14/10/2026

ERSE – the Energy Services Regulatory Authority has published the Technical Quality of Service Report of the Electricity Sector for 2025, which assesses the quality of supply provided to consumers by electricity transmission and distribution network operators.

The quality of supply is assessed using continuity of supply indicators and indicators that monitor the power quality. In 2025, continuity of supply indicators showed a deterioration compared with the previous year, marked, on the mainland, mainly by the impact of the Iberian blackout on 28 April.

On the transmission network, operated by REN – Rede Eléctrica Nacional, there were 92 interruptions, 87 of which related to the Iberian blackout and were classified as exceptional events. Despite the deterioration in the overall continuity of supply indicators, individual standards were met at all delivery points.

In the distribution network, operated by E-REDES, the deterioration in the general indicators was mainly due to seven major-impact events, also classified as exceptional events. Most notable was the Iberian blackout, which affected all customers, with an average duration of around 10 hours per customer. Nevertheless, all general standards applicable to medium- and low-voltage networks were met across the three service quality zones. Non-compliance with individual standards rose by around 53%, to 111,182, and compensation paid to customers totalled approximately 2.1 million euros, double the amount recorded in 2024.

In the Autonomous Regions of the Azores and Madeira, where the operators are EDA – Eletricidade dos Açores and EEM – Empresa de Eletricidade da Madeira, respectively, there was also a deterioration in  continuity of supply indicators.

At EDA, the deterioration resulted from an increase in unplanned interruptions originating from generation and the networks. There was a non-compliance with the general standards  relating to the average number of interruptions in the low-voltage in zone A of the island of Faial. EDA recorded nine non-compliance with individual standards – three times more than in 2024 – and paid compensation totalling around 84 euros. This amount was lower than in the previous year, reflecting the lesser severity of the non-compliances.

At EEM, the increase in unplanned interruptions originating in the networks and the occurrence of an exceptional event linked to extreme weather conditions contributed to the deterioration in the indicators. All general standards were met, but there were 252 non-compliances with individual standards relating to the total duration of interruptions, 85% more than in 2024. The compensation paid by EEM amounted to around 8,228 euros, a sum 4.5 times higher than in the previous year.

Access the Technical Service Quality Report – Electricity Sector 2025

Access ERSExplica – Summary of the 2025 Technical Service Quality Report for the Electricity Sector

Access the interactive dashboard – Technical Quality Indicators for the Electricity Sector