> What I wanted to get at with my questions was "what's the ratio of bad stuff produced per kilometer driven for hydrogen and for batteries?" Right. When compa

> What I wanted to get at with my questions was "what's the ratio of bad stuff produced per kilometer driven for hydrogen and for batteries?" Right. When comparing objects of similar complexity, cost of the object is generally pretty proportional to bad-stuff-produced, with exceptions for unpriced externalities (carbon emissions being a big one, and mining or refining in low-responsibility jurisdictions being another). The carbon emissions of battery pack manufacturing are small[1] relative to lifetime emissions from an ICE car, not totally sure for FCEV. > Both systems are going to have different ratios between Bad Stuff and efficiency and my unqualified guess is that hydrogen _might_ be better. I couldn't find anything specific to FCEV, but my gut instinct is that FCEV would be dramatically worse - hydrogen is reformed from natural gas, necessarily entailing carbon emissions. If you're going to release the CO2 from natural gas anyway, might as well do it by burning in a high-efficiency turbine and use the energy to charge your BEV at high end-to-end efficiency. Or if you're going to consider "green" hydrogen, might as well use the renewable energy to directly charge a battery, at 3x higher efficiency. [1] https://theicct.org/sites/default/files/publications/EV-life-cycle-GHG_ICCT-Briefing_09022018_vF.pdf https://theicct.org/sites/default/files/publications/EV-life...