viability for code with any of these kinds of project.
Anything in the same or adjacent class as PowerWall is going to be code compliant, otherwise it doesn't make sense for the manufacturers to charge such a premium for them. I would classify the PowerWall as a very simple turnkey friendly install, of a UL9540 ESS.
Then starting from there from most broadly code compliant to less broad are:
De jure better due to direct alignment with code
- UL9540 paired listing inverter and battery
- UL9540 separate listing for inverter and separate listing for battery
The PowerWall is obviously (if you are familiar with its internal architecture) a paired listing because it comprises a battery inverter in the same package as a battery
Perhaps de facto better than lower options, but who knows. None of the ones below are not a high enough certification level to be code relevant.
- Factory assembled battery, non UL version of a UL listed product. EG4 has pre UL version of their batteries
- Maybe UL9540A or 1973 batteries
The main advantages are easy insurance (because you have permits) and permission to grid tie in all jurisdictions.