Eel Energy is a French marine energy startup developing one of the most conceptually distinctive approaches to tidal energy generation: a flexible undulating membrane that mimics the swimming motion of a marine eel or manta ray to extract kinetic energy from tidal currents. Based in Cherbourg (Normandy), a city that has become France’s emerging maritime energy hub, Eel Energy has been developing and testing its technology since 2012 — a decade of iterative design, sea trials, and engineering refinement that has brought the company to a 1 MW prototype deployment phase, with a Naval Group partnership providing manufacturing and engineering support.
Eel Energy’s technology occupies a distinct niche within tidal energy. The dominant technology in the sector — horizontal axis tidal turbines, essentially underwater versions of wind turbines — has been developed by companies like SIMEC Atlantis Energy (UK) and Sabella (France), with large rotary turbines deployed in channels like the Raz Blanchard (the most powerful tidal current in Europe, located off the Cotentin Peninsula near Cherbourg, which Eel Energy has also targeted). Eel Energy’s membrane-based approach potentially offers advantages in installation simplicity (no rotating machinery to maintain underwater), marine life interaction (softer contact than rotating blades), and performance in lower-speed tidal currents where rotary turbines are less efficient.
France 2030 Funding & Projects
Eel Energy has received Bpifrance support through ocean energy innovation programs, and participates in France 2030’s deep-sea and ocean energy technology development agenda. France’s Atlantic and Channel coastline, combined with its vast EEZ (Exclusive Economic Zone — the second-largest in the world), gives it a natural interest in marine energy technologies that can harvest the enormous tidal and wave energy resource off its coasts.
The Normandy region’s Cherbourg location — directly adjacent to the Raz Blanchard tidal site — provides Eel Energy with the world’s best test environment for tidal energy technology. Sea trials in the Raz Blanchard, where tidal currents regularly exceed 4 meters per second, stress-test tidal energy devices in conditions that compress years of normal-speed operation into much shorter periods.
Naval Group’s partnership is strategically significant. Naval Group — France’s naval defense contractor and submarine builder — has extensive capabilities in underwater engineering, marine materials science, and offshore manufacturing that are directly applicable to tidal energy device development. The collaboration gives Eel Energy access to engineering resources and manufacturing infrastructure that would be unavailable to a pure startup, and gives Naval Group exposure to marine energy technology that may have dual-use applications in naval deployments (silent power generation for acoustic-sensitive naval installations, for example).
France 2030’s ocean energy development objectives extend beyond tidal to wave energy, offshore wind, and the broader exploitation of France’s maritime EEZ. Eel Energy is part of a portfolio of French marine energy companies that includes Sabella (tidal turbines), Naval Energies (wave energy, now largely suspended), and the offshore wind developers (Engie, EDF, Parc du Banc de Guérande) that are installing France’s first large offshore wind farms.
Technology & Innovation
The Eel Energy membrane generates electricity through a fundamentally different mechanism than conventional tidal turbines. A flexible composite membrane, typically 10-15 meters long and 5-8 meters wide, is anchored to the seabed at its leading edge and free to oscillate at its trailing edge. As tidal current flows over and under the membrane, fluid dynamics forces cause it to oscillate in an undulating wave — essentially the same principle as a flag snapping in the wind, but in a controlled, energy-harvesting direction. Linear generators connected to the membrane convert this oscillation into electricity.
The efficiency potential of undulating membrane tidal generators has been demonstrated in laboratory and tank testing, with conversion efficiencies competitive with rotary turbines under optimal conditions. The sea trials at Brittany tidal sites since 2019 have generated operational data on device performance, structural loads, biofouling (the accumulation of marine organisms on underwater surfaces), and mooring behavior in realistic tidal conditions.
The 1 MW prototype represents a scale-up of approximately 10x from earlier demonstration devices. Achieving reliable continuous operation at 1 MW in the Raz Blanchard — managing the fatigue loads from millions of oscillation cycles, the biofouling challenge, and the maintenance requirements of underwater mechanical systems — is the engineering challenge that will determine whether Eel Energy’s technology can progress from prototype to commercial deployment.
The Naval Group partnership contributes particularly to the structural engineering of the membrane itself. Composite materials capable of withstanding 20+ years of continuous flexural fatigue in seawater, while maintaining the hydrodynamic profile required for energy extraction, represent a materials science challenge at the frontier of marine engineering.
Competitive Landscape
Marine tidal energy as a commercial sector is still in early development globally. The UK has the world’s most advanced tidal energy program, with SIMEC Atlantis Energy’s MeyGen array in the Pentland Firth (the first grid-connected tidal array to supply electricity to UK consumers) and a broader ecosystem of developers including Orbital Marine Power, Tidal Energy Ltd, and Nova Innovation. France’s Sabella has deployed a tidal turbine in the Fromveur Passage (Brittany) and is developing commercial projects.
Eel Energy’s competitive position versus horizontal axis turbines rests on its claimed advantages in low-speed tidal resource extraction and marine life interaction. The empirical evidence for these advantages from commercial-scale deployments is still accumulating, and the comparison is complicated by the fact that membrane and turbine approaches are at different stages of technology maturity.
The most significant competitive risk for Eel Energy is timeline: offshore wind is scaling rapidly and costs are falling, potentially foreclosing the economic case for tidal energy (which will always be more expensive than mature offshore wind on a per-MWh basis) before tidal technology reaches the scale required to compete. The value proposition for tidal energy rests on its complementarity with wind and solar — tidal currents are predictable and continuous in ways that wind and solar are not — and on the specific value of tidal energy in island and remote coastal communities where grid connection costs are high.
Investor Perspective
Eel Energy is a pre-commercial technology company at an early stage of the long journey from prototype to deployment at scale. The investment profile is characteristic of deep-tech ocean energy startups: high technology risk (will the membrane achieve commercial reliability?), long development timelines (10+ years from founding to commercial scale), and a final addressable market that is large but not imminent.
The Naval Group partnership provides partial validation and reduces execution risk on manufacturing, but does not reduce the fundamental challenge: demonstrating commercial viability at a cost of energy that is competitive with alternative renewable generation. France 2030’s support for ocean energy technologies is based on the diversification value of tidal energy and the option value of maintaining French industrial capability in a technology sector with long-term potential — a patient capital rationale appropriate for technologies at this stage.
Related Companies
- Naval Group — Manufacturing partner, defense-maritime industrial base
- Lhyfe Offshore — Offshore energy production, ocean energy ecosystem
- Engie — Offshore wind developer, ocean energy portfolio context
- IFREMER — Deep-sea research, marine energy assessment
- RTE France — Grid operator, marine energy grid connection