It seems like the Zero-Emission transition stands in contrast to biodiversity. However, in the long term, biodiversity has a crucial role to play to reduce climate change. Therefore, it is essential to use more electrical energy and leave the over 10.000-year-old waste products, which are well saved in the depths of our planets, in peace. 

Lately, there has been a big boost in hydropower development in Norway. In 2025, it has been permitted to build hydropower plants in protected rivers, opening a big debate about nature conservation and the cost-benefits of small and large hydropower plants The Guardian.

Hydropower is the dominant electrical energy source in Norway, accounting for approximately 88% of the total national electrical energy production. The country is currently transitioning toward carbon-neutral renewable energies, with energy consumption forecasted to increase by 2050. Most large-scale hydropower projects were developed during an early expansion period between 1950 and 1985. 

Large Hydropower Plants (>10 MW)

New large-scale projects are controversial and have not been adopted by the national government.

• Future Development: While new large projects are limited, future demand could be met by upgrading and refurbishing existing facilities or by developing a few undeveloped sites.
• Benefits: Large-scale hydropower, particularly those with significant storage capacity, provides essential services such as energy storage, water supply, and flood control.
• Environmental Impact: Large projects generally have a much larger total land occupation compared to small-scale projects. However, some studies suggest that large hydropower may have slightly lower overall environmental impacts for similar energy production compared to multiple small projects, though this is uncertain.

Small Hydropower Plants (<10 MW)

Recent developments in Norway have mainly focused on small-scale hydropower plants. The Norwegian Water Resources and Energy Directorate (NVE) has identified approximately 9500 potential sites for these projects.

• Regulation: Simplified regulatory procedures favor the development of small-scale hydropower. Projects under 10 MW are approved by NVE, while micro (<0.1 MW) and mini (0.1-1 MW) projects are under local municipal authority.
• Role: Small-scale hydropower is promoted for its role in local and regional development, allowing for decentralized siting, community involvement, and profitability for local landowners.
• Energy Contribution: Despite the high number of potential sites, small-scale hydropower’s contribution to national energy production is limited, providing only about 8.6% of Norway’s total hydropower production.
• Environmental Impact: While individual small plants have a small environmental footprint and are generally land-use efficient, particularly the larger small plants (1-10 MW), there are concerns about the cumulative effects of multiple small-scale plants. The massive development of small-scale hydropower can lead to the fragmentation of untouched nature and potentially greater overall impacts compared to a single large-scale plant. Developing all potential sites could substantially impact the bioclimatic diversity and representativeness of river gorges.

Environmental Constraints and Policy

Norway is implementing the EU Water Framework Directive and strengthening watercourse protection, which is leading to the introduction of new or revised environmental constraints for hydropower.

• Impact on Production: These new constraints, such as increased environmental flow releases in bypass reaches, are estimated to reduce Norway’s total hydropower output by approximately 3 TWh per year, which is equivalent to about 2% of the average production.
• Dilemma: The implementation of these constraints creates a dilemma between improving ecosystems and ensuring a sufficient and reliable energy supply. The reductions primarily affect flexible production, which is expected to become increasingly valuable as variable wind and solar energy expand.

Norway is destroying the natural area of 38m2 per inhabitant in the last 5 years, thus it is the country in Europe that destroys the most nature per inhabitant. Many people on the street start to believe in nuclear energy, when they think about how to solve the climate and energy crises. Is this where we want to go? How can we better communicate the need of renewable energy and deal with the dilemma between climate crises and biodiversity?

To deepen your understanding of the environmental and social impacts of hydropower, here are some recommended resources that have been cited in the blog:

• 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
• 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