As a response to the actual environmental situation, the power sector shifted his focus to renewable sources to grant an affordable energy supply. However, the development of this sector, is facing, especially in Europe, some difficulties due to the limited available land area. One possible answer to this issue is to develop technologies that exploit marine resources that have great potential but are not yet entirely used. Among the different possibilities offered by the offshore environment, this thesis will focus on tidal energy, first as a stand-alone plant, then as the electricity source feeding an electrolyser for green hydrogen production. The proposed analysis is focused on both the economic side and the energy production one.