CIGRE crucial in decarbonising DC infrastructure in Spain

For decades the Spanish peninsula has been an ‘energy island’, with very limited interconnecting capacity - of almost 100 GW installed, just 3 GW interconnect with France. It is true that the historical peak demand in Spain is below 50 GW, but the amount of renewable-intermittent energy is increasing rapidly, now over 30 GW of wind+solar, and planned to reach 40 to 45 GW by next year. This couples with a planned progressive reduction in nuclear and coal generation (almost 20 GW in the next few years. This means that a considerable amount of the energy consumed will be renewable-intermittent, with limited support of other sources.

 

For years now, major efforts have been made to integrate intermittent sources (operation, prediction, etc.) but additional support is still urgently needed, particularly regarding interconnections. Massive storage is being worked on but still not expected to be sufficient in future years. 

 

Countries have been working on this challenge since the nineties. After several unproductive attempts, in 2007 [to confirm] The European Commission decided that a new interconnection between France and Spain should be built underground, crossing the Pyrenees Mountains. The TSOs started work immediately to develop the project, which had to be DC due to the distances and characteristics. That was an important challenge for Red Electrica (Spanish TSO), whose technicians lacked previous experience in HVDC links of this kind. They turned to CIGRE to learn and gain the experience they needed. In particular CIGRE Technical Brochures, papers and contacts were crucial to develop their standards, specifications, detailed engineering, etc.

 

The link’s commercial operations started in 2016. Since then, important system benefits have been reported including stability, support against undesired events, reduction of renewable curtailments, competition. Importantly, Red Electrica and RTE now have their own experienced people dedicated to HVDC systems: Operation and maintenance of the link, design of particular elements, etc. A prototype replica of the link was also developed to model and prepare for different situations that may one day need to be faced.

 

Development continues. A new interconnection with a submarine cable through the Vizcaya Bay is being planned, subject to satisfactory findings from associated environmental studies. An additional 2 GW of interconnection capacity are planned but, again, the challenges to be resolved are significant: length of the submarine cable, depth, mechanical protection, technical operation issues, converter stations. All these are addressed within different CIGRE working groups (B1, B2, B4), now with increased participation from Red Electrica.