Not sure if I missed it but didn’t see anything in your source to back up this 7 years worth of battery production requirement for what the US needs in stationary storage. Without seeing how we got to the number, I’m skeptical. Things worth considering:
1) decommissioned battery packs from electric cars will eventually have 2nd lives on the grid
2) the manufacturing capacity of li-ion globally today is paltry compared what’s needed just in the batteries for mobility, let alone grid storage. Just like underestimations done for solar and wind, I expect current projections to be undershooting where we’ll end up
3) effective demand response (ramping up and down variable loads like commercial refrigeration, heating water, among others) based on renewable generation levels can effectively replace large chunks of battery storage requirements.
4) wind and solar generation profiles compliment each other - when it is usually sunny, it’s not too windy and when it’s colder (night, winter) wind generates more. Add in negative energy prices in periods of excess generation / curtailment - that is economic opportunity for energy storage to come in and capture value
5) li-ion batteries as they are today are effective for “peak shifting” applications of moving energy across a few hours, but not across weeks or even across seasons. Where it is applicable, pumped hydro and other tech can better fill those other spaces - but we can still make lots of progress prior to those ramping up.
6)Investing in broadening the connectedness of grids across states / countries / continents is another way to reduce generation variability with renewables as across, say North America - it may not be very windy in one state at a given moment but 1000mi away it could be either sunny or windy elsewhere. Smoothing the generation across geographies and types ( connecting hydro and nuclear to more grids) is another way to reduce the amount of energy storage required on a grid.