High Quality Content by WIKIPEDIA articles! Electronic systems’ power consumption has been a real challenge for Hardware and Software designers as well as users especially in portable devices like cell phones and laptop computers. Power consumption also has been an issue for many industries that use computer systems heavily such as Internet service providers using servers or companies with many employees using computers and other computational devices. Many different approaches (during design of HW, SW or real-time estimation) have been discovered by researchers to estimate power consumption efficiently. This survey paper focuses on the different methods where power consumption can be estimated or measured in real-time.