The race to shore up Europe's power grids against cyberattacks and sabotage

It was a sunny morning in late April when a massive power outage suddenly rippled across Spain, Portugal, and parts of southwestern France, leaving tens of millions of people without electricity for hours.

Cities were plunged into darkness. Trains stopped and metro lines had to be evacuated. Flights were cancelled. Mobile networks and internet providers went down. Roads were gridlocked as traffic lights stopped working.

It took 10 hours for power to be restored and 23 hours before the entire national grid in Spain was back up and running, with the incident being deemed the most severe blackout to have affected Europe in the last two decades.

This incident was not caused by a cyberattack, however, the Spanish power outage brings back unpleasant memories of the devastating cyberattack in 2015 that took down Ukraine's electric grid for six hours, which was traced back to Russian online attackers.

Most worryingly, it has shown how delicate the balance is when it comes to keeping national grids stable, and how failures in one country in Europe can cause an instant domino effect in neighboring nations reliant on energy imports.

Recent cyberattacks have revolved around ransomware affecting financial systems, but there is a serious risk that criminals and nation-state attackers could either incidentally, or deliberately, bring down substations or halt fuel supplies, such as in the case of the Colonial Pipeline cyberattack in May 2021.