Construction of new biogas plant stations in Europe is a steadily growing trend, that is the reason why there is a need to find a proper alternative source of energy, which can replace traditional crops used for generation of energy. Microalgae represent a high potential of energy. When comparing microalgae with traditional crops, we can point out their high potential (oil content). During the production of biogas from traditional input materials, it is still a great potential of resulting organic waste – fermentation water (digestate), which can be used in a closed cycle in the intensive year-round cultivation of microalgae. Using the by-product (digestate) generated during the process of anaerobic digestion we can create a system for the cultivation of microalgae, which will in turn be used as a raw material for the biogas plant. Thanks to such application, the biogas plant can be more ‘self-sufficient’. This new innovative process can provide a prerequisite scale for increasing commercial use of bioenergy from microalgae. However, there is a need to find a reasonable way to produce the algae biomass to meet all ecological and economic requirements.