Abstract: Apparatus and method using solar power driven expansion of an electrolytic solution to force said solution through pores in an insulating plate. The pores' surface has fixed surface charge of one polarity. The velocities of the cations and anions through the pores differ because of the fixed surface charge and this produces an electrical charge separation, the streaming potential, as a source of electrical power. Energy absorption can span the full solar spectrum including infrared, visible and near ultraviolet wavelengths. This light is absorbed and degraded to thermal energy of the electrolytic solution for its expansion using (1) a light absorbing electrode contacting the electrolytic solution, (2) light absorbing molecules in the electrolytic solution or (3) light absorbing molecules in a polymeric matrix within the electrolytic solution.