FWE stands for Food, Water, Energy. It's the basic requirements of almost all buildings in Pardus. This section also includes biowaste as it comes from spacefarms.
A 'FWE run' is the term for one of the most used and basic trading cycles, in which you take food and water from a planet to a starbase, then take energy from the starbase to the planet, and repeat. It is a good choice of trading for new players, as it is very common, very simple, and always welcomed.