Resolving Complexities in a Landfill Community Solar Project, part 2: Construction

Located on the outskirts of Beverly, Mass., in Essex County, the Beverly Community Solar Project was four and a half years in the making. Early challenges included waiting for an open incentive program that would make the project economically viable. In late 2018, Massachusetts introduced its new solar incentive program, Solar Massachusetts Renewable Target Program or SMART, and the door opened for the Beverly Solar Project. Little could the project stakeholders anticipate the extraordinary circumstances that were to be encountered ahead.

If you missed part 1, head here.

Part 2: Construction

Landfill Site Challenges and Adjustments

Signal Energy Installs Solar FlexRack on Beverly Landfill Solar Project.

The Beverly Community Solar Project is largest landfill solar project BlueWave Solar has built to date, and construction on the Beverly site came with some expected and unexpected challenges. The developer selected Signal Energy DG as the engineering, procurement, and construction (EPC) firm. Based in Union, N.J., the company is recognized for its creative solutions and the exceptional value they bring to every project. Signal’s team also had successfully completed several other projects for BlueWave.

Paramount for every landfill project is vigilant attention to the integrity of the environmental cap that tops the landfill. This unique aspect permeates every activity from the initial planning phase, logistics, scheduling, design, installation, to post-construction work.

Signal Energy DG proved the value of their relevant experience early in the project addressing some potential issues. They made minor modifications to the equipment pad locations that optimized the plant by reducing voltage drop. The improved design also made access to the equipment easier for installation and maintenance, while reducing access road length and associated costs. The EPC firm also worked directly with the utility to finalize the medium voltage run to ensure a smooth interconnection and worked in conjunction with the landowner to carry out a portion of the modification that included land clearing for the re-location of power poles.

One area where the project caught a break was space. Space is a premium on landfill projects. There is constant concern over protecting the environmental cap as personnel and regular shipments of equipment move in and out of the site. In this respect, the Beverly Landfill site was extraordinary. The site had an acre’s worth of laydown area off the cap giving the team a luxury rarely seen. From staging areas to office trailers, parking, and accepting all deliveries off the cap, this project was as good as it gets.

In contrast to other landfill projects, the engineering and construction teams were faced with additional challenges at the project site:

• Exposed rock and ledge surrounding the landfill
• Extreme soil resistivity; and
• Sloping terrain

Signal Energy DG performed grounding studies above and beyond normal requirements to address the resistivity issue. The engineering team worked to formulate a specific design that would adequately ground all areas and safeguard them. The solution included extensive grounding grids throughout the site in addition to the standard rods and rings typically installed.

Solar FlexRack’s project support team assisted with developing solutions for the slope challenges. In areas throughout the site where the slope was extreme, stone armoring was employed to help solidify the racking foundations. The site was installed with its B3P-X Series racking known for its ease of installation and adjustability to accommodate sloping terrain. The design characteristics of the ballasted racking are self-squaring for better module alignment and better flow with the topography of an undulating site.

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Best Practices

From the Construction Perspective

Ballasted Solar FlexRack installed by Signal Energy

• Effective planning, communication, and execution
• Put the time into due diligence, focus on detail
• Assess and validate the project delivery plan
• Explore access routes and traffic patterns and impacts far in advance from the perspective of isolating and simplifying travel paths, road work to ensure access, identifying deliveries and unloading areas on-site, limiting and managing weight on the cap
• Place high importance on timing and strict abidance to requirements
• Maintain effective communication
• Hire highly experienced and responsive contract partners from cradle to grave of the project to not only successfully execute the work but proactively collaborate with the teams to manage potential challenges

Tip: “We conduct both a pre and post-construction site analysis. In the case of the Beverly Landfill, we came in prior to active construction to fill in any depressions to avoid ponding and assure all low spots due to settlement were rectified. This is, then again, verified post-construction. Our goal is to leave the landfill and cap in better condition than when we started.” — Mark Anderson, Project Manager, Signal Energy

Normally this would be the end of the story, but 2020 isn’t a normal year. Stay tuned for Part 3: The COVID-19 Challenge, next week.

— Solar Builder magazine

[source: https://solarbuildermag.com/featured/resolving-complexities-in-a-landfill-community-solar-project-part-2-construction-and-site-challenges/]