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| Siwastaja:
Quick recap of why hydrogen is not a practical power source for vehicles: 1) Very poor roundtrip efficiency, 30% that of battery EV. While crap efficiency is not problem during excess power generation, we are far from annual net excess, thus efficiency matters. 2) Expensive fuel cell system (large, even more expensive fuel cell, or smaller coupled with still expensive high-power battery pack); li-ion battery pack cost crossed the fuel cell system cost years ago, now being around $5000. 3) Need for distribution system comparable to that of gasoline distribution, with chicken-and-egg problem. (Compare this to EVs where the chicken-and-egg problem just went away a decade(!!) ago already, thanks to two factors, any-socket charging and general simplicity/low cost of fast charging stations) Any single of such problems could be manageable, but all three together makes it a total no-go, which is exactly why it has not happened despite all predictions by certain non-technical people, and will not happen. It is worth noting there are no solutions to any of these; they are unsolvable*, something that can only be worked around / accepted as they are. *) except for point 2, where theoretically a lower cost system could emerge, but don't hold your breath If neither modern li-ion cells nor gasoline vehicles existed, then hydrogen would probably be a good idea for a fresh start, instead of fossil (or biofuel) gasoline/diesel ecosystem. But real world is not tabula rasa. It is quite interesting we are still having this discussion in 2023 but I guess some people just will remain blindfolded, regardless of glaring evidence around their daily lives. |
| Marco:
--- Quote from: Infraviolet on July 09, 2023, 04:21:12 pm ---If we want to get fossil fuels out of transport the only hope is hydrogen fuel cells (or hydrogen combustion engines) --- End quote --- I used to think the same, but the cost projections for CO2 capture combined with the free near unlimited capacity methane synthesis reactors under ground make renewable methane something to consider too. It's not a great fuel for consumer cars either, but trucks already use liquid methane right now. |
| Marco:
--- Quote from: Siwastaja on July 11, 2023, 05:46:32 pm ---large --- End quote --- SOFC can be made extremely high power density. I'd like to see F1 move to liquid hydrogen and SOFC. PS. there are no 10 MW range chargers for fast charging of trucks. Fast charging costs are going to rise as the slack goes out of the grid, fast charger stations will start needing storage (probably sodium batteries). |
| Siwastaja:
--- Quote from: Marco on July 11, 2023, 06:14:30 pm ---PS. there are no 10 MW range chargers for fast charging of trucks. Fast charging costs are going to rise as the slack goes out of the grid, fast charger stations will start needing storage (probably sodium batteries). --- End quote --- You forget that the contender for hydrogen is not just battery, it's gasoline/diesel, using the existing infrastructure. Those long-haul semi trucks already are the pinnacle of fossil fuel engineering and run at significantly higher efficiency than most road vehicles, and as being heavy and expensive anyway, come with quite complex exhaust purification systems (like adblue, particulate filtering and whatnot), which also have some chances of working as the use cycle is non-stop driving in optimized process conditions. These large vehicles are the last to be electrified. We don't need to convert them to either BEV or hydrogen EV. Remember, while the general aim should be towards zero fossil fuel use, in reality it's not all-or-nothing. There are still many low-hanging fruits to be picked. These are passenger vehicles and smaller delivery trucks (BEV) and building heating systems (heatpumps). In other words, making large changes for small gains makes absolutely no sense, when you can make smaller changes for larger gains. |
| tom66:
--- Quote from: Marco on July 11, 2023, 06:14:30 pm ---PS. there are no 10 MW range chargers for fast charging of trucks. Fast charging costs are going to rise as the slack goes out of the grid, fast charger stations will start needing storage (probably sodium batteries). --- End quote --- If a truck can go 9 hours on one charge (90 kph * 10 hours = 810 km/~500 miles) then it doesn't need ultra fast charging to be available. It is usually not legal for a driver to go longer than that (the UK allows 10 hours, but only twice in every week.) A 500kWh battery can achieve that. It's a big unit, probably would add about 2-4 tonnes to a vehicle payload. EV trucks are allowed to weigh up to 46 tonnes in the UK to accommodate this. (Standard limit is 44 tonnes.) But another option is catenary charging or charging in the mandatory 45 minute rest break at the 4.5 hour point. (40 minutes at 500kW charging adds almost 60% to the battery pack.) Unlike cars, trucks have the advantage of central logistics and hubs, with logistics managers planning most of their routes, so they will plan stop times and destinations would have overnight charging available (50kW DC charging would be fine in this case.) Double crewing is more difficult but AFAIK that's rare in UK/EU, more common in the US. Those truck drivers would probably prefer hydrogen. The faster transport would be balanced against the higher cost of energy and likely higher operational cost of the vehicle. |
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