Illinois wind farm delivers clean power-and cash crop

EDP Renewables has contributed in a big way economically to McLean County in Illinois, with the Bright Stalk Wind Farm-its third project in theregion-providing local farmers with a stable, drought-resistant cash crop in the form of lease payments.

By Robin Brunet

It's not unheard of in the energy sector that waiting years before actually breaking ground on a project can result in better outcomes than if construction had begun right away.

That is certainly the case with global renewable energy company EDP Renewables' (EDPR) recently completed Bright Stalk Wind Farm, a 205-megawatt (MW) installation located amidst the vast corn and soybean fields of McLean County, about 130 miles southwest of Chicago.

Bright Stalk, which consists of 57 turbines spread out over 5,000 acres, is the county's fourth wind farm (and EDPR's third in the vicinity), and it's delivering enough clean energy to power 73,000 average Illinois homes annually. Walmart and Salesforce helped kick-start the project by agreeing to purchase 123 MW and 80 MW of the wind farm's capacity, respectively.

Moreover, Bright Stalk created several hundred construction jobs and 19 permanent positions, and EDPR notes that it is complementing its rural surroundings by "providing local communities and farmers with a stable, drought-resistant cash crop in the form of property taxes and landowner lease payments."

In short, Bright Stalk is a boon to McLean County, and arguably it's just as well it took slightly over a decade to come to fruition.

"A decade ago was when we began talking to the various landowners and collecting wind data, having been struck by the potential of this specific region," says Erin Bowser, EDPR's director, project management-eastern region. "Then for a variety of reasons, we had to shelve the project, and by the time we reactivated it in 2017, we had to undertake lengthy and involved permitting.

"But by then, wind technology had evolved substantially, and that in turn enhanced Bright Stalk's capabilities."

Bright Stalk builds on a precedent already well established by EDPR in McLean County. The company also owns and operates the 398-MW Twin Groves I and II Wind Farms, which have been functioning since 2007 and 2008, respectively—and through these operations, EDPR has paid approximately $31.2 million to local governments and $27.7 million to landowners through 2018. It's estimated that $108 million has also been spent within 50 miles of the wind farms.

EDP Renewables, which entered the North American market in 2007 with the acquisition of Horizon Wind Energy LLC, has grown to become the world's fourth-largest wind energy producer with assets in 14 countries including Brazil, Canada, France, Poland, Romania, Spain, and the United Kingdom. In Illinois, the company operates 797 MW of wind energy projects. "The Bloomington Moraine region of McLean County where Bright Stalk is located has a very strong wind resource," says Bowser. "The location for Bright Stalk was also attractive because it was close to a transmission grid, meaning we wouldn't have to build miles of new transmission line."

Development in earnest began in 2017 with EDPR methodically acquiring operational rights to the desired properties; ultimately more than 100 lease agreements in three townships were secured. "We had a lot of things in our favor," says Bowser. "We already had wind farms in operation nearby, so the landowners were familiar with us, and since Illinois is a big wind farm state, we had government support as well." But it could be argued that a perfect storm of circumstances is what really propelled Bright Stalk forward. First, more and more coal plants were being de-commissioned, causing a significant increase in the state's energy demand. Also, in 2018, Salesforce (a global customer relationship management organization with data centers near Bright Stalk) entered into an agreement with EDPR to secure 80 MW from the wind farm via a 15-year power purchase agreement, which would advance the company's commitment to work toward 100 percent renewable energy consumption.

It took approximately $320 million and 360,000 man-hours to create the Bright Stalk wind project in Illinois, and over its 30-year lifespan it will pay up to $2.6 million annually in local taxes, which will contribute to McLean County's schools, roads, and other important public services.

"By the time Walmart came onboard with its 123-MW agreement, we had an ideal situation in that we had buyers prior to going ahead with construction—which is what we aim for in all of our projects," explained Bowser. Equally important, in the time between EDPR first considering the Bright Stalk site to securing the lease agreements, turbine technology had improved significantly. "Individual wind turbine generators produce more megawatt hours than ever before, and the towers and blades are taller, which allows each unit to capture wind from a greater wind swept area," says Bowser. Anchoring these turbines were larger concrete foundations fortified with more rebar than in older wind farms.

