Cost, efficiency, and emissions concerns have motivated the application of advanced control techniques to multiple carrier energy systems. Research in energy management and control over the last two decades has shown that significant energy and CO₂ emissions reductions can be achieved. Within the last decade, this work has expanded to the domain of interconnected energy systems. The interconnection control of multiple energy carriers, conversion devices, and energy storage provides increased flexibility and energy/CO₂ reduction potential. The focus of this article is on outlining the control methods required for these systems over a range of energy consumption and timescales. Dynamic interactions between multicarrier systems occur over timescales ranging from 15 minutes to seasons. The constrained nature of the resulting control problems favors optimization-based approaches.