Ancillary services are all services that NOSBiH procures from ancillary service providers (hereinafter ASPs) for the purpose of maintaining safe and reliable work of the power system in BiH and continuous and qualitative supply of electricity users.

Grid Code (local language) defines types and technical specifications of ancillary services as well as the technical requirements that must be satisfied by entities providing ancillary services, while the required scope of services, their procurement, nomination and engagement and commercial relations between ASPs and NOSBiH are defined by documents accompanying the Market Rules: Ancillary Services Procedures and Rules on Daily Balancing Energy Market Operations (local language).