The water-energy nexus might sound like a secret organization run by a mysterious Bond villain, but in reality, it’s nothing to fear. Quite the contrary: Scientists believe that the relationship between water and energy, the world’s two most critical resources, could help save the planet.
That’s because the two resources are not just intertwined, but interdependent. Power generation requires huge volumes of water, while humans need energy to extract, transport and treat the water that we use. One company that knows all about the water-energy link is Atlanta-based Emrgy, which is harnessing the power of water flowing in irrigation channels — the man-made canals and waterways that crisscross arable land — to generate thousands of megawatt-hours of energy.
Emrgy’s “micro hydrokinetic” technology might sound mysterious, but what it amounts to is a “beautifully simple” miniature hydropower plant, says Nicolas Serrie, hydro product management leader at GE Renewable Energy, which has partnered with Emrgy to commercialize its products. Serrie describes a U-shaped concrete box smaller than a shipping container that houses two turbines that resemble large egg beaters. The module can be lowered into the flowing canals in farms that source water from reservoirs and rivers and channel it towards crop fields. “You can just rest the module on the canal bed and connect it up to the grid,” he says.
The kinetic energy of the water running in the canal does the rest. Water flowing at a rate above 1 meter per second turns the rotors, which activates a gearing and drive system that can generate as much as 10 kilowatts. Just a single concrete box containing two turbines can generate up to 80 megawatt-hours per year — equivalent to the consumption of seven U.S. households.
If canal operators space the modules every 50-100 meters along the waterway, they end up with a veritable fleet of small-scale hydropower plants. The only limit is the length of the canal itself. “You’re just capturing the kinetic energy of the water flowing in the canals,” Serrie says. A 100-strong force of modules — easily feasible on a long canal — would generate 1 megawatt, enough to supply nearly 1,000 households.
The small hydropower plants have another advantage: They do not require any civil engineering works and can be up and running in just a few hours. A semitrailer transports the concrete structures and a crane lifts the modules into the canal. They stay anchored to the canal floor by their own weight. Serrie says the grid connection kit varies according to the size of the project, but typically involves standard cables, power cabinets and circuit breakers. “It depends on the site, but we mostly expect to be using overhead cables.”
The plug-and-play modules are a low-risk win for canal owners. They can either sell the power generated by the turbines to the grid or consume the electricity themselves. Watering the crops could become a self-powered operation, Serrie says.
Power producers that operate large hydropower plants might also be interested in the product, because it allows them to squeeze extra megawatt hours out of upstream trickles. “These power producers sometimes operate canals to channel water toward their larger turbines,” Serrie explains.
Hydrokinetic generation also has almost zero intermittency issues. Apart from a couple of weeks of maintenance per year, the turbines can generate electricity around the clock; as long as the canal water keeps flowing, the rotors will keep spinning and generating power. “Above 70-80% capacity factor, the levelized costs of energy are on a par with solar and wind,” Serrie says.
GE will procure and also act as sales agent for the turbines in selected geographies. That arrangement offers the Atlanta-based company unparalleled economies of scale, global reach and speed to market. “This partnership combines cutting-edge technology and innovation with world-class procurement and sales capabilities,” says Emrgy CEO Emily Morris.
The turbines are already generating power for a U.S. Bureau of Reclamation-led project on the Denver Water-owned canal in Colorado. “We are [also] investigating opportunities in California and elsewhere in North America, but also in Latin America, the Philippines, Pakistan, Kyrgyzstan and many other places,” says Serrie. In fact, he’s always keeping his eyes peeled for opportunities.
“I live in Paris, which is hosting the Olympic Games in 2024 and looking at innovative ways to generate power for the grid,” Serrie says. “I’m always looking at the city’s flowing water and wondering about possibilities.”