TenneT and Alcatel Submarine Networks (ASN) have signed a frame agreement for the supply and installation of its OptoDAS Distributed Acoustic Sensing (DAS) solutions at onshore and offshore substations within the Netherlands. The framework agreement encompasses 19 projects with planned cable lengths up to 498 km.
As the energy landscape evolves — with increasing demand and a growing share of renewables — TenneT is preparing its infrastructure for the future. The grid of tomorrow will depend not only on new connections, both onshore and offshore, but also on enhanced performance from existing systems under heavier loads. To meet these challenges, TenneT is implementing advanced cable monitoring systems. These systems will offer critical insights into the asset health of the cables, ensuring optimal operation as Europe transitions to a more sustainable energy future.
ASN’s OptoDAS suite is based on a unique interrogation technique, named frequency swept interrogation, that allows long optical pulses to be launched into the fibre without impacting spatial resolution. The gauge length of the measurement is configurable in steps of 1 m, from 2 m to 40 m enabling small events to be detected even on very long cables. The large optical loss budget allows for distortion free measurements over distances up to 150 km in standard optical fibres.
ASN is also providing proprietary Cable Threat Monitoring (CTM) software to measure and locate seabed disturbances several kilometers away laterally from the cable. CTM then tracks the anomalies spatially in real time, providing actionable alerts to the TenneT operating center to support situational awareness and cable damage prevention.
Menno Buisman, Asset Specialist Cable Monitoring at TenneT, said: “ASN’s expertise and proven technology make them a valuable partner for supporting the monitoring of our cable infrastructure. We look forward to working together and leveraging their capabilities to help us maintain the reliability and security of supply of our grids at the high standard that TenneT’s mission requires. ASN’s long-range DAS systems help us address the challenges associated with monitoring increasingly long cable connections.”
Eric Bouvart, Alcatel Submarine Networks Director of Sales and Marketing, said: “We are proud to support TenneT in such large projects, which will provide monitoring for the secure grid connections between offshore renewable energy sources and the onshore transmission network.”
About Alcatel Submarine Networks (ASN)
For over 160 years, Alcatel Submarine Networks (ASN) has been a leading player in the submarine cable industry, with more than 900,000 km of optical systems deployed worldwide—equivalent to 21 times the Earth’s circumference.
With 3 factories located in Europe and an exclusive fleet of 7 cableships, ASN designs, develops, deploys, and maintains turnkey submarine transmission systems for telecommunications operators, digital content providers and cloud services. Additionally, ASN serves the offshore energy market with dedicated technologies.
Leveraging a comprehensive service portfolio and unique expertise, ASN meets the growing and specific demands of its clients to deliver enhanced connectivity across seas and oceans.
ASN is 80% owned by the French State Investment Agency (APE).
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About TenneT
With over 11,500 kilometres of high-voltage connections both onshore and offshore, our role as a Transmission System Operator (TSO) is to ensure a secure supply of electricity to over 18 million end-users in the Netherlands, and to create the infrastructure needed to secure supply today and tomorrow.
TenneT Netherlands is one of Europe’s biggest investors in national and cross-border electricity transmission capacity on land and at sea, bringing together the Northwest European energy markets and efficiently unlocking large-scale renewable electricity sources, with EUR 5.0 billion of investments in 2025. We collaborate with a wide range of partners in the energy market to develop and apply new, smart technologies to contribute to the energy transition.
