Somerset zoning board continues battery storage hearing to Nov. 12, awaiting final plume study reviews

SOMERSET Somerset's zoning board made no decision Thursday on the Montaup site battery storage plant and continued the hearing to Nov. 12, when the town's two peer reviewers are expected to give final comments.

The Zoning Board of Appeals voted for the continuance near the end of a session that ran about an hour in the Cucinotta Room of the Somerset Public Library. Somerset Energy Storage LLC is asking the board to approve a planned development under Section 6.10 of the zoning bylaw for a commercial battery energy storage system at 1606 Riverside Ave., Assessor's Map B2, Lot 203, in the Industrial Zoning District and the Business Industrial Overlay District.

The project would put battery units behind a sound wall, 24 feet high by Flatiron's description, next to the Stevens Street neighborhood, and the board has spent its recent sessions largely on fire safety and the toxic gas plume a battery fire could send toward nearby homes.

Where the peer review stands

The lead presenter for Flatiron Energy, the company behind the project, told the board that two reviewers working for the town, Jensen Hughes and a second firm, had agreed to attend the Nov. 12 session and give final comments in person. Both want to see the updates to the plume study before they issue final letters, she said, and Hazard Dynamics, the firm that wrote the study, was working them in, with the company hoping to have the revised study Wednesday, Nov. 11.

If the updated study comes in too late for a full read, she said, the reviewers may have to send their final comments in writing after Nov. 12. She said none of the remaining changes affect what matters to firefighters, that the study's method had been confirmed and that none of the distances in its buffer maps would change. She described the open items as technical points, such as the matrix used to map how the plume disperses, and some editorial wording.

A Jensen Hughes engineer who joined by video said his firm had met with Hazard Dynamics earlier in the week and that proposed resolutions were on the table for its plume study comments. On the first part of the firm's review, which covered the hazard mitigation analysis, the emergency response plan, the noise study and a decommissioning plan under NFPA 855, the national battery storage standard, he told the board no issues were outstanding, though his firm had not yet seen updated final documents.

Noise letter and more memos

Flatiron said it received a noise review letter from Jensen Hughes dated Nov. 5 confirming that the newer battery model the company now plans to use is quieter than the one it first modeled. Asked by the board whether noise would comply at the homes with both the state limit and the town bylaw, the Jensen Hughes engineer said it would, once his firm and the company had sorted out a misunderstanding about how some of the early noise figures should be read.

The company also put three memos before the board: a combustion toxicology memo from a fire research firm, an updated particulate matter memo from the engineering firm VHB that now addresses Massachusetts air quality standards, and a Hazard Dynamics memo on particulate matter, smoke exposure and its modeling scenarios. Draft conditions Flatiron wrote to collect what has been agreed so far are also with the board, and one reviewer could add more in its next round of comments.

Members want the letters in hand

One member said having the final letters in hand mattered, noting that getting final review letters from both consultants by Nov. 12 had been the goal when the board last met. Members noted short weeks ahead, and one said the board also expects to meet Nov. 18. The presenter suggested the board hear both reviewers Nov. 12 and then decide whether it was comfortable or needed more time.

The board's chairman also asked how conditions on a technical plume study could be enforced, saying conditions that cannot be enforced are only words on paper. Another speaker at the board's table answered that the building inspector, the Board of Health or whichever office has jurisdiction enforces a board decision, and a member asked whether a condition could require approval from a third-party reviewer, something the building inspector could check. The Jensen Hughes engineer said the study's results should be spelled out so the site's emergency response plan has enough practical information to inform the public if there is a fire, and that the plan should be in place before the plant begins operating. Flatiron said its draft conditions include a third-party code compliance review and the fire chief's approval of the hazard analysis, the response plan, the final site plan and hydrant locations.

Another member said every question the board had raised about the plume, smoke and thermal runaway had been answered to that member's satisfaction, and that the fire chief appeared comfortable with the plan and the police chief comfortable on security, including round-the-clock monitoring and police access to the site's cameras.

Trees and the sound wall

A member read aloud an email from a resident asking that a tree survey be made a condition, to protect the large native oaks along Riverside Avenue and Stevens Street. A VHB representative on the project team said two large trees marked on the site preparation plan must come down: one about 48 inches across near the County Street side, where the board stood during its sound wall demonstration, and one at the site entrance in the northeast corner, estimated at the table at about 24 to 30 inches, a size the team said it would confirm. The large trees along Stevens Street are outside the work area and would stay, he said.

The fire chief wants no trees close to the wall, so crews can reach its doors and raise an aerial ladder from Riverside Avenue or County Street, a project team member who joined by video said, adding that NFPA 855 also keeps vegetation away from the facility. The tree plan will be updated with the demolition permit filing, the team said, and the company will also plant new shade trees the zoning bylaw requires. A member asked that the existing trees along Stevens Street be saved wherever the fire chief's needs allow, and the company said it would remove only what is necessary.

Flatiron said the wall will be a sound-absorbing composite panel with a red brick finish, modeled on the brick facades at the middle and high schools after a neighbor suggested it. The company has not settled on a manufacturer, has written a draft condition to submit samples or renderings and said it would bring a sample to the Nov. 12 session.

What a resident asked

In public comment, a County Street resident asked whether the land would be cleaned of old oil from the power plant years. A speaker at the board's table said sampling has been done and more would be done during construction if needed, under the state's contingency plan rules. When the resident asked about income the plant might bring the town, he was told that was a question for the Board of Selectmen, not the zoning board.

The board then approved the minutes of its Oct. 22 and Oct. 29 meetings and adjourned.

What happens next

The board's Nov. 12 agenda lists the same petition at 6 p.m. at the Old Town Hall, 1480 County St. Thursday's session moved twice before it was held at the library, so the town's Agenda Center has the final location. The meeting is recorded for YouTube, and the application and plans are on file at the town clerk's office.

Background on the hearing so far, including the October plume study and fire plan: Somerset battery storage hearing on the Montaup site moves to the public library Thursday.

Label: Reported by us, from the town's posted records.