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DESCRIPTIONThis is a hydro power plant beneath the sea.
The development of Oyster A shallow water surging wave energy converterPresented by
INTODUCTION: THE objective of this paper is to give an introduction into wave
energy converters and their impact on power systems. Ocean wave energy is a renewable energy source with a large potential that may contribute to the worldwide increasing demand for power. High variability rates over both short and long time scales characterise this concentrated form of solar energy. The paper starts with some generalities about wave energy. Next, different types of wave energy conversion systems and examples of systems are discussed . Subsequently, the consequences of wave energy for the power systems will be shortly discussed. Finally, some conclusions will be drawn.
2.DESCRIPTION OF OYSTER TM In its present configuration OysterTM is essentially a
wave powered hydroelectric plant located at a nominal water depth of 12m which in many locations is relatively close to the shoreline. The system comprises a buoyant flap, 18m wide and 10m high, hinged at its base to a subframe which is pinned to the sea bed using tensioned anchors. The surge component in the waves forces the flap to oscillate which in turn compresses and extends two hydraulic cylinders mounted between the flap and the sub-frame which pumps water at high pressure through a pipeline back to the beach On the shore is a modified hydro-electric plant consisting of a Pelton wheel turbine driving a variable speed electrical generator coupled to a flywheel. shown in figure 1
3. HYDRODYNAMIC PERFORMANCE A time-domain numerical model of the Oyster hydrodynamics and PTO system has been developed using a second-order differential equation of the hydrodynamics and calibrated using results from the wave-tank model. Even though for computation speed and model simplicity the numerical model lacks the convolution integral or
additional modes typically seen in a hydrodynamic model, it has typically predicted the average power capture of Oyster to within 10% of that obtained with the wavetank experimentation. This is related to the relatively small magnitude of
4. Wave loading and survivability Survivability is the first and most important achievement
of any wave power system and consequently a substantial part of the test programme has been wave load testing. The objective was to ascertain the envelope of heave, surge and torque loads on the foundations of Oyster in both the extreme and the most frequently occurring seas. This data provided the input to both the foundation design and the fatigue analysis of the structure.
Two distinct sets of experiments were conducted to meet
different objectives. In the first set the envelope of the maximum loads was measured in a range of seas up to the most extreme seas which exist at a water depth of up to 12.4m. In the second set the most commonly occurring seas were used in order to provide data for the fatigue analysis of the structure.
5. Installation and recovery A major cost in marine renewables . This is more difficult
with devices attached to the sea bed. A key development with Oyster has been the design of a system which enables self installation and removal with the aid of small service vessels. As the flap and the sub-frame is an integral unit the flap provides the buoyancy to control the lowering of the subframe onto the sea bed foundation pads. Once the sub frame is locked into the clamping mechanisms the chambers in the flap are flooded sinking it onto the sea bed thus enabling divers to make the final connections next to a static object. When the installation is complete the flap is de-ballasted and the unit commences generation. The procedure is reversed for removal in the event of the requirement for major maintenance.
6. Future prospectswave energy.
In future this plan can establish in our country to save the
Than other countries India is the greatest country form with
three basins of sea. So it can establish with high number and can reducing in usage of resources and save energy for future generation.also high velocity flow.
We can also improve this process in our drainage canal and
MODEL OF OYSTER
7. Concluding remarks The Oyster wave power system is about to be demonstrated after an extensive research and development programme during the last six years. It is a wave powered hydroelectric plant in which a nearshore bottom hinged flap pumps water ashore to drive a Pelton wheel coupled to a generator. The most significant aspects are; One of the highest power to structural weight ratios relative to other systems under development. The development of an installation and removal system which can A modular
system in which individual flaps can be arranged in clusters pumping water to a single PTO system of up to 5MW capacity. The clusters can be combined in 10