Wind turbine reliability data review and impacts on levelised cost of energy

Abstract

Reliability is critical to the design, operation, maintenance, and performance assessment and improvement of wind turbines (WTs). This paper systematically reviews publicly available reliability data for both onshore and offshore WTs and investigates the impacts of reliability on the cost of energy. WT failure rates and downtimes, broken down by subassembly, are collated from 18 publicly available databases including over 18 000 WTs, corresponding to over 90 000 turbine‐years. The data are classified based on the types of data collected (failure rate and stop rate) and by onshore and offshore populations. A comprehensive analysis is performed to investigate WT subassembly reliability data variations, identify critical subassemblies, compare onshore and offshore WT reliability, and understand possible sources of uncertainty. Large variations in both failure rates and downtimes are observed, and the skew in failure rate distribution implies that large databases with low failure rates, despite their diverse populations, are less uncertain than more targeted surveys, which are easily skewed by WT type failures. A model is presented to evaluate the levelised cost of energy as a function of WT failure rates and downtimes. A numerical study proves a strong and nonlinear relationship between WT reliability and operation and maintenance expenditure as well as annual energy production. Together with the cost analysis model, the findings can help WT operators identify the optimal degree of reliability improvement to minimise the levelised cost of energy.

Offshore wind turbine reliability and operational simulation under uncertainties

“…When simulating the operation of a new OWT, the turbine designers and developers (experts) can specify the likelihood that a component's reliability gets a value of its reliability in a reference reliability database. In addition, there are reviews on existing wind turbine reliability databases, 12,35 which investigate a large population of wind turbines and provide averages and ranges of failure rate and downtime. Data obtained from this large population can be used to estimate the reliability data uncertainty and probabilistic reliability matrices P f and P d .…”

“…Existing operational simulation models often assume a fixed failure rate or failure probability for the wind turbine. In the literature, reliability data are often collected and analysed for the turbines that have been operating for several years, 11,12 whereas the operational simulation needs to model and predict the operation of future OWTs. The lack of data problem has been an issue in the research community, which has been mentioned in previous studies.…”

“…The lack of data problem has been an issue in the research community, which has been mentioned in previous studies. 12,13 Particularly, operators and manufacturers tend to keep reliability and cost data for themselves, and there have been very few sources of offshore reliability data published. Data sometimes are published, but information about wind farm/wind turbine is commonly anonymised.…”

Maximum Power Extraction from Active Pitch Controlled Standalone Variable Speed Wind Turbine

“…(2) Power coefficient C p (λ ,β ) is given by the standard equation as in ( From [1], for a range of values of the pitch angle β, the characteristic function C P (λ, β) vs λ, is illustrated in Fig.1. From the graph it is found that C Pmax =0.36, for β = 2º and λ=9.6.…”

“…With remarkable advancements in power electronics, wind energy sector grows rapidly and becomes equally competitive to other types of renewable sources and also due to its reliability, cost effectiveness and quality of power [1]- [2]. Wind energy conversion system (WECS) consists of either horizontal axis or vertical axis wind turbines, either doubly fed induction generator (DFIG) or permanent magnet synchronous generator (PMSG) generators, control system, and interconnection apparatus [3].…”