The use of a variety of algae has been considered because of their direct and indirect biocatalytic effect on the splitting of water in H2 and O2 (Melis and Happe 2001; Hallenbeck and Benemann 2002; Nath and Das 2004; Savage et al. 2008). In spite of a nearly 70-year history of research, actual production of H2 by algal systems is still very low, about 2 g of H2 per square metre of culture area per day (Melis and Happe 2001), and H2 has to be withdrawn continually as the overall conversion of glucose into H2 is energetically only slightly favourable to H2 (Savage et al. 2008). At realistic solar irradiation, solar conversion efficiencies in optimized systems for direct and indirect biophotolysis seem to be in the order of 1% or lower, when pure cultures can be maintained (Hallenbeck and Benemann 2002; Yoon et al. 2006; Rupprecht et al. 2006; Burgess and Fernandez-Velasco 2007). And as pointed out before, the cumulative energy demand for algal H2 production is probably of the same order of magnitude as the energetic output, when the solar energy conversion efficiency does not exceed 1% (Burgess and Fernando-Velasco 2007).