WHAT-IF: an open-source decision support tool for water infrastructure investment planning within the water–energy–food–climate nexus

Abstract. Water infrastructure investment planning must consider the interdependencies within the water–energy–food nexus. Moreover, uncertain future climate, evolving socio-economic context, and stakeholders with conflicting interests, lead to a highly complex decision problem. Therefore, there is a need for decision support tools to objectively determine the value of investments, considering the impacts on different groups of actors, and the risks linked to uncertainties. We present a new open-source hydro-economic optimization model, incorporating in a holistic framework, representations of the water, agriculture, and power systems. The model represents the joint development of nexus-related infrastructure and policies and evaluates their economic impact, as well as the risks linked to uncertainties in future climate and socio-economic development. We apply the methodology in the Zambezi River basin, a major African basin shared by eight countries, in which multiple investment opportunities exist, including new hydropower plants, new or resized reservoirs, development of irrigation agriculture, and investments into the power grid. We show that it is crucial to consider the links between the different systems when evaluating the impacts of climate change and socio-economic development, which will ultimately influence investment decisions. We find that climate change could induce economic losses of up to USD 2.3 billion per year in the current system. We show that the value of the hydropower development plan is sensitive to future fuel prices, carbon pricing policies, the capital cost of solar technologies, and climate change. Similarly, we show that the value of the irrigation development plan is sensitive to the evolution of crop yields, world market crop prices, and climate change. Finally, we evaluate the opportunity costs of restoring the natural floods in the Zambezi Delta; we find limited economic trade-offs under the current climate, but major trade-offs with irrigation and hydropower generation under the driest climate change scenario.

[1]  David Yates,et al.  WEAP21—A Demand-, Priority-, and Preference-Driven Water Planning Model , 2005 .

[2]  Rikard Liden,et al.  Enhancing the climate resilience of Africa's infrastructure : the power and water sectors , 2015 .

[3]  Jay R. Lund,et al.  An open-source Python implementation of California's hydroeconomic optimization model , 2018, Environ. Model. Softw..

[4]  Amaury Tilmant,et al.  Agricultural-to-hydropower water transfers: sharing water and benefits in hydropower-irrigation systems , 2009 .

[5]  Peter Bauer-Gottwein,et al.  Optimizing Wellfield Operation in a Variable Power Price Regime , 2016, Ground water.

[6]  Bruce A. McCarl,et al.  Model Use in WEF Nexus Analysis: a Review of Issues , 2017 .

[7]  Peter Bauer-Gottwein,et al.  Optimization of regional water - power systems under cooling constraints and climate change , 2018, Energy.

[8]  Peter Bauer-Gottwein,et al.  Joint optimization of water allocation and water quality management in Haihe River basin. , 2019, The Science of the total environment.

[9]  Amaury Tilmant,et al.  Economic valuation of benefits and costs associated with the coordinated development and management of the Zambezi river basin , 2012 .

[10]  Simon Parkinson,et al.  Spatial and temporal synchronization of water and energy systems: towards a single integrated optimization model for long-term resource planning , 2016 .

[11]  Fernando Miralles-Wilhelm,et al.  Development and application of integrative modeling tools in support of food-energy-water nexus planning—a research agenda , 2016, Journal of Environmental Studies and Sciences.

[12]  W. Kinzelbach,et al.  The cost of noncooperation in international river basins , 2012 .

[13]  H. Winkler,et al.  Climate change and hydropower in the Southern African Power Pool and Zambezi River Basin: System-wide impacts and policy implications , 2017 .

[14]  Semida Silveira,et al.  OSeMOSYS: The Open Source Energy Modeling System: An introduction to its ethos, structure and development , 2011 .

[15]  N. Djilali,et al.  A Continental‐Scale Hydroeconomic Model for Integrating Water‐Energy‐Land Nexus Solutions , 2018, Water Resources Research.

[16]  Zarrar Khan,et al.  Integrating water and energy models for policy driven applications. A review of contemporary work and recommendations for future developments , 2017 .

[17]  Keywan Riahi,et al.  Power-generation system vulnerability and adaptation to changes in climate and water resources , 2016 .

[18]  R. Tharme.  A global perspective on environmental flow assessment: emerging trends in the development and application of environmental flow methodologies for rivers , 2003 .

[19]  Y. Mohamed,et al.  Optimal operation of a multipurpose multireservoir system in the Eastern Nile River Basin , 2010 .

[20]  C. Scott,et al.  The Water-Energy-Food Nexus: A systematic review of methods for nexus assessment , 2018 .

[21]  Mohammad Shahidehpour,et al.  Co-optimization of electricity transmission and generation resources for planning and policy analysis: review of concepts and modeling approaches , 2016 .

[22]  Anthony J. Jakeman,et al.  Environmental decision support systems (EDSS) development - Challenges and best practices , 2011, Environ. Model. Softw..

[23]  Megan Lickley,et al.  Climate change impacts and greenhouse gas mitigation effects on U.S. water quality , 2015 .

[24]  Peter Bauer-Gottwein,et al.  Optimization of Multipurpose Reservoir Systems Using Power Market Models , 2015 .

[25]  A 1998 Social Accounting Matrix for Malawi , 2001 .

[26]  David L. Woodruff,et al.  Pyomo — Optimization Modeling in Python , 2012, Springer Optimization and Its Applications.

[27]  Liming Yao,et al.  Optimal allocation of regional water resources: From a perspective of equity–efficiency tradeoff , 2016 .

[28]  Andrew J. Draper,et al.  Economic-engineering optimization for California water management , 2003 .

[29]  Chunlian Jin,et al.  Investigating the nexus of climate, energy, water, and land at decision-relevant scales: the Platform for Regional Integrated Modeling and Analysis (PRIMA) , 2015, Climatic Change.

[30]  Dolf Gielen,et al.  Considering the energy, water and food nexus: Towards an integrated modelling approach , 2011 .

[31]  B. Flyvbjerg,et al.  Should We Build More Large Dams? The Actual Costs of Hydropower Megaproject Development , 2014, 1409.0002.

[32]  E. Assoumou,et al.  Water modeling in an energy optimization framework – The water-scarce middle east context , 2013 .

[33]  Birger Mo,et al.  Joint optimization of regional water-power systems , 2016 .

[34]  E. Wood,et al.  Development of a 50-Year High-Resolution Global Dataset of Meteorological Forcings for Land Surface Modeling , 2006 .

[35]  R. C. Griffin.  Benchmarking in water project analysis , 2008 .

[36]  L. S. Pereira,et al.  Crop evapotranspiration : guidelines for computing crop water requirements , 1998 .

[37]  David E. Rosenberg,et al.  Hydro-economic models: concepts, design, applications, and future prospects. , 2009 .

[38]  Randall Spalding-fecher,et al.  Electricity supply and demand scenarios for the Southern African power pool , 2017 .

[39]  Omotola Awojobi,et al.  Were the hydro dams financed by the World Bank from 1976 to 2005 worthwhile , 2015 .

[40]  H. Velthuizen,et al.  Integrated analysis of climate change, land-use, energy and water strategies , 2013 .

[41]  Manfred Denich,et al.  Bioenergy, food security and poverty reduction: trade-offs and synergies along the water–energy–food security nexus , 2015 .