A renewable energy company in Portland has cities across the globe taking a closer look at their water pipes.
Lucid Energy has designed a hydropower system that draws power from drinking water as it makes its way to the tap. Its turbines are small enough to fit inside a city water pipe, and they tap the power of gravity as water flows through.
The company recently launched its first commercial project in Southeast Portland. It's now generating enough electricity to power 150 homes, and it's drawing the attention of government officials from California to Brazil, India and South Africa.
"We've just been inundated with interest all around the country and all around the world," said Lucid Energy CEO Gregg Semler. "Their first reaction is, 'This makes so much sense.'"
Earlier this summer, officials from the South African city of Johannesburg flew to town to see the project firsthand. To get to the pipe, they climbed down a ladder into a vault under the street in a Southeast Portland neighborhood. A big metal door in the pavement is one of the only signs the project is there.
"When you drive by, you don't see a thing," said Susan Priddy, director of operations for Lucid Energy. "You have no idea when you drive by that we're there running all day all night, generating energy."
Inside the vault, there's a huge royal blue pipe with four turbines inside. You can't see the four turbines, but Portland Water Bureau director Mike Stuhr likens them to the bulbs of an old-fashioned, hand-crank egg-beater.
"The technology is what I would call elegant from an engineering point of view," Stuhr said. "Basically that egg beater sits in a stream of water, and as the water flows by, the egg beater turns and turns the generator that's sitting on top of the pipe."
To Johannesburg Mayor Parks Tau, that egg beater has a lot of potential. His city is regularly forced to shut off the power to its residents when there's not enough electricity to meet demand. The Lucid system could generate much-needed energy in the pipes the city already uses to deliver water.
"The ability to harness energy out of what we're already using in the system makes it such a great prospect," he said. "And we've also looked at the pricing. It looks competitive in a country where we're currently facing energy supply problems."
Because they're nestled in water pipes, the Lucid Energy turbines don't have environmental impacts like hydroelectric dams in rivers. They tap the power of gravity, which means they don't burn anything or generate carbon emissions. And the system runs continuously – unlike solar panels and wind turbines. But there's a catch.
Charlie Allcock is the business director for Portland General Electric, the utility that buys the power coming out of the Lucid Energy water pipe. He said with four turbines in one pipe, the Lucid project in Portland has 172 kilowatts of capacity. That's a tiny fraction of the 200 megawatts Portland General Electric customers use in a year.
"We're going to need thousands of these to get to what we can generate using one of our typical dams," Allcock said. "The big question is whether you can find enough of these facilities. They don't get placed on every street corner or at every location."
Tau said he knows Johannesburg will need a lot of Lucid's little turbines to make up for his city's power shortages. Lucid Energy CEO Gregg Semler said that's part of his vision for the technology.
"Nobody wants small amounts of energy," Semler said. "So, we see ourselves having many of these nodes throughout a city's infrastructure that a city can produce power from."
There are limits to how and where Lucid Energy turbines will work. As Semler explained, they operate like a valve in gravity-fed water systems, relieving excess pressure in city water pipes and converting it into electricity. The system works best in cities with mountains, where gravity does the work of delivering water to cities and the Lucid Energy turbines can substitute for pressure-relieving valves.
"So instead of using a valve which basically burns off pressure that's embedded in the flow of the water, we use a turbine," Semler said.
In Portland, Stuhr said his agency isn't planning to put any more turbines in its water pipes. There aren't many places where the city wants turbines siphoning off the gravity-fed energy it uses to deliver water. And, he said, even if there were, his calculations show the turbines aren't likely to pay off. The cost of installing the pipes is so high and the cost of power is so low that the city could only make a 1 percent return on its investment.
"I think people think the idea is cool," Stuhr said. "They may not have done what we have to do, which is to analyze the economics of it and see just how cool it really is."
Stuhr noted that the system could pay off in places where power is more expensive. But even with Lucid Energy paying for the installation costs on the existing pipe, the city of Portland only stands to make a few thousand dollars a year off the system.
"It's not a large deal for the city," Stuhr said. "Technically it will bring your water bill down a tiny, tiny bit."