Currently, wind energy is the most mature renewable energy. With the current global environmental concern, it will continue to grow, as it is expected to play an important role in the future electricity market. Wind turbines have experienced a remarkable growth in a relatively short period of time, thus still needing to address important challenges. Regarding end-of-life scenarios of wind turbines and wind farms, decisions are complex, and the experiences to date are very limited. Aging wind farms face three options: lifetime extension, repowering or decommissioning. Thus, in order to reach a solution that increases the operator’s revenue, is legally feasible, and does not compromise safety of operators or citizens, end-of-life scenarios must be carefully reviewed to make a decision. The present Special Issue aims at investigating current trends, identifying existing challenges and awarding the latest research in lifetime extension of wind turbines, both for onshore and offshore wind farms. Topics of interest include but are not limited to:End-of-life issues of wind turbines; End-of-life issues of wind farms; Operations and maintenance; New operational strategies; Wind turbine assessment; Novel condition monitoring techniques; Novel health structural assessment; Safety and risks associated to lifetime extension; Influence of reliability and availability on lifetime extension; Analysis of the age of the wind turbine fleet in different locations, regions, countries, and/or geographical areas; Economic analyses (CAPEX, OPEX, COE, etc.) towards decision making; Application of new techniques, including Artificial Intelligence, Machine Learning or Big Data; Related review papers.
Keywords: lifetime extension; remaining useful life; reliability and availability; operations and maintenance; operational strategies; condition monitoring; asset management; safety and risks; decision making; OPEX.