Representatives from Eversource hosted a virtual open house Tuesday to introduce Hopkinton and Milford residents to its proposed underground cable modernization project.

The session is the beginning of Eversource’s outreach to gather community feedback. The project involves the replacement of two high-pressure gas filled (HPGF) lines with modernized cross-linked polyethylene (XLPE) technology. The replacement will follow the same or similar route of the existing HPGF lines, which run a 1.3 mile route between a portion of South Street in Hopkinton through to Purchase Street in Milford between the two existing substations.

Eversource project manager Ian Kea, who led the presentation, explained that the existing 126-501/502 HPGF electric transmission lines in Hopkinton and Milford were installed in 1998, and they are among the last remaining HPGF lines in operation within the system.

This proposed project is part of a larger Eversource program to modernize cables throughout its service territory in Massachusetts and Connecticut. Replacing these lines aligns with the state’s goal to achieve net carbon emissions standards by 2050. It will also help accommodate the increased demand for power.

Kea said the work will not disrupt normal electrical service to customers.

Construction is scheduled to start in the fall of 2025 and be completed in two years, pending necessary approvals. But the timeline is uncertain because of permitting issues that potentially could delay the project by as much as 18 months.

One reason for replacing the lines is that there is limited manufacturing of existing cable lines. The XLPE cables are wider to meet future energy demands.

Eversource representative Allie Klein explained that the lines “allow us to provide larger amounts of power between our substations.”

The project will involve the installation of six vaults, which is expected to reduce the need for future street excavation. Trenching will be performed to install the vaults and new manholes.

“This project will require a completely new duct bank and manhole system,” Klein said. “Technology at each splice point requires a separate duct bank for each line. This will both facilitate cable installation and allow for additional access points for future maintenance, repair work or any inspections that are required.”

“It’s important to note that not all of this happens concurrently,” said Eversource representative Joshua Sklodowska-Johnson of the different aspects of construction work. The project will be performed in segments.

Saw cutting will allow for the removal of pavement for excavation, he explained. After the excavation, pipe will be installed. Concrete trucks will install the duct bank. Backfill will be added to allow for driving.

“As much as possible, we will maintain a lane of travel for traffic so the street will still be in use,” said Sklodowska-Johnson. “Our goal is to make sure that the work is as minimally invasive as possible.”

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