A confluence of market deregulation, drive for energy security and grid decarbonization, and improved distributed energy resources (DER) economics has spurred microgrids to emerge from pilot trials into the commercial market, offering the promise of resilient and green energy. To reap these benefits, microgrid operations need a strong communication foundation: an agile network that can securely connect microgrids everywhere. This white paper explains how a software-defined WAN (SD-WAN) provides a such an agile foundation for microgrids, supporting network automation for microgrids deployed across corporate and institution campuses, data centers and residential communities near and afar.