Risk assessment of marine energy projects

Abstract: The marine energy technologies (Wave Energy Converters, Tidal Energy Converters and floating wind turbines) are still at an early stage of development since no commercial array exists today. Their development has to face three main issues: the lack of feedback from the field, the great diversity of the existing technologies and the harsh marine environment. This thesis proposes a methodology and a support tool to assess the financial risks linked to a marine energy project based on the reliability of systems. The first part of the methodology is a reliability and maintainability assessment which is directly based on the classic FMECA (Failure Modes, Effects and Criticality Analysis) methodology. Then an Excel prediction tool was developed so as to assess the financial risks linked to a marine energy projects. This support tool is based on a Monte-Carlo method and relies on reliability data provided by the FMECA. The whole methodology developed is simple since no accurate data exists. Moreover, the support tool is designed so as to be adapted for a large variety of technologies and maintenance strategies. Finally, all the outputs of this support tool are quantitative. The main outputof the methodology is the LCOE (Levelized Cost Of Energy) since this value is a function of the CAPEX (CAPital EXpenditures), OPEX (OPerational EXpenditures) and the availability of the array. To prove the validity of the support tool, this one was tested on several existing WECs thanks to the input parameters provided by the developers. So as to keep the confidentiality of these data, it was decided to develop in this thesis one fictive example including two different WECs. In depth analysis and comparison of technologies are carried out: sensibility analysis on several parameters, optimization of the design for one technology (dry-mate connector Vs. wet-mate connector), optimization of the maintenance strategy for one technology. The strength of the methodology developed lies in the ability to really calculate both the OPEX and the availability of the array based on reliability data and without performing an exhaustive analysis of each system. However, the support tool is limited to 13 components per technology. So, if more components need to be taken into account, a functional analysis has to be done in order to gather components in functions. Moreover, because of the lack of data, the FMECA performed is simplified: failure rates are linked to components instead of failure modes.