Extending the life of wind turbines is a preoccupation of our industry today. Ángela Angulo, TWI Ltd, tells PES how the TOWERPOWER project will help wind farm owners, operators and insurers collect extremely valuable data.
As EU energy policy calls for 20% of the EU’s 3,040 Terra Watt hours per year electricity demand to come from renewable sources by 20201,2,wind energy is the clear front running renewable energy source. Wind power installations have become the second largest contributor to installation of electricity capacity in the EU over the last decade3,4. Technological advancement in the design of wind turbines has allowed for the introduction of higher capacity turbines with towers exceeding 100 meters in height5. Although offshore wind has the potential to deliver the highest quantities of energy, it is not yet competitive with onshore wind mainly due to higher Operating & Maintenance (O&M) costs and the plausible risk of lower availability due to difficulties in obtaining access to the wind turbines during bad weather. This deters SMEs from exploiting the potential of the offshore wind based energy generation limiting their market. In light of this, technical and economical efforts should be directed at achieving the optimal structural performance over the life of the wind turbine. Avoiding failures is clearly the best way to limit O&M costs. Under normal operating conditions 30-40% of the maintenance costs are inspection related and failure costs related to structure failures do in some cases exceed 10% of the total overall maintenance costs (without taking into account the loss of production due to downtime). The deterioration processes, such as degradation, fatigue and corrosion, typically affect offshore structural systems. This damage decreases the system’s performance and increases the risk of failure, thus not fulfilling the established safety criteria.
Coordinated by the cluster Capenergies, the TOWERPOWER project (Figure 1) is a 3 year project co-financed by the European Commission within the 7th Framework Programme for Research and Development. Started in 2014, the project involves 12 partners from 8 EU countries, from the research to the industrial background (KCC,TDA ,WLB ,Tecopy, MONITEYE, CETIM ,Innora and TWI), including a number of asociations and clusters of SMEs (Capenergies, AIPnD, CYLSolar, AEE). The project objective is to create a Continuous Structural Monitoring (CSM) system that provides real-time structural analysis of the wind turbine tower structure through a novel integration of NDT techniques and advanced electronic communication. This potentially offers to drastically reduce the incidence of repairs/replacements and associated downtime. Although tower structure failures represent only 5% of total failures, they are responsible for more than 22% of the associated downtime. The outcome of the project will provide the wind farm owners, operators and the insurers with extremely valuable data to base decisions of extending the life of the wind turbines. This is in agreement with life-extension programs, recently pioneered by firms such as Nabla and turbine manufacturer Gamesa: with the installation of new and additional condition monitoring equipment around 90% of turbines can potentially carry on working for up to a decade beyond their original 20-year stated operational life6.
