While it is difficult to predict the flow of a stream and installing dams and generating hydropower can be environmentally degrading, the consistent flow in city water pipes presents a new frontier to be explored. City systems pump water daily at a fairly constant rate, which allows for a consistent flow of energy. It could also help safeguard cities’ hydropower sources against drought, Laura Wisland, senior energy analyst for the Union of Concerned Scientists, said. California, for instance, the historic four-year drought has lowered snowpack levels and depleted reservoirs, leading to a decline in hydropower production in the state. To account for this decline, the state shifted over to natural gas — a move that cost Californians $1.4 billion more for electricity between 2011 and 2014 than in typical years, according to a Pacific Institute report.
LucidEnergy tested out the project in Riverside with funding from the Department of Energy. Semler said he targeted Riverside because he knew the city was “really progressive in terms of energy efficiency.” In Riverside, the electricity generated from the pipes is used to power street lights. Portland’s project has a bit more heft to it: it produces, according to Gregg Semler, president and CEO of LucidEnergy, an average of 1,100 megawatt-hours of electricity a year. That’s enough for about 150 homes.
CREDIT: LUCID ENERGY
The system is installed in 50 feet of Portland water pipes, in sections where the water flows downward due to gravity. There are four sections of pipe, and each has a generator on top and a 42-inch turbine that spins as the water flows inside. According to the company, up to four units of the so-called LucidPipe can be installed “in a standard 40-foot” section of water pipe, and one mile of 42-inch diameter pipeline has the potential to produce more than 3 megawatts of electricity.
In Portland, the turbines were installed by replacing a section of existing pipe with Lucid’s pipe, and bolting that new pipe to the existing water system in a process “sort of like Legos,” Semler said. But he also said there’s a market for the technology in cities that are building new networks of water pipes — cities that may have more need of water due to an influx of residents, for instance. In those cities, the new sections of pipe could incorporate Lucid technology.
A lot of cities around the world are dealing with aging infrastructure and facing questions about how to replace it, said Amy Nagy, business development coordinator at the Portland Development Commission, which worked with Lucid to get the project off the ground in Portland. As cities go through and make improvements to their infrastructure, she said, they could be looking into whether they could get a dual purpose out of it.
“Water pipes deliver clean water, and LucidPipe adds an additional benefit of clean energy production, and producing revenue that the city can go back and reinvest,” she said.
CREDIT: SHERRI KAVEN/LUCID
Semler is already looking at expanding the system to other cities. Johannesburg, South Africa announced earlier this year that it would be employing the technology in its water system. And Semler said he’s gotten interest from cities in China, Brazil, Canada, and Mexico. A city interested in LucidPipe must first agree to adopt the system, and then go about securing private capital. Portland’s project cost about $1.7 million, which was paid for by private investors. It’s expected to produce $2 million worth of energy over 20 years. The revenue generated from the energy goes partly to Portland, partly to Lucid, and partly to the third-party investor, similar to solar panel leasing. “We see LucidPipe as a tool that water agencies can use to bring private capital into building out new water infrastructure projects, or to reduce operating costs,” he said.
“It’s not going to be generating as much power as a large scale solar farm,” she said, “but its part of a growing trend of taking advantage of existing infrasturcture. We have water pipes all over the country, so I think it just makes sense.”
Wisland said that one barrier that could prevent the system from being used in all water pipes is the fact that, with hydropower, there needs to be some pressure to move the water. So the pipes would be best used in gravity-fed systems, or other systems where there’s a possibility to create a little pressure.