Derivation of an energy source from the movement of the tides is the reason for considering a lagoon to trap seawater in Swansea Bay. But while the professional engineers are investigating the possibility of that development, this student group has undertaken a study of the viability of developing biological sources of energy in this restricted environment. Having concluded that farming microalgae would not be economic, they focused on macroalgae, selecting "Saccharina latissima" as the best species to use. They investigated methods of farming and harvesting it and went on to research anaerobic digestion and build their own prototype anaerobic digester. Finally, they investigated potential markets for their fuel. [This article was also written by the following students of Gower College, Swansea: Jamie Dougherty, Ruth Harvey, David Small, Alana Borthwick, Anna Bevan, Joshua Cox, and Jiaman Cheang.]