Nowadays, energy issue and environmental problem are two of the most crucial points to deal with. In 2018, less than the 15% of the sources of the total energy supply were renewable. Being so addicted to coal, oil and natural gas brought to an emission of 33.513 Mt of CO2 in that year[1]. For these reasons, a drastic change and a new strategy are needed forcing us to harvest energy from renewable sources. Due to the fact that the 71% of the Earth is water-covered, recovering the potential energy stored in the water is a suggested way forward. In the last years, there has been a growing interest in the so-called "Blue Energy", which is linked to all natural phenomena related to water that cause movement of energy.