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Clénera builds solar power-in wind-rich Iowa

Iowa may be more known for its wind power projects, but Clénera recently wrapped up work on the largest solar project in the state: the 127.5-megawatt Wapello Solar project.

By Robin Brunet

While renewable energy company Clénera has successfully completed 24 projects in nine different states involving 83 landowners and 12 utility companies, the Wapello Solar project was a rare chance for the company to kick-start solar capacity in Iowa—a state that is more known for wind power.

"We are constantly having conversations with landowners, utility managers, corporate leaders, and other professionals, and in 2017 our internal greenfield development team became interested in the land that would eventually accommodate the Wapello solar farm," explained Michael Gallego, Vice President of Operations at Clénera.

While the 127.5-megawatt project is mid-sized for Clénera (which is well known for its 251 megawatt Boulder City, Nevada solar power installation and its 238 megawatt Los Banos, California solar project), Wapello Solar is significant because "solar is just getting started in Iowa," says Gallego. "Up until now the focus has been on wind power, to the degree that by the end of this year, wind power will provide 70 to 75 percent of Iowa's total energy requirements."

Jared Mckee, Vice President of Business Development at C Clénera, is particularly bullish about Wapello Solar as a harbinger of more solar to come.

"Ten years ago solar prices prevented us from expanding our activities in the Midwest, but the technology has steadily improved and become more affordable, and today, Wapello Solar is among the first of several regional Clénera projects that will be constructed in the Midwest region."

Wapello Solar's 318,000 solar panels will ultimately generate 215,000 MW-h of energy, enough to power 21,000 homes, and create more than $5.2 million in economic benefits to Louisa County over its lifespan. It is, at 127.5 MW, the largest solar project in the state.

As with other Clénera ventures, Wapello Solar was born from legwork. "We're constantly on the lookout for sites that would be amenable to solar and in close proximity to the necessary power infrastructure, and our development team utilizes Clénera's priority systems and processes across the country to determine new opportunities," Mckee explains.

The 800 acres for Clénera's inaugural Iowa project are located two miles south of the town of Wapello, and the site would have normally been covered by corn and soybean plantations. "We reached out to the Central Iowa Power Cooperative (CIPCO) in Des Moines, a generation and transmission electric cooperative that includes Eastern Iowa Light and Power, which serves rural Wapello," Mckee says. "Near our proposed site was a 100 MW substation, which is ideal for the solar projects we undertake because it achieves economies of scale and lower interconnection costs, leading to significantly lower costs for consumers."

The 800 acres for Clénera's inaugural Iowa project are located two miles south of the town of Wapello. A 100 MW substation is near the site, which allowed the project to achieve economies of scale and lower interconnection costs.  

CIPCO and Eastern Iowa expressed interest in partnering with Clénera, having already decided to undertake a 60-megawatt project to repower the Summit Lake Generating Station in Creston, Iowa, (the work includes demolition of a 70-year old steam plant and installation of efficient natural gas-fired reciprocating engines by late 2022).

In addition, the Heartland Divide Wind Energy Center was expected to come online at the end of 2018, with CIPCO set to purchase 100 percent of the energy produced by the 103.5-megawatt facility. "CIPCO was heavily involved and interested in expanding its alternative energy portfolio, so what followed for us was a lot of old fashioned door-knocking and relationship building with the property owners, about 10 in all," Mckee says. "As mundane as this process may seem, it is the key to our success and lasted about a year."

The solar farm proposal was presented to local development leaders and a few other interested parties during a meeting at the Briggs Civic Center in downtown Wapello. Brad Quigley, a Louisa County Board of Supervisors member who attended the event, was struck by the potential economic benefits. "A project of this size is going to bring in a lot of opportunities," said Quigley. "It's going to put us on the map and bring a lot of contributing business" (it should be noted that Wapello is a town of just over 2,000 residents). The construction phase alone, in early 2020, created over 350 jobs.

From there, events occurred "at a quick pace," according to Gallego, who credits CIPCO for being "very good to work with, very helpful." Under a Power Purchase Agreement with C Clénera, CIPCO will purchase 100 percent of the energy and capacity output of the solar array for 25 years.

CIPCO CEO and executive vice president Bill Cherrier remarked when the project was formally announced: "This is a milestone as we look to strike a meaningful balance with energy cost, reliability and stewardship for our members. Energy produced by the sun provides an excellent complement to wind energy, and energy from Wapello Solar will be produced during our daily and seasonal peak demand times.

  The tracking system on the Wapello project is the FTC Solar 'Voyager' single axis tracker, optimized for bifacial performance. This tracker boasts an up to 0.5 percent yield improvement due to less backside shading and better albedo capture.

"This is an innovative way for us to offer reliability and efficiency to CIPCO's energy portfolio," he added.

CIPCO says that the Wapello project incorporates the latest in solar array technology to provide cost-effective, clean electric energy. Cutting-edge solar panel technology was paired with efficient solar inverters and a single-axis tracking system to maximize energy generation.

Gallego elaborates: "After selecting Renewable Energy Systems (RES) as our engineering, procurement and construction partner, we decided the site would be best served by a 50/50 combination of 400 watt and 405 watt Risen Energy bifacial panels.

"The inverters we chose are Sungrow 3150 central inverters, and for the tracking system we relied on the FTC Solar 'Voyager' single axis tracker, optimized for bifacial performance." This tracker boasts an up to 0.5 percent yield improvement due to less backside shading and better albedo capture.

Gallego adds that the tracker was efficient to install. FTC Solar designed the Voyager to require less than 140 Man-Hours per MW for installation and to use up to 60 percent fewer foundation piles per MW than competing trackers (the system requires only seven piles for a typical 60 meter row, which can lower costs by almost by two cents per watt).

As for the actual construction, which commenced in July of 2020, the biggest challenge encountered by Renewable Energy Systems was groundwater and potential frost conditions that needed alternative foundation methods.

"We ideally prefer dry, fallow dirt for our foundations, but Iowa typically has top surface frost and subsurface moisture, so we had to create deeper than usual foundations and put rock 'sleeves' around some of the piles," Gallego says. "We also used Solar Piles International's Wing-Piles that are outfitted with additional structures that provide added hold to subsurface material when the piles are sunk, and help provide better stabilization."

Working during a pandemic posed no problems. "COVID-19 had some impact on the supply chain but none in construction," Gallego says. "By November, the solar array was nearing completion, and we were producing test energy generation in December." Wapello became fully operational in January 2021.

Clénera is currently involved in 45 projects in 26 states, and Gallego says the company is interested in further developing Iowa's potential for solar energy generation. "We're very excited to be a part of this ground-breaking renewable energy project and appreciate the people involved in making Wapello Solar a success. We think there's plenty of opportunities for solar to grow in Iowa; certainly there are plenty of potential sites—and the Wapello Solar facility will have a positive influence in that regard."

Mckee added by way of conclusion: "Over the next 10 years we'll be able to get more megawatts out of better panels with less wiring, without having to go bigger in size. Not only can we compete with natural gas projects, we're very attractive to utilities in our own right. So, I think we're in store for many exciting developments in the foreseeable future."