Hydropower versus irrigation—an analysis of global patterns

Abstract

Numerous reservoirs around the world provide multiple flow regulation functions; key among these are hydroelectricity production and water releases for irrigation. These functions contribute to energy and food security at national, regional and global levels. While reservoir operations for hydroelectricity production might support irrigation, there are also well-known cases where hydroelectricity production reduces water availability for irrigated food production. This study assesses these relationships at the global level using machine-learning techniques and multisource datasets. We find that 54% of global installed hydropower capacity (around 507 thousand Megawatt) competes with irrigation. Regions where such competition exists include the Central United States, northern Europe, India, Central Asia and Oceania. On the other hand, 8% of global installed hydropower capacity (around 79 thousand Megawatt) complements irrigation, particularly in the Yellow and Yangtze River Basins of China, the East and West Coasts of the United States and most river basins of Southeast Asia, Canada and Russia. No significant relationship is found for the rest of the world. We further analyze the impact of climate variables on the relationships between hydropower and irrigation. Reservoir flood control functions that operate under increased precipitation levels appear to constrain hydroelectricity production in various river basins of the United States, South China and most basins in Europe and Oceania. On the other hand, increased reservoir evaporative losses and higher irrigation requirements due to higher potential evaporation levels may lead to increased tradeoffs between irrigation and hydropower due to reduced water availability in regions with warmer climates, such as India, South China, and the Southern United States. With most reservoirs today being built for multiple purposes, it is important for policymakers to understand and plan for growing tradeoffs between key functions. This will be particularly important as climate mitigation calls for an increase in renewable energy while agro-hydrological impacts of climate change, population and economic growth and associated dietary change increase the need for irrigated food production in many regions round the world.

Hydropower dependency and climate change in sub-Saharan Africa: A nexus framework and evidence-based review

“…(vi) The relationship between hydropower and irrigation in multipurpose reservoirs is pivotal: it has been evaluated that while today roughly 54% of global installed hydropower capacity competes with irrigation and 8% complements it, competition is expected to intensify under a warmer climate (Zeng et al, 2017).…”

“…In the last decades (in particular during the wet season in unimodal rainfall climates, where rain falls only during one period per year) prolonged droughts have resulted in severe power crises in several hydropower-dependent countries (including for instance, in Kenya, Tanzania, Ghana, Zimbabwe and Zambia during the 2015-16 El Niño period, characterized by oceanic and atmospheric shifts in the Pacific Ocean which affect weather and climate across the tropics, and in Malawi in 2017), with frequent outages, power rationing , adverse business experience (Gannon et al, 2018) to emergency (and costlier) IPP (independent power producer)-provided dieselfired generators . Water availability issues represent a growing source of risk in different areas, also due to an increasing competition between water use for power generation, irrigation, and municipal water supply (Zeng et al, 2017;.…”

A centurial analysis of rainfall variability in Nigeria

“…Water stored in dams can be used for irrigated agriculture [19] as well as hydropower generation. Irrigated agriculture land will foster greater food security and electricity generated from hydropower will contribute to large scale grid-based electrification which will in turn boost industrial outputs, economic growth and human development [20].…”

Meeting ecosystem needs while satisfying human demands

“…The recent publication by Zeng et al (2017) highlights the trade-offs inherent in managing water resources for multiple demands, focusing specifically on hydropower generation versus deliveries for agricultural irrigation supply. At the global scale, the authors found that over half of all installed hydropower competes with irrigation, broadly.…”

“…As the analysis by Zeng et al (2017) makes clear, global water security will be dependent upon several interacting forces that govern water managed for hydropower, irrigation, and ecosystems. Wada and Bierkens (2014) and others have also made it clear that the future sustainability of human water use is doubtful.…”