Forecast national Surplus Data for 2- 14 Days ahead (SPLD) and 2-52 weeks Ahead (SPLW) supplied by the System Operator and published on the BMRS. Also referred to as OCNMFD and OCNMFW respectively in the CVA Interface Definition and Design Part 2. Surplus is a MW figure representing the Total Output Usable in the System Zone minus the forecast of Active Power Demand in the System Zone, and minus the Export limit in the case of an Export limited System Zone, or plus the Import limit in the case of an Import limited System Zone and(only in the case of a System Zone comprising the GB Transmission System) minus the Operational Planning Margin. For the avoidance of doubt, a Surplus of more than zero in an Export limited System Zone indicates an excess of generation in that System Zone; and a Surplus of less than zero in an Import limited System Zone indicates insufficient generation in that System Zone.