[SS] Cost of Hydrogen
 

In GURPS Spaceships page 46 it shows that hydrogen costs $2000 per ton.
In a Traveller style game a typical 100-ton Scout Ship with 60 tons of cargo will need about 20 ton of hydrogen for a 2 parsec jump. That's a cost of $40K.

On GURPS Spaceships 2 it suggests that freight rates are $10 per parsec per day. So in a typical 2 parsec jump in a Traveller universe would be $140 per ton. In the case of full cargo, for the example above it would be a total of $140 * 60 = $8400.

Fuel Cost: $40K
Freight Revenue: $8.4K

What's wrong? Is the hydrogen cost too high or the Freight rates too low?
What changes do you suggest?

Re: [SS] Cost of Hydrogen
 

Using a ship with just 3% of it devoted to cargo is normally not very cost effective for shipping freight.

But in general for Traveller it is better to use the Traveller costs and incomes as Spaceships seems to assume a few thing in their freight costs: No special costs for FTL travel(not true in traveller), low crew requirement(the example designs are such), massed need for trade causing mega freighters and long repayment times for ships(not unrealistic if you assume low wear value, low interest rates and low risk to losing ships).

Re: [SS] Cost of Hydrogen
 

Well, using GURPS Traveller Intestellar Wars for pricing:
Fuel is about $350/dTon.
Freight is $700/dTon/parsec for major or minor routes, and $800/dTon/parsec along branch routes.

If that helps at all.

Re: [SS] Cost of Hydrogen
 

I always assumed Hydrogen's cost was so high in SS, because in reality most easily accessible is locked in water. Getting it out takes energy that has its own added cost.
Traveller has power production that all but eliminates that hidden cost.

Re: [SS] Cost of Hydrogen
 

The cost of hydrogen is basically determined by the cost of producing and liquefying it; most of the time, the raw materials are quite cheap. As such, its price can realistically vary quite a lot depending on your tech assumptions.

Re: [SS] Cost of Hydrogen
 

I use an advanced gas giant refining economy in my campaign, making hydrogen fairly cheap. The PCs are also mainly operating in a star system that specializes in gas mining, so fuel is *very* cheap in system.

Re: [SS] Cost of Hydrogen
 

For what it's worth most industrial liquid hydrogen in real life comes from natural gas through a process called steam methane reforming. It's also often produced more or less on-site with a fairly short distance between the processing plant and the site that's going to use it. (Most industrial hydrogen is used to make ammonia.)

The real life price of liquid hydrogen (in 2002) was roughly $0.70/kg (roughly $650/ton) if processed on site and between $2.0-3.08/kg ($2,000 to $2,800/ton) if it has to be transported. Considering GURPS uses 2004 dollars and tries to base its prices on real life if at all possible this matches the value in Spaceships. I'd argue a science fiction spaceport probably produces it on site (real life spaceports do) and maybe go with $1,000/ton to represent profit and various fees and taxes, etc.

Re: [SS] Cost of Hydrogen
 

Producing hydrogen by electrolysis of water requires 285 kJ/mol or 142 GJ/ton or about 40 MWh, which is a couple thousand dollars at bulk electricity prices. Aqueous ammonia can be electrolyzed for a mere 27 GJ/ton; simple electrolysis won't work for methane and I'm not sure exactly what reactions are used. In space, I suspect icy asteroids containing ammonia ices are the easiest source of hydrogen.

Re: [SS] Cost of Hydrogen
 

There's a few other processes used in special cases and the oil refining industry produces elemental hydrogen as a waste product of other useful refining.

Re: [SS] Cost of Hydrogen
 

Spaceships clearly bases its prices on the default tech, which does not include a fuel requirement for FTL travel.

I ran into the same issue you did, and did some calculations based on a ship that was just the minimums for surface-to-surface freight transport, using my house-ruled Traveller ship rules:

That a jump drive is always one system in size (and costs the listed price for an FTL drive times (1+ J-number)/2)

That jumps take one system of hydrogen per parsec (because Spaceship designs require much bigger control systems, etc., than Traveller ships).

The result was the following:

Freight and Passenger Rates:

In order to account for the cost of jump fuel, prices are adjusted to the following: Cr300 per ton per parsec for freight, and passengers pay for each jump according to the following table:

Distance...Standard
J-1..........2K
J-2..........4K
J-3..........6K
J-4..........9K
J-5..........12.5K
J-6..........18K

Luxury fares cost three times as much, economy half as much, and low-berth one quarter as much.

These numbers do not allow for the extra mortgage repayments for the high-jump drives, just for the fuel costs. Also, as they were based on a ship that had the maximum cargo space (or passenger space) and assumed each voyage was with a full ship for the maximum jump range, PC's owning ships are unlikely to find these rates attractive (intentionally).