Unless I missed it, there is no mention of the environmental cost of the process itself. What I mean by that is all the chemistry / electrolysis / carbon nanot

Unless I missed it, there is no mention of the environmental cost of the process itself. What I mean by that is all the chemistry / electrolysis / carbon nanotube stuff, they do mention that this is where the main cost is, but what happens when that equipment needs to be replaced? What is the environmental impact of the equipment itself?