Wind energy use has been rapidly expanding worldwide in recent years. Driven by global decarbonization goals and energy security concerns, this growth is expected to continue. To achieve these targets, production costs must decrease, with operation and maintenance being major contributors. This paper reviews current and emerging technologies for monitoring wind turbine drivetrains and highlights key academic and industrial challenges that may hinder progress.

Hollow forging and air hardening ductile steel enable higher power densities for wind turbine main bearings units. For a 2.3 MW base load-optimised wind turbine, a 37 % increase in rotor shaft power density was achieved compared to a casted shaft. By using green, air hardening steel, hollow forging achieves a comparable global warming potential to casting. The economic viability of hollow forging is not given for the current surcharges found in small series production.

The production of green hydrogen from wind power is a promising approach to store energy from renewable energy sources. This work proposes a method to optimize the design of wind–hydrogen systems for onshore wind farms in order to achieve the lowest hydrogen cost. Therefore, the electrolyzer position and the optimal hydrogen transport mode are calculated specifically for a wind farm site. This results in a reduction of up to 10 % of the hydrogen production cost.

In the last decades, the size of wind turbines has continuously increased. The increasing rotor diameter results in higher loads acting on the main bearings of wind turbines. In this study, it is discussed how these loads can be estimated using accessible sensor signals and regression models. Therefore, measurement data has been acquired on a full-scale wind turbine test bench. It is shown that linear regression using displacement signals provides good accuracy in estimating main bearing loads.

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.