Electric power grid contains three main subsystems, i.e., power generation, power transmission & distribution, and customer facilities. Recently, wireless sensor networks (WSNs) have been considered as a promising technology that can enhance all these three subsystems, making WSNs an important component of the smart grid. However, environmental noise and interference from nonlinear electric power equipments and fading in harsh smart grid environments, makes reliable communication a challenging task for single-channel WSNs for smart grid applications. To improve network capacity in smart grid environments, multi-channel WSNs might be the preferred solution while achieving simultaneous transmissions through multiple channels. In this paper, the performance of multi-channel WSNs is investigated for different spectrum environments of smart power grid, e.g., 500kV outdoor substation, main power control room and underground network transformer vaults. In addition, we also introduce potential applications of multi-channel WSNs along with the related technical challenges. Here, our goal is to envision potential advantages and applications of multi-channel WSNs for smart grid and motivate the research community to further explore this promising research area.