Sea wave energy is being increasingly regarded in many countries as a major and promising resource. The paper deals with the development of wave energy utilization since the 1970s. Several topics are addressed: the characterization of the wave energy resource; theoretical background, with especial relevance to hydrodynamics of wave energy absorption and control; how a large range of devices kept being proposed and studied, and how such devices can be organized into classes; the conception, design, model-testing, construction and deployment into real sea of prototypes; and the development of specific equipment (air and water turbines, high-pressure hydraulics, linear electrical generators) and mooring systems.

Wave energy utilization: A review of the technologies

Oscillating-water-column wave energy converters and air turbines: A review

One of the most abundant energy sources exists in this world is the ocean wave energy. By far, it has shown to be the most clean, renewable, predicted energy and has raised the potential to compete with the current use of non-renewable energy sources. Recent research conducted on wave energy invention has opened a new dimension to slowly reduce the dependency on fossil fuel by introducing new technology on the renewable world but relatively lacking in economical aspect. This review brings the latest status on integration of wave energy device with other marine facilities, which is the breakwater structure that may possibly aid to cost sharing. Most researches done on this field highlighted countries experiencing rough sea condition and focused less on countries with medium wave condition as faced by the Asian continent. The potential for energy extraction and wave dissipation for medium wave condition will be discussed in this review by considering several aspects including reliability, effectiveness and performance. Finally, this review shows that the integration opens up a new dimension to acknowledge the technology harnessing ocean wave, especially for the Asian countries experiencing medium wave condition.

Wave energy device and breakwater integration: A review

Current status of self rectifying air turbines for wave energy conversion

Wave energy is substantial as a resource, and its potential to significantly contribute to the existing energy mix has been identified. However, the commercial utilization of wave energy is still very low. This paper reviewed the background of wave energy harvesting technology, its evolution, and the present status of the industry. By covering the theoretical formulations, wave resource characterization methods, hydrodynamics of wave interaction with the wave energy converter, and the power take-off and electrical systems, different challenges were identified and discussed. Solutions were suggested while discussing the challenges in order to increase awareness and investment in wave energy industry as a whole.

https://www.mdpi.com/1996-1073/11/5/1250/pdf

Ocean Wave Energy Converters: Status and Challenges

Mighty Whale is a floating wave power device based on the Oscillating Water Column (OWC) principle. It converts wave energy into electric energy, and produces a relatively calm sea area behind. The open sea tests were begun in September 1998 in Gokasho Bay, Nansei Town, Mie Prefecture. Measurements collected since then include performance data in typhoon seasons. This paper presents the measurements of wave energy absorption, floating body motion, and wave height dissipation. It is expected that these results will be useful in the design of offshore wave power devices in the future.

The Offshore Floating Type Wave Power Device ”Mighty Whale” Open Sea TestsPerformance of The Prototype –

This paper presents the characteristics of wave conditions, wave energy absorption, response of hull-motion and wave height dissipation based on the results of the open sea tests. 0.5–1.0m of significant wave height and 6–7 seconds of significant wave period appear the most predominant, and average wave energy is estimated 4.88kW/m around the test site. Average power output for the test is approximately 6kWh and the maximum total energy efficiency is around 15% that is ranging from 6–7 seconds of significant wave period. Slow drift oscillation of hull was observed motion in surge, sway and yaw and the value of its amplitude almost equal to estimated values in design stage. Then the mean value of transmission coefficient is about 0.8 under 8.0 seconds of significant wave period. We are considering that the results of the tests should be useful for optimum design of an offshore floating type wave power device.Copyright © 2002 by ASME

The Open Sea Tests of the Offshore Floating Type Wave Power Device “Mighty Whale”: Performance of the Prototype

The Offshore Floating Type Wave Power Device ”Mighty Whale” Open Sea Tests – Environmental Conditions –

PROBLEM TO BE SOLVED: To provide marine self-support equipment for a large-sized floating body structure capable of being stably moored even in a sea area having the deep depth of water and self-supporting energy such as required power and water. SOLUTION: The large-sized floating structure 10 installed on the sea is installed by being connected with a floating breakwater bank 20 in a breakwater sea area of the floating breakwater bank 20 moored and installed at the bottom of the sea and equipment for self-supporting required power is constituted by mounting power generation equipment using natural energy usable in the breakwater bank 20 and the large-sized floating body structure 10. As a result, a mooring rope for installing the large-sized structure 10 becomes unnecessary, the large-sized floating structure 10 can be installed in a breakwater sea area, the structure 10 can be installed in an offing having the deep depth of water, a vessel is capable of approaching and coming alongside the pier, and power is self-supported by mounting the power generation equipment using natural energy usable on the sea on the floating breakwater bank and the large-sized floating structure.

Marine self-support equipment for large-sized floating body structure

https://www.jstage.jst.go.jp/article/jjasnaoe1968/2001/190/2001_190_407/_pdf

Teruhisa Ogata

Papers

The Offshore Floating Type Wave Power Device ”Mighty Whale” Open Sea TestsPerformance of The Prototype –

The Open Sea Tests of the Offshore Floating Type Wave Power Device “Mighty Whale”: Performance of the Prototype

The Offshore Floating Type Wave Power Device ”Mighty Whale” Open Sea Tests – Environmental Conditions –

Marine self-support equipment for large-sized floating body structure

A Study on Environmental Conditions at the Test Site of the Offshore Floating Wave Power Devise “Mighty Whale”