2.4. Data and assumptionsThis study models a hypothetical bioethanol production whereharvested macroalgae from the Orbetello Lagoon and Køge Bay,respectively, are utilized in a bioethanol plant. We use site-specificdata when available or, otherwise, data based on literature (seeSupplementary data). All the collected data refer to one year ofaverage growth and processing of macroalgae, from January toDecember. This time period includes a representative cycle fromthe growth of macroalgae to the final production of bioethanol. Anexception is for the calculation of wave energy (Eq. (2)). Here, thetime interval considered is only 3 months as this is the actual periodwhen macroalgae are transported from the sea to the coast.All the particular calculations are shown in Supplementary data.Specifically, inputs of nutrients are from three sources (agriculture,wastewater and fish farming) but for all we assumed that the UEVof nutrients is the same as in fertilizers (Brandt-Williams, 2002),and this could represent an underestimation.