Zoning board classifies Eastern Avenue battery storage redesign as minor modification, requires design review and security screening

The Chelsea Zoning Board of Appeals voted to treat a design change for the Eastern Avenue battery energy storage project as a minor modification and approved the revised plan conditional on design review and carried‑forward conditions.

Hunter Prange, project manager for Flatiron Energy, explained the project moved from an internal building design to a containerized, outdoor enclosure system. He said the containers will be installed to a 14‑foot design flood elevation to address sea‑level rise, storm surge and 100‑year flood events. Prange also said the project was selected through a Massachusetts DOE contracting process to procure energy from the site for a 12‑year term.

Aaron Baker, lead developer, said the site will be mostly remotely operated with periodic maintenance visits; he estimated routine visits will involve a small team of technicians rather than full‑time on‑site staffing. Fire department leadership indicated support for the containerized design, and the project team said Eversource interconnection and the planned on‑site substation remain unchanged.

Board members asked about visual impact and site security because the project replaces a building that previously screened the equipment. Flatiron Energy described plans for a screen wall, vegetation and options including a community mural; board members and the planning department encouraged solutions that minimize massing and do not create a fortress‑like appearance. The planning department recommended carrying forward applicable conditions from the original approval and required design review to finalize wall details, landscaping and security measures.

Because the containerized design reduced some prior zoning impacts — eliminating the previously approved variance for front yard setback and removing the height exemption need — the board concluded the modification did not change the project’s use or create new zoning conflicts. Marilyn Vega Torres moved to accept the modification as minor with the planning department’s conditions; the motion passed.

The board reiterated that design review and the submission of detailed plans will be prerequisites to final sign‑offs and building or occupancy permits.