Posters

Abstract

The increased penetration of renewables in the energy mix has led to more frequent periods with low or negative energy prices. In addition, operation of newly permitted wind farms is more strongly restricted to mitigate noise immission, shadow flicker or bird strikes. As a consequence, there is a strong increase in number of turbine curtailments in recent years. These curtailments are not limited to normal shutdowns as various wind speeds but also include frequent shifts in power modes to e.g. reduce noise or assist in stabilizing the grid. Although curtailments will lead to more hours of reduced power & standstill, which in theory is beneficial to the asset lifetime of the rotating components, there is a growing concern that frequent shutdowns will lead to increased fatigue damage and lower life time of mechanical and structural components; also potential for offshore substructures to accrue increased fatigue cycles from under-damped wave excitation. In contrast, asset owners tend to pursue lifetimes of 30-35 years which may be at risk with the current way turbines are operated.  This work will present the results of a study towards the impact of increased curtailments on the mechanical and structural components of onshore and offshore wind turbines based on real world examples. Results will be presented based on DNV’s large database of aero-elastic turbine models and in-house developed engineering software Site Suitability Tool. Several scenarios of curtailment operations will be studied.  The results of the study are aimed to serve as a guidance for owners and operators on key considerations and risks to mitigate in order to optimize the turbine operation and lifetime while complying with strict operational restrictions due to the environmental and electrical grid demands.