Microsoft this week detailed an obscure command line tool for Connected Standby (now InstantGo)-based PCs and devices that will help identify which applications are causing battery drain while the machine is sleeping. Dubbed Sleep Study, the tool is part of the powercfg.exe utility in Windows 8.1/RT 8.1 and will tell you how well the system slept and how much activity it experienced during that time.
Source : Paul Thurrott's SuperSite for Windows
