Abstract: A power generation system produces electrical power from the flow of a fluid, such as water. Particularly, the fluid flow may be driven by evaporation of the fluid. A conduit for conveying the fluid is defined through a substrate includes at least one opening for allowing evaporation of the fluid. A dielectric substance is disposed within the conduit and impelled through the conduit by the evaporation of the fluid. The dielectric substance has a permittivity different from the permittivity of the fluid. A variable capacitor has a first plate and a second plate separated by the conduit. As such, the capacitance of the variable capacitor varies as the fluid and the dielectric substance flow between the plates. A charge pump circuit is electrically connected to the variable capacitor to store charge generated by the variable capacitor into a storage capacitor.