At a few sites I have experienced a problem where none of the Power Management charts will show in the canned SQL Reporting Services reports. Everything looks like fine from the client side, power management is part of the inventory and data is being send correctly back to the Management Point. Yesterday evening I found the solution the Technet forums (credit goes to Paul024).
In order to fix the problem, log on to the SQL Reporting Services point and run Dunsetup.exe (found in Configuration Manager install dir\Bin\I386\)
The report after running Dunsetup.exe