Fuel

"Fuel" is fusion fuel, a rare compact substance (deuterium) that powers fusion reactors of virtually all machinery, from farming implements to space freighters. Due to its relative ease of transport and universal usefulness, it is considered a basic exchange unit. EC are usually used as a substitute for virtual exchanges.

Obtaining

Fuel can be obtained from scouring any kind of planet, but it is most abundant in crusts of cold planetoids lacking a core. Obtaining fuel on a core-active planet would involve either mass mineral processing or digging into the core, first being usually not profitable, latter requiring very advanced and expensive engineering projects.