The recent advances in extraction technologies and the discovery of enormous shale reserves around the world have generated a great interest in exploiting of this resource to satisfy the current increasing energy demand in addition to the low greenhouse gas emissions associated to this fossil fuel. However, shale gas industry is surrounded by several challenges such as the sustainable planification of new gas supply chains considering all the aspects involved in shale gas production (which is relevant mainly for the regions where the shale gas production is not currently carried out but it is planned to start in the short term). Hence, this work proposes the holistic design of a gas supply chain through an optimization approach considering economic and environmental targets in shale gas production. Additionally, the model formulation considers that the fixed gas demands of the markets can be met by shale gas in conjunction with conventional gas as well as the possible importation of gas. Then, the methodology requires unit costs and environmental indicators for each source of gas including its transportation route. Other important aspect accounted by the proposed approach is the optimal selection of the fracking fluid with the purpose to evaluate the performance of a set of fluids that have been efficiently tested in this task. Also, the mathematical model is configured to consider the processing hubs installation for shale gas once it is produced; these types of plants are commonly employed to eliminate undesired residues and even to compress the gas.
Moreover, the economic objective consists in maximizing the total annual profit, which is composed by the gas selling in markets and shale and conventional gas production costs (including the fracking and processing costs), the importation of gas, as well as the transportation costs and the capital costs generated by the required processing hubs. Whereas the environmental aspect deals with the minimization of the global warming, human health and eutrophication categories with the purpose to find a supply chain pathway with the lowest impact It is worth to mention that these indicators were evaluated using the Tool for Reduction and Assessment of Chemicals and Other Environmental Impacts (TRACI) technique.
Finally, an example for the case of Mexico is implemented to evaluate the proposed methodology, it should be noticed that Mexico has not yet exploited its shale reserves on a large scale.
