The Centers for Medicare & Medicaid Services (CMS) recently announced that microgrids, which combine distributed energy generation, energy storage, and smart controls, can now be used as an alternative source of emergency power for healthcare facilities.
This is a significant step forward. Traditionally, CMS and NFPA 99 have required generators with an uninterruptible fuel source to provide emergency power capable of starting automatically within 10 seconds and sustaining essential systems for at least 90 minutes. The new guidance recognizes that advances in battery storage, solar photovoltaics, and energy management systems can provide equal or greater reliability while reducing emissions.
But what does this mean for Ambulatory Surgery Centers (ASCs), and is it practical?
ASCs fall under CMS Conditions for Coverage (§416.44) and the NFPA Life Safety and Health Care Facilities Codes. These codes require a safe and sanitary environment and sufficient emergency power to protect patient safety during outages. Traditionally, that has meant a generator as part of an essential electrical system with separate life safety, critical, and equipment branches. To qualify under CMS, a microgrid must still:
Activate automatically within the same time frame as a generator (typically 10 seconds or less).
Be capable of supporting the ASC’s essential loads for the required duration.
Be maintained, tested, and monitored according to NFPA 99 and 110 standards.
In short, a microgrid can replace a generator, but it must perform like one.
Microgrids can be a smart, forward-looking solution for certain Ambulatory Surgery Centers, but their practicality depends on scale, energy strategy, and site conditions. They are most feasible when the system can provide benefits beyond emergency power alone.
A microgrid may make sense when:
Critical power demand is significant, for instance in a very large ASC, or when multiple buildings or tenants can share infrastructure.
The facility is part of a larger medical or mixed-use campus, where the microgrid can support combined loads and improve overall resilience.
On-site renewable generation (such as solar) and battery storage can be integrated to reduce operating costs, demand charges, or emissions.
The ASC’s owner places a premium on sustainability and long-term resilience, such as pursuing LEED, WELL, or Net-Zero Energy certification.
The site experiences frequent or extended utility outages that could disrupt surgical schedules and revenue.
In these settings, a microgrid can do more than meet CMS and NFPA requirements—it can provide seamless power quality, reduce reliance on fossil fuels, and help future-proof the facility against changing energy and regulatory landscapes.
For most Ambulatory Surgery Centers, emergency power loads are modest compared to hospitals or large medical campuses. Smaller, single-specialty ASCs may have comparably low critical power demands, and even larger multi-specialty centers often fall well under the capacity of a typical hospital emergency system.
Microgrids are rarely cost-effective at smaller scales. The economics begin to improve only as critical demand rises, or when the microgrid can serve multiple buildings, integrate renewable generation, or offset high utility demand charges. Failing that, the fixed costs of controls, switchgear, and battery storage outweigh the benefits.
In most cases, a conventional diesel generator remains the most practical and straightforward way to meet CMS and NFPA requirements for emergency power.
Microgrids also come with regulatory complexity, as each state and utility sets its own rules for interconnection, islanding, and testing. These hurdles can add time and expense to projects that operate on tight capital budgets.
The inclusion of microgrids in CMS’s emergency power framework signals a broader shift toward resilient and sustainable care environments. For designers and operators, it opens new opportunities to rethink how outpatient facilities approach reliability and carbon reduction.
As technology continues to improve, hybrid systems that combine solar arrays, battery storage, and smaller generators are likely to emerge as a cost-effective middle ground.
For now, microgrids are technically feasible but only situationally practical. They make sense for next-generation ASCs that want to model sustainability and resilience, but not yet for every facility.
Still, CMS’s recognition of microgrids marks a turning point. It gives architects, engineers, and healthcare owners permission to innovate, to design surgery centers that are not only safe and compliant but also environmentally responsible and future-ready.
And for those of us in ambulatory healthcare design, that is an opportunity worth seizing.