Cranberry Bogs Under Solar: Massachusetts Proves Dual-Use at 5.4 MW

Two Massachusetts cranberry bogs have just finished their second harvest beneath operating solar arrays — a combined 5.4 megawatts of built capacity that its builders call a national first for the crop.

The projects, both constructed by Distributed Energy Infrastructure, pair a 4.4-MW array with a 13.5-MWh battery in Kingston and a 1-MW array in neighboring Plymouth. This fall marked the second season cranberries came off the vines under the panels.

"We are literally proving it can be done," said Prateek Tare, co-founder and executive vice president of Distributed Energy Infrastructure.

Why Massachusetts is pushing solar onto farmland?

Solar development is central to Massachusetts' statutory target of net-zero carbon emissions by 2050, and the state has run solar incentives since 2001. Siting is the bottleneck. The state is densely populated and heavily wooded; rooftop and parking-lot installations raise costs and limit capacity, while proposals for undeveloped land draw opposition from residents and environmental groups. Pre-cleared farmland looks attractive, but it takes agricultural acres out of production.

Agrivoltaics — panels elevated above active farming — is the state's preferred compromise, and in 2018 Massachusetts became the first state to pay a premium for it. Arrays between 1 MW and 5 MW receive a base rate of 23.17 cents per kilowatt-hour; dual-use projects collect an additional 9 cents per kWh. Farmers who lease land also receive payment for maintaining the landscape around the panels and poles.

Cranberry bogs have a specific claim on that money. Unlike sheep pastures or cornfields, which can be sold to housing developers, bogs are protected wetlands and cannot be built on even when they leave production. Grid-connected bogs, therefore, gain a financial instrument they did not previously have.

"This is a farm viability opportunity," said Iain Ward, a solar consultant, longtime cranberry grower, and the manager of the growing operations at both sites.

Who owns what, and how the engineering works?

Clean energy developer Greenbacker Renewables bought both properties — bogs farmed for decades — from growers exiting the business, then contracted Distributed Energy Infrastructure to build the arrays and hired Ward to run the crops. Both projects operate on a community solar model, selling power to subscribers.

The engineering departed from standard practice, according to Tare. Conventional solar foundations sit 8 to 10 feet into the ground; bog pilings had to go well deeper to reach stable soil, and the team needed trial and error to find a machine that could sink piles that far. The boggy ground could not take buried wiring, so the conductors hang overhead. The panels mount 10 feet above the bog on trackers that tilt to follow the sun, with pilings spaced wider than standard so harvesting equipment can pass freely.

"You're trying to figure it out from a farmer's perspective," Tare said.

What comes next for bog agrivoltaics?

The Kingston and Plymouth builds have generated follow-on work for the company: arrays planned or underway in apple orchards, a cattle pasture and a Christmas tree farm, plus preliminary work at another bog. Tare expects each subsequent cranberry project to get cheaper and faster as lessons accumulate.

A stalled project in nearby Carver may also revive. Five years ago, two bogs there were slated to become the nation's first cranberry agrivoltaic operations. The arrays were built and crops grow beneath them, but the developer went bankrupt before commissioning. The new owner has "every intention to finish them," Ward said.

"They're not a failure," Ward said. "There is an opportunity for them to be finished."

Momentum has been slow, both men concede, but Ward expects acceleration. "It is picking up steam, and the lessons learned have been significant," he said. "When you change a paradigm it takes a little time."

The next measurable milestone is the Carver restart — two built arrays, crops already growing, waiting on a financing decision to go live.