Research on Offshore Installation Time Estimation Model for Floating Offshore Wind Farms

Abstract

　In this paper, to calculate the offshore installation cost more precisely during the development stage, a model is proposed to estimate the offshore installation time of floating offshore wind farm. The concept of this model is based on the CBS (Cost Breakdown Structure). It entails dividing offshore installation processes into seven main processes and their respective subprocesses. Thus, the total installation time can be estimated by summing up the operational time of seven processes. This estimation is achieved by determining eight model parameters which represent the efficiency of the installation process. Using the actual installation data from Japan and Europe projects, the model parameters of each project are analyzed and compared. To achieve the efficiency level of current European FOWT installation, the loading time, and the total time of pre-installation and ultimate holding force verification, both per mooring line, should be improved by twenty and five times, respectively, from the present levels. The velocity of cable trenching, and the time for connecting one-side of dynamic cable to the floater, should be improved by six and eight times from the present levels, respectively. Comparing the results of model parameters from actual installation data in Japan and Europe projects with that obtained from the model, the proposed model is validated in view of reproducing the process of offshore installation of floating offshore wind farms.