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Tough winter solar install in Minnesota

GP JOULE faced some challenging winter conditions in the installation of six community solar projects in Minnesota, totalling 12 MW, but the company was able to draw upon its experience in cold temperatures to successfully complete the project.

By Tony Kryzanowski

Minnesota is home to the largest number of small-scale community solar garden projects in the United States, some as small as one megawatt (MW). While this type of solar garden program has many moving parts to pull together to bring it to success, there's no denying the positive economic impact it is having across the state.

David Shaffer, executive director of the Minnesota Solar Energy Industry Association (MnSEIA), says while the state does support large-scale solar development, a 100-MW solar project may only have a single developer, a single engineering, procurement and construction (EPC) provider, and a single module and racking manufacturer. Further, it will only be located in one place, so the local community where that project happens to be located earns a lot of benefit, while the rest of the state may not see much.

However, with a distributed portfolio like the community solar garden program, one hundred 1-MW projects benefit many developers, EPCs, suppliers, and workers. It will also help a lot of local economies as the installers stay at local hotels, buy from local stores, and spend more money in smaller communities.

"Our state's financiers are injecting capital into developers who then turn around and furnish services from EPCs, local land agents, suppliers, electricians, lawyers, landscaping contractors, and so on," says Shaffer.

Despite its northern geographic location, Minnesota and local utility Xcel Energy have been strong advocates for solar development in the state. Minnesota is now the 14th-largest solar power producer in the United States, with 89 percent growth experienced during the first three months of 2018. It currently generates over 850 MWs of solar power—enough to support 116,670 homes.

Officially called the Solar Rewards Community program, Xcel's solar garden initiative fits within its goal of providing one third of its energy to its customers from renewables by 2030; but by taking the solar garden approach, someone else takes the development risk while Xcel simply pays for and transmits the power. The Minnesota Public Utilities Commission approved Xcel's solar garden program in 2014.

Xcel describes the program as an alternative to private onsite solar panels. Residents, business owners, nonprofits, and municipalities can purchase a subscription for power generated by a solar garden owner without having to install solar panels on their own roof or property. It says that as of June 2018, 364 MW were being provided by 105 community solar gardens. According to MnSEIA, the program is on track to provide 500 MW of power by the end of 2018. That's compared to only 25 community solar gardens producing 80 MW a year ago, so there has been a dramatic increase.

 
  

The program originally had a minimum production capacity of 5 MW per installation, but that has now been lowered to one MW.

"Our program is so large because it has no cap on how many megawatts of solar can be installed through the program," says Shaffer. "Developers are free to plan and develop their project without need to win a request for proposals or some other bid. Instead, they can get all the pieces they need together and apply for an interconnection with the utility, much like how most rooftop solar projects work around the country."

But the solar garden development process of signing up local subscribers, construction, transmission tie-in, compensation, and billing is somewhat complicated.

According to Shaffer, solar garden owners are paid $100/MWh by Xcel Energy for the power they produce and transmit through Xcel's transmission system. They are responsible for signing up local subscribers for their solar garden power, requiring at least five. They handle power purchase negotiations with subscribers and coordination with Xcel's billing system, so that the subscriber is credited on their bills for the solar power they purchase.

To construct the project, an owner may hire companies like GP JOULE Canada Inc. to either supply equipment for a project or to act as the EPC. GP JOULE recently completed construction and equipment supply for six Minnesota solar garden projects measuring in size from one MW to 3.7 MW, for a 12-MW total of solar power production. Two projects were for developer ET Solar MN, and four were for AMP Solar.

"AMP was fortunate to work with great partners on the portfolio, from acquisition midway to development to commercial operation of each of the projects," says Jared Donald, AMP's senior vice president, head of USA for AMP.

With its extensive history constructing and supplying solar projects in Canada, specifically in Ontario, Fabienne Rodet, director of marketing at GP JOULE, says the company's participation in the roll-out of Minnesota's aggressive solar garden development program was a natural extension for the business. That's because it has developed both a reputation and product line designed for high performance in places like Minnesota, which can experience bone-chilling temperatures and heavy snow accumulation similar to Ontario. She also described smaller systems of up to 5 MW as a business 'sweet spot' for the company.

 
GP JOULE Canada Inc. recently completed construction and equipment supply for six Minnesota solar garden projects measuring in size from one MW to 3.7 MW, for a 12-MW total of solar power production. Two projects were for developer ET Solar MN, and four were for AMP Solar. 
  

Two of the six projects featured the company's PHLEGON single-axis tracker system.

