Planning board hears peer-reviewed sound study for proposed 5 MW Breckenridge Road battery project; hearing closed and decision continued

DP Battery DevCo representative Pete Forte told the Planning Board the company is proposing a 5 megawatt energy storage system off Breckenridge Road consisting of five storage containers, two medium-voltage substations, secondary containment and an access road. "DP Battery DevCo is proposing a 5 megawatt energy storage system off of Breckenridge Road," Forte said.

Mark Wallace of Tech Environmental presented the sound study and peer-review results, describing baseline monitoring and modeling under MassDEP policy. He said baseline L90 measurements were as low as 24 dBA at night and that worst-case manufacturer sound-power data (used for conservative modeling) required mitigation to meet state noise rules. "The facility design limit is 34 decibels, which we need to meet at the nearest residential property lines as well as at the nearest residences," Wallace said.

Under an unmitigated baseline model the predicted property-line sound levels ranged from about 29 to 49 dBA and included a modeled pure-tone condition. With a manufacturer noise-reduction kit installed on each container (the kit was described as approximately 3 feet tall and proprietary), Wallace reported modeled reductions of roughly 20 dB, bringing predicted property-line levels to the low-20s and eliminating the pure-tone condition, which the consultant said demonstrates compliance with the MassDEP noise policy.

Residents questioned durability, installation quality and ongoing monitoring. Greg Owen asked, "My concerns about the noise mitigation kits are, 1, how well will they be installed? What is the lifespan of that kit since it's going to be exposed on the top of the unit?" Developers responded the kits ship from the manufacturer, are factory-installed and the project team expects equipment life comparable to battery life; DP said it would fund follow-up testing if complaints arise and that operations and maintenance checks would be part of the program.

After discussion, a board member moved to close the public hearing and direct that a draft decision be prepared for town-counsel review; the motion passed unanimously. The board said it will accept written public comment and expects to consider a final decision at either the Oct. 6 meeting (if paperwork and review permit) or Oct. 20.