Portugal wants European regulators' agency to lead Iberia outage investigation

LISBON (Reuters) -Portugal wants European energy regulators' agency ACER to lead an independent investigation into the causes of the huge power outage that brought most of Spain and Portugal to a standstill last month, its acting energy minister told Reuters.

Maria da Graca Carvalho said Prime Minister Luis Montenegro wants an independent investigation led by the European Agency for the Cooperation of Energy Regulators to complement the technical report being prepared by the European network of transmission system operators ENTSO-E.

"ACER, as a suitable entity to coordinate any external evaluation process, could bring more confidence, impartiality and transparency to the conclusions," Carvalho said in an e-mail, responding to questions from Reuters.

"As for speculation about cyber attacks, sabotage or human error, at this time there is no evidence" that any of those could have caused the outage, the minister told Reuters in a written statement.

Spain's energy minister said last week that an abrupt loss of power generation at a site in Granada, followed by outages seconds later in Badajoz and Seville, triggered the unprecedented blackout across Spain and Portugal on April 28.

Iberia lags behind the EU's target for all countries to have 15% of their energy system interconnected to the broader European network by 2030, with Iberia's share stuck at just 3%.

Carvalho said that, regardless of the causes of the blackout, Portugal was pondering how to strengthen the resilience and security of the national electricity system, which is a "strategic imperative".

(Reporting by Sergio Goncalves; editing by Andrei Khalip and Jan Harvey)