The NExus Solutions Tool (NEST) v1.0: an open platform for optimizing multi-scale energy–water–land system transformations

Abstract

Abstract. The energy–water–land nexus represents a critical leverage future policies must draw upon to reduce trade-offs between sustainable development objectives. Yet, existing long-term planning tools do not provide the scope or level of integration across the nexus to unravel important development constraints. Moreover, existing tools and data are not always made openly available or are implemented across disparate modeling platforms that can be difficult to link directly with modern scientific computing tools and databases. In this paper, we present the NExus Solutions Tool (NEST): a new open modeling platform that integrates multi-scale energy–water–land resource optimization with distributed hydrological modeling. The new approach provides insights into the vulnerability of water, energy and land resources to future socioeconomic and climatic change and how multi-sectoral policies, technological solutions and investments can improve the resilience and sustainability of transformation pathways while avoiding counterproductive interactions among sectors. NEST can be applied at different spatial and temporal resolutions, and is designed specifically to tap into the growing body of open-access geospatial data available through national inventories and the Earth system modeling community. A case study analysis of the Indus River basin in south Asia demonstrates the capability of the model to capture important interlinkages across system transformation pathways towards the United Nations' Sustainable Development Goals, including the intersections between local and regional transboundary policies and incremental investment costs from rapidly increasing regional consumption projected over the coming decades.

Transboundary cooperation a potential route to sustainable development in the Indus basin

“…Although all nations committed to the SDGs in 2015, first we consider the case that might occur in absence of progress on the SDGs -Business As Usual. Currently, about 55% of electricity in the basin is produced from fossil fuels, hydropower production is underexploited and renewable energy generation is less than 5% of total production [37,38]. We estimate a fourfold rise in electricity demand in the basin by 2050 compared to 2020 driven by population growth and improved electricity access.…”

“…We use a modelling framework that links hydrological modelling with engineering-economic capacity planning (NEST [37]), and we study a set of long term scenarios to 2050 (see Table 1). By comparing the developments of water, energy and agriculture sectors in a Business-as-usual (BAU) pathway with a scenario with sustainability targets (SDG), we assess the investment gaps to achieve the targets, and we quantify several associated socio-environmental co-benefits.…”

Nexus vs. Silo Investment Planning Under Uncertainty

“…Uncertainties are often considered by exploring the five shared socio-economic pathways (Riahi et al, 2017) or sampling across their assumptions (e.g., Lamontagne et al, 2018). • A new family of nexus models (e.g., WHAT-IF-Payet-Burin et al, 2019;NEST-Bakhshianlamouki et al, 2020;Sridharan et al, 2020;Vinca et al, 2020) fill the gap between the two first categories, as they represent interactions between the water, energy, and food sectors at finer spatial and temporal scales. Uncertainties are usually addressed using sensitivity analysis techniques or scenario analysis based on the shared socio-economic pathways.…”

Development of the Community Water Model (CWatM v1.04) – a high-resolution hydrological model for global and regional assessment of integrated water resources management

“…C Seasonal is a factor depending on the day of the year, which varies the snow melt rate. A similar factor is used in several other models (e.g., Anderson, 2006;and Viviroli et al, 2009). At high altitudes the model tends to accumulate snow without any melting loss, because temperature never exceeds 1 • C. In these altitudes snow is accumulated and is converted into firn, which is then converted into ice as glaciers move to lower regions over decades or even centuries.…”