ERSE raises energy tariff by five euros per megawatt-hour

The Energy Services Regulatory Authority (ERSE) has updated the Energy tariff by €5/MWh, effective from October 1, 2026, by decision of its Board of Directors published in Directive No. 4/2026, in the Diário da República, 2nd series, no. 202, of October 19, 2026. The directive carries out the first amendment to Directive No. 1/2026, of January 7, which set the electricity tariffs and prices for 2026 and the parameters for the 2026-2029 regulatory period. The update results from a deviation of +€17.59/MWh in the forecast of the energy acquisition cost of the supplier of last resort.

A quarterly tariff adjustment mechanism

Article 178 of the Tariff Regulation of the electricity sector, approved by Regulation No. 1218/2025, of November 7, 2025, rectified by Rectification Declaration No. 17/2026/2, of January 7, 2026, provides for a pre-established mechanism to adjust the tariff to the energy acquisition costs monitored quarterly by ERSE.

The parameters of this mechanism were set for 2026 by Directive No. 1/2026: whenever the deviation is equal to or greater than €10/MWh, in a positive or negative direction, half of that limit value is passed on to the energy tariff, i.e., €5/MWh. With a deviation of +€17.59/MWh compared to the forecast implicit in the prices in effect until September 2026, the quarterly monitoring determined the maximum permitted update.

Who pays for the increase

The update is passed on to all active energy prices, broken down by time period, of the tariffs applied by the Supplier of Last Resort (CUR) in mainland Portugal, covering:

the transitional tariffs for Sales to Final Customers;
the Social tariff for Sales to Final Customers;
the tariffs applied within the scope of supplementary supply.

In the autonomous regions, the increase applies to all active energy prices of the Sales to Final Customers tariffs, including the social tariff, and to the Energy and Marketing tariff for electric mobility in the Autonomous Region of the Azores and the Autonomous Region of Madeira.

Validity and legal basis

Directive No. 4/2026 enters into force on the day following its publication, but takes effect from October 1, 2026, therefore the increase is already being applied to current invoices. The legal instrument amends articles 11, 26, 28, 31, 32, 33, 35, 36, 38, 39, 42, 43, and 44 of Directive No. 1/2026, relating to the prices of period IV.

The decision was signed on September 15, 2026, by the ERSE Board of Directors, composed of Pedro Verdelho (president), Ricardo Loureiro (member), and Isabel Apolinário (member). It is based on the ERSE Statutes, approved by Decree-Law no. 97/2002, of April 12, on article 207 of Decree-Law no. 15/2022, of January 14, and on article 12 of Directive no. 1/2026.

What changes for the consumer

The increase of €5/MWh applies only to the energy component, not to the total bill, and applies to those supplied by the supplier of last resort — a typical situation for customers who have not contracted an offer in the liberalized market. The increase is uniform across all time periods, so the final impact depends on each customer’s consumption. ERSE justifies the measure based on the actual evolution of energy procurement costs, which were €17.59/MWh above forecast, and not through a discretionary review of tariffs.

Source: Diário da República, 2nd series, no. 202, of October 19, 2026, Part C — Government and direct and indirect state administration (official reference: Directive no. 4/2026).