Did you know that only 3% of US dams generate electricity? I know, right? All that nice water going to waste when it could be spinning turbines and generating zero emission electricity. Sad! Well, cheer up. The US Department of Energy has been exploring some low-cost hydropower solutions, and the agency just pumped another round of $1.5 million into one especially promising project, a cutting edge turbine from the company Natel Energy.
Fake Fish To Help Real Fish
The Energy Department is looking at existing, nonpowered dams as part of a broader hydropower initiative called HydroNEXT. The initiative also includes undeveloped streams or canals and pumped-storage as part of a road map for increasing the nation’s store of hydropower (including upgrades for existing hydro dams), but let’s zero in on that existing water infrastructure angle:
…A DOE assessment found that more than 90% of U.S. dams are used for services, such as regulating water supply and controlling inland navigation, and lack electricity-generating equipment. The assessment found that existing U.S.non-powered dams could provide up to 12 gigawatts (GW) of clean, renewable hydropower capacity from 50,000 suitable non-powered dams.
Talk about your low hanging fruit!
So, what’s the catch? Part of the problem is that it’s prohibitively expensive to retrofit existing dams with new turbines. Another issue is the environmental stewardship angle (shocker, right!), and that’s where the fake fish come in.
To take on the environmental angle, Natel’s arrangement with the Energy Department includes a partnership with a Pacific Northwest National Laboratory project called Sensor Fish. The little device is designed to “experience” the physical force of hydroelectric facilities the way an actual fish might.
Back in 2014 the Energy Department issued a Sensor Fish explainer, which notes that the device is a lot more complicated than it sounds. It was developed over the course of 15 years:
The Sensor Fish provides researchers with quick, reliable feedback on changes in pressure, acceleration, strain, turbulence, and other forces as the neutrally-buoyant device moves through hydro facilities — providing a close picture of what the fish would experience.
That’s a load of difference from conventional test processes, which consisted of computer modeling or sending live fish through the system:
Researchers can now use the Sensor Fish in combination with other available methods to collect better data and help improve the design of more fish-friendly turbines and hydropower projects, improving the survival rate of fish populations and lessening the chance of individual fish injuries.
A New Hydropower Life For Unpowered Dams
As for the new Natel Energy turbine, that caught the Energy Department’s eye last year with $225,000 in initial funding aimed at helping the company bring costs down and compress installation times. In Phase I, the company designed two versions of its LP turbine and was able to demonstrate a savings of 30% to 40% in the levelized cost of energy.
The basic idea is that the new turbine’s “low-head” modular design lends itself to low-cost installation on existing dams while reducing the need for expensive new infrastructure. Phase I was promising enough for the Energy Department to chip in another $1.5 million just a couple of days ago.
Some of that funding will go to the Sensor Fish tests, and some will be dedicated to a partnership with the flow specialists at Alden Research Laboratory. That part of the project will focus on shaking down the performance of the LP over a range of conditions.
Natel describes its signature turbine — the Linear Pelton hydroEngine, to be precise — as a turnkey, modular “water-to-wire system for low head hydro applications,” defined as between 10 and 60 feet. The modular units are highly scalable, from 25 kW to2000 kW.
Here’s the rundown from Natel:
The Linear Pelton hydroEngine employs a unique linear drivetrain with two parallel shafts and carbon fiber belts between these hafts to make a horizontal loop. Cups analogous to Pelton turbine cups are mounted by cross bars on the belts so that the cups make two parallel rows outboard of the belt. A unique, flat nozzle projects flow from the center out to the two rows of cups. Flow is converted to force in the belts much like Pelton cups react with the water stream.
If this is sounding like a super high tech water wheel, you’re on the right track.
The infrastructure savings comes in here:
…the hydroEngine sits above tail water, greatly reducing civil cost considerations, and does not require a draft tube….The technology utilizes the highly efficient fluid mechanics of a Pelton-style bucket on a linear power train, and removes the need for a draft tube, stators, wicket gates, or stay vanes.
Ease of maintenance is another consideration:
…the modular design of the hydroEngine ensures easy maintenance and repair: the hydroEngine’s drivetrain is easily accessible by opening the “hood” of the casing and is mounted on an extractable cassette that can be removed from the engine case.
No wonder the Energy Department is interested. According to Natel, installation sites could include irrigation canals and ambient river currents in addition to existing dams.
Natel also describes the new turbine as “fish-friendly” but we’ll let Sensor Fish be the judge of that.
More And Better Hydropower For The USA
Hydropower doesn’t get nearly as much attention from CleanTechnica as certain other topics (looking at you, Elon), but as recently as 2013, hydro still accounted for fully half of the renewable energy electricity generation in the US.
Wind caught up to hydro this year (solar still lags far behind), but if you throw unpowered dams, undeveloped streams, and pumped storage into the mix, there’s a good chance that hydro will hold its own — and help integrate more renewable energy into the grid.
One good example is a pumped hydro energy storage project in Massachusetts that will complement wind power.
Our friends up in Canada could also come into play, if a proposed new hydropower transmission line for New England gets off the drawing board.
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Photo (screenshot): via US DOE.
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