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Abstract

The issue of a flexible, robust, simple and directly industry-targeted method for the exploitation of sea wave energy, has long been the core of international, high quality, extensive research work.Current European assisted research at Daedalus Informatics, has managed to outline the successful candidate solution and offer a resume of a such experience in a simple, robust and commercially viable industrial prototype. An obvious further step was to expand into an integral, environmentally friendly solution of exploiting a complementary resource, as is wind, through the innovative design of a new breed of Wind energy converter. It became principally evident that such a general purpose hybrid RET installation should utilize compressed air as the thermodynamic medium. This approach provides the foundation for a multipurpose RET system suitable for a variety of applications besides electricity production -such as energy storage, desalinization, etc.


Introduction

The works of the present project aim at offering a new approach in the wave energy exploitation cycle, in complementary combination with a radically new wind energy driven air compressor. The common delivery of both devices is realized by intermediate conversion into compressed air and direct exploitation via conversion into electrical energy or other application. The methodology proposed offers a complete solution which, although innovative, follows a simple and robust design rational, is composed of easily available industrial components and is totally modular. Among other benefits, the method allows for closely related issues to become attractive, such as intermediate energy storage, complementarity with other renewable resources, etc.

Part of the current research work, was conducted under the activities of the JOULE II program (JOU2-CT940315, ELECTRICITY GENERATION BY PILOT REALIZATION OF A WAVE ENERGY CONVERTER). Our research team aims to present a brief introduction to the design characteristics of two discrete renewable energy exploitation devices (WECA and WECON), which may be either operated autonomously, or in tandem operation.


What is Wave Power

Although not strictly an issue of the current article, it is essential for the uninitiated reader to acquire some basic background of the overall philisophy, rational and technology infrastructure compiling the field of Wave Energy in the RET domain. Perhaps, the best way to attain this in a terse but vivid description, is going through the book of Mr DAVID ROSS which from, the following excerpts are cited below




Power from the Waves

David Michael Ross
Journalist and socialist, born March 6 1925; died August 9 2004

Incorporating and expanding on Energy from the waves by the same author

Oxford New York Tokyo OXFORD UNIVERSITY PRESS 1995



Preface

The story which follows is a moral tale, the triumph of good over bad. It takes us all the way from the development by a Japanese naval commander of a method of turning the energy of the waves into a stream of air, to the invention of an Edinburgh engineer who turned the capture of wave energy into a mechanical problem which he could solve.Then came the building in Norway, India and the Inner Hebrides of small stations on the shore. And on 2 August 1995 the launch took place of the first power station designed to stand alone on the seabed, away from the coast, generating smoke-free electricity from the renewable energy of the waves. It is a story which resembles that of the Pied Piper of Hamelin: the comfortable, established burghers summoned him to rid their city of the rats and then when the pest and their fear had gone they lost enthusiasm for paying him his due. It was much the same in Britain. In 1976, there was enthusiastic official backing as the government contemplated the prospect of an Arab oil boycott or at least a drastic rise in the price of oil (which happened).

The mood changed when it was discovered that the energy 'gap', forecast to arrive in the mid-199Os, was going to be delayed. The North Sea & Alaska oil reserves came on-stream. So the comfortable burghers snapped shut their cheque books, turned away, and tried to pretend that we could go on burning oil, coal and particularly gas without heed, and that global warming & growing pollution were not happening. We were even subjected to a propaganda campaign on behalf of 'clean gas', ignoring the millions of tonnes of carbon dioxide it adds to the atmosphere.

But why wave power? Because the sea covers more than 70 per cent of the world's surface. Engineers and scientists have discovered how to harvest its power in this generation. It can provide vast amounts of electricity without cooling towers, without pollution, without any risk of the 'fuel' running out, because the waves go on for ever... So why has it been largely ignored for so long? There are a mixt- ure of reasons. Money is the main one. But wave power is not about saving money: it is about saving the world. It was nuclear power that was supposed to be dirt cheap. And it is ironic that the British wave energy programme, which dominated the scene from 1976 until 1982, was masterminded from, of all places, Harwell, the home of nuclear power. It was assigned there on the grounds that both sources were 'alternatives'. And the work was given to the Energy Technology Support Unit (ETSU), a subsidiary of the Atomic Energy Authority (AEA). The years passed and ETSU rejected wave power as being hopelessly expensive, both now and in the future. And then came the OSPREY, to be based in Dounreay at the site of the fast breeder reactor, which had also been abandoned by the government. And it was the AEA, the parent body from Harwell, which was happy to offer its facilities, its people and its backing to wave power. 'Sweet are the uses of adversity, which like the toad, ugly and venomous, wears yet a precious jewel in his head', as Shakespeare wrote.


