Connections between the national electricity systems have been historically developed in parallel to each country’s internal networks. Initially, the connections sought foreign support in case a failure affecting the reliability of the national electricity supply should occur. However, it has been shown that connections are not only useful for exceptional situations, but that they offer outstanding benefits also under normal operating conditions: power plant daily production optimization, better opportunities for use of renewable energies, creation of competition, and improvement of the supply conditions.
These were the objectives of the new connection between France and Spain, operational since 2015, which brings both countries even closer, and represents a significant step towards a more integrated Europe from an energy point of view. The new ±320 kV line doubles the power exchange capacity prior to the connection and goes from 1,400 to 2,800 MW, a jump which will allow for a greater incorporation of renewable energies to the European network, and which adds supply solidity and reliability, not only in Spain and France, but throughout the EU.
Prior to the construction of the new connection, surplus wind production generated in Spain could not be exported to the rest of the continent due to the limitations of the four high-voltage power lines connecting France and Spain (Arkale-Argia, Hernani-Argia, Biescas-Pragnères, and Vic-Baixas.) With the new infrastructure, electricity is no longer circulating between both countries through "back roads" but rather through a "multiple lane highway", which facilitates the incorporation of clean energy - the generation of which is less stable, and is subject to weather conditions - without putting the supply at risk. As it operates within the European electricity system, one of the largest networks in the world, the leeway for action is greater in case of a supply failure both in France and in Spain.
The European Union recommends promoting the electric connection capacity between its States. France exchanges electricity with six countries of the Union, but Spain, conditioned by its geographical location, has been traditionally considered as an "energy island". The connection between Baixas and Santa Llogaia brings Spain closer to the 2002 EU recommendation that a State’s connection capacity be at least 10% of the country’s total electricity generation. The importance of the connection between Baixas and Santa Llogaia transcends, therefore, the cross-border level, and is a key element for the development of the European energy policy.
Security of supply
Electricity systems are more stable the more networked and interconnected they are. Interconnections are the main factor in supply security.
European electricity market
By using surplus capacity on the lines that is not used for supply security, electricity trade exchanges are set up on a daily basis to most efficiently harness the electricity production differences in each country.
As interconnection capacity increases, the volume of renewable production that a system is capable of integrating safely is maximised given that the renewable energy not needed by its own system can be sent to other neighbouring systems instead of being wasted.