The Mediterranean Sea is one of the most thoroughly studied water bodies in the world Its location and geopolitical importance since before the rise of the Roman Empire has stimulated study since the early eras of human civilisation. More recently, the Sea, like many of the world’s oceans, has attracted the attention of engineers considering the extraction of renewable energy.This paper outlines the complexity of the domains which underpinning modelling must consider. The Mediterranean Sea is a semi-closed water body connected to the Atlantic Ocean through the Strait of Gibraltar in its far western extremity.The main basin is divided into two principal sub-basins, which together cover a surface area of 2.5 × 10⁶ km², with a maximum measured depth of 5.1km. The Sea is characterised by its three distinct water masses: surface, intermediate and deep.These cover the whole Mediterranean basin and circulate independently.The general circulation pattern of the Sea has its own features and characteristics, which are described in this paper, drawing upon published research results.

This paper outlines present thinking on the determination of accessible tidal current resources within channels and other potentially exploitable locations. The fundamental principles behind tides and tidal currents are briefly discussed and the implications of temporal and spatial variations on the evaluation of the resources considered in the context of artificial energy exploitation. The thinking behind the flux approach to resource estimation is presented and an example based on the Pentland Firth is considered. The impact of energy extraction on the flow patterns is considered in both one and two dimensions and the principles required for three-dimensional analyses are presented in a generic form.