Navisun’s first foray into agrivoltaics produces valuable insights on dual-use

When BlueWave Solar came knocking in 2021, a tenant blueberry farmer wasn’t ready to give up his cropland in Rockport, Maine. But, after conversations with Navisun and the University of Maine (UMaine), an agreement was reached: the blueberries would stay and solar panels would be added to the land in what was, in 2021 (when it energized), the largest dual-use project in the country.

The 4.2 megawatt (MW) agrivoltaics experiment was Navisun’s first foray into dual-use development; the 10-acre project was a pilot project in conjunction with the University of Maine to see if traditional blueberry farming methods and traditional solar development could work together with few changes to their methodologies. Could the economics of the project still pan out without being significantly more expensive?

Challenge

BlueWave had developed the Rockport project initially, and wanted to find a distributed generation Independent Power Producer (IPP) that believed in the underlying viability of the dual-use project and its ability to provide valuable insight into the feasibility of agrivoltaics on blueberry farms. Having previously worked with Navisun on other projects, BlueWave pitched the idea. The goal of the project was not to optimize blueberry production but to open a pilot study to examine the feasibility of dual-use projects from a developer standpoint.

Navisun has always taken its environmental stewardship seriously when it comes to its projects, so although agrivoltaics were a barely emerging concept in 2021, Navisun recognized that the concept of allowing blueberry farming to continue under an operating distributed solar project was an innovation risk it was willing to take and agreed to purchase the project from Bluewave. Input from Lily Calderwood, a blueberry specialist at UMaine, cemented the idea that a blueberry-based dual-use project was worth a shot, as covering the crops could make them more resilient to the elements. Still, she wondered what impacts the panel installation could have on blueberry growth. 

Developing the site wasn’t easy despite the support; the hilly project site was rocky, blueberries have particular soil and management requirements that must be met to grow successfully, and bringing the project through red tape was a tedious task. Plus, a lack of state-level subsidies for dual-use projects meant that panels had to be installed closer to the ground than usual for agrivoltaics projects.

Solution

Navisun, BlueWave, and UMaine spent months coordinating project logistics with the tenant farmer, a suite of consulting firms, and the city of Rockport before anyone set foot on the site. The multifaceted collaboration resulted in a logistics plan for the site that described everything from what the farmer would do (and when) and how solar installers could access the site, to the guidelines for UMaine’s research and techniques to get buy-in from investors and locals alike. The ultimate goal of the pilot project was to determine impact to crop during construction, and then long-term viability and output of both the crop and energy production.

Ultimately, Navisun and BlueWave determined that the south-facing hill was not only conducive to blueberry growing conditions, but actually enabled panels to be placed closer together despite being closer to the ground. But, the tighter-knit array and ground-level crops meant it was tricky for vehicles to enter certain parts of the site for panel maintenance and agricultural purposes. 

To examine the way construction of the facility impacted the crops a system was designed to test varying construction methods. Navisun, Bluewave, and UMaine collaborated with the project's EPC contractor, CS Energy, in breaking the project up into three distinct sections. The first section included construction at the highest level of soil and crop protection.This encompassed approximately 2.5 acres of the project footprint. Equipment was required to remain on nylon matting during the installation of the racking foundations and vehicular and foot traffic was limited to specifically identified routes to reduce crop interaction. The second section of construction provided a medium protection of crops; several of the stringent protections were dropped or reduced in this middle section of the array. The middle protection section also encompassed approximately 2.5 acres of the footprint. The final section, covering the remaining 5 acres of the project, allowed for unrestricted means and methods of construction.  

When the project was initially conceived by BlueWave, prior to Navisun coming onboard, they entered into a five year agricultural management agreement with the existing tenant farmer to compensate them for lending their farming expertise and creative solutions to managing blueberries under the array. Navisun happily agreed to this arrangement when it came on as the IPP, as it treats tenant farmers as partners and saw great value in giving back to the landowner and broader Rockport community. 

Outcome

It appears that the major impact of the project on the blueberries below the panels is that the shade from the panels did reduce blueberry yields. However, the reason for doing the pilot was to provide a result that could be studied. All involved with the project agree that the project produced valuable insights about agrivoltaics best practices and what variables would need to change for blueberries to grow successfully under an array. Several ideas have been developed as a result of the pilot that could improve the ultimate crop yield of projects in the future that try this methodology.

Rather than static panels, single-axis trackers that could follow the sun’s movement would allow more light to reach the blueberries, and wider row spacing would also allow more sunlight to the crop below. One key takeaway of the pilot was that while there was short term visual impact from the different construction methods, the use of low ground pressure tracked machines without matting produced little impact on the blueberries, as performance between all three zones was roughly the same. 

The project was extremely successful from an owner and developer perspective as it provided a key datapoint for future agrivoltaic projects about crop viability, land use optimization, and long term operation impacts of a dual-use site. Rockport proved that dual-use projects need agrivoltaic-specific designs to be productive agriculturally and energy wise, and the site continues to serve as a research hub for UMaine’s work on sustainable agriculture. From the long term ownership perspective, Navisun has taken away key logistical processes and methods in understanding how farm workers who care for the crops can do so in a safe way while interacting with an operating power plant.

Ultimately, the biggest takeaway (and success) of this project for Navisun was the blueprint that was created for how to execute agrivoltaic projects that involve various stakeholders and how to best align roles and responsibilities. The learnings from this Rockport project can now serve as a guide for everyone from farmers and developers to owner operators across the country, on how to successfully, and collaboratively, execute their own projects.