As technology advances rapidly in the energy marketplace, there is an increasing need for more efficient power conversion cycles if thermal power sources are to remain competitive. One such cycle under development is based on the use of supercritical CO2 instead of steam as the working fluid. There are a number of variants and configurations, which are discussed. The key attributes and thermodynamics of sCO2 cycles, applications, the status of some key sCO2 projects and the key challenges/ barriers are presented.