The Bulgarian energy regulator said it has launched an audit at the power distribution companies operating in the country and the heating utility of the capital Sofia.
The move was prompted by a series of complaints from customers of the local units of Czech companies CEZ and Energo-pro, and Austria's EVN, the State Energy and Water Regulatory Commission said.
The audits will continue four months but may be extended on the basis of the interim findings. The companies' operations back to July 1, 2008 will be checked.
EVN Bulgaria operates in southern Bulgaria. CEZ Razpredelenie Bulgaria operates in the region of Sofia, western and northern Bulgaria. Energo-Pro's units operate in the northeastern part of the country.