Broadleaf Solar, a renewable energy supplier, is seeking to drill transmission lines under the Farmington Canal Heritage Trail in East Granby as part of a large-scale solar project on a former agriculture field.

The New York based solar company paid nearly $10.2 million for the 600-acre Monrovia Nursery property in Granby and East Granby in 2021, officials said. Its plan includes building a 100-megawatt solar facility on 322 acres of the former agricultural property.

As part of the plan, Broadleaf would use horizontal drilling to install transmission lines to connect 100 megawatts of electrical power to an Eversource 345 kilovolt transmission line near Route 20, according to the company’s project proposal. The project site is at 35 Floydville Road and 90 Salmon Brook St.

The proposal calls for drilling under Salmon Brook River, Route 20 and under the popular “Rails to Trails” bike and walkway.

Broadleaf had been waiting for Monrovia to phase down its use of the property. Monrovia announced in 2023 that it will leave the Connecticut nursery altogether by mid-2025 and has now ceased operations at the site. The land is 60% in Granby and 40% in East Granby, according to officials. Part of the land was used for decades as a growing field for tobacco.

The operation would be by DESRI, which operates power-generating solar facilities from Hawaii to New England. DESRI, a renewable energy company, develops, owns, and operates utility-scale solar, wind, and battery storage projects.

“The Broadleaf Solar project remains in the development phase; no construction has begun. From the outset, we have committed to responsible, well-engineered development, informed by thorough studies that guide permitting, engineering, and environmental safeguards,” Aaron Svedlow, executive director for Broadleaf/DESRI, wrote in an op-ed in the Granby Drummer.

“All necessary state permits and licenses will be secured before any work commences by qualified contractors, and contingency plans will be in place to address unforeseen conditions. To date, site activities have been limited to standard survey work, including a recent geotechnical investigation to assess subsurface conditions for advanced engineering,” Svedlow wrote.

The project still needs to get permitted. According to town officials, no permits have been filed yet with Granby and East Granby. The Connecticut Siting Council, the entity that has legal jurisdiction over the siting of power facilities and transmission lines, would need to give the final approval. Under state law, Granby and East Granby do not have regulatory authority over Broadleaf’s application but can provide input to the Siting Council’s recommendation.

Broadleaf intends to file permits within the next 60 days for the project.

An updated project schedule released in June pushed back the projected construction timeline until the end of 2026. The site intends to be fully operational in 2028 under the current projection. That timeline is delayed from a previous proposal in 2024 that showed an operational date for December 2026.

Broadleaf said the project will create 150 construction jobs and contribute to economic development in the region. In addition, the project will create enough energy to power approximately 24,000 homes annually and remove approximately 127,000 metric tons of carbon per year, according to the project site plan.

Some residents and town officials are concerned that the project will have environmental impacts, including temporarily disrupting use of the popular trail. Broadleaf Solar has proposed to drill the transmission lines below Traprock Land Conservancy-owned land, the Salmon Brook River, Route 189 and under the Farmington Canal Heritage Trail and Route 20, according to maps included with the project proposal.

“The Salmon Brook and Lower Farmington River is officially registered in the United States registry of rivers as national wild and scenic rivers,” said longtime Granby resident Reinhard Maier. “Those rivers and streams are under the National Park Service, so they are offered certain protections. The drilling proposal goes under the Salmon Brook and zig zags under Route 20.”

Maier, who was out biking on the rail trail last July, said he got more interested in the project when he saw heavy equipment drilling core samples right near the popular bikeway. He said that he was told the drilling was to get a sentiment sample to understand the feasibility of drilling transmission lines under the trail. Broadleaf confirmed they conducted a “geotechnical investigation” last summer.

The Granby resident said he is concerned about the proposed use of horizontal drilling for the project and wrote an op-ed detailing potential hazards. Horizontal drilling generally reduces environmental impacts compared to traditional drilling by minimizing surface disruption and avoiding sensitive areas like rivers and wetlands, but one risk includes “inadvertent returns” where drilling fluids may leak, potentially contaminating groundwater and surface water, he said.

Svedlow noted in his op-ed that protecting the Salmon Brook and safeguarding the localized watershed and ecosystem is a high priority.

“The project will employ best-practice methods to avoid and minimize impacts to surface water and other sensitive features. Electrical connection to the existing grid will be made via underground collection lines installed beneath Salmon Brook using Horizontal Directional Drilling (HDD) — a proven method that avoids disturbing the surface and sensitive resources,” he wrote.

“DESRI has successfully implemented HDD projects in Connecticut and nationwide,” Svedlow added. “Other aquatic resources on-site will be avoided during construction, with best management practices ensuring site stabilization, appropriate spill and release response plans, runoff reduction, and establishment of long-term vegetation.”

Broadleaf said it is anticipating some disruption to the trail if the project moves ahead, but that it will most likely be brief and temporary. No time period has been established yet for how long that disruption may last if the project is given approval from the Connecticut Siting Council.

Stephen Underwood can be reached at sunderwood@courant.com.