Minneapolis start-up wants to install small-scale hydropower without the need for dams

Ted Christopher wants to capture the energy of flowing water, but without a dam.

"I grew up around rivers, and if you have ever been knee-deep in them, you know how powerful they are," said Christopher, who was born in La Crosse, Wis.

His Minneapolis-based start-up company, Verterra Energy Inc., has been working to develop a run-of-the-river turbine to generate electricity.

The aim is to produce steady, renewable power without damming rivers and causing ecological harm.

Christopher isn't the only entrepreneur focused on the hydrokinetic energy of flowing water and tides. Hydro Green Energy tested its technology in the Mississippi River at Hastings in 2009-11. Verdant Power Inc. has installed turbines in New York City's East River and tested models at the University of Minnesota's St. Anthony Falls Laboratory.

Verterra Energy's innovation is a horizontal design that Christopher says mostly avoids an old problem for water power — debris clogging the moving parts. The company has patented the design, built a scale model using a 3-D printer and tested it in waterways.

Christopher said the low-profile unit, called Volturnus, sits on the bottom of a river, canal or tidal area. As water flows toward the unit's tapered front, it is swept up and then downward, similar to water flowing over a submerged boulder. The idea is to deflect debris but capture energy.

"It creates a rise in the water that falls down through the turbine," he said. "So many other designs are adapted from wind turbine designs. … As we found out right away, there is so much debris. Even in man-made canals, there is garbage and branches. Logs fall in. So focusing on that, and the ability to operate around the clock, has been real important."

Christopher, who is not an engineer, said he began working on the concept after taking a break from playing in a rock band in 2008. He earlier attended Minnesota State University, Mankato but did not graduate.

To learn how to fabricate turbine parts, Christopher said he took a job in his second-cousin's San Diego machine shop in 2008. He worked there two years, learning 3-D engineering design, welding and fabrication, then moved back to Minnesota and incorporated Verterra, he said.

Verterra raised about $500,000 to develop the early test versions of Volturnus but now needs millions more over several years to build full-sized commercial products, he said.

Christopher said Verterra is looking for grant money and private investment. The goal, he said, is to build commercial products in two years.

The units would be deployed in rivers or canals in groups of five, each rated at 10,000 watts, he said. The total output would be enough to power 25 to 40 average homes, he added. Potential markets include remote areas in advanced or developing economies with high electricity rates because of reliance on diesel generators, he said.

Finding a market could be a challenge, as another run-of-the-river hydro company discovered.

Hydro Green Energy, based in Illinois and Texas, tested its submerged turbine technology at Hastings for about three years. Afterward, the company shifted focus from river-run deployment, like Verterra's approach, to larger installations at low-head dams without existing hydropower.

"One of the challenges we had was getting a price for the power we were selling that made the project economically viable," said Wayne Krouse, Hydro Green's founder, chairman and vice president of technology. " … That is part of the reason that we focused on low-head hydro at non-hydro dams because you get more energy for the same capital expenditure. The energy density is higher."

Christopher said he's confident that Verterra's small, low-profile, low-cost technology can make economic sense in run-of-the-river applications.

"We have a device that you can literally float in and deploy on the spot," he said. "There is no doubt that it is a challenging place to generate electricity, but that is why we have worked so hard on the fundamental problems and have a purpose-designed device."

David Shaffer • 612-673-7090 • @ShafferStrib