I want an hybrid inverter that can for example supply a 2000W load If I'm only getting 1000W from a solar array by combining it with 1000W from the grid. but if conditions change from getting 1000W to now 3000W from the solar array I want it to adaptively start using 2000W for the load and use the remaining 1000W to charge a battery bank.
Pretty much all hybrid inverters do that.
I would also like to be able to supplement the solar array power with battery power at times as well.
Same
The main goal is to never give back to the grid and only taking from it to supplement the array power short fall when I need to.
I also might want to go completely off grid one day and would also like the inverter to be rated at 5-6 kW.
thanks in advance.
No issues, that's what a hybrid inverter is for.
You have several choices to make:
1) High voltage battery or low voltage battery (48V)
High voltage is more efficient. But it is proprietary, each inverter brand is married to a battery brand so you have to cross fingers that customer support will be available during the life of both components, it also means more expensive. Some countries also impose special safety requirements (ie, more expensive installation) because a >200V DC battery with huge output current capability is not something you want to have any chance of getting zapped by.
48V has lower efficiency (about 10% energy loss in both directions) but there are tons of compatible battery options, voltage is safer, less safety precautions, cheaper. If your inverter or battery dies in 10 years you WILL find a new one compatible with the rest of your system, because 48V is like Ethernet, lol.
2) Injection or pass through
These inverters have two AC ports: grid and backup. Some have three: grid, generator, and backup.
If you want to be able to use a generator to charge your batteries in case of blackout, not all inverters support it (Deye does).
Most inverters use injection: it measures power drawn by the house from the grid and injects enough power to compensate it. Power for the whole house does not go through the inverter, which means the inverter does not need to be sized for the whole house. Only essential loads are connected to the backup output, which stays powered in case of blackout. Thus you have to rewire some loads and make a secondary "backup" panel.
Some inverters use pass through: you have to pass the power for the whole house through the inverter, it will backup the whole house, and it will draw as little power as it can from the grid. In this case the inverter has to be rated for the power used by the whole house, which is more expensive.
Backing up the whole house is only realistic if you have a huge installation. It is wiser to just backup essential loads, that way your freezer will still work and your battery won't be drained by all the non-essential stuff.
3) Idle power use
If you intend to go offgrid, mind the idle power use of the inverter. Some are pretty high.
If you go with 48V and injection you'll end up with the usual suspects list: Victron, Solis, Deye (Sunsynk, Solark), SOFAR, etc