What actually changed?

So random consumer who just bought a ton of batteries here: i don't follow the hype closely, nor am i a crazy battery dude, but i have tracked over the years the cost of doing battery backup vs generator, etc.

It's definitely the case for me (and friends of mine), that between reasonably priced batteries, inverters,etc, doing good battery backup for the house (and peak demand shaving/etc, i use a lot of power and take advantage of time of use tariffs) is now less than half the price of a generator.

Most of my friends spent 35-45k on a generator.

I will have spent <20k on batteries + inverters. It would actually be even less, but i have 600amps of split phase for the house, and 150 amps of 480v 3 phase for the shop, so i need two different kinds of inverters.

It is all literally being installed right now.

I would actually go completely off grid, but i live in a historic area and have slate roofs so can't really do solar easily ;)

As for what changed - 12 months ago this setup would have been almost double the price, just because of the availability (or lack thereof) of the right kinds of products necessary to achieve it. I know because i priced it :)

Availability here isn't in terms of stock, but literally in terms of "variety and choice of product".

For example - the availability of UL certified low cost 48v batteries in various sizes has skyrocketed in the past year. Lots of states require UL certification, assuming you are doing this in a permitted/etc way) Additionally, a lot more outdoor batteries are now available (my setup is outdoors but mostly protected).

The availability of choices in higher kVA but still residential grade inverters has also skyrocketed, etc.

As for why the price was doubled - before i would have needed 2x the number of inverters, and you really couldn't get a good 480v inverter except with high volt batteries that are wildly less available and wildly more expensive. On top of that, the batteries you could use that were UL certified and outdoor rated or could easily be done in outdoor enclosures was much lower than it is now.