Question about Alenium Units

I'm going through my first playthrough of the game, and I've started getting to the point where alenium-powered vehicles are an option (e.g. the corsair, the scimitar, etc). My question is: does using these units consume alenium from your inventory or is it just a flat cost for building it (I seem to remember some of the vehicles in the original XCOM doing the former)?

seems like you don't need to refuel with alenium, so it is just a flat building cost.

There are mods that make more expensive alenium missiles and warheads cost alenium part of their re-balancing.

Even with mods, you'll never have to refuel them, as some Xenopedia entry said, an alenium reactor has enough fuel to last the entire war, no matter who wins.

Which is probably fair, all told. We don't need to refuel nuclear reactors all that quickly either.