1. Where for technical reasons it is temporarily not feasible to apply the monitoring methodology plan as approved by the regulator, the operator shall apply a method based on alternative data sources listed in the monitoring methodology plan for the purpose of performing corroborative checks in accordance with Article 10(5), or, if such an alternative is not contained in the monitoring methodology plan, an alternative method which provides the highest achievable accuracy according to the generic data sources and their hierarchy laid down in section 4 of Annex VII, or a conservative estimation approach, until the conditions for application of the approved monitoring methodology plan have been restored.

The operator shall take all necessary measures to achieve a prompt application of the approved monitoring methodology plan.

2. Where data relevant for the baseline data report are missing, for which the monitoring methodology plan does not list alternative monitoring methods or alternative data sources for corroborating data or for closing the data gap, the operator shall use an appropriate estimation method for determining conservative surrogate data for the respective time period and missing parameter, in particular, based on best industry practice, recent scientific and technical knowledge, and shall provide due justification for the data gap and the use of those methods in an annex to the baseline data report.