Complexity and uncertainty have impacted wind power systems and their applications.Commercial wind power asset exhibits complex system behaviour due tostochastic loading characteristics of its installation context. However, differentstakeholders’ practices in whole life cycle processes try to treat multi-disciplinarycomplexity issues. Moreover, wind power system failures, stoppages, faults, supportdelays and human/organizational errors provide a clear proof of increasingthe needs for dependability. Therefore, dependability is considered as an aggregatetheory for RAMS (Reliability, Availability, Maintainability, Safety & Supportability)in order to cope with complex systems (i.e. physical systems and their assetmanagement systems) and their behaviour phenomenon. Consequently, to addresswind power practical problem as one of the modern complex and interdependentsystems, it is worth to enhance both the way of how we look at dependability andthe method of inquiry. Technical system complexity, system interdependency andsystem learn-ability are the main challenges within system dependability field.Therefore, this research work is done to integrate both terotechnology and systemsengineering methodologies to enhance systems dependability theory and practices.In particular, it focuses on three main aspects within systems dependability engineering:challenges, practitioners’ concepts and system-level methodologies.The research methodology of this thesis has utilised the mixed research approachof qualitative and quantitative methods to extract the empirical findings that arerequired to validate the dependability theory developments. Qualitative survey isused to identify the challenges of dependability theory within wind power applications.Grounded theory is used to define the practical understanding of windpower stakeholders concerning to dependability and asset management concepts.Case study is implemented to validate the systems dependability engineering, ascross edge theory of dependability and systems engineering. Moreover, the phenomenographymethod is used to capture the individual experiences and understandingof purposefully selected stakeholders, due to different site-specific circumstancesfor each wind farm.In general, the thesis contributes to the body of knowledge of five fields: dependability,terotechnology, asset management, systems engineering and wind energy.In particular, the focus of thesis contributes with retrospective review to be as referenceline for system dependability theory. Simultaneously, on basis of empiricalfindings, it contributes to be a pivot point for further enhancements from both theacademic contributions and industrial developments.