Ocean waves: Across the Earth
Why west coasts at 40-60 degrees get the biggest waves
What this tab covers How the resource varies with latitude, climate, terrain and geology: the richest and poorest regions and the leading countries.The richest wave climates lie between about 40 and 60 degrees latitude in both hemispheres, especially on west-facing coasts exposed to long ocean fetches. Enclosed and tropical seas have little wave power.
Prevailing westerly winds over long stretches of open ocean build the largest waves, so west coasts at 40 to 60 degrees north and south receive the most. Coasts on enclosed seas, the tropics and leeward (east) coasts receive far less.
Rich and poor regions
| Region | Resource | Level |
|---|---|---|
| Southern Indian Ocean (Kerguelen to southern Australia) | above 120 kW/m3 | high |
| Chile | 20 to 100 kW/m, rising with latitude3 | high |
| West coast of Ireland | 50 to 60 kW/m3 | high |
| Pacific north-west of the US and Canada | above 46 kW/m3 | high |
| New Zealand | Average about 40 kW/m (over 60 kW/m off the South Island)8 | high |
| Japan and Russian Bering Sea | 20 to 40 kW/m3 | medium |
| Enclosed seas: Baltic, Black Sea, Persian Gulf, Caribbean | 0.7 to 1.5 (Baltic), 1.6 to 6 (Black Sea), below 2 (Persian Gulf), below 8 (Caribbean) kW/m3 | low |
Wave power density falls sharply towards shore as waves lose energy over shallow seabeds, so the figure quoted for a country depends on the distance offshore at which it is measured. For Ireland, one review gives 50 to 60 kW/m for the west coast while a European project summary quotes an average of 35 kW/m; New Zealand and the US average about 40 and 32.5 kW/m respectively, and China only about 6 kW/m.
Within the United States, the theoretical resource is dominated by Alaska (2,000 TWh a year), followed by Hawaii (380) and California (320); the East and Gulf coasts have average wave power below the 8 kW/m threshold for a technical resource.
Sources
- Review of Wave Energy Resource Characterisation, Metrics, and Global Assessments (Ramos-Marin and Guedes Soares, Journal of Marine Science and Application 24, 53-75) Springer / Harbin Engineering University, 2025
- Wave energy around the world WEDUSEA project (EU Horizon Europe), 2024