Preliminary study on the establishment of a transferable evaluation framework of Water-Food-Energy nexus

The issue of water, energy and food (WEF) nexus attracts a lot of attention recently due to the competitive allocation of available resources in the advancement of modernization and urbanization. Due to the geographical differences, cultural variation, differentiation in resource abundance and exploitation priority among areas around the world, each governing authority may set up its own plan for WEF nexus allocation. Unfortunately, the reported evaluation results were obtained based on different assumptions considering the regional characteristics and differences, and comparison among these results were often impossible or in appropriate since they were derived through different approaches. Along with this idea, this study employed a straight-forward linear multi-parameter simultaneous equation system to examine the sustainable WEF indices which enabled the evaluation of the overall environmental sustainability.

In the present study, the WEF normalized data of the US, Japan and Taiwan were collected and analyzed. The independent parameters included energy price, shared percentage of green energy, industrial electricity consumption, domestic electric consumption, farmer's salary, major food price, cultivated agro-produce supply, livestock supply, fishery supply, access of tap water, treated percentage of wastewater, industrial water consumption, agricultural water consumption, domestic water consumption, population density and gross domestic production.

The WEF models for the three investigated countries were constructed, and the results showed an acceptable agreement between calculated and observed data with the coefficients of determination greater than 0.7. An overall model also constructed considering all the normalized data from the three countries as one dataset, the obtained regression also demonstrated a high R-square value above 0.7. Using this obtained model to calculate the sustainability index revealed that the overall sustainability exhibited in the following trend: the US > Japan > Taiwan, if considering all the WEF resources are equally-weighted. From this study, it demonstrated the possibility of model result comparison if all the calculations were conducted on the same bases.