Assessment of Sweet Sorghum-Based Ethanol Potential in China within the Water–Energy–Food Nexus Framework

Xiaoxi Yan,Mengmeng Hao,Dong Jiang,Jingying Fu

doi:10.3390/su10041046

Abstract

As bio-ethanol is developing rapidly, its impacts on food security, water security and the environment begin to receive worldwide attention, especially within the Water–Energy–Food nexus framework. The aim of this study is to present an integrated method of assessing sweet sorghum-based ethanol potential in China in compliance with the Water–Energy–Food nexus principles. Life cycle assessment is coupled with the DSSAT (the Decision Support System for Agrotechnology Transfer) model and geographic information technology to evaluate the spatial distribution of water consumption, net energy gain and Greenhouse Gas emission reduction potentials of developing sweet sorghum-based ethanol on marginal lands instead of cultivated land in China. Marginal lands with high water stress are excluded from the results considering their unsuitability of developing sweet sorghum-based ethanol due to possible energy–water conflicts. The results show that the water consumption, net energy gain and Greenhouse Gas emission reduction of developing sweet sorghum-based ethanol in China are evaluated as 348.95 billion m3, 182.62 billion MJ, and 2.47 million t carbon per year, respectively. Some regions such as Yunnan Province in south China should be given priority for sweet sorghum-based ethanol development, while Jilin Province and Heilongjiang Province need further studies and assessment.

Highlights

Energy shortage and climate change are two great challenges today
Developing sweet sorghum-based ethanol on marginal lands would cause 36.66 million tons of Greenhouse gases (GHG) emissions, and the GHG emission reduction potential would be 2.47 million tons of GHG emissions, equivalent to the GHG emissions caused by 0.86 million tons of petrol
This study presented the spatial distribution of net energy gain, GHG emission reduction potentials, which is more helpful for policy makers to decide which regions should be given priority for sweet sorghum-based ethanol development

Summary

Introduction

Energy shortage and climate change are two great challenges today. In December 2015, the Paris Agreement confirmed that the increase in the global average temperature should be held below 2 ◦C, and that countries should dedicate greater efforts to limit the temperature increase to 1.5 ◦C [1,2]. The energy sector must be decarbonized to fulfill the temperature requirement confirmed by the Paris Agreement [3]. The share of renewable energy would probably at least triple from 3.5% to 10% according to 2017 REN’s Renewable Global Futures [3]. For the application of renewable energy in the transport sector, 100% liquid biofuels, such as bio-ethanol and bio-diesel, or biofuels blended with gasoline are the main entry points [3]. Paper for the Bonn2011 Conference: The Water, Energy and Food Security Nexus; SEI: Stockholm, Sweden, 2011. The Water-Energy-Food Nexus: A New Approach in Support of Food Security and Sustainable Agriculture; FAO: Rome, Italy, 2014.

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