The invention relates to hydraulic systems with constant delivery of fluid under pressure, using continuous balancing of pressures generated by liquid accumulated in a reservoir and coming from a collecting system. The system converts motion of liquid to operate individual high-pressure pumps, which pump water through water pipes from a natural body of water into the reservoir above sea level. A device for pressure conversion of the flow of water coming through the water duct from the reservoir in the consumption energy for the production of useful work. Tanks are at the bottom of the reservoir and connected to high-pressure pumps that pump water at high pressure, and which are equipped with pressure accumulators to normalize the pressure. A buffer vessel at the bottom of water duct, below the reservoir and above the sea level, is equipped with pressure accumulators.