1,376,234 research outputs found

    Sea Clam Wave Energy Converter

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    After five years of research, the U.K. wave energy programme is nearing a point of decision on whether to progress towards full-scale testing or to continue on a research basis with reduced funding . The decision will be almost certainly based on the potential economics of wave energy and as a result, several device research teams are firming up on their designs prior to a cost assessment by consultants towards the end of this year. The chosen device or devices will probably have to produce electricity for the national grid at an estimated cost of less than 5 pence per unit at today's prices based on the costings of a 2 GW station located off the Outer Hebrides. Sea Energy Associates Limited and the Coventry (Lanchester) Polytechnic have been involved in the national wave energy programme since 1975, first, on the 1/lOth scale duck programme, (1, 2) and then more recently, on the second generation device known as the Clam (3). The Clam arose out of the need to redl'ce the high costs attributed to the first generation of wave energy devices and represented a new approach to the problem by an experienced team. By defining a sjmple concept which utilised components already identified as attractive, whilst at the same time avoiding known problem areas, the Clam quickly evolved into its 1979 design (3). This design has been tesled at 1/SOth scale in both natural and indoor waves with very satisfying results. Optimisation of the 1979 design has led to further design improvements which reduce the capital cost and increase the overall productivity. The final 1981 design should meet the cost criteria laid down and still retain some potential for further development. This paper discusses the merits of the Clam device and reviews the progress to date. of a floating spine breathe in response to wave forces. This causes air to be forced through self-rectifying turbines into and out of the hollow spine, allowing interchange of air between Clam bags. The randomness of sea wave patterns allows phased operation of the Clam elements, enabling the spine to act as a stable reference body. Typically a 1 OMW generating unit would feature ten Clam elements on a 27 5 m long spine, moored at an angle to tne waves, as illustrated on the cover

    Costing Annexe To Consultants Preliminary Report

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    The procedure for costing the Reference Designs of the Wave Power Devices is described in Chapter 3 of the Consultant's Preliminary Report. The detailed breakdown of the prices determined for each Device, together with tabulated comparisons of the data received from contractors, is given as an Appendix to this Cost Annexe. The following tabulated summaries cover the overall capital cost of the construction of a 200 MW installed capacity power station for each Device. They should not be taken outside the context of the Consultants Preliminary Report, in which the reservations to be placed both on the preliminary Reference Designs and on the preliminary costing exercise are clearly stated. During this study, time did not permit the exploration of the many avenues which are available for potential cost reduction both by redesign and the study of alternative construction procedures. In particular there has been no opportunity for discussion of the costing exercise with the Device Teams. However, a study of the cost breakdowns indicates areas in each Device where cost savings should be achieved by appropriate design changes or more detailed analysis

