The "shale revolution" has been a game changer in the global energy market and raised the importance of optimal design and operations of shale gas energy systems. This article highlights key challenges and identifies potential research opportunities in the corresponding area. A brief introduction of shale gas energy systems and their significant impacts are first presented, followed by a comprehensive overview and classification of relevant publications. Based on the literature review, we further investigate and discuss the research challenges of developing integrated, sustainable shale gas energy systems under the guidance of "triple bottom line" and integrated approaches of material flow analysis and life cycle optimization. Leveraging the large amount of data from shale gas industry, data-driven optimization methods could open up new research opportunities for hedging against uncertainty in design and operations of shale gas energy systems. Moreover, potential opportunities are explored by introducing game theory into modeling and optimization of decentralized shale gas systems with multiple stakeholders. The benefits of enabling emerging technologies/operations are discussed as well. (C) 2017 Elsevier Ltd. All rights reserved.