Mesa council advances BESS zoning package, splits on residential setbacks

The Mesa City Council on Dec. 1 advanced two zoning items governing battery energy storage systems (BESS) for formal introduction while deferring final decisions on separation distances from homes.

Residents, industry representatives and fire-safety experts delivered sharply contrasting views during a lengthy public comment and staff briefing. Resident Mary Mabinow said the newer lithium technologies “if they do catch fire, they are extremely difficult to put out,” and urged that large BESS installations be sited well away from homes because of fire, air-quality and noise risks. Developer and industry counsel Court Rich and attorney Jeff Crockett asked the council to set the items for discussion and vote on Dec. 8 and to reconsider a 1,000-foot separation as too restrictive for renewable projects.

Staff explained the ordinance distinguishes principal uses (utility-scale) from accessory uses by a 5 megawatt threshold (5,000 kilowatts). Mary Mabinow of Development Services said the 5 MW cutoff was raised from an earlier 1 MW recommendation “to regulate utility-scale BESS,” and that accessory systems remain subject to base-zone development standards. The city’s Fire Marshal, Sean Alexander, described permitting changes that will require decommissioning plans and hazardous-waste disposal protocols and explained that the NFPA 855 equipment setback — 100 feet from battery equipment to the property line — is distinct from the council’s proposed separation distance from the facility perimeter to residential zoning.

Trade groups and a fire-safety consultant urged closer alignment to national practice. Autumn Johnson of the Arizona Solar Energy Industries Association said the national average setback is “50 to 150 feet” and that NFPA 855 recommends about 100 feet; Matt Quinn, a fire protection consultant, told council there is “no justification” for a blanket 1,000-foot residential clearance and recommended following NFPA 855.

A council member who identified experience fighting battery fires pushed for the larger 1,000-foot distance from residences, calling it a reasonable protective measure for homeowners. Staff noted that sensitive receptors such as schools, parks and churches would remain at 400 feet under both ordinance options and that the 1,000-foot figure on the table applied only to residential zones.

The council first declined to introduce all four BESS items as a single package. After debate, the council voted to introduce items 7a and 7b (the pair tied to the larger residential separation option) for future consideration; the other pair (7c and 7d) was left for a later decision. Staff told council that decommissioning bonds and other financial-security measures are not finalized and would be studied further before being required, and that any bond-market availability concerns would be returned to council for consideration.

What’s next: The council introduced items 7a and 7b for formal consideration, and staff indicated that additional language or a third option could be drafted and brought back if council wants different combinations of separation distances or protections. A full vote on any ordinance was not taken on Dec. 1.