Cause of Spanish power outage: Did Net Zero and Spain's push for renewable energy cause the blackout - or was it a cyber attack?

The cause of one of Europe's biggest ever power system collapses remains unclear with Portuguese pointing fingers at neighbouring Spain as the source of the issue. Red Electrica pointed to a "strong oscillation in the power flow which triggered "a very significant loss of generation".

Aurora Energy analysts said the frequency of the grid dropped from the nominal 50Hz to 49.85Hz, triggering automatic emergency protocols. "The frequency decline likely began due to severe oscillations in high-voltage lines in southern France or inland Spain. Hypotheses include a physical fault (line disconnection), a sudden loss of generation within Spain or an atmospheric phenomenon," they said.

Some have jumped on the suggestion that Spain’s push to use renewable energy had made an impact. Last year, renewables accounted for 53 per cent of the country’s power generation. Solar photovoltaic (PV) accounted for 59 per cent of Spain's electricity at the time of the blackout, wind nearly 12 per cent, nuclear almost 11 per cent and combined cycle gas plants 5 per cent, Red Electrica data showed.

In a span of just five minutes, between 12.30pm and 12.35 pm local time on Monday, solar PV generation plunged by more than 50 per cent to 8 gigawatts (GW) from more than 18 GW, the data showed. There have been reports that a lack of “inertia” in the grid may have contributed to the blackout. Grid inertia helps maintain electricity supplies at a stable frequency, and is created by generators with spinning parts – such as turbines running in fossil fuel generators or hydropower – which solar panels and wind turbines do not have. In a blackout, you need to rebuild inertia before bringing things back online.

But Spanish Prime Minister Pedro Sanchez ruled out the possibility that an excess of electricity generated by renewable sources caused the power blackout. Mr Sanchez said on Tuesday that technicians were still attempting to find the precise cause of the collapse and the results of their enquiries would be used to reinforce the system.

On Monday, Spain was forced to activate emergency measures to restore electricity across parts of northern and southern Spain, including switching hydroelectric plants across the country back on and importing power through giant cables with France and Morocco. Traditional energy systems have mechanisms which allow them to keep running even if there is a shock, such as a surge or loss of power. However, solar and wind do not have the same ability.

Duncan Burt, a former British grid operator and strategy chief at Reactive Technologies, said: “If you have got a very high solar day then your grid is less stable, unless you’ve taken actions to mitigate that. So you would expect things to be less stable than normal.”

Richard Tice, the Reform party’s deputy leader and energy spokesman, said the events in Spain should be a warning to Britain and showed the risks of net zero. He said: “We need to know the exact causes but this should be seen as a wake-up call to the eco-zealots.”

The cyber security wing of the European Union suggested a technical or cable fault was responsible for the outage. Preliminary findings from the the European Union Agency for Cybersecurity (ENISA) suggested it was not an attack and a spokesman told The Telegraph: “For the moment the investigation seems to point to a technical/cable issue.” Mr Sánchez said in a televised address on Monday: “We still do not have conclusive information about the reasons for this outage ... It’s better not to speculate, we will know the causes, we do not rule out any hypothesis.”