Increasing integration of renewable forms of energy production has prompted a significant growth in storage technologies to address the intermittent nature of renewable energy generation. Due to the ubiquitous nature of power cables in this environment, power line communications (PLC) is a natural solution to enable robust wired communication in energy management systems. In this paper, we address electromagnetic compatibility (EMC) issues for such systems. We begin by modeling the power cables as transmitting and receiving antennas to determine the impact of radiated emissions caused by PLC on neighboring applications. By illustrating the uniqueness associated with PLC applied in an energy storage unit, we use the standardized EMC limits to determine the maximum feeding signal strength that can be allowed on battery cables. Further, we characterize the electromagnetic interference caused by the PLC signal on nearby wired communication networks, and in particular, derive the interference power spectral density levels that are radiated onto neighboring broadband PLC communications.