Cranberry bogs and solar installations at first seem like a weird combination. Why crowd usable farmland with solar?
One bog in Carver, Massachusetts, proved the relationship could work. A 1.1-MW ground-mount sits atop the plants because shade actually creates an ideal growing environment for the cranberries underneath. The land now has a dual purpose—growing fruit at a more productive rate while also generating solar power.
Although this solarized cranberry bog is not the flooded-type that Ocean Spray commercials have familiarized, owner Mike Paduch does use the land to grow healthy plants that are later transplanted to other bogs for harvest. So while there isn’t a sea of floating red berries underneath the solar array, there are living, growing plants that need careful attention.
Cranberries grow on vines low to the ground and can survive only under specific conditions. They thrive in wetlands layered with peat soil, sand, clay and gravel during an April to November growing season. Air pockets inside the berries allow them to float, which is why most bogs are flooded to more easily separate the berries from the vines during harvest. These unique growing conditions, and the fact that the bog in Carver was already planted with live vines, made the installation of a solar array slightly tricky.
“One of our main concerns was the timing of the install,” said Dan Girard, director of EPC and global business development at S&C Electric Company, which was the EPC on the project. “It was explained to us by the owner of the site that in spring, plants are more flexible, as compared to summer or fall when the plant becomes more brittle and more substantial damage could occur.” Pile driving had to be done earlier in the year so as not to damage or break the cranberry vines on the functioning bog.
Local contractor Synergy Solar assisted with the installation. President Noah Jones said the project was challenging because of the logistics—machines had to be carefully moved around the living plants.
“The largest challenge on this project was the tight, confined space,” Jones said. “We had to protect the live plants. We had to use a matting for the machinery. Any time we moved a machine, we had to make sure we had matting under it so it didn’t rip up or damage the plants. We had to have a decent force of manpower just to move the matting.”
However, the layered ground conditions provided a silver lining for positioning piles.
“In New England, we typically run into a lot of refusals when we run the piles,” Jones said. “Cranberry bogs are mostly sand. This was pretty easy to do.”
Although a smooth installation, the piles did have to go a bit deeper than normal for a secure foundation. Jones said RBI Solar’s ground-mount system used on the project was easily adaptable to depth differences.
“The advantage to RBI is their ability to change their post lengths to get different embedment depths. That was useful,” he said. “The ability to change as we’re going [and] re-engineer on the fly is critical at an installation like this.”
S&C’s Girard said the arrays were designed to be higher than standard rack level for future harvest and flooding considerations.
The project, which was completed in 2016, is owned by Connecticut-based Lodestar Energy, a long-time S&C partner. Astronergy 310-W modules and Yaskawa – Solectria Solar string inverters were also used.
Although initially assumed to be an impossible installation combination, cranberry bogs and solar prove to be a good working pair. Installing solar on usable farmland doesn’t necessarily mean giving up growing. Use that fun fact to start a conversation over the cranberry sauce at the next Thanksgiving.