The Dam Dilemma: the potential of hybrid solutions and horizontal governance for a more just energy future?

A quarter of a century later, a new study led by Sergio Villamayor-Tomas, researcher at ICTA-UAB, analyses how the context has changed profoundly, with new climate narratives, the rise of China as a global actor, the expansion of private investment and the growing influence of environmental justice movements—and what opportunities this new landscape offers for more effective and equitable hydropower governance.

While large dams can provide electricity, irrigation and flood control, they also cause deforestation, biodiversity loss and social conflicts, and often fail to deliver the development benefits used to justify them. In addition, large hydropower projects are not climate-neutral, particularly in tropical regions. Reservoirs can emit significant amounts of carbon dioxide and, especially, methane due to the decomposition of submerged organic matter. The study estimates that planned hydropower projects in Africa could increase current emissions from the continent’s electricity sector by around 7%, calling into question their automatic contribution to decarbonisation.

Against this centralised model, the study highlights the potential of small-scale hydropower, in-stream turbines and microgrids as more flexible alternatives with lower socio-environmental impacts, as well as hybrid solutions that combine hydropower with solar, wind and battery storage. Documented experiences in countries such as the Dominican Republic and Brazil show that community-managed systems can supply electricity to remote areas and reduce emissions without the need for large reservoirs. However, the authors warn that these solutions require careful strategic planning to avoid cumulative impacts at the river-basin scale.

Published in Nature Sustainability, the study also focuses on who finances and decides which projects are built. In recent decades, the financing of large dams has shifted from traditional multilateral institutions towards a diverse constellation of public and private actors, among which Chinese banks and companies stand out, which have invested more than USD 44 billion in hydropower projects abroad between 2000 and 2020. According to the authors, this fragmented landscape weakens accountability and the enforcement of social and environmental standards.

At the same time, affected communities and environmental justice movements have gained global visibility. More than 4,000 socio-environmental conflict cases—12% related to dams—are recorded in the Global Atlas of Environmental Justice, and mobilisations have succeeded in stopping, modifying or transforming 37% of documented projects. The authors argue that these movements represent a key actor in building a more horizontal and democratic governance of the sector and, together with the hydropower industry, mainly represented by the International Hydropower Association, could form the basis of an international system for recognising good practices.

The study concludes that the current energy and climate context offers an opportunity to fundamentally rethink the role of hydropower in the ecological transition. Rather than continuing to rely on large dams that concentrate risks and impacts, the authors advocate for energy portfolios that combine multiple renewables, storage and distributed solutions, alongside life-cycle impact assessments and governance mechanisms that give real voice to affected communities. This approach would allow the benefits of hydropower—such as its capacity to support solar and wind power—to be harnessed while minimising emissions, social conflicts and environmental damage associated with past large-scale infrastructures.

 

Reference article: Villamayor-Tomas, S., Lopez, M.C., Arantes, C.C., Del Bene, D., Chea, R., Kramer, D.B., Schulz, C., Siciliano, G., Tilt, B. & Moran, E.F. (2026). Challenges and opportunities for the governance of hydropower. Nature Sustainability. https://doi.org/10.1038/s41893-026-01782-2