User blog comment:Gundam Legilis/Dust makes the world go round/@comment-24260323-20140824234609/@comment-24891101-20140825044913

Probably. Just because they have an abundant fuel source doesn't mean that they haven't looked at other things; we're in a similar position with oil. They have to know it's finite.

And that it's termed an energy propellant suggests to me that it is consumed, in much the same way as other conventional fuels. And steam engines and ICEs are basically just ways of harnessing burning fuel, by creating rotational motion, they put fire dust into something largely equivalent, just, perhaps, without oxidizer input necessary, so the engines would be only slightly different. They have fossil fuels also, since they have biomass, and a planetary history, so they know how those work. Their engines just use dust as a fuel, instead of hydrocarbons. The ICE is a little bit trickier, because of the oxidizer, but they'd have it.

Similarly, the idea of a hydroelectric dam is an outgrowth of a water-wheel, essentially, connected to the concept of generating electricity via rotation. And they exist in our world for the exact same reasons that they'd exist in Remnant: Dust is expensive, and the price is slowly rising, and occasionally difficult to transport, especially since it probably can't be pumped, as oil is, and the river is convenient.