Germany made a profit on its additional emissions abatement, above what was required: it met the regulations by abating all of the emissions that was required of it (RReq). Additionally, Germany sold its surplus permits to Sweden, and was paid "P" for every unit it abated, while spending less than "P". Its total revenue is the area of the graph (RReq 1 2 R*), its total abatement cost is area (RReq 3 2 R*), and so its net benefit from selling emission permits is the area (Δ 1-2-3) i.e. Gains from Trade