To provide a self-supporting power generation system which combines photovoltaic power generation, excess nighttime power and an independent power plant for an emergency to solve the problems: 1) reduction of carbon dioxide and prevention of global warming by use of alternative energy, 2) assurance of electricity to sustain life in case of emergency or disaster, 3) power saving and elimination of power shortage by equalization of power by use of excess nighttime power, 4) contribution to districts by self-supporting power generation not relying on external power other than excess nighttime power, and 5) assurance of 10 years or more of durability and prevention of secondary environmental pollution by storage batteries.

A nighttime power combined photovoltaic power generation system comprises: a photovoltaic power generation apparatus, a power storage device 3 which compensates for shortage of electricity supply by the photovoltaic power generation apparatus, and a self-supporting power generation system equipped with a private power generation apparatus based on an internal combustion engine. The power storage device 3 is a lead acid battery which contains a noninonic dispersant in its electrolyte and incorporates a lead sulfur coating removal device which applies minute pulse currents of ±2 to ±5 V in voltage amplitude 4000 to 7000 times per second.