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Electrical energy can be produced from the chemical potential difference of two liquids with dissimilar salinities. This source of energy is known as salinity gradient power. In this paper, the theory, the technologies used to exploit the power, the major challenges, and their development trends are first presented. Then a modeling of fluxes across semi permeable membranes is proposed and validated. Next, an energy balance study is done in order to estimate the power potential for a given salinity gradient system. By applying this study to several rivers in Quebec, the salinity power gradient potential is estimated to 45 TWh/yr based on the minimal flow rate of each river. V C 2012 American Institute of Physics. [http://dx.

We present a theory for optimizing the thermodynamic efficiency of an electroosmotic (EO) pump with a large surface area highly charged nanoporous silica disk substrate. It was found that the optimum thermodynamic efficiency depends on the temperature, the silica zeta potential, the viscosity, the permittivity, the ion valency, the tortuosity of the nanoporous silica but mainly the effective normalized pore radius of the substrate scaled with respect to the Debye length. Using de-ionized water as the pumping liquid, the optimized EO pump generates a maximum flow rate of 13.6ml∕min at a pressure of 2kPa under an applied voltage of 150V. The power consumed by the pump is less than 0. 4W. The EO pump was designed to eliminate any bubble in the hydraulic circuit such that the pump can be operated continuously without significant degradation in the performance.