Wave Energy

Wave Energy

Wave Energy Converters (WECs) are being developed all over the world under the regulation of carbon dioxide emissions to prevent global warming. The research of WEC is lead by Europe and the United States, and research is being vigorously carried out from small-scale model to commercial scale.

Carbon neutrality in 2050 have been declared by many countries. It requires a major shift from fossil fuels to renewable energies. Renewable energy will account for 27.3% of global power generation in 2019, of which hydropower will account for 15.9%, wind power 5.9%, solar power 2.8%, and biomass 2.2% ¹⁾. Wave energy was installed in the EU at 500kW in 2018, and a cumulative total of 2.9MW from 2010 to the present ²⁾.

Table 1 shows the classification of WEC, and Table 2 shows the WEC that has been tested in recent years. The devices shown in Table 2 are almost commercial scale and tested in grid connection. A few years later, a demonstration test of a farm consisting of 5-10 units will be scheduled, followed by a demonstration test of a large-scale commercial farm.

The survivability of the device in rough sea condition such as typhoons becomes a serious problem. Survival strategies differ depending on the device, but in general, the strategy is to stop power generation and pass off the wave power. On the other hand, some devices have a system that protects critical elements during a typhoon. Wavestar, for example, raises the float from the water, and Aquamarine Power's Oyster folds the flaps near the ocean floor to prevent damage to the device due to excessive waves. However, in most cases, it must be built with a structure that can withstand extreme waves. Small-scale models can be tested in tanks for large waves that occur once in a hundred years, but it is necessary to show that full-scale aircraft can withstand long-lasting storms in real waters. Therefore, after conducting the test at the actual sea test site for the prototype test, it will move to the original installation point.

Each country is also focusing on the development of this sea test site. The flagship is the European Marine Energy Center (EMEC) in Orkney, England, which has been in operation since 2004 ³⁾. It has four berths with grid-connected underwater power transmission facilities, and has support facilities such as data monitoring on the coast. EMEC is currently the benchmark test site for wave energy conversion device. Other sites are summarized in the Web GIS database created by IEA-OES ⁴⁾.

The European Technology and Innovation Platform for Ocean Energy (ETIP Ocean) has shown the issues and priority topics for research and development of ocean energy in the field of ocean energy ⁵⁾.

• Demonstration of ocean energy device to increase experience in real sea
• Demonstration of ocean energy pilot farm
• Improvement and demonstration of power extraction and control system
• Application of innovative materials
• Development of new wave energy device
• Improvement of tidal blade and rotor

• Advanced mooring and connection for floating ocean energy device
• Improvement of connection system for seafloor fixed ocean energy device

• Optimization of marine logistics and operations
• Instrumentation for condition monitoring and predictive maintenance

• Commercial development and demonstration of ocean energy in niche markets
• Quantification and demonstration of the benefits of the system scale of ocean energy

• Ocean observation and modeling that optimizes the design and operation of ocean energy device
• Open data repository of ocean energy

• Improving the environmental and socio-economic impacts of ocean energy
• Standardization and certification