A method for selectively generating electrical power by using waste water
gravity flow to generate electrical power includes attaching ends of a
water flow diversion pipe to a waste water pipe. At least some of the
waste water flowing by gravity through the waste water pipe is diverted
into and through the diversion pipe and back into the waste water pipe.
An electrical power generator is driven to generate electrical power in
response to the waste water flowing through the diversion pipe. At least
a portion of the electrical power generated by the at least one
electrical power generator is stored and can be tapped later to
supplement the output of the electrical power generator.