Rocket Fuel vs Solid Fuel cost analysis

[GregFirehawk]

I'm sure this has been covered heavily before, but this is still a commonly searched question and I happened to quickly recalculate this recently so I thought I'd just share the findings for anyone interested.

From a materials perspective, rocket fuel costs roughly 32% more per MJ. It requires 11 times as many resources for only ~8.3 times as much energy as a single solid fuel.

From a pollution perspective, rocket fuel is over 3 times as expensive. The crafting recipe for solid fuel is 1 second, and 15 seconds for rocket fuel. Rocket fuel also requires 10 solid fuel, making it a total of 25 seconds spent in chem plant, vs solid fuels ~8.3. So the chem plants alone contribute 3 times as much pollution, and it still requires 32% more material, which means 32% more pollution at the refinery stage also.

Rocket fuel offers a top speed boost of 15%, and an acceleration boost of 80%. Since it's 32% more material, and over 200% more pollution, rocket fuel should not be used for anything beyond rockets

For posterity in case the game gets rebalanced, the current value for solid fuel is 12MJ, and the current value for rocket fuel is 100MJ

[Tertius]

The point of rocket fuel isn't just that it can be burned but also that it is a required intermediate. You simply have to produce rocket fuel as product, not for burning.

If you just look at the energy balance, keep in mind you're able to use productivity modules in the rocket fuel production step. With 4 normal productivity modules in the assembling machine 3, you get 40% more.
Input energy is essentially 11 solid fuel, which has energy value 11 * 12 MJ = 132 MJ.
Output energy is 1.4 * 100 MJ = 140 MJ.
So this is a net gain of 6%. Not much, but still a gain.

People usually don't compute the energy demand for a moduled rocket fuel production line, since there are so many options for power production. However, when you are able to use modules on a larger scale, you have probably infinite energy from nuclear power anyway and are not producing rocket fuel for burning any more.

On Aquilo, this is different: you're able to use the ammonia rocket fuel recipe in the cryogenic plant, which you can equip with 8 productivity modules. Ammonia is infinite, so it's not very important to be efficient, but it's an output of:
1.8 * 100 = 180 MJ.
This is 36.4% more and additionally you need the increased energy density of rocket fuel to power all your heating towers. Otherwise you're exhausting your resources just for distributing huge amounts of solid fuel.


So if you need to power a steam power plant on Nauvis in the early and mid game there, it's most energy efficient to use solid fuel. But is it really what you should do?

At this early stage of the game you don't have access to many crude oil resource patches. If you use your precious oil to produce solid fuel and burn this for electricity, it can happen you don't have enough for producing plastic and the other oil products you need for mall and science production. It might be a better decision to use coal for your steam power plants instead of solid fuel, since coal is abundant and you just need to mine it without any intermediate refining step. It's increasing pollution, but this is not an issue for most bases.

[NineNine]

From a materials perspective....

From a pollution perspective...

...rocket fuel should not be used for anything beyond rockets

Assuming, of course, you care about materials or pollution. Oil pumps don't ever completely run out. On Nauvis, pollution is largely irrelevant once you have artillery. And then, if you're playing Space Age, pollution doesn't even matter on the other planets.

But, for the early part of the game, before you launch a rocket, I generally agree with you. Solid fuel is good enough in most cases. (Unless you want to do something funky like megabase before you even launch a rocket).

[eugenekay]

I think that the “Production Cost” for each Burner Fuel type is actually the least important factor - assuming that you have enough Electricity to run an Oil refinery and a couple of chemical plants. If not, add more Reactors! Producing Power from Chemical Heat is a silly thing when Uranium comes out of the ground in infinite quantities; processing it into Fuel cells won’t hurt ya.

I have found that the Energy Density is actually far more meaningful, since this affects how long a Vehicle can run before needing to Refuel. As an example, a Locomotive can hold 3 stacks of Fuel (plus one piece “in the engine”)

• Wood: 301 * 2MJ = 0.6GJ
• Coal: 151 * 4MJ = 0.6GJ
• Solid Fuel: 151 * 12MJ = 1.8GJ
• Rocket Fuel: 61 * 100MJ = 6.1GJ
• Nuclear Fuel: 4 * 1.21GJ = 4.84GJ

Clearly, Rocket Fuel is the best fuel - it has the biggest numbers

There is also a nice Acceleration and Top Speed bonus for each tier of fuel - and a bit more with higher Quality, which is a nice use of Quality Scrap —>Solid Fuel waste… I have not found it worthwhile to setup Nuclear Fuel for the entire Train Network, because Locomotives have to refuel more often (or distribute Fuel to every stop, which is a Logistical nightmare!).

[NineNine]

(or distribute Fuel to every stop, which is a Logistical nightmare!).

One blue chest requesting fuel at each train stop.

[DaveMcW]

In Space Age, rocket fuel has an infinite productivity tech. It will always beat solid fuel when you get productivity high enough.

Even in vanilla, it's possible to get rocket fuel productivity up to +40%, where it beats solid fuel.