Re solar not working when the grid is down- there are inverters that can run while the power is off- these are called 'hybrids' and they do cost more than simple gridtie inverters...
Depending on how much you want to spend, the cheapest hybrids (cost about twice as much as a standard gridtie one) simply run at reduced power from solar only- no batteries- so these will usually deliver about 1/5th of the panels rated output, and only during solar generating hours ie they can be handy when there is extended periods of outages such as cyclone damaged grids here in Australia, which could take a week or more to be repaired- a 'solar only' hybrid allows you to recharge 'camping lights' phones, tablets and laptops, or even a small battery to run a camping 12v inverter offand keep your fridge running during the day (turn it up to full, and fill the fridge and freezers unused areas with plastic bottles 3/4 filled with water- these will keep it cool at night even with no power) - these often only have a single socket on the front panel to plug stuff into...
(Outback makes inverters that can do this- a well known company that makes both gridties, hybrids and offgrid inverters, another is well known one is Growatt (note that not ALL their range does this, just selected ones, in both cases)
Next you have hybrids with a attached battery pack- often 24v or 48v- these require a sparky to isolate the circuits you want power to, these are then put on a separate sub-board- depending on the inverter, it may incorporate automatic switching, or have a manual 'changeover' switch needed (mine is such an inverter, although I use it purely as offgrid only) obviously more expensive than a straight gridtie only one (in my case about four times the price but as I am offgrid entirely, a straight gridtie would be pretty useless lol)
Mines a 230v, pure sinewave, 12kw continuous, 36kw for 20 seconds peak, dual MPPT solar inputs rated at 3kw each, circuits connected to the output have auto switching, and can be used as 'changeover' or in UPS mode, where they run continuously off the inverter, and it runs off the mains (good for places with 'dirty power') by Sigineer
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Another option that is popular here in Australia is the 'powerwall' type system- may here have it to reduce electricity costs by storing power generated during the day from their solar in the powerwall first, then exporting any excess like a normal gridtie, during the night the powerwall supplies your household needs, only if the battery is close to depleted or the power required is more than its internal inverter can supply, will it go back to the mains grid- sorta like being 'offgrid' but using the grid as the 'emergency backup' instead of a petrol powered genny...- these run in the hundreds of volts range, Tesla is the one that 'everyone talks about', but there are many others Panasonic, BYD BBox etc that have been around just as long if not longer, and are far better value for money than the Tesla offerings...
https://www.savingwithsolar.com.au/byd-b-box-australia-review-price/(not affiliated in any way with any of them, I'm just a mostly retired sparky who has been doing solar for the last forty years lol)