In earlier articles from the INFINITY project, we have explored how design choices shape environmental performance, how circularity can be integrated from the start, and how different parts of a wave energy system interact. As the technology moves closer to real-world application, attention is shifting towards how these systems perform over time, in practice and under real conditions.
Wave energy is often described as a promising source of renewable electricity. The potential is clear, but turning that potential into systems that operate reliably year after year remains a challenge. It is not only about capturing energy from waves, but also about ensuring that the technology can handle both extreme events and continuous operation over time.
Within the INFINITY project, this work is addressed through a structured focus on reliability and maintenance. The aim is to better understand how systems respond to different load conditions, and how this affects their lifetime and performance.
Pär Johannesson, Senior Researcher in Mechanical Reliability at RISE, leads the work on reliability and life monitoring. His contribution brings expertise in reliability engineering and statistical methods for analysing loads and lifetime.
Understanding loads over time
Wave energy devices operate under highly variable conditions. During storms, components are exposed to extreme loads that can involve complex, non-linear effects. At the same time, long-term reliability depends on how systems handle a wide range of load cases during normal operation.
– The wave energy devices are supposed to operate in a very harsh ocean environment. The device needs to survive not only the most severe storms but also have a long-term reliability in normal operation, says Pär Johannesson.
This creates two parallel challenges. On the one hand, extreme load cases must be understood and managed. On the other, it is necessary to assess how repeated and varying loads affect components over time.
Not all failures can be predicted. Some of the most difficult ones are those that have not been foreseen. For that reason, reliability work needs to be systematic and continuous, starting from early concept development and continuing through design and operation.
From monitoring to maintenance decisions
Monitoring plays a central role in this process. Data from operating systems can be used not only to identify deviations, but also to actively influence how the system behaves. For example, loads on critical components can be reduced during storms or when anomalies are detected. This makes it possible to balance performance and reliability in a more controlled way.
Reducing maintenance needs is closely linked to this approach. A well-designed structural health monitoring system makes it possible to combine planned maintenance with more responsive actions when needed. This helps reduce unnecessary interventions while still addressing emerging issues in time.
At system level, reliability depends on identifying and managing critical components. Since a system is limited by its weakest link, these components require particular attention in both design and maintenance. In some cases, redundancy can also be introduced to improve overall system reliability.
– The project also looks at specific components, such as ball screws used in the InfinityWEC system. Here, one of the key challenges is to develop models that capture the most important mechanisms affecting lifetime, without becoming too complex to use in practice, says Pär Johannesson.
Designing systems that can handle both extreme conditions and long-term use is still a shared challenge. But step by step, this work is helping move wave energy closer to something that works not just in theory, but in everyday operation.