Here, an unlikely underground source generates renewable energy
Portland, Oregon, has set a 20-year goal of generating $2 million worth of power from within its water system.
Parts of the system have been in place since 2015. Portland General Electric (PGE) customers are already drawing electricity from turbines within downward-sloping, 3.5-foot-wide water pipes. The revenue returned to the city offsets a portion of its water system expense.
Drinking water propels the small hydroelectric generators. There is no impact on fish migration or available water supplies. By relying on gravity, the renewable energy continues in all weather and all hours of the day.
 OPB.org (Oregon Public Broadcasting)