Great potential with great challenges
Wave power is a concentrated form of renewable energy that comes from the friction between the water surface and the wind. The energy is built up by the wind to high levels on the open seas and then transported to locations closer to the shore, where it can be extracted. This makes wave power very area efficient and the average energy content changes more slowly and predictably compared to, for example, the wind.
But the high energy density also leads to occasionally extreme energy levels during storm conditions (up to a 100 times higher than during normal conditions). There are also large fluctuations in the energy content from wave to wave. The peak wave energy may be over 10 times larger than the average wave energy. In a wave energy converter, this results in low utilization or low energy capture if the captured energy is not sufficiently smoothed.
OHT´s technology shows very promising results to solve these challenges with the use of a simple and low cost accumulator in the form of a counterweight.
Wave energy resources
The worldwide wave power resource potential is huge. Future Energy Solutions highlight that the global power potential has been estimated to be around 8,000-80,000TWh/y (1-10TW), which is the same order of magnitude as world electrical energy consumption.
The best wave climates, with annual average power levels between 20-70 kW/m of wave front or higher, are found in the temperate zones (30-60 degrees latitude) where strong storms occur. However, attractive wave climates are also found within +30 degrees latitude where regular trade winds blow, the lower power levels being compensated by the smaller wave power variability.
Wave farm installations
Wave energy converters will be installed in large wave farms, approx. 100-200 MW or larger. If an already existing wind farm exists at a suitable location, there are considerable synergies when combining the technologies. Wave and wind power do not compete for the same resources and the wave energy is delayed compared to the wind energy. When combined, the power production of the used area and the utilization of the power transmission to the area are greatly increased.
