Bulgaria’s transmission system operator ESO has invested more than EUR 182 million in modernising the country’s electricity network since the start of 2026, according to the operator. The spending is part of a programme to improve the reliability of electricity supply. It is also intended to prepare the grid for additional generation and new connections.
The work involves building and reconstructing more than 120 kilometres of transmission lines. It also includes upgrades to overhead infrastructure and substation equipment in several parts of Bulgaria. These measures aim to strengthen existing assets and provide capacity for future projects.
Substation upgrades are designed to make system operations more robust and allow electricity supply to be restored more quickly after network incidents. They are particularly relevant in autumn and winter, when storms and other adverse weather can damage lines and interrupt service. Bulgaria’s power system connects neighbouring countries with significantly different generation mixes and levels of demand, making reliable transmission important for domestic security of supply and commercial cross-border electricity exchanges.
Grid capacity and system reliability
Reinforcing the network can enable new solar, wind and other generation assets to connect. Demand for grid connections can grow faster than transmission capacity, making equipment availability, substations and operational flexibility important factors in project schedules.
The programme highlights that investment in generation alone does not remove constraints across the energy system. Its longer-term impact will be assessed through improved reliability, effective use of existing grid assets and the ability to bring additional projects into operation without creating new bottlenecks.
