Electrical grids are operated under a regime of concession, as follows:
- Mainland Portugal:
- Low-voltage grids belong to municipalities, with 99% managed by E-REDES.
- Medium and high-voltage grids are also operated by E-REDES.
- Redes Energéticas Nacionais (REN) exclusively operates very-high-voltage transmission.
- Island Grids:
- Madeira’s and Azores’ grids operate independently as isolated microgrids exempt from some EU directives, with EEM (Empresa de Electricidade da Madeira) and EDA (Electricidade dos Açores) operating under regional concessions. In the islands of Madeira and the Azores, the local LV, MV and HV grids are operated under concessions from the respective Regional Governments by EEM in Madeira and EDA in the Azores.
- The electrical power systems of the Azores and Madeira islands are considered isolated microgrids since, according to Article 26 of this directive, they have been exempted from the application of Directive 2003/54/EC.
- The island grids are not interconnected with the mainland or interconnected among them, except for the case of the island of Culatra in the Algarve, where there is an MV interconnection with the mainland.
- The grids of the islands of Berlenga, and in the South of Portugal (Algarve), are operated by the Portuguese DSO E-Redes.
- On the island of Culatra, there is a pilot project of a community of renewable energies.
- Municipal Concession Framework: New provisions limit low-voltage distribution grid concessions to 20-year terms, while MV and HV concessions, managed by REN, have a 50-year limit, subject to extensions based on public interest considerations.
- Pilot and Technological Free Zones: Zonas Livres Tecnológicas (Technological Free Zones) have been designated for innovation in renewable integration, supporting experimental projects in three defined regions for oceanic, agro-energy, and hybrid renewable development.
- In Madeira as well as in the Azores, there are strategic policy documents issued by the regional governments defining ambitious targets for renewable energy integration, as follows:
- Plano de Ação para a Energia Sustentável da Ilha da Madeira approved by Resolução n.º 244/2012 do Conselho do Governo da Região Autónoma da Madeira;
- Estratégia Açoriana para a Energia 2030, defined in Resolução do Conselho do Governo n.º 92/2018, de 7 de agosto.