12. The competent authority may grant a derogation from the obligation to comply with the emission limit values provided for in paragraphs 2 and 7 in cases where a medium combustion plant using only gaseous fuel has to resort exceptionally to the use of other fuels because of a sudden interruption in the supply of gas and, for this reason, would need to be equipped with secondary abatement equipment. The period for which such a derogation is granted shall not exceed ten days except where the operator demonstrates to the competent authority that a longer period is justified.
Member States shall inform the Commission, within one month, of any derogation granted under the first subparagraph.