    Consultants Second Report, Volume 2: Technical Appraisal Of The Devices - Part 1

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    This report is the second general assessment prepared by the Consultants for the Wave Energy Steering Committee, the first having been submitted in August 1977. The primary objective of this report is to present to those responsible for directing the U.K. wave energy programme a full assessment of the devices now under development from the point of view of their potential for large scale implementation. The Consultants have attempted to assemble as firm a basis of factual information as is possible at this stage, to guide future decision making. The report is presented in three volumes, Volume 1 is an Executive Summary and includes the conclusions for the whole report. Volume 2 is the main body of the report and deals with the technical assessment, Volume 3 contains the costing information. The report assesses devices and not Device Teams. The Consultants have tried to present as fair a picture as possible of the devices as conceived by the Teams, and the Teams are of course the principal source of information. However, the text also refers to work from other sources. Every effort has been made to identify the inherent strengths and weaknesses of the devices independently of the work of the development Teams. It is recognised that at some stage certain devices will be dropped from the programme to allow concentration of effort on the more promising schemes. The Consultants have therefore given special prominence to those topics which are likely to have most influence on such decisions. An important limitation imposed on this report is its timing. It finds many Device Teams halfway through planned programmes of work, and in many areas detailed information necessary for a complete assessment is missing. In these areas attention is drawn to those factors which may later modify the stated conclusions on particular aspects of devices. However, the Consultants feel that it is now possible to reach reliable conclusions on many of the broader aspects of device development. Seven devices are included in the assessment. Some are much further advanced than others, and some are much more complex. The depths of the assessments carried out reflect these factors. Chapters 4 to 10 of this Volume present for each device a Reference Design which has been used as the basis of assessment. Table 1.1 sets out the key parameters of the Reference Designs. These designs have either been produced in their entirety by the Device Teams, or have been in part worked up by the Consultants in consultation with the Device Teams. The devices are described and assessed technically in terms of their material and workmanship content, and in terms of their annual average power output (termed 'productivity' in this report). For each device a brief summary of the fundamental mechanism of wave power extraction is given as general information, and for comparison between devices. There is a strong link between these fundamentals and the most important engineering problems, including costs. Except where it is directly applicable to the assessment, this report does not deal in any detail with the extensive programme of support work which has been initiated in areas of interest to all devices. This work is undertaken by Technical Advisory Groups (TAGS) and their work is documented in numerous separate reports

    The Availability Model: Consultant's Working Paper Number 32

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    This note describes some results obtained from the Consultant's Availability Model. They are based on preliminary data provided by Y-ard on the reliability of devices, and by Kennedy & Donkin on the transmission scheme. It is estimated that about 20% of the total energy output of a system might be lost due to repairs of its component. (This does not include lossed due to routine maintenance activities) . Assuming a value of 5p/kwh, this is equivalent to a cost of about £40m per annum for a 2gw station. station. There are several possible ways of reducing such losses, however , the most important being: - The reduction of failure rates by improvements in design, added redundancy in critical areas, or additional preventive maintenance. The use of larger numbers of repair crews, boats, etc .. - The reduction of live repair times in order to take advantage of the short weather windows which occur during the winter months, and/or the improvement of access to devices so that repair work can be carried out in more severe sea conditions. The trade-offs which exist between investing money in these areas and the resultant savings in energy losses are discussed, with the conclusion that the optimal solution for any scheme is likely to be one that reduces such losses to a minimum, by capital investment or high O+M expenditure. The appendices give an outline of the Availability Model and a revision of the sea-state information given in Working Paper 24, based on a more extensive analysis of the data

    Catching the Right Wave: Evaluating Wave Energy Resources and Potential Compatibility with Existing Marine and Coastal Uses

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    Many hope that ocean waves will be a source for clean, safe, reliable and affordable energy, yet wave energy conversion facilities may affect marine ecosystems through a variety of mechanisms, including competition with other human uses. We developed a decision-support tool to assist siting wave energy facilities, which allows the user to balance the need for profitability of the facilities with the need to minimize conflicts with other ocean uses. Our wave energy model quantifies harvestable wave energy and evaluates the net present value (NPV) of a wave energy facility based on a capital investment analysis. The model has a flexible framework and can be easily applied to wave energy projects at local, regional, and global scales. We applied the model and compatibility analysis on the west coast of Vancouver Island, British Columbia, Canada to provide information for ongoing marine spatial planning, including potential wave energy projects. In particular, we conducted a spatial overlap analysis with a variety of existing uses and ecological characteristics, and a quantitative compatibility analysis with commercial fisheries data. We found that wave power and harvestable wave energy gradually increase offshore as wave conditions intensify. However, areas with high economic potential for wave energy facilities were closer to cable landing points because of the cost of bringing energy ashore and thus in nearshore areas that support a number of different human uses. We show that the maximum combined economic benefit from wave energy and other uses is likely to be realized if wave energy facilities are sited in areas that maximize wave energy NPV and minimize conflict with existing ocean uses. Our tools will help decision-makers explore alternative locations for wave energy facilities by mapping expected wave energy NPV and helping to identify sites that provide maximal returns yet avoid spatial competition with existing ocean uses