"No battery farm can protect a solar/wind grid from an arbitrarily extended period of bad weather." Generally agree. However, I want to point out that it could

"No battery farm can protect a solar/wind grid from an arbitrarily extended period of bad weather." Generally agree. However, I want to point out that it could defined be possible if designed the right way. You can use "batteries" like pumped hydro, which could protect against longer duration outages. Bonus is that when there's no sun, there's usually rain, which one would hope would also offset some of the draining of the water.