only a couple of times, Weippert said.

Apart from those scenarios, ev’ry night Elk City residents and their honey lambs can sit alone and talk, and watch wind turbines–instead of hawks–”makin’ lazy circles in the sky.”

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