Technology-based computer-aided design models have been used to predict the static and dynamic performance of ultrahigh-voltage (UHV) 4H-silicon carbide (SiC) P-i-N diodes, insulated-gate bipolar transistors (IGBTs), and gate turn- off (GTO) thyristors designed for 20-50 kV blocking voltage capability. The simulated forward voltage drops of 20-50 kV device designs range between 3.1 and 5.6 V for P-i-N diodes, 4.2-10.0 V for IGBTs, and 3.4-7.8 V for GTO thyristors at 20 A/cm 2 for room temperature operation. Moreover, with a low switching frequency application (i.e., 150 Hz) in mind, the switching energy losses using a 30 kV SiC GTO thyristor design are approximately E ON /E OFF _ GTO = 268/640 mJ, E ON /E OFF _ FWD = 388/6 mJ diode recovery losses, and E ON / E OFF _ SNUB = 954/22 mJ snubber component losses. The corresponding values for an SiC IGBT design are E ON / E OFF _ IGBT = 983/748 mJ, both operated at 448 K, τ A = 20 μs, and with 30 A/cm 2 . The simulation output is used in a benchmark evaluation for a 1 GW, 640 kV application case, employing modular multilevel high-power converter legs comprising series-connected UHV SiC devices and state-of-the-art 4.5 kV Si bi-mode insulated-gate transistors. It is concluded that the high-voltage SiC power electronic building blocks present promising alternatives to existing high-voltage Si device counterparts in terms of system compactness and efficiency.