The Industrial Emissions Directive (IED) aims to achieve a high level of protection of the environment as a whole and of human health. In this purpose, the IED requires the implementation of techniques with performance equivalent to the Best Available Techniques (BATs) described in the reference documents (BREFs). However, when drawing up or revising a BREF at European level, it is not possible to cover each industrial sector or subsector for all or some of the Key Environmental Issues (KEI). There are then different types of situations for which BREFs are incomplete or non-existent. Industrial plants involved in these activities without reference are not exempt from implementing BATs. However, the lack of reference technologies “officially” considered as BATs may lead operators to skip their installations concerned in their BAT analysis and/or the competent authority not to fully check BAT compliance. In view of these observations, this article is aimed at studying the possibility of using the methodological approaches available in the scientific and grey literature to compare the performance of an installation to BATs in the absence of an official and complete BAT reference. Following the description of the research methodology that enabled to conduct this literature review, this article first examines whether methods designed for local use can address this problem. Noting that this is not the case, the possibility to use sectoral methods to build a local BAT reference is also studied. Finally, key specifications for a suitable methodology to address this problem are proposed.