Bulgaria’s net electricity exports increased 62% to 3.5 TWh in the first nine months and opening days of October 2026, according to transmission operator data cited by the Association for Production, Storage and Trading of Electricity. The increase was linked to expanding renewable generation and battery storage. Net exports rose from 2.16 TWh during the comparable period of 2025.
Total electricity generation grew 12.24%, while domestic consumption increased 8.45%. Renewable generation reached approximately 11.5 TWh, nearly 34% higher year on year. Renewables accounted for nearly 80% of the increase in national electricity production.
Solar output and batteries shift electricity from daytime to evening hours
The data point to a change in Bulgaria’s generation mix, with solar power contributing additional electricity. Batteries increasingly enable production to be moved from low-price daytime periods into more valuable evening hours. This supports a shift in how renewable output can be monetised in wholesale trading.
Battery systems reportedly delivered approximately 1.72 TWh to the Bulgarian electricity system between January and early October, compared with around 190 GWh a year earlier. The increase reflects rapid expansion of installed storage and its growing role in wholesale-market optimisation. On October 8, Bulgarian solar generation approached 4.3 GW during the early afternoon, exceeding domestic consumption of around 4.1 GW.
Battery charging absorbed a substantial part of that surplus, allowing electricity to be retained for later delivery. Without storage, additional solar capacity could deepen midday price collapses and increase curtailment. With batteries, part of production can be shifted into hours when Romania, Hungary and other neighbouring markets face stronger demand and higher prices.
Nuclear maintenance and low river levels affect firm generation availability
Bulgaria’s growing renewable and storage capacity is tied to operational constraints affecting its nuclear fleet. Kozloduy unit 6 entered scheduled maintenance in October, while unit 5 has been exposed to low Danube water levels. Together, these factors reduced available firm generation and increased the importance of solar, batteries and other dispatchable resources.
Bulgaria also faces seasonal constraints as solar generation declines during winter while electricity demand increases. The next investment requirement is expected to include additional wind, longer-duration storage and transmission capacity able to move electricity towards regional scarcity markets.