Author(s): Wolf Ludwig Kuhn; Bjorn Winther Solemslie; Ulrich Pulg And Ole Gunnar Dahlhaug
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Keywords: TDG supersaturation environmental impact TDG mitigation strategies ecological risk management
Abstract: Norwegian rivers downstream of hydropower plants experience elevated levels of total dissolved gas (TDG) saturation, i. e. TDG supersaturation, a phenomenon with potential ecological impacts. High TDG saturation levels can lead to gas bubble disease (GBD) in fish and other aquatic organisms, causing significant disruptions in ecosystem health and function. Given the reliance on hydropower in Norway’s renewable energy strategy, addressing these environmental challenges is important. This study reviews the outcomes of two different Norwegian projects: 1. the current TDG supersaturation status in Norway, focusing on hydropower-related influences, and 2. effective technical mitigation strategies developed through recent research at the NTNU Waterpower Laboratory. Key approaches, such as ultrasonic degassing and bubble curtains, show promising results in decreasing TDG saturation levels and minimizing environmental impacts.
Year: 2025