There appear to have been a number of consultations held on this proposal, one of which was a survey sent out to a group of unnamed "participants and stakeholders of the EU ETS," including "involved 517 companies, government bodies, industry associations, market intermediaries and NGOs." Later, "the Commission decided to consult further by means of a separate Working Group on the Review of the EU ETS within the framework of the European Climate Change Programme (ECCP)." The Working Group and a list of its various individual presenters are available online, but none of the original documentation used by the speakers is available. 

The InterEURO team contacted the EUropean Commission requesitng this documentation and was informed that the Commission was not in possession of the consultation documents.