Tides: Across the Earth
A handful of funnel bays and racing straits
What this tab covers How the resource varies with latitude, climate, terrain and geology: the richest and poorest regions and the leading countries.Tidal energy is concentrated in a handful of funnel-shaped bays and fast tidal straits; most coastlines have too little range or current to be worth tapping.
Range depends on how a basin resonates with the tide, not on latitude: the open ocean rises by well under a metre, while some bays amplify it to over 14 m. Strong streams occur where water is squeezed between islands or headlands.
Rich and poor regions
| Region | Resource | Level |
|---|---|---|
| Bay of Fundy, Canada (Burntcoat Head, Minas Basin) | Mean spring tidal range 14.5 m, the world record9 | high |
| West coast of South Korea | Tidal range 9-14 m; site of the 254 MW Sihwa plant2 | high |
| Best sites worldwide | Range up to 17 m between high and low tide2 | high |
| Pentland Firth, Scotland (MeyGen) | 86 MW consented, potential 398 MW; four 1.5 MW turbines operating6 | high |
| Rance estuary, Brittany, France | 240 MW barrage over a 22 km2 basin3 | medium |
| Open deep ocean | About 1 TW dissipated, spread over most of the ocean area and not harvestable5 | low |
Largest operating tidal plants by country 2024 6
| Country | MW installed |
|---|---|
| South Korea (Sihwa) | 254 |
| France (La Rance) | 240 |
| United Kingdom (MeyGen, Phase 1) | 6 |
| Faroe Islands (Minesto Dragon 12) | 1.2 |
Good tidal range sites are few and well known: Fundy, the Severn estuary, Brittany, Korea's west coast and Russia's Penzhina Bay among them. Planned barrages in India, Korea, the Philippines and Russia once totalled about 115 GW but few were built. Tidal stream activity is concentrated in north-west Europe, notably Scotland, France and the Faroes, with China testing a megawatt-scale turbine that had produced over 4.5 GWh by the end of 2024.
Sources
- Tidal Energy: Technology Brief IRENA, 2014
- La Rance Tidal Barrage (Annex IV site page) Tethys, Pacific Northwest National Laboratory / OES-Environmental, 2024
- Significant dissipation of tidal energy in the deep ocean inferred from satellite altimeter data (Egbert and Ray, Nature 405) Nature (abstract via RePEc), 2000
- Renewables 2025 Global Status Report: Ocean power REN21, 2025
- Greatest tidal range Guinness World Records, 2024