Rhodopseudomonas palustris was grown under continuous irradiances of 36, 56, 75, 151, 320, 500, and 803 W m(-2), for a co-production of both bio-H-2 and biodiesel (lipids) using fed-batch conditions. The highest overall bio-H-2 produced [4.2 l(H-2) l(culture) (-1)] was achieved at 320 W m(-2), while the highest dry biomass (3.18 g l(-1)) was attained at 500 W m(-2). Dry biomass contained between 22 and 39% lipid. The total energy conversion efficiency was at its highest (6.9%) at 36 W m(-2).