I saw this interesting news report today. I thought this technology was pretty cool. In Portland most of our water comes from reservoirs that are at higher elevation than the city. Valves must be used to lower the pressure of the water as it goes down hill. This company, Lucid Energy, has a come up with a vertical axis turbine that lowers the pressure of the water a bit and generates electricity on the side. These pipe sections can be placed in series to lower the pressure as much as the utility needs. The unit in this article generates enough electricity for 150 homes (1100 MW a year).
http://www.kgw.com/news/business/Water-bureau-teams-up-with-energy-company-225277792.html
