Tidal energy, first used by seventh-century Irish monks for milling grain, offers predictable clean power but struggles with high costs. The first modern plant at La Rance, France, built in the 1960s, powers 225,000 people. Today, coastal regions seek tidal energy to balance wind and solar fluctuations.

Two main technologies exist: tidal range, using barrages like dams to capture high-low tide differences, and tidal stream, deploying underwater turbines in fast currents. While predictable, tidal power hasn't reached commercial scale. Elisa Obermann, chief executive of Marine Renewables Canada, notes high upfront costs and reliance on government subsidies.

Experts expect prices to drop as supply chains mature, similar to solar's trajectory. Environmental concerns persist, particularly for barrage projects disrupting migratory species like eel and salmon and intertidal habitats. Afryea Charles, founder of Ecolexica, says spatial planning can mitigate impacts.

Tidal energy can stabilize grids but remains limited to coastal areas with strong currents, serving as a complement rather than a predominant energy source.