To support the safe passage of fish through hydropower facilities, Natel Energy completed two successful fish passage tests with 100% survival rates. While most industry fish passage tests focus on passing small fish through large turbines, Natel Energy’s initial testing assessed the ability for large adult rainbow trout (200-400 millimeters long) to safely pass through the Restoration Hydro Turbine’s (RHT) relatively small turbine diameter (1.9 m) at the company’s Monroe Hydro Project in Madras, Oregon.

These high fish survival numbers indicate the RHT may eliminate the need for expensive screens or plant-level structures that redirect fish away from turbines. Validation of the RHT’s fish-safe performance, coupled with hydraulic efficiency, offers the potential for new modes of operation of hydropower facilities while meeting or exceeding environmental goals with respect to fish passage and protection.

Biologists from Pacific Northwest National Laboratory (PNNL) confirmed 100% survival of all 60 trout that passed through the turbine. Natel Energy is continuing to conduct turbine passage testing of relevant species in its closed-loop hydraulic test facility in Alameda, California. PNNL also conducted a passage test of 47 American eels measuring 34-49 cm in length. The eels passed through a 55-cm-diameter RHT unit operating under 10 m of hydraulic head at 670 revolutions per minute, again concluding with 100% survival.

Natel Energy’s RHT is uniquely suited for small, modular hydropower due to its compact and cost-effective design, which leverages advanced manufacturing techniques from other industries, such as wind energy, automotive, and aerospace. Accomplishments from these successful tests have potential to help future projects meet environmental standards for fish passage without the need for screening.