Heathrow’s power outage brought one of the world’s most advanced transportation hubs to a standstill. It was not the fire alone that caused the disruption—it was the absence of foresight in how the system was designed to respond.
At Sesame, we believe that infrastructure should not only work when everything goes right—it should hold up when something goes wrong. Because when you’re powering an airport, a city, or a planet, failure is never just local. It’s global.
Check out our recent article: Sesame Insights: Enhancing Energy Resilience with Data-Driven Power Reliability.
On March 21st, 2025, Heathrow Airport—the busiest in Europe—went dark. A fire at a nearby electrical substation triggered a complete power outage, grounding over 1,300 flights and stranding more than 145,000 travelers worldwide. In a matter of hours, a localized electrical failure spiraled into a global disruption, affecting not only passengers but power supplies, train lines, and traffic infrastructure across London.
For those working in critical infrastructure, this event wasn’t just a fluke—it was a flashing red warning. The Heathrow incident is a textbook example of how highly interconnected systems can harbor fragile fault lines beneath their polished surfaces. And it poses a fundamental question: how reliable are the systems we rely on every day?
Heathrow is no stranger to complexity. Serving over 80 million passengers a year, the airport depends on a tightly choreographed dance of power, data, and logistics. But on that Friday, it took just one failure—a fire at the North Hyde substation—to unravel the entire system.
The cascading effects were staggering:
– Flight operations shut down for over 24 hours
– Thousands of travelers diverted across Europe and North America
– Power outages hit nearly 67,000 homes in West London
– Local transport networks, including the Heathrow Express and parts of the Elizabeth Line, came to a standstill
The root cause? A single point of failure in Heathrow’s electrical supply chain. The substation, managed outside of the airport’s direct control, was evidently critical to keeping operations running—without adequate backup, switching, or real-time contingency planning.
What this reveals is a broader truth: the infrastructure supporting critical services like aviation, health, and energy often contains hidden fragilities—fragilities that only become visible when things break. At Sesame, we call this “the reliability blind spot”: the difference between a system that works and a system that endures.
Not all failures are created equal. Some are rare but recoverable. Others—like Heathrow’s outage—are low-frequency but high-impact, with no room for improvisation. Understanding this distinction requires two critical concepts: reliability and resilience.
– Reliability is about how consistently a system performs its intended function under normal conditions. It’s predictive, probabilistic, and closely tied to system design, redundancy, and maintenance.
– Resilience, on the other hand, is about how a system responds when things go wrong. It’s dynamic, response-focused, and deals with recovery time, adaptability, and damage control.
In Heathrow’s case, both concepts were tested—and both fell short. The reliance on a single substation suggests reliability weaknesses: perhaps a lack of redundancy, underinvestment in backup capacity, or misjudged risk assessments. The slow and fragmented recovery process points to gaps in resilience: no rapid failover, no coordinated contingency, and limited ability to keep partial operations running.
What’s worrying is that Heathrow is not unique. Across sectors—from ports and data centers to hospitals and water utilities—many critical assets are exposed to similar reliability blind spots. The challenge isn’t just that things can go wrong; it’s that our systems often hide those risks until it’s too late.
This is where tools like Sesame come in: by helping infrastructure operators visualize, model, and quantify failure pathways, we can shift from reactive crisis management to proactive system design.
While no system can be entirely failure-proof, the Heathrow outage demonstrates that some failures are not just possible—they’re predictable. A structured, data-driven reliability analysis—like the kind Sesame enables—could have exposed the fragility of the airport’s power supply architecture before a substation fire plunged operations into chaos.
A Smarter Approach to Resilience
The conventional thinking in infrastructure planning often centers on redundancy—install a generator, add a failover switch, and hope for the best. But as we’ve seen in both Heathrow and our cross-sector modeling work, that approach is outdated. True resilience requires scenario-specific modeling, grounded in the realities of system demand, failure modes, and financial tradeoffs.
At Sesame, we model resilience the same way we model sustainability: using hourly system simulations, outage scenarios, and region-specific risk data to guide smarter decisions. Applied to an asset like Heathrow, this kind of analysis would have raised red flags around:
– Overdependence on a single substation
– Delayed recovery due to limited on-site generation capacity
– Unmodeled exposure to common-cause failures (e.g., regional grid faults, weather-linked fire risk)
What Could Proactive Modeling Have Enabled?
If Heathrow’s infrastructure had been modeled using Sesame:
– Outage simulations could have assessed how different durations or times of year would impact airport continuity.
– A cost-risk optimization might have shown that a modest investment in localized storage or grid interconnection upgrades would have dramatically reduced risk.
This is not hypothetical—we’ve seen real-world results. In our recent resilience study across commercial and industrial facilities, we found that optimized solar + battery configurations could reduce grid dependence by up to 40% during peak outages and cut energy costs by 20% annually in some regions.
The Real Cost of Not Knowing
At Heathrow, the cost of failure is measured not just in cancelled flights, but in lost confidence, economic ripple effects, and long-term reputational damage. The lesson? The cost of not modeling is far greater than the cost of modeling well.
The Heathrow outage is more than a disruption—it’s a blueprint for what can go wrong in a tightly coupled, high-stakes system when risk is misunderstood or underestimated.
What’s needed now is a mindset shift. Instead of asking, “How often do things fail?” we should be asking, “What happens when they do?” Resilience isn’t built through optimism—it’s built through modeling, stress-testing, and planning for the improbable.
Three Actions to Strengthen Critical Infrastructure:
1. Map Interdependencies
Airports, hospitals, data centers—these are all deeply interconnected with energy, water, and communications. Reliability analysis can uncover systemic risks hidden in those linkages.
2. Invest in Redundancy Strategically
Not all backups are created equal. Digital modeling helps identify where redundancy offers real value versus where it introduces complexity without payoff.
3. Quantify, Don’t Guess
Reliability and resilience can be measured, simulated, and improved. Making them part of standard operations planning—rather than a post-crisis review—changes outcomes.
Heathrow’s power outage brought one of the world’s most advanced transportation hubs to a standstill. It was not the fire alone that caused the disruption—it was the absence of foresight in how the system was designed to respond.
At Sesame, we believe that infrastructure should not only work when everything goes right—it should hold up when something goes wrong. Because when you’re powering an airport, a city, or a planet, failure is never just local. It’s global.
