Wave energy

Wave energy has been considered being researched in the most extensive way in the world among the ocean energy. The wave-activated device patent, which was visible in literate, can be traced back to the year of 1799, what was proposed by the Jiladas in France. Before 1960s, the devices, which had been reported to implement, had at least more than 10, in the region of U.S, Canada, Australia, Italy, Spain, France and Japan. In early of 1960s, wave-activated generation device for buoys was successfully researched in Japan, which created the precedent for commercial utilization of wave energy. But large scale and scheduled research and development on wave energy were starting after the petroleum crisis in 1970s. Represented by England, U.S, Norway and Japan, comprehensive experimental research were conducted upon the wave energy conversion theory. Since 1980s, the utilization of wave energy entered into the stage of applied demonstration aiming to be practical and commercialized, and the design theory and construction method of wave-activated device were established. The demonstration and practical device of wave energy has been expanding more than 30 in the recent 20 years in the world. Table 2 shows the introduction of the major device. 

Table 2 Lists of Major Wave-activated Device in Each Country in the World

China is also one of the most important countries to develop the research of wave energy in the world. From the early of 1980s, research was conducted mainly on fixed and floating oscillating water column wave energy device and pendulum wave energy device. In 1995 GIEC achieved the successful research and development on symmetrical turbine wave power generation device for navigation buoys. After the development in more than 10 years, variable types of products ranging from 60W to 45W are obtained. After improvements, totally more than 600 sets are being utilized in the costal areas in China and exported to Japan. 

During the seven five-year period, the prototype wave power station was constructed and in 1990 succeeded in test run in Dawanshan island of Zhuhai city lead by GIEC and supported by former state science commission ocean department. The installed capacity of the power station was 3kW; the diameter for symmetrical wing turbine was 0.8m. During the eighth five-year period, 20kW on-shore power station, 5kW backward floating wave power station device and 8kW pendulum power station were constructed respectively and succeeded in test run by GIEC and the state ocean bureau Tianjin ocean technology institute. 

The 20kW on-shore wave power station was reconstructed on the basis of the former 3kW power station in Dawanshan Island. Due to the limit of budget in the construction of 3kW power station, the rooftop of air chamber was comparatively lower which impacted on the safety of the generation sets; and the installed capacity was also too lower. Therefore, based on the air chamber in the former power station with the width of 4m, depth of 3m and height of 5m (above the sea level), the transition chamber was built in the former generation room and an air duct with the height of 7.4m was also constructed above the transition chamber in order to allow the position of turbine generator sets 15m above the elevation which will greatly raise the safety and reliability of the power station. The 20kW variable-rotational-speed and constant-frequency generator sets jointly operated with diesel engine was employed which can work in a variable rotational speed ranging from 1000 to 2000 r/min. The diameter of symmetrical turbine was 1m. The total efficiency of the power station was 50% to 20%, which was higher to the standard of similar power station in foreign country. The max. output power measured was 18kW. The power station was shutdown after the test run of 3 months, due to the absent of uniform utility grid and the utility cannot stand the 24-hour-operation by diesel engine.

During the night five-year period, 100kW on-shore oscillating water column power station was constructed in Shanwei of Guangdong by GIEC under the support of State Ministry of Science and Technology. The air chamber of the power station was a cylindrical with the bottom diameter of 6.4m, the top diameter of 2.5m, the height above the sea of 10m, the draft of 4m. The trumpet incident wave wall was connected to the open sea. The draft of front wall was 2m, and the opening width was 6m. The power station will be installed with one set of 100kW asynchronous generator and connected to the utility grid, which was scheduled to produce electricity in 2000.

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