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The Olisipo Submarine Cable System


Enhancing Connectivity Unlocking the Hub Potential of Sines

In today's interconnected world, reliable and efficient communication infrastructure is vital for economic growth and social development.

The Olisipo submarine cable system, developed by EllaLink, is set to support the digital development of Portugal, particularly in the region of Sines, enabling its transformation into one of the hottest places in Europe for data centre construction and connectivity hub.

With Diego Matas, EllaLink COO, we will be guided in understanding how and why submarine cable systems play an important role in sustaining the connectivity ecosystem while highlighting the myriad benefits it brings.

In 2021, the EllaLink optic fibre submarine cable has made the task easier by establishing a direct link between Europe and Latin America, and enabling faster and more reliable communication, fostering economic growth, and strengthening cultural ties between these regions.

Today, Sines is already much more than subsea cables! The city is witnessing the development of an impressive hyperscale Data Centre campus of up to 495MW, a project with an ultimate investment size of up to €3.5 billion – Start Campus is a name to remember and the first building of the campus with a total capacity of 15 MW, is set to open in September.

Seawater cooling system, use of existing industrial infrastructure to minimize environmental impact, strong capillarity in Portugal and connection with international high-capacity fibre optic cables, availability of 100% green electricity – the Start Campus project will take advantage of the strategic geographic location of Sines and Portugal on the European periphery with the EllaLink submarine cable already in operation and other more cables already announced.

With the complement of the Olisipo cable system, the connectivity infrastructure will play a crucial role in sustaining Portugal's connectivity ecosystem, bridging Sines with the Lisbon Metro Area.

Data centre and subsea cable symbiosis

Data centres and submarine cables have a symbiotic relationship that is crucial for the functioning of the modern internet.

This interdependency ensures seamless global connectivity, efficient data transmission, and reliable network infrastructure. Data centres and cloud providers rely heavily on submarine cables to facilitate data transfer between several locations.


Cables provide the necessary long-haul infrastructure for data centres to store, process, and distribute massive amounts of data generated by users.

Depending on the type of site (content site or computing site), there is a symbiotic relationship between data centres and submarine cables that create the cornerstone of the digital ecosystem.

The symbiotic relationship between data centres and submarine cables also enhances the overall reliability of the global internet infrastructure.

Redundant connections allow data centres to reroute traffic during disruptions or cable damage, ensuring uninterrupted connectivity and data accessibility. Submarine cables offer diverse and redundant paths for data transmission, ensuring continuous operation and minimizing downtime for data centres.

For instance, cloud providers count at least 3 to 5 diverse routes to secure a POP location.  

The Olisipo submarine cable system: Sines to Lisbon

The Olisipo submarine cable system, planned to be RFS in Q12025, is an ambitious project that aims to provide enhanced connectivity between the new data centre development area of Sines and the Lisbon metro area.

It will allow not only to bear the massive data generated by the data centres towards the Lisbon metro area and the interconnection with other cables, but as well to provide a new secure and robust route in complement to existing and future terrestrial long haul infrastructure.

This new submarine cable connection will bring numerous benefits to the connectivity ecosystem as we go through the key technical features:

  • The Olisipo submarine cable system will provide direct DC to DC Dark Fibre Connectivity, allowing for efficient and secure communication between the DCs, eliminating the need for additional routing and offering enhanced reliability and low latency.
  • With 96 unrepeated fibre pairs and an optimized optical design, the Olisipo submarine cable system will offer ultra-high-capacity transmission capabilities, with an ultra-high capacity and optimized optical design.
  • The Olisipo submarine cable system will utilize armoured cable and will be a buried subsea and land cable configuration. This design ensures DC entry point diversity and provides protection through Horizontal Directional Drilling (HDD) in Sines, the landing point.
  • The robust and diverse route design enhances the overall reliability and resilience of the cable system.

In addition to the Olisipo submarine cable system, the EllaLink system already in operation brings another diverse low latency route connecting Sines to Latin America.  

Sines: The Best Next Interconnection Hub in Europe

“Sines and Lisbon together will be able to compete with major European Hubs as both cities are being seen as a preferable gateway to Europe already."

Diego Matas

Recognizing the potential of Sines, EllaLink has identified it as the ideal location for the next interconnection hub in Europe.

Sines offers unique advantages that make it an attractive gateway to Europe. Its strategic location along the Portuguese coast provides a natural landing point for undersea cables, including the Olisipo submarine cable system. The availability of land in Sines provides ample space for developing data centres and other related infrastructure.

This generates opportunities for economic growth, job creation, and innovation in the region. Sines, with its strategic location, has the potential to become the next interconnection hub in Europe.

The presence of the Start Campus and its commitment to developing green energy ecosystems, including establishing a giant green data centre, further strengthen the region's position as a gateway to Europe.

Sines is poised to unlock new opportunities for economic growth, innovation, and the development of sustainable digital infrastructure. Sines, with its strategic location, available land, sustainable power sources, and water availability, has the potential to become the next interconnection hub in Europe.

The presence of the Start Campus and its commitment to developing green energy ecosystems, including the establishment of a green giant data center, further strengthens the region's position as a gateway to Europe. Sines is poised to unlock new opportunities for economic growth, innovation, and the development of sustainable digital infrastructure.

Moreover, Sines benefits from sustainable power sources, including renewable energy. Portugal has made significant investments in renewable energy, such as wind and solar power, making it a leading country in the clean energy transition.

Sines can leverage these sustainable power sources to meet the energy demands of data centres and other digital infrastructure.

This aligns with the growing demand for environmentally friendly solutions and positions Sines as an attractive location for companies seeking to establish sustainable operations.

The proximity of Sines to the ocean ensures abundant water availability, which is essential for cooling data centres and other industrial operations.

This proximity also enables the utilization of seawater for desalination, providing a potential solution to water scarcity issues that other regions may face.

Additionally, the maritime connection of Sines opens possibilities for future underwater research, exploration, and marine-related industries. Furthermore, the development of the Start Campus in Sines adds another layer of significance to the region.

Start Campus is a company dedicated to developing 100% green energy ecosystems. It is responsible for establishing a green giant data centre in Sines, Portugal.

This initiative aligns with the global shift towards sustainable practices and positions Sines as a pioneer in hosting environmentally friendly data centres. The Start Campus project further enhances the potential of

Sines as a hub for innovation, research, and development in the digital realm.

SubTelForum article
This article was featured on issue #131 of SubTel Forum, which explores Regional Systems in the submarine industry, featuring a Submarine Networks World '23 preview.

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