Hi,
I run a small solar panel on my balcony. I want to measure the energy (in watts) which the solar panel produces using a WLAN connected plug. Do you have any recommendations which plug is suitable for outdoor usage, and can be connected via an existing binding to openhab via wlan?
I don’t want to setup any additional hubs (like zigbee, mqtt, etc.) as I don’t know how to do it?
Best regards
Hannes
Duplicate by purpose or error?
mqtt does not need a hub, as it’s only a protocol (like http). So you don’t need to worry about complex setup or expensive hardware.
When using openHABian, simply go to openhabian-config and chose 20->23 Mosquitto, as mqtt is a client-server-based protocol.
When not using openHABian, just search about how to install Mosquitto and install it 
In a simple LAN environment (such as a FRITZ!Box and maybe a switch) the mqtt broker then will be available for all devices which are bound to the LAN/WLAN, including openHAB, which also will act as a client to Mosquitto.
You can use other options to communicate with hardware, but please be aware that mqtt is by far the simplest solution (of course after learning how mqtt is working).