Having more than 70,000 wind turbines installed globally, turbine producer Vestas has the acumen to constantly self-improve, and in the years Bright Stalk was being developed it brought to market Large Diameter Steel Tower (LDST) technology that combines proven steel construction with an innovative design to deliver strength and height.

Vestas also produced new turbines that are configurable to achieve optimum power curves, with the configurations maximizing annual energy production while adhering to the operational envelope of the design lifetime.

The recently completed EDP Renewables Bright Stalk Wind Farm, a 205-megawatt installation located amidst the vast corn and soybean fields of McLean County roughly 130 miles southwest of Chicago, consists of 57 turbines spread out over 5,000 acres.

It was determined that Bright Stalk would require Vestas V136 3.6-MW turbines, each with a tower height of 99 meters, blade lengths of 66.7 meters, and tip heights of 167.2 meters. The aerofoil design would deliver high energy production even in low and medium wind conditions while minimizing structural loads, and advanced aerodynamics (particularly at the blade tips) would decrease the maximum noise emission level.

The civil work on Bright Stalk began in May 2019, and several different construction disciplines were undertaken. EDPR's primary contractor, M.A. Mortenson Company, built access roads to the turbines, which included entrances off the township and county roads. The new roads were cement stabilized for strength and durability and capped with rock, and the township roads were fortified prior to the delivery of the turbine components. Given the huge scale of the turbines, several turning radii had to be built on the county and township roads to facilitate delivery (they were removed after deliveries were completed and the areas returned to their previous grades).

In addition to the civil construction work performed by M.A. Mortenson, M.J. Electric performed the engineering and construction of the interconnect switchyard and Michels performed the project substation construction. Vestas, in addition to manufacturing and supplying the wind turbine components, was also responsible for the installation and commissioning of the wind turbines.

To accommodate each Vestas 3.6 MW turbine, foundations were created by excavating up to 12 feet deep and more than 75 feet in diameter, after which rebar was installed, followed by 600 to 650 yards of concrete, delivered each night from an onsite batch plant.

Power from the turbines is delivered through the collection system to the substation, and this required more than 100 miles of cable to be installed at four-to-six-foot depths throughout the project site. The collection system included several bores under roads and irrigation ditches as well as multiple junction boxes. The trenches contained a grounding cable, a fiber optic line inside a plastic inner duct tube, three separate 34.5 kV medium voltage cables (one per phase), and a colored warning tape one foot above the cables.

"Between July and September of 2019, the turbine components were delivered, the majority of them coming from the U.S. but some parts shipped from Europe," says Bowser. A total of 627 components were brought into the Chenoa railhead via train and delivered to the site by truck.

In order to accommodate each massive turbine, foundations were created by excavating up to 12 feet deep and more than 75 feet in diameter, after which rebar was installed and 600 to 650 yards of concrete (delivered each night from an onsite batch plant) poured.

Once the foundations cured, the holes were backfilled, and the turbines were installed by crane, following the familiar pattern of the towers erected first in sections, then the hoisting of the nacelle, followed by the installation of the blades. The two main cranes used to finish the installations were walked from turbine to turbine and occasionally broken down to pass under existing power lines.

In total, it took approximately $320 million and 360,000 man-hours to create Bright Stalk, and over its 30-year lifespan it will pay up to $2.6 million annually in local taxes, which will contribute to McLean County's schools, roads, and other important public services.

More importantly, in addition to its energy generation, Bright Stalk is expected to save McLean County more than 355 million gallons of water each year (that would have been required with a fossil-fueled power station), displace carbon emissions from fossil fuels, and mitigate the health effects of air pollutants.

In the greater scheme of things, Bright Stalk is enabling businesses to reach their green goals—which in turn may motivate others to follow suit. Salesforce is relying on the wind farm to help achieve its goal of using 100 percent renewable energy by 2022, and Walmart is aiming to power 50 percent of its operations with renewable energy by the end of 2025.

Upon completion of Bright Stalk, project operations manager J.C. Finfrock echoed the sentiments of his colleagues when he told the media: "After the immense effort that went into the development, regulatory, and construction processes for Bright Stalk, I am thrilled to see our wind farm up and running.

"We're grateful for the strong support from our local stakeholders, EDP Renewables, construction team members, and power purchasers for making this a reality."