War in Europe and rising geopolitical tensions raise the risk that states might employ high-altitude, non-lethal nuclear blasts designed to generate widespread High-Altitude Electromagnetic Pulse (HEMP) that, though not physically destructive via blast, could cripple critical infrastructure (especially continental-scale electrical grids) by illuminating them with a high-power electromagnetic field. Such an attack would disrupt power generation and distribution, paralyzing essential services (healthcare, communications, transport, emergency response), portentially triggering cascading failures, economic collapse, resource shortages, and possible civil unrest. Although U.S. presidents have long mandated study and mitigation of HEMP threats, and major powers (US, Russia, China) possess or develop HEMP-capable systems, Europe’s preparedness remains limited and uncoordinated.
This report addresses the growing threat posed by HEMP events to Switzerland’s critical infrastructure, with a particular focus on the national power grid. HEMP, generated by nuclear detonations at altitudes above 30 kilometers, can severely disrupt electronic systems without causing traditional blast damage. Modern societies, including Switzerland, are increasingly vulnerable to such threats due to their heavy reliance on interconnected digital infrastructures across sectors such as healthcare, transportation, communication, and energy. Recent geopolitical developments and advancements in nuclear and electromagnetic technologies have elevated HEMP from a theoretical concern to a pressing national security issue requiring immediate and strategic attention.
The study systematically analyzes the distinct impacts of the three HEMP components—E1, E2, and E3—on power grid infrastructure, making reference to published studies, standards and reports. E1 pulses, characterized by nanosecond-scale rise times and extreme electric fields, can instantly disrupt or destroy sensitive electronic control systems, including digital relays, SCADA systems, and protection devices. E2, although lower in amplitude, follows E1 and can exploit any weaknesses already created, potentially overwhelming surge protection devices. E3, with its geomagnetic characteristics, induces quasi-DC currents over long transmission lines, leading to transformer saturation, overheating, and possible grid-wide voltage collapse. Taken together, these effects reveal a multilayered risk profile in which both immediate and delayed failures threaten grid integrity and societal continuity.
Given these risks, the report proposes a two-phase protection strategy. The first phase focuses on interim protection measures primarily targeting E1 vulnerabilities. Key actions include enhancing control room shielding, reinforcing cable protection through fiber optics and Electromagnetic Interference (EMI)-shielded entries, improving grounding and bonding practices, isolating critical communications systems with fiber optics, and deploying resilient architectures with redundant protections. Additionally, the implementation of ”no-regret” measures—such as advanced lightning protection and EMI monitoring—provides immediate resilience benefits at relatively low cost. The second phase outlines a long-term modernization program encompassing comprehensive infrastructure upgrades. These include hardening substations and control centers with Faraday cages, adopting transformer designs resistant to Geomagnetically Induced Currents (GIC)s, expanding simulation and testing capabilities, and developing detection and early warning systems specific to Switzerland or Europe.
Cost considerations are critical in evaluating the feasibility of the proposed measures. U.S. studies from 2008 and 2020 estimate nationwide HEMP protection investments between hundreds of millions to tens of billions of dollars, depending on the scope—ranging from selective protection of critical transmission and generation assets to comprehensive shielding of communications and control infrastructure. Extrapolating these figures to Switzerland suggests that comprehensive protection could cost between $85 million and $809 million, depending on whether scaling is based on geographical area or population. However, these projections should be viewed as upper bounds. Switzerland’s power grid already incorporates robust construction standards, and some existing protections may significantly lower actual costs. Furthermore, integrating hardening measures during scheduled infrastructure upgrades could limit incremental costs to approximately 1–3% of the original equipment price, offering a cost-efficient path to significant resilience improvements.
Nonetheless, a simple extrapolation is insufficient for precise budgeting. The report strongly recommends securing a representative reference site within Switzerland to conduct a detailed cost analysis based on real-world conditions. This approach would allow for more accurate assessment of material, labor, and operational costs associated with retrofitting or new construction, while accounting for Switzerland’s unique grid characteristics.
In conclusion, while the financial investment required to protect the Swiss power grid against HEMP threats is considerable, the cost of inaction could be exponentially higher. A successful HEMP attack could cripple critical infrastructure, destabilize the economy, and undermine national security with cascading effects that could last for months. Strategic investment in resilience measures not only strengthens the immediate survivability of essential systems but also ensures long-term societal stability in an increasingly uncertain global environment. Protecting the power grid against HEMP is therefore not merely an option but a necessity for safeguarding the continuity of Switzerland’s modern society.
