Berlin in the dark: inside an urban outage that exposed grid risks

Berlin, pushed out of its energy comfort zone

In early January 2026, a major power outage affected southwest Berlin. The incident quickly became a relevant case study for the European energy sector, not because “the lights went out,” but because of what it revealed about the vulnerability of urban energy infrastructure.

Berlin is not just any city from an energy perspective. It is a mature metropolitan hub, with a grid developed and expanded over several decades, a high density of residential and non-residential consumers, and an energy infrastructure deeply embedded in the urban fabric.

Traditionally, cities like this are perceived as energy-robust: redundant grids, established procedures, experienced operators. Precisely for this reason, the scale and duration of the outage raised serious questions among energy professionals.

What happened, in brief

On January 3, 2026, a significant part of Berlin’s urban power grid was taken out of operation following an act of sabotage targeting critical energy infrastructure. The incident triggered a large-scale outage, with effects felt over several days.

Districts such as Lichterfelde, Zehlendorf, Dahlem, and Wannsee were affected—predominantly residential areas that also host public institutions, critical infrastructure, and economic activity.

Tens of thousands of households lost their electricity supply, and thousands of companies and institutions were directly impacted. While power was partially restored relatively quickly in some areas, full restoration took several days – an important factor that set this event apart from typical grid interruptions.

Authorities and the grid operator quickly confirmed that the outage was not caused by a technical malfunction or weather-related conditions. The case was escalated to federal authorities and treated as a potential attack on critical infrastructure.

Why this matters now

Europe is undergoing a profound transformation of its energy system, driven by several overlapping trends:

• accelerated electrification – no longer just a policy objective, but an operational reality. Electric mobility is expanding rapidly in both private and public transport, while industry and residential sectors increasingly shift toward electric heating solutions, particularly heat pumps. These changes introduce new, more intensive and less predictable consumption patterns.
  
• growing integration of renewable energy sources – with clear decarbonization benefits, but also direct implications for grid stability. Weather-dependent, variable generation creates shocks and imbalances that must be absorbed by infrastructure originally designed for far more predictable operating conditions.
  
• rising pressure on existing grids, especially in urban areas – many networks were designed for less dense cities and relatively stable demand. Today, higher urban density, more electrical equipment in homes, electric vehicles, heat pumps, and widespread photovoltaic installations (both residential and commercial) generate peak loads and bidirectional power flows that grids were not initially dimensioned to manage.
  
• large, constant loads driven by digitalization – data centers and associated IT infrastructure introduce stable, high-bandwidth demand that stresses networks differently from traditional residential or commercial consumption, further reducing system flexibility.

In this context, energy infrastructure can’t be treated as an invisible background that simply “works.” Events like the one in Berlin show that grid resilience has become just as important as expanding generation capacity.

Anatomy of a critical point

From an energy perspective, the incident was not a localized fault, but a grid event with systemic implications. A physical infrastructure node where multiple critical circuits converged was affected simultaneously.

Why location matters

The attack occurred along an infrastructure route crossing the Teltow Canal, used to carry several power lines through the same area. Such solutions are common in large cities, where space is limited, underground infrastructure is dense, and routing is optimized for cost and accessibility.

Problems arise when multiple critical circuits share the same physical point.

What types of lines were affected

According to confirmed information, the fire simultaneously damaged:

• 110 kV lines, part of the urban high-voltage network supplying substations;
• 10 kV lines, part of the medium-voltage distribution network supplying end consumers.

This combination is key to understanding the scale of the impact.

Why simultaneous damage changes everything

Under normal conditions:

• a 10 kV line can be resupplied from another substation;
• a 110 kV line can be rerouted;
• protection systems isolate faults quickly.

In this case, however:

• alternative supply paths relied on the same affected routes;
• rerouting capacity was severely limited;
• multiple grid levels were impacted in parallel.

The result was a temporary loss of redundancy and not just a line outage.

From fault to systemic event

From a grid operations perspective, this was the tipping point:

• the fault could no longer be absorbed by the system;
• the grid entered a degraded operating state;
• restoration required complex physical interventions, not just switching operations.

In dense urban environments – where access is difficult, works are slow, and public safety is a priority – restoration time increases exponentially.

Why redundancy failed

Redundancy is a fundamental principle of grid design. In theory, every critical element should have a functional alternative. The Berlin case highlights the difference between conceptual redundancy and effective redundancy, the kind that matters during extreme events.

In mature urban grids, substations are supplied from multiple directions, lines are looped, protection systems act quickly, and resupply is handled through controlled switching. On diagrams, the system looks robust.

The problem arises when alternatives are not physically independent.

Shared routes: efficiency versus vulnerability

In Berlin, several circuits considered redundant were routed along the same infrastructure corridor, crossing the same technical bridge. Operationally, this approach is common in large cities due to space constraints, high costs of fully separate routes, and the difficulty of modifying existing infrastructure.

From a resilience perspective, however, shared routes create single points of failure.

Redundancy versus resilience

The incident underscores a critical distinction:

• redundancy means having alternatives;
• resilience means the system can continue functioning even when alternatives fail.

A system can be redundant without being truly resilient.

Sabotage as a stress test

Confirmation of sabotage shifted the discussion from grid operations to critical infrastructure security. From an energy perspective, however, sabotage explains the trigger – not the scale – of the incident.

Energy infrastructure is inherently difficult to fully protect and remains a vulnerable target in any country. What differentiates this case is that a localized, intentional act had wide-ranging effects, indicating that isolation and rerouting mechanisms were insufficient.

Strategically, the incident raises a broader question: how well are grids prepared for deliberate risks, not just technical failures or extreme weather? When redundancy is not physically independent, a single intentional act can simultaneously affect multiple grid layers.

What happened shows that energy security is not only about physical protection, but also about infrastructure architecture. The sabotage acted as an extreme stress test, exposing existing structural vulnerabilities.

What remains after Berlin

The outage was not a one-off operational failure. It was a real-world stress test for a mature urban grid, in a context where such tests are likely to become more frequent.

It showed that:

• critical vulnerabilities are not always where we first look;
• historical efficiency of urban grids often comes with structural trade-offs;
• resilience is not an automatic outcome of redundancy, but of how redundancy is physically implemented.

For the energy sector, the key lesson is not about sabotage, but about design, prioritization, and realistic risk assumptions. In an increasingly electrified, interconnected, and exposed system, infrastructure can no longer be treated as something that functions “by inertia.”

All of this leads to a clear conclusion: “owning the energy is the key.” Resilience solutions cannot come exclusively from the central grid; they must also be built locally, at the points where energy is produced and consumed.

One practical direction is the deployment of energy storage systems at key points across the energy system, serving both as backup and as tools for stabilizing grid operation:

• at the prosumer level, storage systems enable higher self-consumption and provide backup during outages;
• for small-scale residential solutions, including balcony PV systems, dedicated storage can sustain essential household loads during disruptions;
• for self-producers and industrial consumers, storage becomes critical. Systems sized for at least two hours of solar production can significantly reduce grid dependency and improve response capacity during critical moments;
• at grid level, storage deployed at 110 kV, 10 kV, and low-voltage (380 V) levels can deliver balancing and flexibility services, act as local backup, and support system restart in blackout scenarios.

Importantly, energy storage has become far more accessible in terms of cost, and ongoing technological advances continue to improve performance and long-term value, making storage a natural upgrade for modern, resilient energy systems.