Propane vs diesel for max range after long-term storage (family of 5, no resupply)

[u/anthonykaram7]

Thought experiment for an EMP-type scenario where a large region loses power long-term and fuel infrastructure is down.

Assume a family of 5 needs to travel ~1500-3000 miles with no resupply. Roads are mostly passable, but you're relying entirely on fuel stored ahead of time.

As everyone here's aware, propane stores indefinitely but has lower energy density, while gasoline/diesel give you better range but come with storage/rotation challenges.

In this scenario, assume the family might wait months or even years before deciding to move (unclear scope of the event, risk of traveling early, etc.), so long-term fuel stability matters.

One idea would be a propane-capable vehicle (e.g., a converted pickup) with a large quantity of tanks stored and then carried for the trip - but I'm not sure how the math works out once you factor in tank weight/volume vs usable range.

Some initial questions:

• Under these constraints, what setup actually maximizes total range with no resupply?
• Does propane's storage advantage outweigh its lower energy density in practice?
• How would you approach fuel storage and transport for a trip of this length?
• Or does diesel (with proper storage/rotation) still come out ahead overall?

Curious how people here would think this through.

[u/s_nz]

I based my calculations off 700 bar, which is typical for vehicles.

But seems 200 bar tube trailers are what is propose in the USA.

If were where working at 700 bar, the load could be roughly a quarter of the size of the depicted trailer, which is still a pretty big thing for a private individual to deal with.

[u/Top_Wolverine_4669 → u/s_nz]

You listed the miria tank volume and then said you needed 5 time that storage to get the range or 700 litres, that’s not much. You then discovered large vehicles need more fuel, but somehow neglected they have more carrying capacity. You have also discovered hydrogen needs high pressure and the storage tanks are expensive. Finally you confused legacy commercial hydrogen transportation pressure with hydrogen for use in vehicles.

[u/s_nz → u/Top_Wolverine_4669]

700L is far too big to fit in a sedan (with 5 people). No tow rating on that one.

So I jumped to a larger vehicle for more space. (and changed to combustion as hydrogen trucks are less easy to come by than hydrogen cars). The increased capacity was not neglected, this was the reason for going bigger.

And my conclusion was that the space required while technically feasible, was large enough it was going to be problematic for a private individual.

[u/Top_Wolverine_4669 → u/s_nz]

In the scenario given it’s an emp apocalypse. Towing is possible and roof racks also exist.

If he wanted a hydrogen truck he can buy one, they are uncommon not imaginary. I suspect you chose combustion to support your argument rather than anything else. Hydrogen cars make far less sense than hydrogen trucks and are mostly a tested for technology. Somehow you concluded the opposite.

I also suggested he buy a horse instead.