Norway is currently transitioning toward carbon-neutral renewable energies, with energy consumption most likely to increase by 2050. Hydropower is the dominant electrical energy source, accounting for approximately 90% of the total national electrical energy production. 

Different legislations apply to large (>10 MW) and small (<10 MW) hydropower plants. While large hydropower plants are owned by the public, small hydropower plants can be privately owned. Most large-scale hydropower projects were developed during an early expansion period between 1950 and 1985. 

Since 2000, Norway has experienced a massive boom in small hydropower. Although these facilities are often marketed as “green” and low-impact, they collectively pipe far more kilometers of river per unit of electricity than large hydropower plants. In many cases, long stretches of natural rivers are diverted into underground pipes, leaving only minimal water in the original riverbed, thus putting pressure on local ecosystems.

Supervision has not kept pace with development: only a handful of plants are inspected each year, many lack proper environmental impact assessments, and some are legally allowed to dry out parts of the river entirely. Although each installation might seem insignificant on its own, the cumulative effect on biodiversity could be far greater than policymakers anticipated. 

Since 2025, it has been permitted to build hydropower plants in protected rivers if the societal benefit is sufficiently high compared to the ecological impact. This leaves room for a lot of interpretation.  In some areas, such as Verdal, rivers were only protected from hydropower development around 20 years ago, and their ecological state might be poor. However, there is a risk that the legislation could be exploited to promote small hydropower development for private economic benefit. This can increase scepticism within the population against hydropower. 

By opening protected areas, it seems like the Zero-Emission transition stands in contrast to nature conservation. However, in the long term, reducing climate change is also essential to conserve nature. An unpopular solution for nature conservation would be to set limits for energy supply and to adapt society to those limits. 

We must think about what we are aiming for.

How can we contribute better to dealing with the controversy of increased energy and need for nature protection?

Literature recommendations:

• Bakken, T. H., Sundt, H., Ruud, A., & Harby, A. (2012). Development of small versus large hydropower in Norway – comparison of environmental impacts. Energy Procedia, 20, 185-199. https://doi.org/10.1016/j.egypro.2012.03.019
• Bakken, T. H., Aase, A. G., Hagen, D., Sundt, H., Barton, D. N., & Lujala, P. (2014). Demonstrating a new framework for the comparison of environmental impacts from small- and large-scale hydropower and wind power projects. Journal of Environmental Management, 140, 93-101. https://doi.org/10.1016/j.jenvman.2014.01.050
• Harby, A., Davidsen, J. G., Finstad, A. G., Sundt, H., & Øien, D. I. (2024). Kunnskapsgrunnlag for vurdering av vannkraft i vernede vassdrag – Verdalsvassdraget som pilot (Report No. 2024:00494). SINTEF Energi AS. ISBN 978-82-14-07205-1.
• Hedger, R. D., Kenawi, M. S., Sundt-Hansen, L. E. B., Bakken, T. H., & Sandercock, B. K. (2025). Evaluating environmental impacts of micro, mini and small hydropower plants in Norway. Journal of Environmental Management, 373, 123521. https://doi.org/10.1016/j.jenvman.2024.123521
• Erikstad, L., Hagen, D., Stange, E., & Bakkestuen, V. (2020). Evaluating cumulative effects of small scale hydropower development using GIS modelling and representativeness assessments. Environmental Impact Assessment Review, 85, 106458. https://doi.org/10.1016/j.eiar.2020.106458
• Arvesen, A., Schönfelder, L. H., Graabak, I., Harby, A., Haugen, M., & Mo, B. (2025). Power system impacts of potential environmental constraints for hydropower in Norway. Environmental Research Letters, 20, 084004. https://doi.org/10.1088/1748-9326/ade4e1
• Ocko, I. B., & Hamburg, S. P. (2019). Climate-impacts of hydropower: Enormous differences among facilities and over time. Environmental Science & Technology, 53(23), 14070-14082. https://doi.org/10.1021/acs.est.9b05083

Sahra N. Sabil, 

She did my Master’s in Civil Engineering in Toronto at TMU (Canada) and in Karlsruhe at HKA (Germany). She has worked one year as a researcher at the group of ecohydraulics at SINTEF in Trondheim (Norway), focusing on impact from hydropower plants on nature, e.g. supersaturation, green house gas, water temperature. Currently, she is doing her PhD at NTNU in Trondheim (Norway) and researching how to dampen floods via hydropower reservoirs under climate change. Society and the environment are her main interests and she is wondering every day if we really need to use so much energy in the global north.

NTNU,IBM, S. P. Andersens veg 5, 7031 Trondheim