Process and Technology Status: Wave energy converters capture the energy contained in ocean waves and use it to generate electricity. There are three main categories; oscillating water columns that use trapped air pockets in a water column to drive a turbine; oscillating body converters that are floating or submerged devices using the wave motion (up/down, forwards/ backwards, side to side) to generate electricity; and overtopping converters that use reservoirs to create a head and subsequently drive turbines. On top of that, each category can be subdivided according to the technologies used to convert wave energy into pneumatic/mechanical energy (rotation/ translation), their power systems (air turbines, hydraulic turbines, hydraulic engines), their structures (fixed, floating, submerged), and their positioning within the ocean (shoreline, near shore, off shore). More than 100 pilot and demonstration projects exist throughout the world, but only a handful of technologies are close to commercialisation. The next step on the road to commercialisation is the demonstration of wave energy farms in the range of 10 megawatts (MW).
Cost projections: Due to the limited commercial experience, the estimates for levelised cost of electricity (LCOE) of wave energy technologies in 10 MW demonstration projects is in the range of EUR 330-630 per megawatt-hour (/ MWh). However, there is considerable scope for economies of scale and learning, with the projected LCOE for wave energy in 2030 estimated to be between EUR 113-226/MWh if deployment levels of more than 2 gigawatt (GW) are achieved. Considerable research is going into improvements of the power take-off systems, which account for 22% of project life costs. In particular, efficiency improvements in air turbines (currently 50-60% efficient) and hydraulic systems to dampen the variability, are being explored. Furthermore, synergies with other offshore industries such as oil, gas and wind, are being pursued to reduce the costs of installation, operation and maintenance, and mooring (accounting for 41% of project life costs).
Potential and Barriers: With 2% of the world’s 800 000 kilometre (km) of coastline exceeding a wave power density of 30 kilowatt per meter (kW/m), the estimated global technical potential is about 500 gigawatt electrical energy (GWe ) based on a conversion efficiency of 40F%. Large wave energy resources can be found across the globe. At the same time, the wave regimes vary substantially across the different regions, resulting in a 4 Wave Energy | Technology Brief wide variety of technologies. Consequently, there is a lack of industrial cohesion and limited supply chains for the variety of components required. For both planning and technology development purposes, synergies with other offshore industries would be advantageous to the wave energy industry. Similarly, there are opportunities to create more dedicated infrastructures – including ports and transmission grids – to support the installation and operation and maintenance of wave energy converters.