From RenewableEnergyWorld.com (Russel Ray):
Researchers…have made significant progress in the development of low-head turbine technologies. Today, several companies are experimenting with technologies capable of generating power from small amounts of water that drop as little as five feet. These improvements mean the rushing water in irrigation canals can now be used to produce anywhere from 100 kW to 2 MW of clean energy.
Colorado has 3 million acres of irrigated land and is the nation’s third largest irrigation state, using more than 12 trillion gallons of water a day for irrigation, according to the U.S. Geological Survey. The potential power that could be wrung from the state’s irrigation canals is being studied by Colorado State University and engineering firm Applegate Group Inc. The study, funded by a $50,000 grant from the Colorado Department of Agriculture, will identify turbines that could generate power from irrigation water that drops between five feet and 30 feet. The study calls for a survey of roughly 250 ditch companies and individual ditch operators in Colorado. “We’re identifying where hydropower could be applied in those irrigation channels,” said Dan Zimmerie, a mechanical engineering professor at CSU. “There are good places in the irrigation system that will generate significant amounts of power. But we need to explore this issue with utilities, the approval process, interconnection standards and potential revenue.”[…]
“New low-head technologies have potential at sites previously considered unfeasible for hydro development because of a lack of significant elevation drop,” [Lindsay George, a water resource engineer at Applegate] said. “Irrigation canal drop and check structures, as well as existing diversion dams and outflows, may provide the drop necessary to implement these new low-head hydro technologies.”
More low-head hydro coverage here and here. More hydroelectric coverage here and here.