3000 cycles “lifespan” but most of the degradation happens in the first couple of years with the rate of degradation about 3% a year, capacity still remains and the product will still have significant capacity in 20 years.

As opposed to say a synchronous converter which requires annual downtime and continual replacement of parts, and (being limited by inertia) can’t provide the same stability and support that a battery can.

The payback period is ~18 months so lasting less than 10 years is mostly irrelevant.

On top of that these systems are still useful well below their original capacity, so they can rather than a sudden huge bill you simply add more capacity as the original battery’s degrade in a fairly predictable fashion. Over time you end up with a much smaller annual investment than your saving every year.

payback is not the goal though, it's about avoiding sucking earth resources

You can always recycle the batteries and use it to create new batteries.

Recycling uses resources too.

But grid batteries directly save resources, in this case money saved is a good proxy for less resources used.

Payback is a prerequisite to people to actually buying your less earth sucking technology so while it might not be the end goal it's a goal nonetheless.

yeah indeed