Santa Fe County commissioners pressed AES Clean Energy on fire safety and emergency response for the proposed Rancho Viejo solar and battery project during a special hearing on the county’s appeal of Planning Commission case 24‑5200. The board’s questioning centered on suppression design, spacing of battery containers, how much water would be available for firefighting, and who would be on site to monitor and respond.

Why this matters: Commissioners said public safety, particularly given nearby communities, schools and detention facilities, is the primary conditional‑use standard for approval. The commissioners repeatedly asked for more concrete evidence that the company’s fire measures will work in high‑fire environments and for operational guarantees the county can enforce.

The applicant, represented by AES project staff, described multiple layered protections. AES’s Joshua (full name not provided in the hearing) said the company is the developer, engineer and intended operator and “bring[s] in outside experts” for design work. Mike Simpson, identified on the record as an AES speaker, said the company’s enclosures and mitigation systems are designed to meet applicable standards and that the technology has been field‑deployed for years: “we are, UL 95 40 certified as well.”

Discussion highlights

- Suppression and spacing: Commissioners asked whether AES would accept a condition to space containers 10 feet apart. AES responded it was willing to “accept a design modification to space the containers 10 feet apart.” AES staff also said certain enclosure designs are engineered so close spacing (reportedly as little as 3 feet in some products) will not propagate fires, but they relied on full‑scale tests and modeling to justify that. Commissioners asked for the underlying test reports to be submitted for review before any final decision.

- Water supply and response approach: Fire department staff described the local approach to water supply for remote sites. A county fire representative said the intersection at Highway 14 has a blue‑top hydrant capable of more than 1,500 gallons per minute and that the department uses tender‑shuttle (water tanker) operations to move water to distant sites. AES had proposed a 30,000‑gallon on‑site tank for defensive protection; county fire staff said the applicant agreed to increase that to 60,000 gallons and that the increase would be required as a condition of approval. The county noted trucked water and hydrant use would be coordinated through a site emergency operations plan.

- Whether water is needed to cool adjacent containers: AES staff said water is not required by their design to cool adjacent containers, and that their enclosures provide hazard mitigation without external water in typical deployments. Fire staff and commissioners, however, emphasized that county emergency responders plan to use water defensively to protect exposures and to cool proximate containers as part of incident response plans.

- Testing, monitoring and sensors: AES described full‑scale laboratory fire tests—40‑foot enclosure tests instrumented with hundreds of sensors—and modeling calibrated to that data. AES said its deployed fleet totals more than 1.3 gigawatt‑hours using the specified architecture and that those deployments have not produced an on‑site thermal runaway event requiring the company’s clean‑agent systems in the field. Commissioners requested copies of the testing and modeling reports; AES agreed to submit them for reviewers prior to final action.

- Operational staffing and inspections: AES said it plans four full‑time operations and maintenance staff assigned to the site. Company representatives also described a 24/7 remote operations center that continuously monitors cell‑level sensors and alarms. Santa Fe County Fire officials said the department will perform annual inspections of energy storage facilities and that local tender‑shuttle resources (county tenders average roughly 2,000 gallons each, the county said) would be used for sustained water supply during an incident.

What the board and staff directed or agreed:

- Water tank: County staff said the 30,000‑gallon on‑site tank proposed by AES will be increased to 60,000 gallons; staff identified that as a required condition for approval.

- Spacing/design modifications: AES said it would accept a design modification to space containers 10 feet apart if imposed as a permit condition; AES also said other protective measures (passive insulation, enclosure design and active thermal‑runaway propagation protection systems) are part of its design. The board asked that the final design and any spacing plans be documented and provided to staff.

- Submittal of reports: Commissioners requested AES provide the full test and modeling reports and any documentation required for NFPA/UL compliance before the board makes a final decision.

Formal meeting actions linked to this topic

- Executive session motion: The board voted to go into a brief executive session to discuss the order of questioning (motion carried by roll call).

- Condition language: County staff indicated the 60,000‑gallon tank would be included as a condition (referred to on the record as Condition 24), and that annual fire inspections would be required. These were presented as permit conditions, not as a final board approval in this hearing.

What remained under discussion: Commissioners continued to press for clarity about whether AES testing reflected high‑fire‑risk desert conditions at scale, how external wildfires would be detected and handled at the perimeter, and how water logistics would work over 2–3 miles of rural access roads. AES said it could add external infrared or thermal cameras and other monitoring at the county’s request.

Closing and next steps: The hearing recessed for scheduling and the board voted to reconvene later to continue questioning of staff and to allow submittals. Commissioners asked staff to post any new AES test materials and for the fire‑safety conditions to be formally drafted and circulated before final action. The board also required that no additional written submissions be filed by the applicant or parties of standing after the stated close of the record.