Austria is not prepared for a nationwide blackout.

On Saturday, 5 October 2024, the time will come around again – at 12 noon, the civil defence test alarm will take place in Austria. More than 8,000 sirens, as well as the ‘KATWARN Österreich’ and AT-Alert apps, will be tested. The aim is to check the technical equipment of the warning and alarm system and to raise public awareness of these signals and their meaning. Crisis-proof communication is essential for comprehensive public safety.

In the event of a widespread blackout (power outage) in Austria, however, this crisis-proof communication cannot be guaranteed. Although the Austrian Broadcasting Corporation (ORF) can continue to broadcast emergency messages via its own alerting system and a crisis-proof VHF network, the communications infrastructure of the emergency services poses a major problem. This is because both the TETRA radio system used by the emergency services (police, fire brigade, ambulance) and large parts of the siren network in Austria will no longer function after just 24 hours in the event of a widespread blackout.

TETRA radio network

In both Austria and Germany, the TETRA (Terrestrial Trunk Radio) system is used by authorities, security forces and emergency services. TETRA is a closed radio network that combines digital radio, mobile radio and data transmission (Moechel, 2023). The radio network is tied to local transmission masts on the ground, whose functionality is linked to the supply of electricity.

A large part of the Austrian TETRA radio network would fail after just 24 hours in the event of a widespread blackout. Tyrol is the only federal state to have set up its own redundant radio network with generators, which includes more than 80 TETRA stations. The other federal states have no comparable back-up. The Austrian Ministry of the Interior assumes that mobile generators could be used to regularly recharge the batteries of the more than 1,200 transmission masts. However, this is logistically almost impossible, as most masts are designed for 24-hour operation without a power supply and the charging times of the lead batteries are very long. Experts agree that after just one day, only a few dozen of these masts would still be operational. This means that the authorities in large parts of the country would be dependent on local radio equipment. These uncertainties pose a significant risk to the effective coordination of the emergency services and the warning of the population. Without a stable and reliable communication infrastructure, the population would be dangerously exposed, especially in the event of natural disasters, terrorist attacks or major power outages.

Siren network

Austria is covered by 8,300 sirens for warning the population. What many people don’t know is that a large part of this alerting system consists of outdated E57 motor sirens. These and similar devices are still used in large numbers by volunteer fire brigades in Austria. These sirens, which are often several decades old, are loud and robust, but have the major disadvantage of being dependent on three-phase current at 380 volts and as such also have a high average power consumption. Generators that can deliver three-phase current at the required power cost many times more than the usual four-stroke units at 230 volts / 3 KW and are therefore rare.

To minimise these risks, the outdated systems urgently need to be replaced with modern electronic sirens. Classic mechanical sirens are unreliable because they depend on the existing power grid and would therefore fail during a blackout. Electronic sirens that have alternative energy sources such as solar cells or emergency batteries offer a much more robust solution and can be operated independently of the general power grid for a longer period of time. Kockum Sonic sirens, for example, can be operated independently of the power grid for up to five days. These modern electronic sirens can also emit a wider range of warning signals and pre-recorded messages, so that the population can be alerted to a variety of threat scenarios.

A comprehensive conversion from mechanical to electronic sirens is therefore not only a question of efficiency, but also of security. In addition to the expansion of the physical infrastructure, innovative solutions such as redundant radio relay networks and decentralised energy systems should also be considered. The resilience of the systems against blackouts also depends on the availability of alternative energy sources.

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Sources information:

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Kanton Bern. (n.d.) 13. Oktober: Internationaler Tag der Katastrophenvorbeugung. Retrieved 25. September, 2024 from: https://www.bsm.sid.be.ch/de/start/themen/bevoelkerungsschutz-zivilschutz/bevoelkerungsschutz/13–oktober–internationaler-tag-der-katastrophenvorbeugung.html

Ladinig, J. (n.d.).  Blackout: Die Kehrseite der erneuerbaren Energien.  Retrieved 25. September, 2024 from:: https://www.power-days.at/de-at/story/blackout-erneuerbare-energien.html

Moechel, E. (2023). Weder Sirenen noch Blaulichtfunk gegen Blackout gesichert. Retrieved 25. September, 2024 from:: https://fm4.orf.at/stories/3018360/

Sirene (Gerät). (2024). Retrieved 25. September, 2024 from: https://de.wikipedia.org/wiki/Sirene_(Ger%C3%A4t)

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