Multivariate analysis of the reliability, availability, and maintainability characterizations of a Spar–Buoy wave energy converter farm

Abstract

Quantitative reliability, availability, and maintainability (RAM) assessments are of fundamental importance at the early design stages, as well as planning and operation of marine renewable energy systems. This paper presents an RAM framework adaptable to different offshore renewable technologies, conceived to provide support in the choice of the device components and subsequent planning of the O&M strategies. A case study, characterizing a pilot farm of oscillating water column (OWC) wave energy converters (WECs), is illustrated together with the method used to obtain reliable estimate of its key performance indicators (KPIs). Based on a fixed feed-in-tariff for the project, economic figures are estimated, showing a direct relationship with the availability of the farm and the cost of maintenance interventions. Consequently, the probability distributions of the most relevant output variables are presented, and the mutual correlations between them investigated using principal components analysis (PCA) with the aim of discovering the relationships influencing the performance of the offshore farm. In this way, the contributions of the individual factors on the profitability of the project are quantified, and generic guidelines to support the decision-making process are derived. It is shown how this type of analysis provides important insights not only to ocean energy farm operators after the deployment of the devices, but also to device developers at the early design stage of wave energy concepts.

A stakeholder framework for evaluating the ‐ilities of autonomous behaviors in complex adaptive systems

“…We showed how maintainability can be defined using reliability, specifically how it applies to the wave glider thruster component throughout life cycle performance 68 . Future work suggested by Rinaldi requires a framework to analyze maintainability metrics and assess design sensitivities, and our research demonstrates that by performing DOE on autonomous behaviors for CASs to illustrate such sensitivities 69 …”

Incorporating stochastic operation and maintenance models into the techno-economic analysis of floating offshore wind farms

“…The second computational model used in this investigation is the UNEXE O&M tool, a performance characterisation model described in [13,22]. The validation is performed in [16] and further examples of its utilisation are presented in [23]. This model employs a time-domain approach based on the Markov Chain Monte Carlo technique [24][25][26], an established and widely used methodology for the simulation of O&M problems.…”

Life Cycle Assessment of a Point-Absorber Wave Energy Array

“…As such, three O&M scenarios were considered, each assuming bimonthly array inspections and 5-yearly planned maintenance activities. Instances of unplanned failures are varied from scenario to scenario, based on the commonly used assumption of two maintenance operations per year [12] (Scenario 1) and failure rate analysis of point absorber WECs in the literature [32,33] (Scenarios 2 & 3). The rate of annual instances of each of these operations per WEC are shown in Table 6.…”