Introduction

On 29 April 1976, the Chief Scientist of the Department of Energy, Dr Walter Marshall, announced in London that the British Government was to spend just over 1 million on investigating the possibility of harvesting the energy of the waves. It was the beginning of a long struggle--against nature, against engineering and scientific problems, and against the established powers in the energy and political worlds. But wave energy has won through. In Norway and the Inner Hebrides, pioneering wave power stations have been built. Others are under construction now (1995) off Dounreay in the north of Europe and the Azores in the south. Others are working or in preparation in Japan, India, and Indonesia. They are only a start, small in capacity compared with what is to come. The ultimate prize is an inexhaustible source of non-polluting energy which has still to be achieved on a large scale. But the story so far is one of a triumph of science and engineering. The difficulties which had to be overcome were immense but the major problems have been solved. Progress since the early days, the mid -1970s, when the world was galvanised by a growing energy crisis, has been remarkable. We have learned an astonishing amount. We know how the waves behave and what has to be done to capture their elusive motion & turn it into useful energy. We know how to absorb a fluctuating supply and use it so that the lights do not go out or even flicker. Now what is needed are governments, utilities,and industries with the capital & the will to turn today's pioneering wave power devices into major energy providers, and start out seriously on the road to generating energy without the pollution that comes from burning gas, oil, coal, wood, and rubbish. There is no such thing as smoke-free smoke and the person who first rubbed two sticks together has a lot to answer for. The damage this does has been evident since the Industrial Revol- ution, when smoke turned central England into the black country. Only the descriptions vary. It started life as fog and became a pea-souper, then smog, then acid rain, global warming, and the greenhouse effect. We are aroused from time to time by a conference or a learned paper or an alarming symptom of environmental change. There is a moment of headline panic. Society recognizes that something must be done, but then loses interest because solutions are not easy. Nuclear power has tried to present itself as a clean alternative, but has proved unacceptable because of regular emissions of radio- activity into the atmosphere and the sea, and because there is no agreed method of dealing with nuclear waste or with power stations awaiting decommissioning; and the memory of Chernobyl and other nuclear accidents has meant that most societies have turned their backs on that option. But is wave energy the answer? It is not intended to be exclusive. For those countries blessed with vast,empty countryside, wind power may be a suitable renewable source. In equatorial regions, solar power may be the appropriate technology. There is also a good case to be made for tidal and other forms of hydroelectric power where the topography permits. But for many countries it is the waves that provide the best hope of developing a major energy source with no environmental objections to overcome. And the waves contain the amount of energy the world needs.

Anyone who has stood on the deck of a ship and watched the ceaseless, tireless stirring of the sea exploding in a useless waste of froth must have wondered whether we could capture that perpetual motion & turn it into something useful. To ignore it is a crime against nature. But how much useful energy is available? Is it a significant resource? The answer is that the waves contain about as much energy as the world is using today. To avoid any misunder- standing, let me repeat--energy, not just electricity. The best estimates, to which I shall return, put the figure for wave power at 1 terawatt (TW), the equivalent of the world's electricity production, from the waves arriving at the coast, and at 10 TW for the power in the open sea. That is comparable with the world's power consumption. A terawatt is 1000 gigawatt (GW) or 1000 000 megawatts (MW). For comparison, an industrialised country such as Britain has a grid capacity of around 50 GW. The question of cost was a secondary issue, raised largely at the start by the culture of the Central Electricity Generating Board (CEGB). It was beholden by Parliamentary statute to produce electri- city as economically as possible and this had become its credo. It dedicated much effort to proving that whatever method it had chosen was the cheapest. It argued that nuclear power was 'too cheap to meter' and used this argument as justification for spending vast amounts of money on it. And so when wave energy became a possibility, it naturally turned first to the question of cost and found a ready audience in governments which had watched in horror as the price of oil rose,first in response to the Arab-Israeli war of 1973. A barrel of oil which had cost $1.80 in 1970 rose to $2.90 by mid-1973, and to $11.65 by December of that year. It was later to reach $45 for brief periods, after the overthrow of the Shah of Iran in 1979. That was the sort of problem which transfixed governments. But the real crisis, which is still with us, is far worse than that: it is that we are consuming 65.5 million barrels of oil a day, the inheritance of countless millions of years, and using up coal and gas in a wild, irresponsible splurge. As to money, let us try to keep our minds on the fact that it was nuclear power that was supposed to be dirt cheap. Wave energy is not about saving money; it's about saving the world. The first consideration must remain: can we find ways of illuminat- ing and warming & empowering our lives without pollution and without running out of fuel? The 'energy gap', the excess of demand over supply which was accepted as a fact in the 1970s, and was due to paralyse the nation by the mid-1990s, remains a likely prospect although the date has slipped. But given the speed at which we are using up fossil fuels, and the collapse of the nuclear industry in most countries, the world is going to encounter a famine of useful energy within the lifetime of today's children if we do not change our pattern of production and consumption. We need depserately to develop renewable sources, however uncertain the need may appear at times. The question of cost is a luxury.

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