On 28 April 2025, Portugal was in the dark; for many, it was like going back in time to the night of 9 May 2000.

Twenty-five years ago, a stork caused a blackout when it crashed into a power line in Lavos, Figueira da Foz. The incident, which occurred at 22h00 on 9 May 2000, resulted in hours of darkness affecting half of the country, south of the incident, including Lisbon, the south bank of Lisbon, Alentejo and the Algarve.

The failure of the EDP automatic protection system caused the short circuit to spread, making the situation even worse. At the time, the then Prime Minister, António Guterres, opened an inquiry to investigate the causes of the accident.

"The National Electricity Network (REN) spokespeople say that it all started with the electrocution of a stork, on the high voltage pole 327, located near Figueira da Foz. "Inexplicably", EDP's automatic protection system did not detect the short circuit."

At the time, it was reported that "at REN alone, according to its own statistics, the average annual number of short circuits is close to a thousand. For a "blackout" to occur, the Protections must not work in the correct order. In other words, there must be more Protections than necessary disconnecting equipment that should not be disconnected. This may result from a failure of the Protections themselves, or from deficiencies in their parameterization, assembly, verification or periodic inspection. The consequences of a failure on the Protections can be serious, as has been seen."

So, how was the communication then? Radio and television (half of Portugal still had electricity)... Around the year 2000, there was no dependence on social media like there is now (nor smartphones similar to today's), for instance, it was only in 2004 that Flickr and Facebook were created.

White stork nests, perched on high-tension poles, are now part of the landscape in Portugal. And the birds, which were an endangered species in the 1980s, have now adapted perfectly to their new homes and thrived. According to the National Electricity Network (REN), nests installed on electric poles will correspond to at least 25% of the national white stork’s population.

New planning

After the blackout 25 years ago, one of the consequences was a new planning of the grid, maintenance operations and the need for some precautions, such as the placement of deterrent elements to keep birds away from the most sensitive areas of the grid. Platforms are also built on “safer” locations on the poles, which are bases for nesting.

Over the years, technologies have been developed to keep storks away from high-voltage line supports. However, in certain more critical locations, near agricultural fields, they persist, which can affect the quality of service of the REN and put their own lives at risk. In 20 years, storks were the second biggest cause of disruptions in the REN lines (the first cause being electrical discharges).

With this motivation, the installation of anti-landing and anti-nesting devices for large birds prevents and minimizes the risk of electrocution of birds when applied to the supports of High and Medium Voltage lines. The anti-nesting device is constructed with highly durable, weather-resistant A2 galvanized stainless steel elements. Also, the installation of wind-powered paddle-type elements as anti-nesting devices has been used. Both with some success but showing also that further solutions are needed to complement it.