Type of infrastructure:
Location:
Country:
Spain
Targeted species or habitat:
Implementation period:
2022 - ongoing
Implemented by:
Red Eléctrica and ECOncrete
TRL:
8
Funding:
Red Eléctrica

Knowledge sharing

Information about the project and results are available on the Case Study Briefing (Spanish version, English version).

Database Project

Eco-friendly subsea cable protection in the Canary Islands

Objectives

This project aims to investigate how eco-friendly concrete trench blocks placed around subsea electricity cables can enhance marine biodiversity. Specifically, the project focuses on stimulating the natural recovery of reefs (Habitat of Community Interest 1170).


Short description

In 2022, Red Eléctrica, the Spanish electricity grid operator, installed a 14.5 km long subsea cable between the islands of Lanzarote and Fuerteventura in the Canary Islands. This interconnection facilitates the integration of renewable energy sources into the system and strengthens the connection between the islands.

To protect the cable, support natural recovery after the trenching process, and enhance the local marine ecosystem, Red Eléctrica collaborated with ECOncrete to install 480 eco-friendly concrete trench blocks over the subsea cable. These blocks feature a complex 3D texture that mimics the rocky seabed of the islands. They are made from low-carbon concrete and incorporate a specially formulated solution that significantly enhances biodiversity compared to conventional materials.

In 2023, one year after installation, ecological monitoring was conducted, with professional divers capturing video footage. Preliminary results showed that marine life was already developing along this nature-inclusive design solution. The footage revealed various species, such as algae, sponges, crustaceans, molluscs, sea urchins, and fish, using the structure as their habitat. Further monitoring actions will take place in the years to come.

In 2024, the two companies launched a monitoring study to assess biological growth on the eco-friendly concrete trench blocks and the surrounding reef. Results show that the blocks promote algal growth and supports diverse marine organisms, fostering a healthy, stable and resilient ecosystem. Their similarity to adjacent natural reefs highlights their ability to integrate seamlessly into marine environments.

Two years after installation, Red Eléctrica and ECOncrete have demonstrated that this solution effectively protects cables while restoring reef habitats and enhancing marine biodiversity.