Appraisal Of Mass Production Costs For Wave Energy Devices

Abstract

The objective of this report is to express opinions on the order of possible costs obtainable by adopting a mass production approach to the construction of wave energy devices. From our investigations we believe the following points need to be emphasised. it is important to understand how a "cost" is derived and the relationship of the various elements within the total the designs will have to reconcile the best shape for energy absorption with less efficient but cheaper designs for production ultimately the structural cost of a device is the product of two elements: the mass in tonnes the manufacturing cost in £ per tonne The design development must aim to optimise this product to achieve the minimum cost. the eventual choice of the best device and material will need to consider all the factors in total cost. From the manufacturing point of view the key ratio which needs to be monitored is of course the cost/kw. For a device in a particular material this ratio is derived from the mass/output (tonnes/kw) and the cost/tonne (£/tonne) strategic planning will be required of both the manufacturing methods and facilities to suit the device design, again with particular attention to cost minimisation risk assessment should be included to see the effect of variances with the aim of reducing possible excesses cost reduction studies will be required during the detail design development stage and will be most successful if 'value analysis' type methods are used and emphasis placed on an iterative approach attacking the cost of all elements until a minimum figure is reached. As an example, prestressing materials make up half the material cost of the concrete Raft and are therefore a suitable target for cost reduction. This comment is relevant to all sections of the wave energy programme since the goal must be to find the minimum cost of power generation. When design and manufacturing methods can be reconciled, then significant savings in mass production costs in steel are possible. The concrete designs appear to have a reduced potential because of their size and jointing problems. We suggest that attention to manufacturing and launch out cost should be an ongoing activity once the conceptual design has been resolved. This should clarify design development programmes and by imposing disciplines prevent abort i ve development of non-productive ideas.