Water power is staging a comeback thanks to Portland, Oregon-based Lucid Energy, which has been piloting a new technology that promises a new source for clean, renewable energy.

The technology taps into an existing infrastructure that crosses every major American municipality by placing turbines inside municipal water pipes. The turbines can be fitted for pipes ranging from 24” to 96”.

Water flowing downward through the pipes turns the turbines, generating cheap and clean electricity.

The system relies upon gravity rather than forced water current to activate the turbines, which operate without interrupting or disrupting the water-flow and without impacting water quality. By using kinetic energy latent to existing infrastructure, the system generates no waste or unintended negative environmental impacts and sensors embedded into the turbines enable quick detection of water leaks.

The technology has been used in Portland where the Portland Water Bureau installed four 42” turbines. After months of testing the system’s durability and smart technology sensors, the project was declared fully operational and began returning energy to the Portland municipal grid in January 2015.

The Portland project was the first in the United States to secure a Power Purchase Agreement with a local electrical utility for energy from in-pipe hydropower in a municipal water pipeline.

Lucid Energy and the Portland Water Bureau estimate the installation will generate 1.1GWh per year, or 1,100MWh, enough to power 150 homes.

“The Water Bureau’s involvement in this project was possible because of fortuitous timing. Lucid approached the city as the Water Bureau was already planning work for the Powell Butte Reservoir. The Lucid project, which required access to our pipe system and vault, coincided with work we already had planned for the Powell Butte project,” says a Portland Water Bureau spokesperson.

The LucidPipe installation is located in Portland’s Sabin HydroPark, one of more than half a dozen HydroParks in Portland. They all share the same concept to turn previously restricted water facilities into community gathering spaces, with other green features such as recycled park benches and picnic tables.

The United States Department of Energy provided Lucid Energy with more than $1m in Small Business Innovation Research (SBIR) grant funding to develop and field test the technology. The first pilot, a single-turbine system, was installed at Riverside Public Utilities in Riverside, California.

The costs of the Portland installation were funded entirely through private investment from a syndicate including Northwest Pipe, OurCrowd, Star Energy, and the Harbourton Fund. The electricity is sold to the local electrical utility, PGE, and the Portland Water Bureau shares in the revenue with the investors. Lucid Energy pays the Portland Water Bureau a rental fee based on the amount of electricity generated.

It is estimated that the project can provide as much as $2m worth of electricity over its first 20 years and has a projected usable life of up to 50 years.

What remains to be seen is if the combination of fortuitous timing, private investment, and public capital are necessary ingredients for LucidPipe technology to scale up and proliferate to other projects.

The Portland Water Bureau suggests that circumstances were unique.

“The project required access to our pipe at a location that allows the installation of the supporting vault structures. These structures encumber significant right-of-way, and are non-typical of current existing water facility structures. The Water Bureau does not expect to be able to replicate the circumstances that allowed for this partnership,” says the spokesperson.

Lucid Energy COO Bill Kelly is more optimistic about the technology’s future.

“We learned a tremendous amount from the Portland LucidPipe installation and we’re grateful for the Portland Water Bureau for allowing us to work with them. The neat thing is the LucidPipe system is consistently generating the energy we predicted. And now, as a company, we are focused on developing the next generation turbine design with the goal of reducing equipment costs by a factor of two. This will enhance the product’s suitability for a broader range of pipeline applications.”

This article originally appeared in IAPMO’s Official magazine.