Now why didn’t this occur to me?

We all know that moving water can turn turbines and produce electricity. That’s why we dam up lakes and construct run-of-river generating plants. But what about utilizing the most mundane source of all, city water pipelines?

Well, somebody finally thought of that.

No surprise that it happened in green-oriented Portland, Oregon, which has partnered with a company called Lucid Energy to become the first city in the nation to generate clean electricity from the water already flowing under its streets and through its pipes.

Portland has replaced a section of its existing water supply network with LucidPipes containing four 42-inch turbines. As water flows through the pipes, generators feed energy back into the city’s electrical grid.

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How it works: Water flows through LucidPipe’s lift-based turbine, which has been designed to maximize efficiency and energy generation while limiting the onset of bubble-forming cavitation. As water speeds increase, across a wide range, power production increases.

LucidPipe extracts very little head pressure per turbine, often 1–5 PSI. This allows the modular system to be placed in series, while ensuring uninterrupted water flow. LucidPipe does not need to be placed in a pressure transient zone or where extreme differential pressures are needed. In low-flow conditions, LucidPipe can deactivate itself.

The system was created with minimal impact on water operations in mind. It can be configured within a diverse array of pipe diameters, head pressures, and water velocities. Pipes can be installed in a day and grid-connected within a week. And the setup does more than provide electricity: sensors and a “smart” control system can monitor the overall condition of a city’s water supply network as well as assess the drinking quality of the water flowing through it.

The only drawback is that, in order to be cost- and energy-effective, LucidPipe’s generators must be installed where water flows downhill, without having to be pumped, as the energy necessary to pump the water would negate the subsequent energy captured.

First electricity in Portland was generated during system testing in late December 2014, with the beginning of full-capacity power generation slated for March 2015.

Granted, the payoff here is not exactly a game-changer. Once fully operational, the installation is expected to generate $2,000,000 worth of renewable energy capacity over 20 years, based on “an average of 1,100 megawatt hours of energy per year, enough electricity to power up to 150 homes,” according to the company.

So, even if not earthshaking, it still taps into a hitherto-unexploited source of very cheap electricity. We can use all of those we can get.

And if you just can’t wait for LucidPipes to come to your town, there are much smaller generators that aim to harness the energy in gushing home water, such as from gutters and downspouts, or flushing toilets. There’s even an invention that attempts to produce energy every time you turn on your tap. The amount of current to be derived from these devices is obviously very small, and applications are limited. But one of the exciting things about technology is that, once a basic principle is established, there’s no telling where and how far things might go.