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FMGC Cast Iron Shell System for Cost Efficient and Reliable Grid Connection

Aware of the sector’s challenges, FMGC has developed an innovative protecting and ballasting cast iron shell systems aiming at reducing cost and optimizing performance.

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Mechanical Tests Prove the Reliability of FMGC Protecting and Ballasting Shells for Subsea Cables

Today, the marine renewable energy sector is a vigorous market where innovation and product development are essential to ensure quality and cost reduction. Grid connections represent one of the most critical milestones of every MRE project. A reliable grid connection requires reliable cables. Therefore the protection and stabilization of the MRE subsea cables is of critical importance.

Aware of the sector’s challenges, FMGC has developed an innovative protecting and ballasting cast iron shell systems aiming at reducing cost and optimizing performance.

The Grid Connection – Challenges and Difficulties

With the rising support of the renewable energy sources by governments and power suppliers, the demand for submarine cables has been drastically increased. Many projects have evolved and replaced local generation on platforms with power from the mainland. Subsea cables are as well required to transport the energy from offshore wind farms to the shore.

Even a simple damage of the cable can have a negative impact on the electricity supply of an entire city but also an important impact on the project LCOE (levelized cost of energy). The protecting mechanism of the subsea cables should in the same time ensure their position in strong currents. Furthermore, when laying the cables, the entire process, the involved machines and the protecting and ballasting installation should meet strict environmental requirements and leave a minimized to no footprint.

A Revolutionary Solution – FMGC Protecting and Ballasting Shells

The main idea of the design of the FMGC protecting and ballasting shells for submarine cables is to combine the protecting, the stabilizing and the bend restrictor aspects in only one solution. This specific design contributes to an important cost reduction while:

  • Ensuring the installation of the shells on the laying vessel; 
  • Avoiding the need for other stabilization systems such as concrete mattress or rock dumping and the associated vessels; 
  • Limiting the potential damages on the cable by ensuring an important protection due to a higher thickness of the shells compared to other shells on the market; 
  • Providing tailor-made designs dedicated to a specific need or application.

As part of this innovative development FMGC has deeply studied the mechanical properties of the shells and the product behavior in operational conditions.

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The SEM-Rev Installation

FMGC has already achieved numerical and mechanical tests on different scales. These tests has confirmed the reliability and the robustness of the solution. In order to go deeply on its analysis and to bring the best expertise to its customers the company is conducting now some tests with the protecting and ballasting shells system in the waters of SEM-REV. SEM-REV is one of the MRE test sites, with a dedicated team based at Le Croisic. This facility is essential for developing a new industrial value chain in France.

This installation has several purposes:

  1. To validate the design by numerous simulations in operational conditions; 
  2. To confirm the data obtained during numerical simulation by achieving mechanical tests at scale one in tensile and bending;  
  3. To finalize the design and ensure to our future customers the quality and the reliability of the shells by monitoring their behaviors during 1 year in operational conditions; 
  4. To compare the stability performance of the shells according to their weight; 
  5. To analyze the lateral displacement of the weighted cable subjected to hydrodynamic forces.

The FMGC protecting and ballasting shells have been designed and manufactured in the context of the IBOCS consortium. Immersed for one year these tests are expecting to bring to FMGC important knowledges on the last meter caracterisation and will contribute to offer to its customer an important expertise.

Dedicated to innovation, FMGC is experienced in product development and quality assurance. We have been always eager to explore the limits of our products and finally create them limitless in order to suit every customer’s need.