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The development of shale gas resources is subject to technical challenges and markedly affected by volatile markets that can undermine the development of new projects. Consequently, stakeholders can greatly benefit from decision‐making support tools that integrate the complexity of the system along with the uncertainties inherent to the problem. Accordingly, a general methodology is proposed in this work for the evaluation of integrated shale gas and water supply chains under uncertainty. First, key parametric uncertainties are identified from a candidate pool via a global sensitivity analysis based on a deterministic optimization model. Then, a two‐stage stochastic model is developed considering only the key uncertain parameters in the problem. Moreover, the merits of modeling uncertainty and implementing the stochastic solution approach are evaluated using the expected value of perfect information and the value of the stochastic solution metrics. Furthermore, the conditional value‐at‐risk approach was implemented to evaluate different risk‐aversion levels and the corresponding impacts on the shale gas development plan. The proposed methodology is illustrated through two real‐world case studies involving six and eight potential well‐pad locations and two options of well‐pad layouts.

This work investigates the impact of pretreatment technologies in the design of BioSNG supply chains at a regional and national scale. For this purpose, an optimisation-based framework is proposed to account for two possible routes for BioSNG production. The first route considers processing of raw biomass and production of BioSNG in integrated facilities. The second route consists of pretreatment technologies, transportation of intermediate products, and upgrading facilities. The main objective is to investigate the trade-off between capital investment and reduction of transportation costs, and their impact on the economic performance of a BioSNG supply chain. Moreover, the impact of government subsidisation is further investigated through a parametric analysis in which the tariff is varied from £0/MWh up to £100/MWh. Finally, the major contributing factors in the design of BioSNG supply chains are identified through the implementation of a rigorous global sensitivity analysis (GSA). The results suggest that inclusion of pretreatment technologies improve considerably the economic performance, however, their impact is not enough to detach the development from government subsidisation which influences tremendously the possibility of a large-scale deployment.

The use of agricultural residues for bioethanol production greatly depends on availability of raw materials and the proper design of a flexible multi-feedstock facility. Therefore, this article assesses the economic, environmental, and social feasibility of a bioethanol production plant, using multiple coffee crops residues (stems, pulp, and mucilage). A case study was designed for the Colombian context, considering three scenarios for different capacity plant. Results suggest that the production costs of 0.504, 0.508, and 0.515 $USD/l for large, medium and small capacity, respectively, are comparable to the bioethanol market price and are similar to other studies reported in the literature. The CO2 emissions obtained were 1.296 Kg CO2/l, 1.297 Kg CO2/l and 1.3 Kg CO2/l for the large, medium, and small plants respectively. The large plant requires 1,170 million tons per year of fresh water, and generates a gray water footprint of 119 thousand tons per year. However, without recirculation, 2.87 times more water is required. Favorable results were identified in terms of reduction of collateral environmental effects, as well as positive impacts on social aspects. Finally, a sensitivity analysis shows the impacts of key parameters on economic, social, and environmental merits of producing bioethanol from coffee residues.

This study presents the mathematical formulation and implementation of a comprehensive optimization framework for the assessment of shale gas resources. The framework simultaneously integrates water management and the design and planning of the shale gas supply chain, from the shale formation to final product demand centers and from fresh water supply for hydraulic fracturing to water injection and/or disposal. The framework also addresses some issues regarding wastewater quality, i.e., total dissolved solids (TDS) concentration, as well as spatial and temporal variations in gas composition, features that typically arise in exploiting shale formations. In addition, the proposed framework also considers the integration of different modeling, simulation and optimization tools that are commonly used in the energy sector to evaluate the technical and economic viability of new energy sources. Finally, the capabilities of the proposed framework are illustrated through two case studies (A and B) involving 5 well-pads operating with constant and variable gas composition, respectively. The effects of the modeling of variable TDS concentration in the produced wastewater is also addressed in case study B.

Climate change becomes increasingly more relevant in the context of water systems planning. Tools are necessary to provide the most economic investment option considering the reliability of the infrastructure from technical and environmental perspectives. Accordingly, in this work, an optimisation approach, formulated as a spatially-explicit multi-period Mixed Integer Linear Programming (MILP) model, is proposed for the design of water supply chains at regional and national scales. The optimisation framework encompasses decisions such as installation of new purification plants, capacity expansion, and raw water trading schemes. The objective is to minimise the total cost incurring from capital and operating expenditures. Assessment of available resources for withdrawal is performed based on hydrological balances, governmental rules and sustainable limits. In the light of the increasing importance of reliability of water supply, a second objective, seeking to maximise the reliability of the supply chains, is introduced. The epsilon-constraint method is used as a solution procedure for the multi-objective formulation. Nash bargaining approach is applied to investigate the fair trade-offs between the two objectives and find the Pareto optimality. The models' capability is addressed through a case study based on Australia. The impact of variability in key input parameters is tackled through the implementation of a rigorous global sensitivity analysis (GSA). The findings suggest that variations in water demand can be more disruptive for the water supply chain than scenarios in which rainfalls are reduced. The frameworks can facilitate governmental multi-aspect decision making processes for the adequate and strategic investments of regional water supply infrastructure. Refereed/Peer-reviewed

Shale gas production has been the focus of intense debate in recent years. Shale gas supporters claim that it could be the way to transition between fossil fuels and renewable energy sources. For instance, in the United States, power generation from coal is being replaced by power generation from natural gas, which is a cleaner fuel when compared to coal. However, shale gas critics claim that the environmental cost associated with shale gas production is high enough to negate the benefits to society. For example, high water usage as well as the potential for contamination of underground and surface water sources constitute important environmental challenges for the development of shale gas resources. This study presents a methodology for the preliminary assessment of the development of shale gas resources taking into account well-pad design as one of the most important decision variables. To perform the assessment, different performance metrics are proposed to evaluate not only the economics of developing...

This study addresses the quantification of the impact of wastewater quality, i.e. Total Dissolved Solids (TDS) concentration, on both the economics and the water management strategy associated with the development of shale gas resources. The impact of TDS concentration in wastewater on the water management strategy is quantified in term of the variation of water demand and the share of fresh water in the optimal water supply mix. Similarly, the net present value (NPV) and breakeven cost are used in order to measure the impact of the TDS concentration on shale play economics.

In this work, an optimization framework to support the planning of the development of shale gas resources is proposed. Financial aspects are taken into account through the integration of financing options, such as own capital, and external sources, short and long term bank credit lines. The model also includes the design of well-pads in terms of total number of wells, and length and number of hydraulic fractures completed at each well. In addition, different capacities and locations are considered for compressor stations, gas separation plants, and water treatment plants. A case study involving two alternative financing strategies was conducted to demonstrate the capabilities of the model. It is found that external financing can play an important role in the development of a shale gas field, achieving an increase in net profit of almost 65 % when compared to a scenario where only own capital is considered.