Toplofikatsia Sofia's debt to Bulgargaz will pass €1bn by the end of winter, Georgi Tatarski, chief executive of the public supplier, told parliament's energy committee.

The Sofia district heating company owes €900m for natural gas. Nearly €800m of that is the principal, meaning the price of the gas delivered, without interest. The company has paid nothing since May, Tatarski said.

He was replying to Petar Petrov, chief executive of Toplofikatsia Sofia. Petrov said interest on the debt was 11.91% until 2025 and is 10.40% from 2026.

"Bulgargaz is not a bank or a payday lender. We charge legal interest for late payment, and we use it to push for payment for the gas delivered," Tatarski said.

For the winter, the heating company has ordered 5m megawatt hours of gas, the amount that 5 liquefied natural gas tankers carry. At current prices on the TTF gas exchange in the Netherlands, that gas costs €500m.