This modelling study shows that topographic trapped lee waves (TLWs) for modifying the flow behaviour and power output in offshore windfarms. We demonstrate that TLWs can substantially alter the windspeeds at individual wind turbines and effect the power output of the turbine and whole windfarm. The impact on windspeeds and power is dependent on which part of the TLW wave cycle interacts with the wind turbines and windfarm. Positive and negative impacts of TLWs on power output are observed.

Wind Energy will play a central role in the transition of our energy system to a carbon-free future. However, many underlying scientific issues remain to be resolved before wind can be deployed in the locations and applications needed for such large-scale ambitions. The Grand Challenges are the gaps in the science left behind during the rapid growth of wind energy. This article explains the breadth of the unfinished business and introduces ten articles that detail the research needs.

This paper presents the state-of-the-art technologies and development trends of wind turbine drivetrains – the energy conversion systems transferring the kinetic energy of the wind to electrical energy – in different stages of their life cycle: design, manufacturing, installation, operation, lifetime extension, decommissioning and recycling. The main aim of this article is to review the drivetrain technology development as well as to identify future challenges and research gaps.

We have presented a methodology for including multiple wind profile shapes in a wind resource description that are identified using a data-driven approach. These shapes go beyond the height range for which conventional wind profile relationships are developed. Moreover, they include non-monotonic shapes such as low-level jets. We demonstrated this methodology for an on- and offshore reference location using DOWA data and efficiently estimated the annual energy production of a pumping AWE system.