A method comprising providing a power train comprising a plurality of cells, each cell forming a hydraulic loop; producing a power train cycle comprising a controlled concentration-pressure loop wherein the concentration field: (a) osmotically induces a continuous and constant flow rate of substantially salt-free permeate flux throughout the power train; (b) maintains a salt concentration difference across the semipermeable membrane shared by the adjacent cells in the plurality of cells; (c) defines a salt concentration ratio within each cell that ensures a net positive power generation; and, (d) discharges the concentrated brine at the opposing end cell; and operating the power train under conditions effective to generate net positive power at an efficiency of 35% or more.