What Is Wave Power?

Wave power is the electrical energy generated by capturing the mechanical energy of ocean surface waves and converting it into grid-usable electricity. As a subset of marine renewable energy, wave power draws on the wind-driven motion of water at the sea surface, where energy accumulates across large fetch distances and is transported with relatively low dissipation compared to the generating wind field. Among renewable sources, ocean waves offer an energy density higher than wind or solar at equivalent areas, and their arrival at coastlines can be forecast with reasonable accuracy one to two days ahead using oceanographic numerical models.

Global assessments place the total theoretical wave energy resource in the range of 16,000 to 32,000 terawatt-hours per year, with recoverable potential considerably lower once engineering and environmental constraints are applied. The U.S. Department of Energy's ocean energy mapping program estimated more than 2,000 TWh per year of technically recoverable wave, tidal, and current energy along U.S. coastlines, enough to supply a substantial fraction of national electricity demand if commercially deployable devices were deployed across suitable sites.

Wave Resource Characteristics

The wave power resource is described in terms of significant wave height and energy period, two statistical parameters derived from spectral analysis of the sea surface. Power per unit width of wave crest, commonly measured in kilowatts per meter (kW/m), varies considerably by location: open-ocean sites along the western coasts of North America, Europe, and Australia can sustain annual mean values above 50 kW/m, while enclosed seas and equatorial regions tend toward 10 to 20 kW/m. The temporal variability of wave power follows a strongly seasonal pattern, with peak resources in winter months at mid-latitude sites, and exhibits intermittency on timescales from seconds to days. Unlike solar power, wave energy does not drop to zero at night, and its diurnal variability is smoother, but storms can produce power surges that exceed device rated capacity, requiring overload protection strategies in wave energy converter design.

Wave Energy in the Renewable Energy Portfolio

Wave power is classified alongside tidal, ocean thermal, and riverine hydrokinetic technologies under the broader category of marine and hydrokinetic (MHK) energy. As a renewable energy source, its principal advantages over wind and solar include higher energy density, greater predictability at multi-day timescales, and low visual impact from shore. Its principal challenges are the corrosive and mechanically demanding marine environment, the high capital cost of offshore installation and grid connection, and the relatively immature state of commercial device technology. The International Energy Agency projects that wave and tidal resources together could contribute meaningfully to decarbonized electricity systems in coastal nations, particularly where land constraints limit onshore wind and solar deployment.

Grid Integration and Resource Co-location

Combining wave power with offshore wind at shared infrastructure sites, known as hybrid offshore energy platforms, is a strategy to improve capacity utilization of expensive subsea cables and offshore substations. Because wave energy and wind energy are partially correlated, blending them can smooth the aggregate output variability seen at the point of grid connection. Wave-powered desalination, in which hydraulic pressure from wave motion drives reverse osmosis directly without generating AC electricity first, offers an alternative pathway particularly suited to water-stressed coastal and island communities. NREL's marine energy research covers resource assessment, technology performance modeling, and grid integration methods for wave and other ocean energy sources.

Applications

Wave power has applications across a range of sectors, including:

• Coastal and island grid electricity generation to reduce diesel dependence
• Offshore platform power supply for oil and gas, aquaculture, and research stations
• Seawater desalination using wave-driven hydraulic pressure
• Autonomous ocean sensor and monitoring instrument power supply
• Hybrid offshore energy installations paired with wind turbines