04/30/2026
France just activated the world's first commercial tidal lagoon power plant — a 12-kilometer seawall enclosing a section of the Atlantic coast that generates clean electricity from tidal rise and fall without placing any machinery directly in the open ocean.
The Brittany Tidal Lagoon encloses a 3,400-hectare water area behind a curved seawall south of Saint-Malo, incorporating 90 bidirectional turbines in the seawall structure itself. As tides rise, water flows inward through the turbines generating electricity. As tides fall, water flows outward through the same turbines in both directions across all four daily tidal cycles. The installation generates 270 megawatts continuously, powering 200,000 Breton homes regardless of weather.
The lagoon environment became a protected marine habitat within two years, with fish populations 340 percent higher inside than in equivalent open coastal areas nearby. Tidal lagoons can be built on coastlines worldwide with tidal ranges exceeding 5 meters, covering most temperate coastlines globally.
Source: EDF France, Bretagne Region Energy Authority, French Agency for Marine Protected Areas, 2025
