Montena Technology has participated in the drafting of a landmark report commissioned by the Swiss Federal Office of Energy (SFOE), dedicated to analyzing the threats posed by High-Altitude Electromagnetic Pulse (HEMP) events to the Swiss power grid.
An emerging threat to critical infrastructure
A HEMP event results from a nuclear explosion triggered at an altitude of more than 30 kilometers. Without causing direct physical destruction, it generates an intense electromagnetic field capable of simultaneously disabling electronic systems across areas the size of Western Europe. The three components of HEMP — E1 (a nanosecond-scale, very high-amplitude pulse), E2 (comparable in nature to lightning), and E3 (quasi-DC currents induced in transmission lines) — each present distinct risks to the power grid: destruction of digital protective relays, transformer saturation, and cascading voltage collapse.
A concrete assessment of the Swiss grid
For the first time, six substations on the Swiss network — located in the canton of Vaud — were subjected to a qualitative resilience assessment against a HEMP event. The findings show that while substations present genuine strengths (structural shielding, lightning protection, fiber optic cabling in more recent installations), none had undergone a HEMP-specific evaluation or implemented dedicated HEMP protection measures. Several were classified as “probably vulnerable.”
A two-phase protection strategy
The report proposes a structured two-step approach. In the short term, cost-effective interim measures are recommended: improving the shielding of control rooms, replacing copper cables with fiber optics wherever feasible, reinforcing grounding systems, installing surge protective devices, and extending backup power autonomy to a minimum of 72 hours. Over the longer term, a comprehensive infrastructure modernization program is called for: hardening substations with Faraday cages, adopting transformer designs resistant to Geomagnetically Induced Currents (GICs), and developing detection and early-warning systems at the Swiss or European level.
The report estimates the cost of comprehensive protection for the Swiss grid at between $85 million and $809 million depending on the scaling methodology used — significantly less than the potential consequences of a successful HEMP attack, which could paralyze the economy and society for months.
Montena Technology’s expertise in support of grid resilience
With decades of experience in protection against high-power electromagnetic phenomena, Montena Technology contributed its expertise in simulation, testing, and the design of EMP/HEMP protection systems. Our participation in this federal project reinforces our role as a trusted partner for the protection of critical infrastructure in Switzerland and internationally.
Access the full report (ARAMIS / SFOE)
