Energy from ocean waves

Giuseppe Passoni

POLITECNICO DI MILANO, Dipartimento di Elettronica Informazione e Bioingegneria

Thursday 27th April 2017

14:00:00

Aula Seminari 'Saleri' VI Piano MOX-Dipartimento di Matematica, Politecnico di Milano - Edificio 14

Electricity generation from clean, safe and sustainable energy sources is one of the main challenges of the 21th century. Ocean waves represent a vast untapped energy source, which could contribute to energy portfolio diversification and to economic growth in coastal regions. Compared to other renewable energy sources, like solar and wind energy, ocean wave power is characterized by higher energy density, less hour-to-hour variability, higher predictability and lower visual impact. Thanks to its huge potential, ocean energy technologies are currently drawing large interest, particularly in the European Union, which is at the forefront in this technological challenge. The European Commission is now implementing a policy framework to support ocean energy with the aim of installing 100 GW of wave and tidal energy capacity by 2050. Although wave energy technologies are still not economically competitive, a number of devices are starting to be rolled out for large scale development and several others are close to prototyping stage. In this context, the mild Mediterranean wave climate, compared to severe ocean climates, has hampered the research until the last few years. However, the interest in wave electricity production is now steadily increasing, particularly in Italy, as highly energetic Atlantic sites have been proven to be too extreme for devices survivability. In this talk, an overview of wave energy production will be given: from the physical concepts, to the assessment of the available resource, to the classification of the different types of wave energy converters (WECs). Then, recent research on wave energy exploitation in Italian seas will be presented. Starting from the feasibility of wave electricity production off the Italian coasts, some existing devices will be analyzed in terms of their performance at some of the most promising Italian locations. After proper rescaling to the Mediterranean wave climate, some of the existing technologies will result into attractive performance parameters, very close to those of more energetic wave climates. The importance of mathematical modeling in wave energy conversion will be illustrated taking the example of a promising point absorber, directly driven by a linear generator and specifically designed for mild wave climates. A key feature of the mathematical model is the coupling between hydrodynamic and electromagnetic kernel, which allows for taking into account the effect of hydrodynamic interactions on the power take off system, as a whole. Numerical models are also essential tools for assessing the overall performance of wave energy farms, i.e. when looking at the topology of arrays of devices with respect to their mutual interactions and power quality issues. contact: edie.miglio@polimi.it