How are minerals used if I run out of fuel?

Question

A loading tooltip said that if I run out of fuel, minerals will be used to power my ship instead. As minerals are a pointless minigame designed to waste your time can be a bit tedious to obtain, I really don't want to run the risk of this, and I'd like to know what happens if I accidentally forget to refuel. I checked the entry about the Fuel Depot on the Mass Effect Wikia, but neither the article nor its talk page answered my question.

To that end, I would like to know the following:

• At what rate are minerals used as a substitute for fuel? Is it 1:1?
• Which minerals are used? Does it use the most common one I have (Palladium->Platinum->Iridium->Element Zero is the ascending order of rarity) or does it draw from all resource pools equally at once? If different minerals are used, are they used at different ratios?
• What happens if, somehow, I'm completely out of fuel and minerals? Will I be lost in space forever? Will the game automatically place me back in a system with a Fuel Depot? Will I get a Non-standard Game Over?

Answer 1

When you run out of fuel while exploring the nebula, EDI will warn you that an emergency FTL jump to the nearest fuel depot is necessary. As you know, you'll be forced to pay a mineral tax of some sort in the process.

The value of this penalty isn't a 1:1 ratio with the fuel it would take to reach the depot, though - it's always greater, but I can't really seem to discern how it comes up with the numbers. I performed a series of tests where I would purchase 350 fuel, then leave the system traveling in a straight line until I ran out.

In my particular case, the game seemed to heavily favour penalizing me Iridium, although it was not my most abundant mineral. I was also penalized Palladium (which I believe is the most common mineral) once in the chart below, and a few other times where I wasn't collecting the numbers.

 EZ    Ir    Pt    Pd     Penalty
----------------------------------
48400 59773 50491 63801
48400 57649 50941 63801 = -2124 Ir
48400 55119 50491 63801 = -2530 Ir
48400 53954 50941 63801 = -1465 Ir
48400 51512 50941 63801 = -2142 Ir
48400 51512 50491 60854 = -2947 Pd
48400 50065 50491 60854 = -1447 Ir
48400 48915 50491 60854 = -1150 Ir
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
48400 48185 50491 60854 = -730  Ir

In the last case, I simply drove in circles directly outside of the system with the fuel depot. As you can see, the penalty was less, but not by a factor of the comparable distances. I'll need to do some more tests to see if I can come up with a general equation.

If you do run out of fuel and minerals, you get transported to the system without paying any fee. You're required to always have fuel before leaving the system with the depot, however, so you need to be wary about running out of credits. You can still perform Mass Relay jumps, but I do recall early on in one playthrough where I had to scrounge together some credits to safely continue on account of some careless spending.

Answer 2

As far as I can tell, it's random. I ran a few tests and it seemed to drain 500-2000 of a random resource each time. This just moves the Normandy to a nearby system with a Fuel Depot, however. It does not actually buy you any fuel, and EDI won't let you leave a system without fuel.

If you're completely out of minerals and fuel, you still get moved to a nearby system, at no cost.

Since there are lots more resources available than you would ever need for research projects, you shouldn't worry too much about the loss of resources. Unlike Mass Effect 1, Credits are the main resource to worry about in Mass Effect 2.

If you run out of Credits so that you can't buy any fuel, you're effectively constrained to systems containing a Mass Relay.