With seven percent of the nation’s electricity coming from hydropower, the future will bring new dams and updates to current turbine systems. Some 2,400 dams across the country will face relicensing in the coming years, and operators will have to prove that operations won’t impact fish passage.

Pacific Northwest National Laboratory designed Sensor Fish (SF),  a small autonomous device filled with sensors, to act as a body double for live fish. The Sensor Fish technology gives information to hydropower operators and fisheries researchers on what fish experience during downstream migration through dams. The tubular device is deployed in turbines, spillways, and sluiceways and takes 2,000 measurements per second. Sensor Fish is commercially available through Advanced Telemetry Systems.

In 2018, PNNL developed a miniaturized version of Sensor Fish, known as Sensor Fish Mini, to evaluate fish passage conditions and physical stressors in small hydraulic structures. Small hydro accounts for 89 percent of non-federal facilities and has a capacity of less than 30 megawatts.

The technology measures acceleration, rotational velocities, orientation, pressure, and temperature. Sensor Fish Mini is activated with a microcontroller and then dropped into the water. Similar to fish, the current pushes the devices through the hydraulic turbines or small dam and further downstream they are recovered with a net. Each of the SF sensors samples at a rate of 2048 Hz and can store up to 5 min of data. Data collected is uploaded into PNNL’s Hydropower Biological Evaluation Toolset (HBET), a collection of software tools developed for processing and analyzing Sensor Fish Mini data and hydropower evaluation-related technologies. Deployments can be repeated for further studies.

Sensor Fish Mini was successfully deployed in its first field trial and used for evaluations of an irrigation screen in Hood River.

Sensor Fish Mini’s small size make the device a beneficial tool for evaluating the machine dynamics of turbines. One option has a spherical shape and weighs 6.4 grams. It can also be used in different form factors to accommodate other applications.

Applicability

Sensor Fish Mini provides engineers, hydro operators, and fisheries researchers with information on how to improve designs for small hydraulic structures that minimize physical impacts on fish. As the small hydro industry continues to grow, Sensor Fish Mini’s tools will continue to be a useful technology for evaluating structures.

Comparison between SF mini and SF