Home / Industry / Energy /  The hidden hydropower potential in man-made waterways

Hydropower provides low-carbon electricity to millions of homes, but building dams on rivers can affect wildlife and the surrounding environment.

Now, a new study suggests there might be a significant amount of untapped hydropower potential in man-made waterways such as pipelines and irrigation canals, where the environmental concerns aren’t as great.

A report released by the U.S. Department of Energy’s Oak Ridge National Laboratory looked at water conduits across the nation that could be sources of hydropower, including agricultural canals and ditches, municipal and industrial water-supply pipelines, and wastewater-discharge systems—all places where water flows. It concluded that an extra 1.41 gigawatts of hydropower could be captured—enough to power more than a million homes—adding to the 530 megawatts of hydropower capacity in conduit projects currently in the U.S. (One gigawatt is equal to 1,000 megawatts.)

The report says that Western states like California, Colorado and Washington have the most opportunity, thanks to their water supplies and elevation drops (called “hydraulic head") where the power can be created and potentially captured.

In agricultural areas, conduit hydropower can be generated by installing turbines and generators on existing drops in ditches and irrigation canals. For municipal and industrial water supplies, turbines can be added to spots that would otherwise have pressure-reducing valves. Rather than reducing the water pressure and wasting it, the turbines would convert the water pressure into hydropower and regulate the pressure simultaneously. The energy can be used by the organization or company that collects it, or it can be sent to the power grid and sold.

The report notes that there are roughly 350 conduit projects online or in the works in the U.S. Shih-Chieh Kao, one of the lead authors of the report, estimates there are thousands of additional places where water flow could be converted into energy.

Dr. Kao says lack of awareness of conduit opportunities is one of the roadblocks, but so is the cost. Just because it’s possible to generate more hydropower doesn’t mean it makes financial sense—at least not yet. The turbines aren’t cheap.

Brett Bauer, general manager of Canyon Hydro, a company in Deming, Wash., near the U.S. border with Canada, that makes hydroelectric-turbine systems, says a unit that replaces a pressure reduction valve on a pipe can range from $90,000 to $750,000. Two projects the company has in the works now for agricultural conduits, he says, are in the $2 million to $3 million range.

Dr. Kao says his group’s objective wasn’t to determine whether a specific project makes financial sense, but rather to provide the Energy Department with the scope of the opportunity for policy-planning purposes.

Dr. Kao says the opportunity could be greater than what is laid out in the report, particularly in industrial sectors that have few existing conduit projects. He says information about municipal water-supply pipes and agricultural canals is typically more publicly available than information on industrial pipes and conduits.

“We believe there could be more," he says, “but we need to know more from an industry perspective."


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