Investigating Dual-use Solar for Wild Blueberry Farms in Maine

Project Overview

Project Type: Research Only
Funds awarded in 2022: $134,509.00
Projected End Date: 02/28/2025
Grant Recipient: University of Maine
Region: Northeast
State: Maine
Project Leader:
Dr. Lily Calderwood
University of Maine


  • Fruits: berries (blueberries)


  • Crop Production: cropping systems
  • Education and Training: extension
  • Energy: solar energy

    Proposal abstract:

    Maine is the largest and only commercial producing state of wild (lowbush) blueberry. Wild blueberry is the second most important crop to Maine’s economy and grown on 41,000 acres by 485 farmers. Wild blueberry growers face numerous challenges from seasonal drought and frost during bloom to the low market value of their crop. Interest in solar installations on wild blueberry fields has grown in the wake of similar, successful installations on cranberry bogs in Massachusetts. Similar to cranberry, this native perennial ground cover is tolerant of shade and moderate physical disturbance. Solar development firms are interested in installing on agricultural land and wild blueberry farmers are interested in diversifying their revenue streams. To our knowledge, farmers have been offered approximately $2,500/acre within solar contracts. On average a wild blueberry farmer produces 3,000lbs/acre at $0.40 cents/lb for a total of $1,200/acre, making a solar deal look very attractive. 

    This project will investigate if it is feasible to continue wild blueberry production within a solar array and host outreach events at wild blueberry solar development sites that are both dual-use and traditional. In 2021, Dr. Calderwood was approached by a farmer for assistance figuring out how to farm wild blueberry under a solar array in Rockport as a dual-use system. Construction of this dual-use array occurred from March-July 2021 when Dr. Calderwood and her team were able to discuss options with the farmer and solar company in addition to collecting preliminary data. The solar developer agreed to test out three methods of construction (careful, mindful, and standard) in order to identify ways to install the solar array with little damage to future wild blueberry production. Under these three construction methods, research will include monitoring plant health and productivity using photosynthetic active radiation (PAR) sensors to measure sunlight penetration, plant development measures including emergence date, bud, flower, and fruit counts, plant heights, crop cover, and pest scouting. The wild blueberry farming community will be engaged through a research and education program including field meetings, advisory group, annual conference and distributed report, videos, and solar specific web page. A cost of production analysis and solar vs. traditional production comparison will be completed with the Rockport farmer to share as outreach material. 

    This land-farmer-solar company setup is a unique opportunity for University of Maine Extension to follow wild blueberry crop health and production over the course of solar construction and recovery back to production. Ultimately our goal is to increase research based knowledge about growing wild blueberries under a solar array for protection against weather events and as a diversified income stream option with engaged members of the Maine wild blueberry farming community. 

    Project objectives from proposal:

    The project goal is to increase research-based knowledge on dual-use solar for wild blueberry farmers. Without university research on the feasibility of dual-use, growers will either A) not consider solar as a diversification option, or B) stop wild blueberry production for a solar contract. In 2019, 50% of the wild blueberry crop was lost to a spring freeze event and in 2020, 45% of the crop was lost to drought conditions, all while the price for wild blueberries averages a low $0.40/lb. Dual-use may be a practical solution to address both environmental and market stressors for this industry. 

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.