Written by: Leonard Parker | Solar News | 12th November
Rockport, Maine | 4.2 MW
Regular readers of Solar Builder are probably familiar with the Rockport Maces Pond project, our Utility-Scale Project of the Year, which we featured in the Spring issue in a section on agrivoltaics/dual-use solar. Heck, maybe that’s why you all voted for it.
Background: The project, developed by BlueWave, owned and operated by Navisun, is an agrivoltaic community solar project constructed over a wild blueberry farm. The project aims not only to deliver clean energy (and energy savings) to the local community as a community solar farm but also to improve the yield of the wild blueberry crop on site as part of the actual farm.
“Typically, at the start of a project like this we have to beat the drum and pitch to the property owner,” says Alan Robertson, managing director of solar development for BlueWave. “The landowner in this case really wanted to see the blueberries remain on site, which we wanted to do anyway. It was helpful because usually it’s a little lumpy convincing the landlord that it’s the way to go because it’s a little more complicated. We’re going to be a tenant but also the landlord, with the farmer as the subtenant. So luckily, he was bought in from the get-go.”
“I’m hopeful that this effort will help enhance crop production and our ability to work the land for years to come,” says Paul Sweetland, the site’s farmer. “Beyond the benefits to the land, I’m happy to be a part of a project that’s producing clean energy for those around us.”
For Navisun, a frequent owner-operator partner of BlueWave projects, this was its first chance to add a dual-use project to its portfolio.
“We were immediately interested in the opportunity for getting in on the cutting edge of agrivoltaics,” says Steven Campbell, managing director at Navisun. “We are a long-term owner-operator, and we love to feel like we’re part of the fabric of the community in the towns that we own our assets, so we’re always looking for new and interesting ways to give back to the community. The other aspect is we take the environmental stewardship of the industry to heart. We’re not just clearing trees and putting up solar panels. The blueberry farm was a great way to do that.”
Research: To learn more about the impact on the wild blueberry crop, the project, in partnership with wild blueberry growers, specialist networks and the University of Maine Cooperative Extension, will study how wild blueberries perform within a solar array. As part of the research study, the group will review the impact of construction on the wild blueberries. Long-term, sensors will compile data to gauge the impact in terms of yields across the field and under the different module types.
“We had our hypothesis at the outset,” Robertson notes. “In conjunction with our head of sustainability Drew Peterson, we worked with New England Consulting Services on how to not impede on the crop but also improve its development. When you cover the crop, they tend to be more resilient.”
Construction: The dual-use of solar arrays as part of a farm isn’t just a neat gimmick. Agrivoltaics could literally be the future of the planet, which makes all of these early projects crucial to get in the ground and to get right.
“It was pleasantly shocking to see a ‘blueberry construction plan’ binder in the CS Energy trailer that was about 3 in. thick,” Robertson says. “It was cool to see how serious everyone took it.”
Within that binder were instructions for constructing solar arrays within three different zones, each of which would involve a different level of care ranging from limited, medium and normal levels of disruption to the crop.
“The hard part initially was finding what we could use to go in and out of the very careful areas without disturbing the underbrush,” says Tom Milos, senior project manager for CS Energy. After initially thinking plywood, they settled on 4×8 sheets of nylon matting. “Once we got the mindset and feel for what we were doing with the blueberries, that took care of itself. The terrain was more difficult to work with than the blueberry farm — it was rocky and undulates a lot.”
The sloping site actually worked to the advantage of the agrivoltaics component of the array design. Typically, a dual-use array needs to be set higher than normal, about 8 ft or so, to accommodate the farming activity underneath. That means extra costs, which, thus far in BlueWave’s experience has been offset by incentives that Massachusetts has in place to aid in the development of dual-use solar. Maine has no such incentive, but turns out blueberries don’t need much room.
“The lowest part is 4 ft off the ground, which would have been the height anyway, so we had no adjustments to make,” Robertson says. Even better: “Turns out this site is on a hill, and it was tilting toward the south. This allowed us to get creative on the construction side and not change too much on the product side.”
What happens next? Maintenance for the site will cost a little bit more than usual but not much. BlueWave worked with the operations team to come up with a plan for more reporting and checking in on-site as well as a farming plan that jibed with the owner’s objectives and the needs of the crop.
“One thing people forget about solar plants is they are power plants,” Campbell says, reiterating the importance of keeping safety top of mind. The site features more signage than usual and has higher voltage areas sectioned off. “While we want to give the farmers access, we have to keep the plant safe and anyone in there safe.”
BlueWave is also funding the manufacturing of custom farming equipment to be used within the rows of solar panels for wild blueberry management. This equipment will benefit not only the Rockport project, but potentially enable the farming of other small, hard-to-cultivate wild blueberry fields in the state.
Everything from that aforementioned construction binder to that purpose-built ATV for blueberry picking indicates just how much pre-planning work goes into a project like this, both in construction and as part of the long-term ownership and maintenance plan.
“This project worked because we spent months coordinating logistics and how we were going to do it prior to getting on the ground,” Campbell says. “Understanding what Paul and the farmers wanted to do on a long-term basis helped us understand what we could do in our design. All three parties went in eyes wide open wanting this to be a successful partnership and project.”
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