Recent results are shown about the peculiarities of the pseudo-critical region, with special emphasis on properties important for energy production and conversion. The property-map of some materials, which are relevant as model fluids or as working/cooling fluids in energy engineering (argon, methane, water and carbon dioxide) and their relative positions to various adiabats–influencing their stability through the anomalous properties–are presented. Some potential technological problems related to the existence of these anomalies are discussed.