A Smart Grid with distributed generation is critical for reducing greenhouse gas emissions. However, current power converters and circuit breakers built with silicon switches are very bulky and inefficient, making their use difficult in practical Smart Grid systems. The development of high voltage power devices based on SiC will be a critical development in building a Smart Grid with distributed and fluctuating sources of power generation. In this paper, the physics and technology of high voltage (> 10 kV) 4H-SiC power devices, namely MOSFETs, IGBTs, and GTOs, are discussed. A detailed review of the current status and trends in these devices is given with respect to materials growth, device design, and the potential future ranges for use.