I think it’s renewable in a somewhat weaker sense: there is a lot of iron (II) (and perhaps other minerals that can also reduce water) in the crust, and there i

I think it’s renewable in a somewhat weaker sense: there is a lot of iron (II) (and perhaps other minerals that can also reduce water) in the crust, and there is a lot of water, and water percolates and finds these minerals at a rate that may produce hydrogen continuously at a sufficient rate for humanity. More strongly, even if plate tectonics were needed, it doesn’t necessarily take anywhere near 1 TW of power to move enough material to produce 1 TW worth of useful stuff. The energy in question here is chemical, not kinetic.