In the dark: Spain's electricity grid operator warns country could be heading for another blackout

Spain's grid operator, Red Eléctrica, has warned that the country could be on the verge of another blackout after detecting "abrupt voltage variations" across the system for the past two weeks.

The warning comes six months after an outage in April left 60 million people in Spain and Portugal without power for more than 10 hours.

The European Network of Transmission System Operators for Electricity said in a report last Friday that the blackout was triggered by overvoltage, as the grid struggled to absorb sudden power losses.

The recent variations in the system are "such that they could impact the security of supply if the proposed changes are not implemented," Red Eléctrica said in a document sent to market regulator CNMC.

Grid requests technical changes

Red Eléctrica has linked the unusual fluctuations recently detected in the electricity grid to sudden changes in renewable generation and the response time of facilities responsible for dynamic voltage control.

Although voltage remain within permitted limits, they could cause demand or generation disconnections capable of destabilising the system, Red Eléctrica said.

The company has requested urgent technical changes and the temporary approval of several operational procedures related to scheduling, technical restrictions, secondary regulation and voltage control to prevent the system from becoming overwhelmed once again.

These modifications would initially last for 30 day and can be extended by a further 15. The CNMC has opened a public consultation period until 15 October.

How can residents prepare?

Just before the April blackout, the EU asked member states to develop a 72-hour survival kit for citizens to prepare in the case of any crisis.

Such kits, which are optional for member states, proved useful for residents of Spain and Portugal in the aftermath of the blackout.

With the possibility of another blackout on the horizon, experts are warning residents to have at least a basic emergency kit at home that includes essentials such as drinking water, non-perishable food, a first aid kit, a torch, a battery-powered radio and an external battery for mobile phones.

Other essentials for such an incident include drinking water, cash, warm clothes and candles.