Grids seek suppliers for extra-high-voltage underground cable systems
A new open qualification system for underground extra-high-voltage cable systems shows how utilities are reshaping long-term supplier pools and risk control.
A new open qualification system for underground extra-high-voltage cable systems shows how utilities are reshaping long-term supplier pools and risk control.
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On 18th November 2025, Elia Asset, within Elia Group, launched an Open Qualification System for Underground Cable Systems, seeking specialist suppliers to design, supply and install extra-high-voltage underground cables and associated accessories. The move underscores how power and infrastructure operators are leaning on standing qualification systems to manage risk, quality and compliance in technically demanding works.
The new arrangement is framed explicitly as an open qualification system for underground cable systems. Elia Group is looking for suppliers that can cover the full lifecycle of extra-high-voltage underground cables, from design through to supply and installation on site.
The notice highlights three core elements that applicants must be able to deliver:
Suppliers are directed to complete a qualification questionnaire and to request access via the Group's Ariba platform. While the detailed criteria are not set out in the notice, the emphasis on extra-high-voltage usage and a structured questionnaire suggests a strong focus on technical accuracy, safety and regulatory compliance.
By concentrating on underground cable systems rather than overhead lines, the system is clearly aimed at complex, civil-heavy projects where installation conditions, interfaces with existing assets and long-term reliability are central concerns. The requirement that accessories be tailored for extra-high-voltage use further narrows the field to manufacturers and installers accustomed to working at the top end of power infrastructure.
This is not Elia Group’s only move in this space. In July 2025, Elia Transmission Belgium sought expertise for the installation of underground cables between substations through a qualification system for high-voltage underground cable installation works, covering laying, earthworks, junction works and repairs. Together, these notices point to a systematic approach to vetting both the products and the on-site activities that make up underground cable projects.
The Elia scheme sits within a broader wave of qualification systems across European energy and infrastructure. In June 2025, EnBW Energie Baden-Württemberg AG created a qualification system for routing, planning and revision services on 110 kV high-voltage lines, linking it directly to its infrastructure expansion and modernisation goals.
At the same time, operators are using qualification to secure their supply of cables themselves. Hamburger Energienetze GmbH published a qualification system for the delivery and installation of cables, conductors and fittings in August 2025, covering various voltage categories under detailed technical specifications. The same month, Stromnetz Berlin GmbH set up an approval system for bidders to produce and deliver high-voltage, medium-voltage, low-voltage and telecommunication cables.
Further north, N1 A/S moved in October 2025 to establish a qualification system for various types of cables, explicitly to create a list of qualified suppliers that can be invited to tender for contracts as the need arises. Earlier, in July 2025, Norlys Holding A/S launched a broader qualification system for goods and services up to 20–0.4 kV, covering a wide range of products and services for distribution networks.
Network owners are also applying the model to construction works. In July 2025, Polskie Sieci Elektroenergetyczne Spółka Akcyjna introduced a Contractor Qualification System covering construction works on low- and high-voltage lines and power stations, with applications handled through its own procurement platform. In November 2025, ČEZ, a. s., set up a qualification system for suppliers involved in the construction and reconstruction of electrical stations and related infrastructure, aiming to build a portfolio of pre-vetted contractors for future public contracts.
On the materials side, ONTRAS Gastransport GmbH offers a gas-sector parallel. In June 2025 it launched a qualification system for companies manufacturing and supplying pipe material for high-pressure gas pipelines, emphasising technical capability and quality assurance and enabling procurement above EU thresholds.
Together, these notices show qualification systems becoming standard tools for operators managing rolling programmes of grid reinforcement, rather than one-off projects. Elia’s focus on extra-high-voltage underground cable systems fits squarely into that pattern.
Another notable trend is the extension of qualification logic from equipment into services and risk transfer. On 2nd July 2025, RTE Réseau de Transport d’Electricité issued a call to insurers through a qualification system for lead insurers on project insurance policies for its offshore and onshore construction works. Here, qualification is about financial strength and specialist project risk expertise rather than hardware.
Certification and engineering support are being pulled into similar schemes. In October 2025, 50Hertz Transmission GmbH announced a Supplier Qualification System for certification services for offshore converter platforms, covering design, manufacturing and installation certification under BSH standards. Around the same time, TenneT TSO GmbH set up an engineering services qualification system for civil engineering at substations, split into lots for greenfield support and planning with construction supervision.
Network monitoring and control are following. In July 2025, PREdistribuce, a.s., launched a qualification system for the supply and implementation of a SCADA dispatch control system to manage and monitor electricity distribution networks, including hardware, software and interfaces with existing data systems in Prague and Roztoky.
Even specialist investigations are now pre-qualified. On 10th July 2025, Energinet introduced a Supplier Qualification System for geoscience services, spanning geophysical and geotechnical work both onshore and offshore.
Alongside these, several buyers are using qualification systems to manage broad supplier bases across many product categories. REN - Redes Energéticas Nacionais, SGPS, S.A. has set up a supplier qualification system for multiple electrical infrastructure categories. E-REDES has gone further, republishing in November 2025 its Supplier Qualification Systems for various materials and, a week later, its annual supplier qualification notice covering prefabricated cabins, accessories, meters, lighting devices and protective equipment.
These examples show qualification systems evolving into digital, multi-year mechanisms that cover equipment, services and risk management in equal measure. Elia’s extra-high-voltage cable system fits comfortably within this shift.
For manufacturers, designers and installers of extra-high-voltage underground cable systems, Elia’s new scheme is another signal that access to major projects will increasingly run through structured qualification routes rather than standalone tenders.
Across the various notices, certain expectations recur. Infrabel’s qualification system for optical fibre cable installation, published in June 2025, stresses adherence to technical instructions, safety regulations and diverse installation methods. ONTRAS’s gas pipeline system highlights technical capability and quality assurance. Strasbourg Électricité Réseaux’ qualification system for HTA and BT electric works focuses on legal, financial and technical robustness.
Read together, suppliers looking at Elia’s extra-high-voltage underground cable system can reasonably expect attention to:
Some buyers are also pooling their qualification efforts. RETE FERROVIARIA ITALIANA S.p.A. maintains central qualification systems for infrastructure products, and FERROVIE EMILIA ROMAGNA SRL has signalled that it may rely on those systems with an indefinite duration. In Scandinavia, the TransQ joint qualification system serves multiple aviation, postal, rail and transport utilities, supporting both EU-procured and discretionary contracts. For suppliers, this points to fewer, but more demanding, qualification gateways that can open doors to several buyers at once.
The notice from Elia Asset does not specify anticipated contract values or project volumes, but by centring on extra-high-voltage underground cable systems it clearly targets high-specification, safety-critical works. The key questions now are how quickly the qualification list fills up, how it is refreshed over time, and how far other operators follow Elia in carving out dedicated systems for their most complex network assets.
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