Development opportunities | A grey picture


The multi-purpose roles of dams has been out under the spotlight, as a US study suggests grey infrastructure will not be able to meet future energy and irrigation demands


a: current conditions


AVAILABLE WATER STORAGE


Natural hydrologic cycle Nature based solutions Grey infrastructure


Irrigation


Domestic water use


Industrial water use


Flood and hazard control


STORAGE DEMAND


Above: The critical role of water storage for climate mitigation and irrigation. Water storage is critical for hydropower, irrigation, flood and hazard control and domestic and industrial water use. Already today there is a gap between the available storage and what is needed across sectors (a). As hydropower and irrigation play a key role for climate adaptation and mitigation, water demand and storage gaps are expected to grow in the future (b). (Source Schmitt and Rosa, Renewable and Sustainable Energy Reviews Volume 199, July 2024)


Below: India is one of the regions where stored water won’t be able to meet hydropower and irrigation demands


Pumped storage hydropower


STORAGE GAP Irrigation


Hydropower with storage


Domestic water use


Industrial water use


Flood and hazard control


Pumped storage hydropower


Hydropower with storage


b: future conditions


AVAILABLE WATER STORAGE


Natural hydrologic cycle Nature based solutions Grey infrastructure


Deploy nature-based solution


Re-operate grey infrastructure


Climate change Loss of natural storage Reservoir sedimentation


GROWING STORAGE GAP


GROWING STORAGE DEMAND


RESEARCH BY STANFORD UNIVERSITY and Carnegie Science has been described as a first-of-its-kind global overview of the role dams and reservoirs play in providing water storage. Acknowledging that hydropower and irrigated agriculture are critical for climate mitigation and adaptation, as well as meeting basic human needs in the 21st century, the research team highlighted there was a lack of available data to evaluate the multi-purpose role of existing dams and reservoirs. This is important, the research team observed, as both sectors depend on and compete for the same service, namely water storage. Rafael Schmitt from Stanford-University and Carnegie Science’s Lorenzo Rosa said that with future demands expected to increase, it’s important to identify crucial gaps in our understanding of what hydropower and irrigated agriculture contribute to food and energy security. “Water storage is a critical and globally limited


resource,” Schmitt said. “Our study shows that the solutions of the past are insufficient, and can be damaging to already overstretched freshwater ecosystems.”


Published in Renewable and Sustainable Energy Reviews, the study used machine learning to quantify the roles of the world’s 6000 largest dams and reservoirs. The analysis revealed that dammed reservoirs globally store about 1000 times the volume of California’s largest man-made lake, Shasta Lake. Of that, less than 5% reaches irrigated crops. With the analysed dams providing 505GW of hydropower, 40% of current total global hydropower capacity, the


22 | July 2024 | www.waterpowermagazine.com


study projects global demand for hydropower will grow by approximately 35% by 2050, while the global need for stored irrigation water will see a 70% increase.


With over 3700 dams having been identified for


potential development worldwide, if all of them were constructed they could provide about 60% more energy and 40% more stored water for irrigation. Despite this potential, the analysis shows that deficits persist in some countries and regions. Even with the construction of several thousand new dams, the authors say there won’t be nearly enough hydropower and stored irrigation water to meet needs in India, central Europe, and several Asia- Pacific nations.


“Our study by no means advocates for building


more dams. What we urgently need is a global debate about how to meet water storage needs for critical sectors,” lead author Schmitt commented. As demands for irrigation and hydropower grow, gaps between sectoral needs and what dams can provide will widen, and the authors warn, the risk for conflicts between these sectors increases as well. Developing a more detailed understanding of emerging operational conflicts between sectors will require consideration of reservoir operations. However it is acknowledged that such regional to global modelling remains challenging and a topic of ongoing research.


“Developing such an understanding and including it into integrated global assessment models and in sectoral studies will be needed


CLIMATE ADAPTATION DEMAND GROWTH ?


ENERGY SECTOR


WATER AND FOOD SECTORS


CLIMATE MITIGATION DEMAND GROWTH ?


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