Hydropower in Europe: A Historical Pillar of the Energy Transition and a Long-Essential Resource for the Continent
For more than a century, hydropower has held a central place in the European energy bouquet. In 2022, it provided about 13% of the total electricity produced in the European Union, positioning itself as the primary source of renewable electricity until the recent rise of wind and solar power. Dams dot the Alpine, Pyrenean, or Scandinavian rivers, run-of-river power plants irrigate the continent’s rivers, and Norway draws more than 90% of its electricity from hydropower, serving as a model.
The advantages of hydropower are undeniable. It offers stable, controllable, and flexible production, capable of compensating for the intermittency of solar and wind power. Pumped-storage power plants ensure the massive storage of electricity, crucial for stabilizing networks during periods of high demand or low renewable production. From a climate perspective, hydropower has a low level of greenhouse gas emissions compared to fossil fuels, especially in temperate regions like Europe.
Hydropower has thus played a pioneering role in the decarbonization of electricity and continues to make a major contribution to the fight against global warming. It is often presented as a model of sustainable development, combining supply security and low carbon impact. But as needs evolve and pressure on aquatic environments intensifies, the question of its future and forms of exploitation remains more relevant than ever.
Shadows Over the Water: Major Ecological Impacts, Persistent Controversies, and Increasing Challenges to the Environmental and Social Sustainability of European Hydropower
However, behind this green image, European hydropower is now at the heart of environmental debates and growing controversies, in light of recent scientific knowledge and contemporary societal demands. While hydropower is renewable by nature—it uses the water cycle, inexhaustible on a human scale—its impacts on aquatic and terrestrial ecosystems are far from negligible, both in terms of biodiversity and water resource management and land use.
The construction of large dams disrupts the natural functioning of rivers: fragmentation of habitats, blocking of fish migrations, alteration of sediment transport, transformation of river ecosystems into stagnant bodies of water… These phenomena sometimes lead to the disappearance of local species, the reduction of biodiversity, and the degradation of water quality. NGOs and scientists have been warning for years that most European rivers are already heavily modified by humans, and that the construction of new dams would increase pressure on fragile environments. Social impacts, such as the loss of agricultural land, changes in landscapes, or disruption of traditional water uses, add to these environmental issues.
Hydropower, depending on its design and operation, is therefore not always as “green” as one might think. Small run-of-river facilities also have their share of cumulative impacts, especially when multiple installations fragment watercourses over long distances, creating a domino effect on ecological continuity and aquatic fauna. Moreover, under certain conditions, dams can emit methane—a potent greenhouse gas—when organic matter decomposes in reservoirs, although this phenomenon is less pronounced in Europe than in tropical areas.
In response to these findings, European regulation has evolved: the Water Framework Directive imposes the good ecological status of rivers, and the European Biodiversity Strategy plans for the restoration of 25,000 km of watercourses by 2030, notably by removing obsolete structures. This raises the question of the future development of hydropower: should we still build new dams, or prioritize the optimization and modernization of existing ones? The answer will also depend on the social acceptability of projects, the involvement of local stakeholders, and the ability to reconcile energy needs and sustainable preservation of natural environments.
Between Technological Innovations, Energy Sobriety, Reasonable Resource Management, and Increasing Imperatives for Ecological Preservation: What Future for European Hydropower in the Context of an Ambitious, Sustainable, and Socially Accepted Energy Transition?
Faced with these multiple challenges, the hydropower sector in Europe is undergoing a profound transformation that goes beyond mere technical or economic considerations, to fully integrate the requirements of ecological sustainability, energy sobriety, and social acceptability. The time is no longer for the multiplication of large dams, but for the modernization of existing installations, the reduction of ecological impacts, and intelligent integration within a 100% renewable energy mix, capable of adapting to climate changes and the needs of territories.
The avenues for innovation are numerous: development of “fish-friendly” and high-energy-efficiency turbines, construction of efficient fish passes better adapted to biological diversity, ecological management of flows, restoration of natural habitats, dismantling of unnecessary or obsolete structures… Some countries, like France or Switzerland, are experimenting with “renaturation” solutions, allowing for the reconciliation of electricity production and the reconquest of river biodiversity, while promoting ecosystem resilience in the face of climate change.
In parallel, hydropower is called upon to play a key role in energy flexibility and storage, to accompany the rise of wind and solar power, whose production is by nature intermittent. Pumped-storage power plants could be modernized or developed, but their land and ecological impact must be closely monitored, and their social acceptability will depend on transparent and concerted management with local actors.
Europe must therefore arbitrate between the need to secure its low-carbon supply, the preservation of its rivers, the restoration of ecological continuity, and the social acceptability of projects. Energy sobriety, consumption reduction, efficiency of the existing fleet, and citizen participation are now as important levers as the construction of new structures to guarantee the sector’s resilience.
In the end, hydropower remains a renewable energy, but not always “green” or free of controversy. Its future in Europe will depend on the ability to combine energy transition, ecological restoration, and social justice. The challenge: to reinvent a model where water, a source of life and energy, is no longer a factor of destruction, but of resilience and innovation in the fight against the climate crisis.
Sources
- International Energy Agency (IEA) – Hydropower in Europe, 2023
- European Commission – Biodiversity Strategy 2030 and Water Framework Directive
- WWF – Report “European Rivers Under Pressure”, 2022
- International Hydropower Association – Hydropower Sustainability Guidelines
- Ministry of Ecological Transition (France) – Data and studies on hydropower
- European Environment Agency – Renewable energy in Europe 2023: recent growth and knock-on effects
- Nature Sustainability – “Impacts of hydropower on river ecosystems in Europe”, 2021
