I just came across this thread after searching and failing to find an option to add a secondary user account to the portal.
This was prompted by my wife asking to have visibility of the generation data so she can make informed decisions about power use in the house. Note, we have only had the system running for one full day so this level of energy awareness is great!
It would seem that there is not facility to create multiple user accounts so I assume that she will have to use the main account on the app. This is fine but she's not interested in configuration and all the detailed data, just a quick view of current generation an perhaps forecast.
I think a feature providing read only accounts where certain data can be made visible would be a great feature enhancement. I've submitted the request via the feedback route. Hopefully this will be possible in a future release.