Which Fronius inverter do you have? It is relatively easy to access the modbus through emonhub, which is how I get the data for my Fronius Primo. You can write some code to access the push service but then you will probably end up with different scripts and needing to update/integrate when things change (as happens with IP address changes etc). I used to do this but it was fiddly.
The emoncms config file (menu - setup - emonhub - edit config) can be modified to include a modbus call routine, which will then add a new node to your input/feeds page with the data you want.
There are a couple of threads showing how to do this eg fronius.
The main hurdle is using the correct modbus registers, but there is some good experience in this community to help.