Offshore floating vertical axis wind turbines: advantages, disadvantages, and dynamics modelling state of the art

The desire for more cost-effective wind farms has pushed for offshore projects to move further offshore and into deeper water depths: i.e. higher wind resources per unit area, ability to exploit new, wider sites (in particular for those countries with a limited shallow continental shelf), and partial/total elimination of visual impact. As fixed support structures become not economically viable in deeper waters, a transition to floating support structures is required. In this paper, the advantages and disadvantages of using vertical axis wind turbines (VAWTs) instead of horizontal axis wind turbines (HAWTs) on floating support structures are discussed. In recent years, a number of dynamics mathematical models only for floating HAWTs and their numerical implementation have been developed: research on floating VAWTs is just starting. In the present work, the dynamics of a floating VAWT system are illustrated and modelling approaches are discussed. These include aerodynamics, hydrodynamics, mooring line dynamics, structural dynamics and control system dynamics.