AEM/Energy Profiler is not enabled by default for WGM160P target (using WSTK). Until that is being enabled in Simplicity Studio, you can follow the instruction below:
1. Plug your target platform: WGM160P Wi-Fi® Module Starter Kit (SLWSTK6121A)
2. In Simplicity Studio right click on the "J-Link Silicon Labs" debug adapter and choose "Device Configuration":
3. Under the "Device hardware" tab change the "Target Part" to EFM32GG11B820F2048GM64 as shown below.
4. Click OK then launch Energy Profiler
5. Under "Quick Access" select "Start Energy Capture"
6. Choose the J-Link adapter then click OK.
There are two power domains on the STK. One for the WGM160P and peripherals, where the other is for the board controller (debugger, etc.). The Energy Profiler only measures the first one. Therefore the measurements are extremely close to the true power consumption of the WGM160P itself. Also note that the Energy Profiler circuit on the STK has a max reading of 95mA so it might max-out during Wi-Fi transmission.
If you want to get even more precise or more range you would need to use a scope or power analyzer to measure the current at resistor R616 or at J1 on the WGM160P radio board. See/request the board schematic and layout for reference.