Solar panels raised 10 feet are letting Massachusetts cranberry bogs harvest again

Two Massachusetts cranberry bogs that had stopped paying their way are producing fruit again, and the reason is a field of solar panels mounted about 10 feet off the ground. Distributed Energy Infrastructure, a developer based in Kingston, announced the harvests on Oct. 12, calling them the first agrivoltaic cranberry harvests on record.

Save more, waste less: The Cool Down’s newsletter sends smart, simple changes that help you and the planet in your everyday life.

Subscribe to The Cool Down →

We may earn a commission if you sign up.

Farmer Iain Ward praised the builders as “phenomenal at understanding and adapting solar construction,” a notable compliment for a contractor working over soft peat and established vines that had to survive the build. The projects, which sit in Plymouth and Kingston, combine cranberry farming, community solar and battery storage on the same ground.

Black Cat and Ring Road: two bogs, two arrays

The sites are the Black Cat project in Plymouth, rated at 1 megawatt, and the Ring Road project in Kingston, rated at 4.4 megawatts. According to the company’s announcement, Greenbacker Renewables owns both, and each pairs solar with battery storage: 2,700 kilowatt-hours at Black Cat and 13.5 megawatt-hours at Ring Road, selling power under a community solar model that DEI says supports the Massachusetts SMART program and Clean Peak Standard. Both sites were named finalists for the North American Agrivoltaics Awards, and Ward and DEI are founding members of the Solar & Farming Association.

The bogs had been fallow for years because growing cranberries on them was no longer profitable. Electrek reported that lease income from the panels now makes cultivation viable again, and that Ward is paid to manage the agricultural operation on top of what he earns selling berries. Electrek also noted what the announcement leaves out: it does not say how many cranberries were harvested, and it does not compare yields with bogs grown without panels, so the claim that the bogs are productive again rests on the fact of a harvest rather than on a measured crop.

Ten-foot panels, 18-foot aisles and white mats

Cranberries are a hard crop to build over. Writing in the September-October issue of North American Clean Energy, DEI cofounder Prateek Tare described a design shaped around the farmer: posts 30 feet long driven 20 feet into the ground through 10 feet of peat, panels raised to about 10 feet, roughly double standard height, and rows with at least 18 feet of clear space so harvest machinery can pass beneath. Panel orientation and pitch were set to let more light reach the vines, and Tare’s account credits Ward with shaping panel height, row layout, foundation placement and the sequence of construction, since he was on site throughout and could intervene when work put the crop at risk.

Construction took about eight months, roughly twice as long as a comparable conventional project. Ward could stop, alter or reroute work that threatened the crop, and one change was practical: black protective mats were swapped for white ones because black mats absorbed too much heat for the plants.

The same article says Ward kept his crop rights and receives annual fees for managing the operation, and it notes that roughly half of U.S. farmers do not own the land they work, which makes a lease-income model attractive to landowners who otherwise might sell or leave bogs idle.

First harvest results and the Frontiers study

The timing of the harvest needs a careful reading. Tare’s article says Ward celebrated the first agrivoltaic harvest the previous fall, and DEI’s Oct. 12 announcement does not give a harvest date, so the announcement is best read as a report that the crop has now come in under the panels rather than as news of a single picking day.

Yield is the open question. A Now.Solar summary of an annual report filed with the Massachusetts Department of Energy Resources put the first crop at 325 barrels, against 400 expected without panels, and attributed the shortfall to a 2 degree Fahrenheit February freeze and construction during the growing season. Its projection of 750 barrels a year with the array versus 1,000 without is an estimate, not a measurement, and the summary describes the array in different dimensions than DEI does, so those figures are best treated as indicative.

Research on shade is early. A peer-reviewed study of a commercial “Howes” cranberry bog, published in Frontiers in Horticulture, tested panels 3.0 meters above the plants at roughly 30, 35 and 37 percent shading. Moderate shade improved leaf water status and reduced stress, but also suppressed photosynthesis, and the effects grew at 37 percent. It was a first-year study that did not report yield and called for multi-year work. Ward, for his part, told DEI that building over such difficult wetland and getting successful harvests suggests building is possible almost anywhere. That is the argument the two Massachusetts bogs now carry: if solar can be installed over peat without killing the vines, fields with easier ground may be simpler cases, though the missing yield comparison means the full agricultural result is still to be measured.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

Save more, waste less: Subscribe to The Cool Down →

We may earn a commission if you sign up.