Do you guys remember when Edmund’s did some testing a couple years ago and found that you emit more emissions running a leaf blower for 1/2 hour than you would driving a ford raptor all the way from Texas to Alaska? That’s when it really hit me how clean cars are nowadays. I don’t think there is much more that can be done to reduce automotive emissions short of a transition to hydrogen.
Hydrogen has an enormous amount of drawbacks and hurdles. Specifically transportation and storage. It is the smallest molecule and keeping it sealed is a significant challenge. I use Helium mass spectrometers at work constantly and keeping helium contained is extremely difficult, hydrogen is even more so. This isnt a huge issue with helium since its an inert gas but hydrogen is easily ignited so the emphasis to keep it completely contained is much more significant.
Hydrogen combustion efficiency is also terrible with current technology, when compared to gas/diesel (both of which are also terrible). Basically, it takes alot of hydrogen to get anywhere near the same amount of work done when compared to traditional fuels or electricity.
Toyota produces a hydrogen ICE powered vehicle and has been producing it for years now. Recently, the only major fuel provider of hydrogen closed down 90% of their fueling stations, mostly existing in CA, due to lack of demand. Toyota now sells their brand new hydrogen powered vehicles for ~8,000-10,000$ brand new due to the fact that you cant fuel them up anywhere.
Hydrogen has the added benefit that it is super easy to produce. I have built my own electrolysis reactors and they work great, the primary issue is the accelerated oxidation of the anode and cathode plates. My earliest models used solid copper plates. Those survived for maybe half a day in a salt catalysed water solution. Tried stainless steel which sacrifices ~80% electrical efficiency but last many times longer. I then tried silver (INOX-11 alloy) which performed incredibly well but is many times more expensive. I think, ideally the plates would be made of perforated iridium but then cost would skyrocket but should last about as long as is possible and with excellent efficiency. Other problem is that the majority of known iridium is coming out of Russia's extreme depth mining projects, while the US has huge amounts of silver that really doesnt get used for much.
My concept had been, rather than storing the hydrogen in a tank, the reactor could exist at each fueling station in a dormant state, holding water which is easy to transport and store. Solar/wind generation could keep a battery storage system topped off. When a vehicle requests to fuel up, the reactor could trip on, start generating hydrogen and oxygen gas, funnel that into a pressure tank and pipe it directly into your vehicle. Then the only storage issue of compress hydrogen/oxygen is in the vehicle. As with most of these developments, someone needs to pump massive amounts of $$$ into it to make it a reality. Not just the private sector, but the Feds need to back it as well and so far, the feds primarily support fossil fuel first, EV second, and forget about anything after that.