NOVELTY - A power generation system comprises first and second electrode members, an electret coupled between the electrode members, a spatial region, and a volume of fluid.    USE - For generating electrical power.    ADVANTAGE - The inventive system is efficient in generating electrical power.    DETAILED DESCRIPTION - A power generation system comprises: a first electrode member (101) comprising a first region (102); a second electrode member (105) comprising a second region (106), the second electrode member being coupled to the first electrode member; an electret (107) coupled between the first electrode member and the second electrode member; a spatial region (113) provided between the first region of the first electrode member and the second region of the second electrode member; and a volume of fluid (111) adapted to move between the first region and the second region to cause a change in an electric field characteristic within a portion of the spatial region by the movement of at least a portion of the fluid within the portion of the spatial region to generate a change in voltage potential between the first electrode and the second electrode.    INDEPENDENT CLAIMS are also included for:    (a) a method for generating power, comprising providing a volume of fluid within a spatial region provided between a first region of a first electrode member and a second region of a second electrode member, the first region and the second region having an electret material coupled between the first region and the second region, moving at least a portion of the volume of fluid within a portion of the spatial region between the first region and the second region to cause a change in an electric field characteristic within the portion of the spatial region by at least the movement of at least the portion of the fluid, and generating a change in voltage potential between the first electrode and the second electrode from at least the change in the electric field characteristic caused by at least the movement of at least the portion of the fluid; and    (b) a device for detecting spatial movement of an entity, comprising a first electrode member comprising a first region, a second electrode member comprising a second region, the second electrode member being coupled to the first electrode member, an electret coupled between the first electrode member and the second electrode member, a spatial region provided between the first region of the first electrode member and the second region of the second electrode member, a volume of fluid adapted to move between the first region and the second region to cause a change in an electric field characteristic within a portion of the spatial region by the movement of at least a portion of the fluid within the portion of the spatial region, and an output device coupled between the first electrode and the second electrode, the output device being capable of transmitting one or more indications associated with the change in the electric field characteristic within the portion of the spatial volume region provided by the movement of at least a portion of the fluid within the portion of the spatial volume.    DESCRIPTION OF DRAWING(S) - The figure is a simplified diagram of an electret power generating device.    First electrode member (101)    First region (102)    Second electrode member (105)    Second region (106)    Electret (107)    Volume of fluid (111)    Spatial region (113)