Well, this sounds like a good idea. Tons of water flow through the municipal pipelines of every major city. Lucid Energy thought like "Why not using this water flow to produce electricity?" and there it is! The LucidPipe Power System.
LucidPipe is a water pipe with a hydroelectric turbine inside. Flowing water with the force of gravity will spin four 42-inch (107-cm) turbines hooked to the turbine - Voila! Electricity for free. Portland is officially the latest city to adopt this technology.
The 200-kW Portland system was privately financed by Harbourton Alternative Energy, and its installation was completed late last December. It's now undergoing reliability and efficiency testing, which includes checking that its sensors and smart control system are working properly. It's scheduled to begin full capacity power generation by March.
Once up and running, it's expected to generate an average of 1,100 megawatt hours of energy per year, which is enough to power approximately 150 homes.
"Electricity for free": Never possible. This "free energy" is the pump energy (pressure to transport the water) put into the water. Flow passing this turbines will have fall in pressure....
At the end, it costs more energy then you get here, because of losses due to conversion from one kind of energy(flow x pressure) to eledtricity.