An Integrated Approach to Water-Energy Nexus in Shale-Gas Production

Abstract

Shale gas production is associated with significant usage of fresh water and discharge of wastewater. Consequently, there is a necessity to create proper management strategies for water resources in shale gas production and to integrate conventional energy sources (e.g., shale gas) with renewables (e.g., solar energy). The objective of this study is to develop a design framework for integrating water and energy systems including multiple energy sources, the cogeneration process and desalination technologies in treating wastewater and providing fresh water for shale gas production. Solar energy is included to provide thermal power directly to a multi-effect distillation plant (MED) exclusively (to be more feasible economically) or indirect supply through a thermal energy storage system. Thus, MED is driven by direct or indirect solar energy and excess or direct cogeneration process heat. The proposed thermal energy storage along with the fossil fuel boiler will allow for the dual-purpose system to operate at steady-state by managing the dynamic variability of solar energy. Additionally, electric production is considered to supply a reverse osmosis plant (RO) without connecting to the local electric grid. A multi-period mixed integer nonlinear program (MINLP) is developed and applied to discretize the operation period to track the diurnal fluctuations of solar energy. The solution of the optimization program determines the optimal mix of solar energy, thermal storage and fossil fuel to attain the maximum annual profit of the entire system. A case study is solved for water treatment and energy management for Eagle Ford Basin in Texas.

A Stochastic Optimization Approach to the Design of Shale Gas/Oil Wastewater Treatment Systems with Multiple Energy Sources under Uncertainty

“…Hence, thermal and power loads for plants are calculated. Similar approaches have been proposed earlier in the literature for other applications [13,39]. Furthermore, various percentage of solar energy contribution in the total mix of thermal power that supplied to the system is chosen to add further simplifying to a computational approach and to assess the economic feasibility of incorporating solar energy to the system.…”

“…Since energy is needed in treating wastewater, any meaningful strategy should consider the water-energy nexus nature of the problem [7,12,13]. Wastewater treatment systems are mostly driven by thermal energy (e.g., multi-effect distillation, multi-stage flash, and membrane distillation) [14][15][16] or electric energy (e.g., reverse osmosis) [17][18][19].…”

Neutrosophic Optimization Model and Computational Algorithm for Optimal Shale Gas Water Management under Uncertainty

“…The different expected objective functions were incorporated, which led to the existence of uncertainty in the modeling approach. Interested researchers can find recent publications on shale gas development and future research scope in Chen et al [24], Knee and Masker [25], Lan et al [26], Ren et al [27], Zhang et al [28], Denham et al [29], Al-Aboosi and El-Halwagi [30], Jin et al [31], Ren and Zhang [32], and Wang et al [33].…”

Simultaneous Energy and Water Optimisation in Shale Exploration

“…Considering the uncertainties associated with shale gas exploration in terms of water usage for hydraulic fracturing, flowback water generation, the cost associated with water management, and the price of oil and gas, future work will address the uncertainties associated with the process and the possible impact of such uncertainties on the overall project. Future work can also consider multiple desalination technologies and the integration of fossil energy with renewable sources to reduce the carbon footprint of the resulting network [34,35]. Hence, sustainability-based objective functions can be used to optimise the system design [36,37].…”