Micro-hydropower plants could be the next big solution to the climate problem

A group of local high school students taking an environmental science class entered the pumping station in rural Mount Vernon in Washington state’s Skagit Valley, armed with notebooks and clipboards.

Project engineer Sam Shipp, who now works at the nearby Port of Everett, led the group to a room full of large pumps and water pipes.

“This is one of our pump stations,” he said. “We use about 600 miles of pipe, which is a lot of pipe. And we serve about 88,000 people.”

He explained how heavy all that water is. The pressure builds as it flows down from the 6 million-gallon tank to the outside—and it has to go somewhere.

Until recently, excess pressure would go into a valve and be released as heat. But in 2021, the Skagit Public Utility District partnered with InPipe Energy and purchased a special unit that converts excess energy into electricity.

“So now what we do is we run water through the blue pipe. And it goes in there and we have a special — this is a Singer valve — and that goes into the turbine.”

New technology based on old ideas

Shipp then shows it gradually building up after ignition, starting smoothly and increasing to a speed and frequency that match the pressure needed in the turbine. We hear a pop as it starts.

“It’s working now,” Shipp said. “We’re generating energy.”

He added that the device generates enough electricity to power 14 homes, and Skagit PUD sells that power to the utility company for about $12,000 a year.

Students have a lot of questions. They want to know: Was it risky? Was it controversial? How much did it cost and how quickly will it pay off?

Their curiosity is fueled in part by the fact that the utility plans to install a second micro-hydro plant that will generate twice as much power right next to their school. Some of the energy will cover Mount Vernon High’s electricity bill, the rest will power new electric vehicle chargers on site.

The teacher asks how this technology will fit in with intermittent renewable energy sources such as wind and solar power.

“That’s probably one of the best things about it,” Shipp said. “As long as the people of Mount Vernon are using the water, we’re generating power. So it’s working all the time. It’s also very predictable,” he said.

He said the concept is no different from an old-fashioned water wheel… and the technology is so simple that it took only about three days to install. The hardest part was getting the permit, which took several months.

Despite everything, Shipp told the class he saw no flaws.

He said the project costs were mostly covered by government grants for clean energy projects. And the utility expects to recoup the remaining $100,000 it invested in less than a decade.

Washington Governor Jay Inslee hailed the project as a successful clean energy investment made possible by the Climate Commitment Act.

After the tour, even the most skeptical students seemed to agree with me.

Samuel Solano, a member of the school’s debate team, admitted he was worried it might be risky because it was something new.

“Now that I know a little more, I feel like there’s no risk,” he said. “The cost is very… there is. But it’s more of a benefit. So the benefits outweigh the risk.”

His teacher, Rebecca Krueger, said she was excited to be able to plug her car into the school’s new EV chargers. But more importantly, she said, with all the controversy that usually surrounds large hydropower projects, it’s good to see an application that doesn’t seem to do any harm.

“It’s fantastic that energy that would be wasted on heat can be used at no other cost,” she said. “It’s great that we can use hydropower in a way that doesn’t harm salmon and our communities.”

I’m just starting to take off

So why has it taken so long to get more small hydropower projects like this up and running?

Brian Polagye, a professor of mechanical engineering at the University of Washington who specializes in hydropower, said microhydro is still a niche idea. And like any new technology, there is a bit of a chicken-and-egg problem in implementing it. That risk perception is diminishing as costs drop.

“Once you start showing that it’s not a risk, you’ll see the technology become more mainstream,” Polagye said.

He said these new forms of energy tend to start small and grow from there. Think about the first time you saw a solar panel — it was probably tiny and localized, he said — maybe it was on a solar-powered pocket calculator?

“That was an early application. Now we’re seeing solar everywhere, on a larger scale, and moving from residential to utility scale, so there’s always progress in technology,” Polagye said.

Gregg Semler, CEO of InPipe Energy, told KNKX his company has done a lot to make the technology more attractive, especially to water utilities, which are naturally conservative.

“We weren’t the first to have the idea. We were the first to create the solution,” Semler said. He said all of their turbines are installed in a bypass unit, with integrated software and sensors that make it safe and reliable.

“We tried to make it as easy as buying a valve. And we really simplified the technology so that people in the water business could really understand the solution, could see that other people were doing the exact same thing. This isn’t a one-time thing, this is a standard approach.”

One of the company’s current goals is to have at least one InPipe unit up and running in every state. They currently have projects in Washington, Oregon and California, with the first unit in Colorado coming online this month.

Semler said he sees unlimited potential for this type of renewable energy: not just in public water supplies, but anywhere there’s a water pipe with a pressure valve. Think energy-hungry industries like data server farms that use water for cooling. Or developing countries or war zones where new water infrastructure is still being built or rebuilt.

That aside, Polyagye said the next InPipe unit that Skagit PUD is installing at Mt. Vernon High School is a great use case. It will bring renewable energy infrastructure to rural areas that otherwise likely wouldn’t get it for a long time. He said the more people see it in action or hear about it, the more momentum there will be for this type of solution.

The utility said the new unit will be installed in the fall and should be ready to generate electricity in January.