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Wind power is emerging as one of the most sustainable and low-cost options for energy production. Far-offshore floating wind turbines are attractive in view of exploiting high wind availability sites while minimizing environmental and landscape impact. In the last few years, some offshore floating wind farms were deployed in Northern Europe for technology validation, with very promising results. At present time, however, no offshore wind farm installations have been developed in the Mediterranean Sea. The aim of this work is to comprehensively model an offshore floating wind turbine and examine the behavior resulting from a wide spectrum of sea and wind states typical of the Mediterranean Sea. The flexible and accessible in-house model developed for this purpose is compared with the reference model FAST v8.16 for verifying its reliability. Then, a simulation campaign is carried out to estimate the wind turbine LCOE (Levelized Cost of Energy). Based on this, the best substructure is chosen and the convenience of the investment is evaluated.

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The energy innovation scenario sees hybrid wind-wave platforms as a promising technology for reducing the variability of the power output and for the minimization of the cost of offshore marine renewable installations. This article presents a model that describes the installation of a 5 MW wind turbine on a floating platform designed by Fincantieri and equipped with gyroscopic stabilization. The use of gyros allows for the delivery of platform stabilization by damping the wave and wind induced motion on the floater and at the same time producing extra power. Shetland Island was chosen as the reference site because of its particularly harsh weather. Final results show that the total production of power in moderate and medium climate conditions is considerable thanks to the installation of the gyro, together with a significant stabilization of the platform in terms of pitching angle and nacelle acceleration.

Computationally efficient simulation methods for wave energy converters (WECs) are useful in a variety of applications. The simulation task is particularly challenging when non-linearities are present in the WEC model. Using a Fourier projection of the system inputs and variables, harmonic balance (HB) is a computationally-efficient method to solve for the steady-state motion of a non-linear system, preserving an accurate representation of the non-linear effects. In previous work, HB has been used for the simulation of WECs with one degree of freedom (DoF). Here, HB is presented for WEC systems with an arbitrary number of DoFs. A non-linear, 2-DoF model of the ISWEC wave energy device is used as an example of application. The HB implementation of the ISWEC model is described in detail. Through numerical applications, chosen in both regular and irregular waves, general features of the HB method are exemplified, in particular the exponential convergence rate to the actual mathematical solution, and the sensitivity, in some cases, to the starting point of the HB algoritm.