Micro Hydropower (Home Energy Part 17)
Humans have been tapping the power of flowing water for centuries. For example, in the early history of North America, New Englanders tapped the power of water flowing in streams that ran through their towns by installing small dams and water wheels. The water wheels in turn powered the machines of textile factories and grain mills. Hydropower continues to be the biggest source of renewable energy in the United States today. 
Hydroelectricity for the home is typically called micro hydro. In a micro hydro system, moving water turns a turbine. The turbine spins a generator or alternator that produces electricity. From there, like solar and wind you have your inverter and battery bank. Like solar and wind you have the option of being off grid, grid tied, or grid tied with a battery backup. 
For those fortunate to have a good site, hydro is really the renewable energy of choice. System component costs are much lower and watts per dollar return are much greater for hydro than for any other renewable source. Micro hydro, given the right site, can cost as little as a tenth of a PV system of comparable output. Battery banks also do not need to be quite as large as wind or solar systems given that the hydro system is constantly charging the batteries. No worries about windless cloudy days. Moreover, hydropower users often are able to energy consumptive appliances that would bankrupt a PV system. 
Micro hydro is typically installed in remote mountainous terrain in small streams or rivers near the home, the closer the better. 
3. Chiras, Dan., “The Homeowners Guide to Renewable Energy,” March 2006.