I think the other commenters are mostly right but also downplaying the technology advances a bit. The basics of the battery chemistries that are making this wor

I think the other commenters are mostly right but also downplaying the technology advances a bit. The basics of the battery chemistries that are making this work existed two or three decades ago, but there have also been meaningful breakthroughs in the specific components during that time, that (I think) eventually pushed the viability over a tipping point. In 2004, I think it would have been reasonable to think that EVs would always be a niche for small short range "commuting cars". I remember thinking this, and being excited about even that possibility! But now I frequently see these big Rivian trucks and SUVs driving around, and I know their range is similar to a tank of gas. That seems pretty crazy to me! And it wasn't just the economics of scale that has made that work. In the case of stationary batteries, I think just the economics driving the price down has indeed been the most important factor, but something else I haven't seen anybody mention yet is that it also has a lot to do with solar barreling down its cost curve, kicking off massive deployment, to the point that it is a fairly common occurrence now for some locations on some grids at some times of some days to have negative power prices due to solar over-production. Batteries are excellent at sopping up extra power that would have otherwise gone nowhere (or to crypto mining perhaps, but maybe I'm repeating myself).