National Grid ESO

While DNOs manage local distribution, the National Energy System Operator (formerly National Grid ESO) manages the national transmission system - the backbone of high-voltage lines that carry electricity across the country. They're responsible for ensuring the lights stay on, balancing generation with demand second-by-second.

NESO publishes the TNUoS (transmission) and BSUoS (balancing) charges that appear on business electricity bills. They run the control room that dispatches power stations, manages interconnectors with Europe, and coordinates responses to system emergencies. They also administer the Capacity Market auctions.

Key responsibilities:

• Operating the 132kV+ transmission network 24/7
• Second-by-second balancing of supply and demand
• Procuring and dispatching balancing services
• Publishing TNUoS and BSUoS tariffs
• Administering Capacity Market auctions as Delivery Body
• Planning network development

In 2024, the Electricity System Operator was separated from National Grid's ownership and brought into public ownership as NESO. For most businesses, the practical impact is minimal - the same charges apply, just administered by the newly independent organisation.