In 2024, the average US electricity customer experienced 11 hours of power outages. That is double the 5.5-hour average from 2022. For most customers, an 11-hour annual outage is an inconvenience. For a P25 radio tower, a PSAP, or a 911 dispatch center, it is an operational crisis waiting to happen.
Source: EIA Electric Power Annual 2024, reported December 2025
Most public safety backup power systems were designed for a different grid. A decade ago, the planning assumption was that outages would be brief and infrequent, requiring just a few minutes of bridge power while the generator started, maybe a few times per year. That assumption no longer reflects reality. Grid outage durations have grown significantly, and the events that cause major outages are the exact same events that drive peak demand on public safety communications networks.
The backup power systems protecting 911 dispatch infrastructure were not built for this environment. The Evoltix Zero-Glitch Power Module (ZPM) is a power intelligence system designed specifically for today’s environments, providing 2+ hours of rated runtime, battery-first operation, and remote monitoring that tells network teams what is happening before they find out from a dark site.
What the Grid Data Actually Shows
The deterioration in US grid reliability is not anecdotal. The numbers from EIA, NERC, and the Department of Energy tell a consistent story.
Outage duration has nearly doubled in two years
US electricity customers averaged 11 hours of outage time in 2024, up from approximately 5.5 hours in 2022. Outages attributed to major weather events averaged nearly 9 hours in 2024, compared to an average of about 4 hours across the 2014 to 2023 period. Hurricanes Beryl, Helene, and Milton drove much of the 2024 increase. Helene alone left 1.2 million South Carolina customers without power, with some areas averaging 53 hours of outages for the year.
Source: EIA Electric Power Annual 2024, December 2025; Utility Dive, December 2025
70% of US transmission infrastructure is 25 years or older
Seven in ten miles of US power transmission infrastructure was built more than a quarter century ago. Aging transformers and substations are a primary contributor to outage frequency, and the supply chain bottleneck for replacement transformers, which is a known problem since the COVID-era supply disruptions, has not fully resolved. NERC’s Long-Term Reliability Assessment identifies aging infrastructure as one of the most significant risk factors for grid performance through the 2030s.
Source: US Department of Energy Grid Modernization Initiative, 2024; NERC Long-Term Reliability Assessment 2024
Grid-level threats are growing, not shrinking
Physical attacks on US power grid infrastructure rose 70% from 2022 to 2023, according to NERC. The number of extreme transmission stress days in 2024 increased relative to prior years, with five of the top ten most stressful days driven by a single January winter storm that affected a large portion of North America simultaneously. AI data center buildouts and EV charging infrastructure expansion are adding load to a grid that was not designed for this demand profile.
Source: NERC 2025 State of Reliability Technical Assessment; NERC 2024 report on physical security incidents
Why 911 and P25 Infrastructure Faces Disproportionate Risk
Grid reliability statistics describe average customer experience. Public safety communications infrastructure does not have an average experience. It has a worst-case experience, because the grid events that drive the worst outage statistics are the same events that create the highest demand on 911 and P25 networks.
The correlation problem
A Category 4 hurricane makes landfall. Within hours, utility power fails across a wide area. 911 call volume spikes. Field units are deployed. Incident command channels are active across multiple agencies. This is precisely when the P25 radio network, the PSAP, and the 911 dispatch center all need to be operating at full capability, and precisely when the grid providing their power is most likely to be down for an extended period.
The same correlation holds for wildfires (high winds damage transmission lines exactly when fire crews need radio coverage), winter storms (ice loading on transmission infrastructure causes widespread outages exactly when cold-weather incidents peak), and severe weather events generally. Public safety infrastructure does not fail during normal operating conditions. It fails during the abnormal conditions the grid also fails during.
Short bridge power is no longer adequate
The legacy design assumption for P25 tower and PSAP backup power was 5 to 15 minutes of battery backup while the generator starts. That assumption made sense when major grid events lasted 2 to 4 hours on average and were relatively rare. At 9-hour average major event durations in 2024, a 15-minute UPS bridge is not a backup plan. It is a 15-minute delay before the site goes dark.
Generators address part of this problem, but not all of it. A generator that starts successfully and runs through a 9-hour outage still depends on fuel. Remote tower sites in rural areas, coastal regions, and mountainous terrain face fuel logistics challenges during exactly the events that cause extended outages: when roads may be compromised, fuel suppliers are managing simultaneous requests from hundreds of other customers, and dispatch resources are already stretched.
A floor, not a ceiling
The FCC’s backup power rules for covered 911 service providers establish minimum requirements for backup power duration at cell sites and other communications facilities. Those rules were written against a grid reliability baseline that no longer applies in many regions. Technical compliance with FCC minimums is a floor, not a ceiling. As outage durations in many regions have grown well beyond what the rules were designed to address, the more useful question for any agency is whether their actual backup duration matches the outage risk their specific sites face.
