ÜNBs

ÜNBs, short for Übertragungsnetzbetreiber, are the national and regional bodies that own and operate the high-voltage transmission networks used to transport electricity from power plants to distribution networks and large customers. They are responsible for the secure, reliable operation of the grid, system balancing, and cross-border interconnections, as well as grid planning and development of transmission capacity for future generation and consumption patterns. They ensure compliance with reliability standards such as N-1, monitor grid conditions, manage outages, and coordinate with market participants to implement wholesale electricity markets, capacity allocation, and cross-border market integration.

In the European Union, ÜNBs are typically legally unbundled from generation and supply activities to ensure non-discriminatory grid access. They are regulated by national energy regulators and must cooperate with the European networks and institutions, notably ENTSO-E, ACER, and the European Network of Transmission System Operators for Electricity. Through ENTSO-E they participate in a common grid model, network code implementation, and cross-border planning. They also coordinate with neighboring ÜNBs to manage interconnections and regional security.

Examples of ÜNBs include Germany’s 50Hertz, Amprion, TransnetBW, and TenneT; France’s RTE; Italy’s Terna; and many others across Europe. The term emphasizes the critical role of transmission-level infrastructure within the broader energy system, serving as the backbone for electricity supply and market integration.