The bioethanol yield of the macroalgae growing in OrbetelloLagoon has been estimated previously (Coppola, 2008). No site spe-cific data are available for the bioethanol yield of the algae growingin Køge Bay. However, the yield is assumed to be the same asLaminaria hyperborea (Horn et al., 2000) since this as well as thecollected species (Pilayella littoralis and Ectocarpus spp.) belong tothe Phaeophyceae class, commonly called brown algae.