Bulgaria’s transmission system operator ESO has invested more than EUR 182 million in modernising the country’s electricity transmission network since the start of 2026, according to the operator. The spending extends a programme to improve supply reliability. It is also intended to prepare the grid for additional generation and connections.
The work covers the construction and reconstruction of more than 120 kilometres of transmission lines. It also includes upgrades to overhead infrastructure and substation equipment in several parts of Bulgaria. These measures target the resilience of existing assets and the network’s capacity to accommodate future projects.
Substation upgrades are intended to strengthen system operations. They are also designed to enable electricity supply to be restored more quickly after network incidents. This is 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. Reliable transmission supports domestic security of supply. It is also important for commercial electricity exchanges across borders.
Grid capacity and new connections
Reinforcing the network enables new solar, wind and other generation assets to connect. Demand for grid connections can increase faster than transmission capacity. Equipment availability, substations and operational flexibility are important factors in project schedules.
The programme highlights that investment in generation alone does not resolve energy-system constraints. Its longer-term impact will be assessed through improved reliability and the effective use of existing grid assets. It will also depend on the ability to bring additional projects into operation without creating new bottlenecks.