"GP JOULE is the only EPC with a tracker," Rodet says. "Other tracker companies provide installation services, but we are the only EPC with our own tracker. By combining EPC services with our single-axis tracker, we can actually shorten timelines, reduce risk, and deliver a lower total cost per kilowatt hour compared to other manufacturers."

PHLEGON is named after one of the four horses powering the chariot of the Greek sun god, Helios. According to Rodet, PHLEGON is not the most elegant of the Helios horses, or the fastest, but it is the strongest. The tracking system is designed to perform in conditions that encounter extreme cold, heavy snow, and high winds. Rodet says that the tracking system uses up to 60 percent fewer piles compared to competing trackers, has a low fastener count, and offers easy ground maintenance access. The company recently partnered with Alberta's Southern Institute of Technology (SAIT) to test and verify its PHLEGON single-axis tracker's ability to deliver on its promises in the most challenging cold-climate conditions.

"GP JOULE wanted SAIT to test two things," says Tom Jackman, SAIT's principal investigator. "First, how the system will operate in Alberta's climate, and second, what the cost of operating and maintaining the PHLEGON over a 20-year lifespan will be. Our testing protocol introduced freezing conditions that were not considered in their original test plan, resulting in substantial ice build-up and additional weight. All components tested without failure."

SAIT cycled PHLEGON's mechanical components continuously 7,305 times over a 19-day period to simulate two decades of functionality. The tests included a deep freeze below -20 C, confirming the sensitive components can function under extreme temperature.

GP JOULE project manager on the Minnesota projects, Bogdan Dinu, says that the company not only supplies a product that performs well in extreme conditions, it also has the expertise to build projects that perform to specifications.

He says that snow in northern climates like Minnesota is always going to be an issue and not having any control over that precipitation can slow down construction. Also, cold is not wire, module, or equipment-friendly, and it can severely impact the efficiency of crews on the site.

 
GP JOULE has extensive experience working in cold environments and knows how to properly budget and schedule crews at the start of the project, taking into consideration the project's timeline. It takes measures to pre-assemble components, when possible, and deploys heated tents for workers to perform on-site assembly in a warmer, safer environment. 
  

Given GP JOULE's extensive experience working in cold environments, he says the company knows how to properly budget and schedule crews at the start of the project, taking into consideration the project's timeline. It takes measures to pre-assemble components when possible, and deploys heated tents for workers to perform on-site assembly in a warmer, safer environment.

Eugene Koval, GP JOULE director of Engineering, says that when building in cold climates, prioritizing civil and ground penetration activities such as site clearing and grading, road construction, trenching, and pile installation needs to be carefully considered. Issues like ground frost penetration and frost heaving can have a significant impact on the installers' ability to complete work in a reasonable timeframe and at a reasonable expense. These factors are all factored into the engineering and project planning processes.

"You want to be in and out of the ground before the frost sets in," he says, which usually means before mid-November. Once that work is complete, further above-ground installation activities can proceed at a more measured pace. He adds that most individuals working for GP JOULE have more than a decade of construction experience building solar projects in cold climates.

Koval, who has also previously led the company's product development team, says that GP JOULE's industry experience was a major contributor in how it developed its single-axis tracking system. He was involved in the PHLEGON tracker's development in Canada from the get-go.

"While it is designed for harsh climates in the northern U.S. states and the Canadian market, PHLEGON handles other challenging regions such as corrosive environments, hilly terrain, and high winds," he says. "We like to call it farm tech, because PHLEGON is built with industrial-grade steel and other components that are used in heavy, farm-like environments. And because it has fewer moving parts, standardized fasteners, hot-dipped galvanized steel components, and almost no lubrication, PHLEGON minimizes operational costs and failures."

For example, the tracker's heavy-duty linear actuators, which are responsible for moving the entire tracking system, are the only components in the system that have special lubrication within them rated up to -40 C. Designed to withstand wind and snowfall from a one-in-100-year event, the tracking system controls and wiring are rated for installation and operating temperatures of -30 C and -40 C. Finally, the leading edge of the PV panel is typically elevated a meter off the ground, to take into account the snow accumulation.

"Collaboration is key when it comes to community solar," says Chris Gosline, senior vice president of BlueWave Community Solar, who worked with AMP Solar to coordinate billing with subscribers. "Here in Minnesota, we saw a tremendous opportunity to work with top-notch partners. Through our partnership with AMP and GP JOULE, BlueWave was able to focus on doing what we do best—providing unparalleled customer management services for community solar subscribers."

 


September/October 2018