Construction of the submarine cable for receiving offshore energy in the pilot area of Viana do Castelo

Status Done

Start Aug 2016

End Dec 2020


Construction of the submarine cable for receiving offshore energy in the pilot area of Viana do Castelo – Phase 1

The operation consisted of the construction of a submarine cable that extends in an east-west direction, with approximately 17 km, and a cutting station installed at the Port of Viana do Castelo, temporarily operated at 60 kV.

These infrastructures of the National Electricity Transmission Network (RNT), operated by REN, allow the connection of wind power generation centers located offshore of Viana do Castelo, at the western end of the submarine cable.

This cable was designed for a maximum nominal power of 200 MVA when operated at 150 kV (voltage level for which they are prepared: Phase 3, expected by 2030).

In the initial phase of the project - Phase 1, already completed and with these infrastructures operated at 60 kV, the connected generation power is 25 MW from the Windfloat project.

Phase 2 of the project, scheduled for 2026/2027, plans to connect these infrastructures to the current RNT substation in Vila Fria, with new onshore reinforcements prepared for 150 kV but still operating at 60 kV, allowing a maximum nominal power of 80 MVA.

The integration of the above-mentioned power amounts requires onshore network reinforcements in Phase 2, as envisaged in the PDIRT, including, but not limited to, all infrastructure to be prepared from the offshore/onshore transition zone to the RNT substation in Vila Fria.

Project Goals

This project is of special strategic importance for the country and for the region of Viana do Castelo, opening a new field of exploitation of endogenous sustainable energy resources at sea, in full compliance with national and EU objectives of decarbonization of the economy and reducing energy dependence, contributing to the goals of electricity production from renewable energy sources and to reduce greenhouse gas emissions.

Fits in the priority axis 1 of POSEUR, having as specific objective the "diversification of energy supply sources of renewable origin, taking advantage of the endogenous energy potential, ensuring the connection of generating facilities to the network and thus reducing energy dependence".

These objectives are consistent with the national and European objectives of decarbonization and promotion of energy from renewable sources.

At this level, this project will contribute to the achievement of national targets for the participation of renewable energy in electricity production and final energy consumption, as well as the reduction of greenhouse gas emissions that are defined in the Europe 2020 Strategy for Portugal, as part of the actions for the national objectives of carbon neutrality. The project is also an important contribution to the development of ocean energy resources, with the implementation of an infrastructure for the installation of new projects, both commercial and for the purposes of research, technological development and pre-commercial demonstration.



Viana do Castelo 

Technical Data Sheet:

Voltage level: 150 kV, temporarily operated at 60 kV