Norwegian hydropower plants pose a significant threat to aquatic life, particularly fish and bottom-dwelling organisms, due to the release of water that is oversaturated with air. This issue is exacerbated by increasing flooding and extreme weather conditions. Researchers at NTNU, led by Professor Ole Gunnar Dahlhaug and postdoctoral fellow Wolf Ludwig Kuhn, aim to understand and mitigate the problem of gas supersaturation, which can lead to gas bladder disease in fish—a condition akin to decompression sickness in humans.
Hydropower is often regarded as a sustainable energy source, yet it presents environmental challenges. High levels of dissolved air in river water can cause serious health issues for aquatic life, as seen in a case involving a trout in the Otra river, exhibiting symptoms of gas bladder disease. The supersaturation occurs when air is drawn into hydropower plants, leading to dangerous levels of dissolved gases, particularly during floods. Research indicates that nearly 30% of Norway’s 1,800 hydropower plants are at high risk for this issue.
To address these challenges, the DeGas project has developed a novel technology utilizing ultrasound to reduce dissolved air in water. Initial tests have shown promise, with plans to scale up the method for larger flows. However, the researchers stress the need for regulatory measures and monitoring to ensure the environmental impact of hydropower is adequately addressed, as many aquatic deaths likely go unnoticed.
