Dams for hydropower and irrigation: Trends, challenges, and alternatives

Hydropower and irrigation are essential for achieving human development objectives and for climate mitigation and adaptation. These sectors depend on the same grey infrastructure, such as dammed reservoirs, which has created negative socio-ecological externalities and sectoral conflicts in the past. Yet, future needs for infrastructure in both sectors and their interdependencies remain unclear. We address this gap by applying data-fusion and machine-learning approaches and provide a comprehensive global overview and a new dataset that elucidates the role of existing dams and reservoirs for hydropower and irrigation. We then review projected demands for irrigation storage and hydropower by 2050 and analyze how projected growth aligns with the identified potential for irrigation and hydropower dams. Globally, projections point to an increased demand for hydropower in the order of 400 GW by 2050, which amounts to around 60 %–64 % of the identified potential and around +35 % compared to today. For irrigation, fully leveraging sustainable water resources would require 460 km3/yr of stored water, or around +70 % compared to today. Projected demands for hydropower and irrigation are larger than what future grey infrastructure could provide in many regions, especially in Europe, South Asia, and Africa. In such conditions, both sectors will be increasingly in competition for infrastructure. Our findings also highlight the need to study alternative solutions, such as other forms of renewable energy and nature-based solutions for water storage, to meet societal demands while avoiding negative externalities associated with grey water infrastructure.