Offshore floating photovoltaic (OFPV) gain increasing attention in research and from project developers, due to the need for more renewable energy production. OFPV must be proven to be both technically and economically feasible to be a viable option in the offshore environment. S
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Offshore floating photovoltaic (OFPV) gain increasing attention in research and from project developers, due to the need for more renewable energy production. OFPV must be proven to be both technically and economically feasible to be a viable option in the offshore environment. Several incidents of floating PV systems have been observed for mainly inland applications of floating PV. These incidents, which occurred due to malfunction of the system, may induce several risks. Hence, the risks associated with OFPV technology should be assessed, as these risks may affect the feasibility and overall support of the developments. However, the current early stage of industrial development present a gap in the standards and guidelines, as well as the availability of data on all levels, to perform a risk assessment. The aim of this research is to outline the process of assessing technological risks resulting from loss of function (failure) of operating offshore floating photovoltaic systems. The general steps of risk assessment procedure are performed on an OFPV system in this thesis. In the initial step, a generalized OFPV system was modeled and analyzed, which includes the functional decomposition of the system to element-level and a quasi-static load analysis. Then, a preliminary hazard analysis (PHA) is performed to identify a broad scale of hazards and failure mechanisms of the OFPV system in its environment, followed by a qualitative failure mode and effect analysis (FMEA), to relate the identified hazards to the components of the OFPV system. Based on the FMEA and observed incidents, it was found that failures of the mooring lines are a major threat to floating PV systems. To determine the quantitative likelihood (probability) of OFPV system failure in relation to its components, a reliability analysis was performed with a fault tree analysis (FTA). The fault tree analysis includes sensitivity analysis with Birnbaum and Fussell-Vesely importance measures, to allocate the most important elements that contribute to failure of the system. Due to lack of probabilistic data for OFPV, element failure rates were estimated based on substitute data sources, which made the results are prone to data uncertainty. Therefore, structural reliability analysis is included, since this systematically includes uncertainties and correlations, by providing a probabilistic method to determine the failure probability of an element of the FTA. As mooring failures were identified as a major threat to OFPV, this element was analyzed in more detail. Initially, a limit state function was defined to describe the condition under which a mooring chain failure occurs, in terms of random load and resistance variables. The first order reliability method (FORM), including the Rackwitz-Fiessler transformation and the Rosenblatt transformation, was used to iteratively determine the probability of failure of the failure event. Metrics to assess the contribution of the random variables to the probability of failure are included with sensitivity factors. To determine the consequences of mooring failure, hypothetical accident scenarios were modeled with an event tree analysis (ETA). Finally, the results obtained from the previous steps of the risk assessment process are summarized and evaluated. The risk matrix and ALARP principle were introduced, to evaluate the acceptability of the risks. In addition, the contributors to uncertainty of the results are qualitatively assessed per step. This research presented the tasks and potential difficulties that an analyst may encounter when performing a risk assessment for an OFPV system. Guidelines and standards for risk assessment of OFPV are desirable to evaluate the technical and economic feasibility of several concepts, towards further industrial development of the technology. Moreover, this research did not intend to obtain actual quantitative results for a specific OFPV design or concept, mainly due to the lack of descriptive and probabilistic data. With further development of OFPV technology, and as more data becomes available, this research can serve as a foundation for future risk assessments of offshore floating photovoltaic systems.