Laura Castro-Santos

The importance of the activity costs in a shipyard: a case study for floating offshore wind platforms

ABSTRACT Floating offshore wind energy could be one alternative in exploiting ocean wind energy resources when there is high depth as, for instance, in Spain. Therefore, in order to develop this type of offshore energy, floating offshore platforms are needed. The aim of this article is to characterise the importance of the non-direct cost which is implied in the manufacturing of a floating platform. For this purpose, an activity-based costing method will be used. It will distribute direct labour, material and activity costs of the platform taking into account that they are constructed in a shipyard. The methodology has been applied to three different floating offshore wind platforms: semisubmersible, spar and tension leg platform. It introduces a new study concept into the manufacturing process of shipyards: activity costs. In this sense, some results indicate that activity costs are of great importance, representing more than 40% of the total costs.

Floating Offshore Wind Farms and Their Application in Galicia (NW Spain)

The main objective of this chapter is to explain a methodology for the calculation of the life-cycle costs of developing a floating offshore wind farm. In this context, two steps will be considered: defining the life-cycle phases of a floating offshore wind farm (conception and definition, design and development, manufacturing, installation, exploitation, and dismantling) and estimating costs for each phase, whose value will be established as constant or dependent on the particular point of the geography. The result of the tool will be a geo-referenced map of the total cost implied in the development of a floating offshore wind farm. The methodology will be applied to a particular location, Galicia (NW of Spain), where offshore depth and wind resource satisfy the necessary conditions for this type of offshore energy installation. The study will be developed for a semisubmersible floating offshore wind platform and a general offshore wind turbine of 5 MW. The farm will be composed of 21 offshore wind turbines, with a total power of 107 MW. Results show the cost maps of each defined phase and the total cost, which is from 366 to 946 M€ depending on the location (deep, distance from shore, among others), of the life-cycle of a floating offshore wind farm.

Cost Comparison of Three Floating Offshore Wind Platforms

ABSTRACT Castro-Santos, L. and Diaz-Casas, V. 2015. Cost comparison of three floating offshore wind platforms. This paper proposes a method to calculate the total cost of a floating offshore wind farm. The method is based on the phases of the life cycle of such a farm. Each phase is defined by a cost, the value of which is either a constant or a variable parameter depending on the characteristics of a particular region. The tool so developed results in a georeferenced map of the total cost implied in the development of a floating offshore wind farm. Additionally, this method is applied to a floating offshore wind farm located in Galicia (in northwest Spain), as well as the three most important types of floating platforms: semisubmersible, tensioned leg, and spar. This paper is novel in that it helps to estimate the economics of floating offshore wind farms. In this sense, this study is one of the first of its kind to calculate the various costs associated with these types of wind farms.