This graduate thesis describes the energy technology dating back to 1973 and has not yet been commercially implemented. Osmotic power plants as plants in which this energy technology is implemented are described from a techno-economic, ecological and historical point of view. The thesis presents the results of various assessments of the global potential of osmosis utilization for energy transformation. The issue of osmotic power plants has been addressed, and the focus of the problem has been placed on the membranes as the main obstacle to the commercial application of osmotic power plants. The mathematical modeling of the diffusion process through selectively permeable membranes is to a lesser extent shown in this paper, and some of the assumptions used to simplify the conceptualization of mathematical models are listed. The similarity of osmotic power plants and desalination plants of the seawater in inverse osmosis was also shown. Throughout the paper, guidelines are shown so that can serve for future research of this underdeveloped energy technology.