The Distribution Network Options Assessment (DNOA) represents the optioneering phase of the investment planning process, which is the third and final step. More details on its purpose and methodology can be found at National Grid - Distribution Network Options Assessment, alongside the latest published reports.

The data files below provide summaries of current and past DNOA publications, in tabular format. Information includes where the constraints are on the network, when they are expected to occur, the Constraint Management Zone (CMZ) unique identifier where applicable, and the investment decision outcome.

Information on flexibility requirements for active constraints can be accessed at Flexibility – Requirements - Dataset - National Grid's Connected Data Portal.