What This Means for Backup Power Design at 911 and P25 Sites
The grid reliability data changes the requirements specification for public safety backup power in three concrete ways.
Runtime must be measured in hours, not minutes
At a typical public safety tower site drawing 1 to 2 kW of critical load, the Evoltix ZPM 1 provides 3.84 to 7.68 hours of rated backup runtime. At a 1.5 kW load, 5.12 hours. These figures cover most major weather event durations without generator involvement. The ZPM is not bridge power. It is the primary backup system, with the generator as the secondary fallback for extended events.
Battery-first architecture changes the risk profile
A generator-first backup design where the generator starts at the first grid interruption, and the battery only engages during generator startup, is expensive, fuel-intensive, and creates multiple failure points. Every generator start is a maintenance event. Every fuel delivery to a remote site during a weather emergency is a logistics challenge.
The ZPM’s battery-first architecture inverts this logic. The battery carries the site during most grid events. The generator only starts when battery state of charge drops below a configurable threshold, which for most grid events never happens. Operators who have deployed the ZPM report generator runtime reductions of up to 91%.
Visibility is no longer optional
When the grid was reliable and outages were rare, it was operationally acceptable for a 911 network team to find out about a tower site power event when the site stopped responding. When outages average 11 hours annually and can extend to days in severe weather regions, finding out after the site goes dark is too late.
IntelliCore gives network teams real-time visibility into battery state of charge, grid status, and site load from a single dashboard, across every ZPM-equipped site. When a grid event starts, the network team sees it immediately: which sites are running on battery, how long they have, and which sites need attention. That visibility is the operational capability that distinguishes a network that responds to outages from one that anticipates them.
If your backup system was designed for the grid of ten years ago, the math no longer works. Average major event outage durations have more than doubled since 2022. The agencies that discovered this early are the ones that did not wait for a high-profile incident to prompt the conversation.
The Regional Picture: Where 911 Networks Face the Most Exposure
Grid reliability is not uniform across the US. The EIA’s 2024 data identifies significant regional variation that directly affects public safety backup power planning.
- Gulf Coast and Southeast: Louisiana has the highest average outage duration of any state. South Carolina averaged 53 hours of outages in 2024 due to Hurricane Helene. Florida, Texas, and the broader hurricane corridor face recurring multi-day outage events that overwhelm any backup system designed for short-duration grid interruptions.
- Texas (ERCOT): The highest outage frequency per customer of any state, driven by an isolated grid with limited interconnection to neighboring systems, significant extreme weather exposure, and the lesson of Winter Storm Uri still not fully resolved in backup capacity planning.
- California and the West: The largest number of customers affected annually, with wildfire-driven outages increasingly affecting the same geographic areas that P25 radio tower infrastructure serves for wildland fire response. The grid and the emergency network fail in the same places at the same time.
- Rural regions generally: West Virginia has the highest rural outage rate, reflecting the pattern seen across Appalachia, the mountain West, and remote areas generally. Rural P25 tower sites in these regions face both higher outage frequency and longer restoration timelines than urban infrastructure.
For SWICs and state network managers doing backup power planning, the first question is not “what does the FCC require?” It is “how long do outages actually last in the regions where my P25 towers are located?” The EIA’s state-level reliability data, updated annually, is the starting point for that analysis.
What Public Safety Agencies Are Doing About It
The agencies that have already upgraded their tower backup power are responding to the same grid reliability data described above. The common thread is a shift from minimum-compliance UPS systems to purpose-built power intelligence platforms with extended runtime and remote monitoring.
One state DOT network that deployed the ZPM across its public safety communications infrastructure discovered, after deployment, that the number of actual grid events its tower sites experienced was significantly higher than its generator dispatch records suggested. The sites were absorbing short interruptions on battery without triggering a generator start, events that never showed up in the dispatch log but were now visible in IntelliCore data. The reliability they thought they had was partly real and partly an artifact of what they could not see before.
If your agency operates P25 tower infrastructure and you want to run your actual numbers, Evoltix’s TCO Studio lets you model the real cost of your current backup power configuration against a ZPM deployment, using your own site count, load profiles, battery cycle status, and regional grid data. An Evoltix application specialist can walk you through it.
Request a TCO Studio (free cost-benefit analysis) session: evoltixenergy.com/contact/
Call: +1 (855) 964-9274
Related Reading:
What Does a Backup Power Failure Cost a Public Safety Network?
What Causes Public Safety Radio Tower Outages, and How to Prevent Them