Energy act >> www.doe.bg Energy efficiency act >> www.seea.government.bg Regulation for Certification of the origin of electric power generated by renewable and/or combined-generation sources, issuance of green certificates and their trading >> www.dker.bg Directive № 2002 / 415 / EU July 22, 2002 of The European Parliament and The Council of: "The promotion of cogeneration based on a useful heat demand in the internal energy market"