The Refinery produces a steady stream of credits for your base. The Refinery receives production bonuses from being adjacent to Tiberium and Power Plants. It receives a set bonus (based on refinery level) for being next to at least one Power Plant, and another set bonus (based on Power Plant level) per Power Plant. It also receives a bonus (based on Refinery level) for every adjacent Tiberium. Like Research Points, Credits are pooled and shared across all bases allowing Research to be share across your entire empire without need to move them from base to base.