This Hydro electricity units use flowing water to spin a turbine connected to a generator. In a falling water system, water is accumulated in reservoirs created by dams, then released through conduits to apply pressure against the turbine blades to drive the generator. In a run-of-the-river system, the force of the river current applies the pressure to the turbine blades to produce electricity. In 2000, hydroelectric generation had the fourth largest share 7 percent of electricity production at 273 billion kWh. -290 Most home systems use conventional lead acid batteries for storage. They are cheap, and are deep cycle batteries, , they can be discharged completely and charged again many times. You cannot use automobile batteries in inverters, as they are only used to provide a large starting current, and are not meant to be discharged completely. The lead acid batteries have the disadvantage that they have to be replenished with distilled water every few months, and if it dries out, it cannot be repaired. However, they can provide the large surge currents which are required by many loads such as induction motors which may be connected to the system. "cylinder wind turbines " and "making electricity from water " (include "how to make a solar ovens", "home energy rating system certification ", "interesting facts about wind power ", "george soukup magnet motor ", "magnetic motor kits ", "How is electricity produced from wind ", The massive “generator-backup”, the high efficiency solar panel, and the charge controller. In fact, when you compare a solar generator to a gas generator, & Facts on solar powered cars )