Can I run a 100kW inverter off a 1MW busbar?

This is much bigger stuff than I'm used so, but as general principles...

MPPPT - generally that would have to operate independently for each group of panels that could produce output that varied compared with other groups - so if all your panels were identical and installed with the same orientation and lack of shading etc. I guess you could just have one for the lot. More likely you'd need something for each string before they're combined into a single bus (there are DC-DC MPPTs out there for small (battery charging) systems but I've no idea if there's anything for your size of system). Or I suppose you could go old school and just parallel everything up with a few blocking diodes and not worry about extracting maximum efficiency from it.

As for grid-forming (i.e. off (national) grid systems) - it all rather depends on how you intend to match supply and demand. Presuming you can't instantly alter demand to match supply, a battery driven inverter is certainly the most common option. But there are subtle variants out there. Some system can for instance have a conventional generator in the mix, and the PV inverter in effect reduces load on the generator (often the generator is the grid-forming element and the PV system behaves as if it's a conventional grid connected inverter). Likewise I've seen descriptions of systems where a small battery generated inverter does the grid forming, and can work with conventional PV inverters (if necessary tweaking the "grid" frequency to modulate PV inverter output) and/or calling on a conventional generator. I suppose if you had more controllable renewable sources available (e.g. hydro from stored water) you could add that into the mix too. Again these are typically much smaller systems (off grid homes/RVs etc. so may or may not scale). So never say never, but usually a battery is the most practical solution.

   - Andy.

This is much bigger stuff than I'm used so, but as general principles...

MPPPT - generally that would have to operate independently for each group of panels that could produce output that varied compared with other groups - so if all your panels were identical and installed with the same orientation and lack of shading etc. I guess you could just have one for the lot. More likely you'd need something for each string before they're combined into a single bus (there are DC-DC MPPTs out there for small (battery charging) systems but I've no idea if there's anything for your size of system). Or I suppose you could go old school and just parallel everything up with a few blocking diodes and not worry about extracting maximum efficiency from it.

As for grid-forming (i.e. off (national) grid systems) - it all rather depends on how you intend to match supply and demand. Presuming you can't instantly alter demand to match supply, a battery driven inverter is certainly the most common option. But there are subtle variants out there. Some system can for instance have a conventional generator in the mix, and the PV inverter in effect reduces load on the generator (often the generator is the grid-forming element and the PV system behaves as if it's a conventional grid connected inverter). Likewise I've seen descriptions of systems where a small battery generated inverter does the grid forming, and can work with conventional PV inverters (if necessary tweaking the "grid" frequency to modulate PV inverter output) and/or calling on a conventional generator. I suppose if you had more controllable renewable sources available (e.g. hydro from stored water) you could add that into the mix too. Again these are typically much smaller systems (off grid homes/RVs etc. so may or may not scale). So never say never, but usually a battery is the most practical solution.

   - Andy.