Three ways of converting waste into energy or electricity are combined in this research. The first way concerns the energy conversion of wastewater organic compounds into hydrogen and electricity in biofuel cells. The second one is based on conversion of solar energy and organic compounds energy with using of inorganic photocathode in biofuel cell to produce hydrogen. The third way concerns the conversion of solar energy and inorganic waste gases on lipids of phototrophic microalgae. This combination of processes allows to convert different wastes into energy carriers and electricity.