PLATFORM REVIEW | Test-It – Renewable-powered autonomous buoy for at-sea equipment testing

GEPS Techno's Test-It buoy has been moored in the centre of Douarnenez Bay, Brittany, since July 2025, where it serves as a shared offshore testbed operated by the Celadon Sea Test Base association. The platform was towed from Saint-Nazaire and anchored on Celadon's permitted site, with GEPS Techno announcing the installation, carried out with Thomas Services Maritimes (TSM), on July 24, 2025.

The buoy is a platform measuring seven by four metres (23 by 13 feet), standing roughly six metres (20 feet) above the waterline and displacing 32 tonnes. It is held by two mooring lines to the seabed and has no physical connection to the shore. Onboard power comes from solar panels and a wind turbine working alongside a wave energy system, making the platform self-sufficient in energy.

This combination defines the platform's intended use. The platform is intended to host equipment that needs to be installed, powered and run in real marine conditions, without the cost of a shore cable or the emissions and refuelling burden of a diesel generator. GEPS Techno told Mer et Marine the platform, "will also support qualification tests for companies wishing to demonstrate the relevance of their solutions at sea in complete autonomy."

The company's own R&D sits alongside third-party work. GEPS Techno plans to use Test-It for its Energie Grands Fonds deep-sea energy programme, developed with Subsea 7.

Suitable for use with various sensors

Commercial use began at installation. Akrocean and its partner Biotope ran the first campaign, qualifying a DeTect avian radar and a Spoor video-based bird identification system for environmental monitoring around offshore wind projects.

The operating model splits responsibilities across four parties. GEPS Techno supplies the platform for the duration of each campaign. Celadon holds and manages the temporary occupation permit for the Douarnenez Bay site, acts as test operator and runs the buoy on behalf of its members. End users install and trial their equipment, and TSM handled the maritime deployment.

Celadon pools sea-trial resources for members working across defence, cybersecurity, maritime drones, marine renewables, offshore and ocean observation.

Renaudeau framed the buoy in terms of national capability. "This operation forms part of a desire to return to sovereignty, because we need better maritime surveillance capabilities," he told Le Télégramme. "The second development axis is the ecological transition, and in particular the development of offshore wind."

Built to withstand offshore operating conditions

Site selection is also part of the offering. Celadon already runs trials in the Rade de Brest and the Iroise Sea, and it chose Douarnenez Bay for Test-It because the bay stays sheltered while admitting more of the open-sea environment.

"Compared with the Rade de Brest, Douarnenez Bay has the advantage of remaining a sheltered zone but one more open to the elements of the marine environment (greater depths, incoming swell) and, secondly, of being less subject to competing maritime activities," the association said.

For developers, the practical payoff of an operational-environment trial is a step up the European Commission's nine-level Technology Readiness Level scale.

Demonstrating a system prototype at sea on a buoy of this kind supports a TRL 7 claim, one level above laboratory-relevant testing.