There is a general tendency in reporting nowadays, represented by the institutionalization of the environmental reporting in an increasing number of companies. The novelty of our work resides in the fact that this is the first study which analyses the consistency and comparability of the information included in integrated reports. The objective of this research is to determine to what extent the reporting of the environmental performance indicators, including energy, prescribed by the Global Reporting Initiative's guidelines is in line with the consistency and comparability principle. We analysed the reports published by the European organisations included in the Pilot Programme of the International Integrated Reporting Council. We used the following methodology. First, we compared the environmental reporting of 2016 from one company to another, splitting the sample in accordance with the industries. Second, we analysed the reporting practices of the environmentally-sensitive companies, including energy, in 2010, 2013 and 2016, in order to analyse the consistency of the information published. The results of the research show that the environmentally-sensitive companies, including energy, publish more information. Also, the score of information consistency is above average. The best consistency level is registered in the Basic Materials industry, followed by Oil & Gas and Industrials. Emissions and energy indicators are the most disclosed. This research is useful to understand how companies apply the consistency and comparability principle in practice. The importance of this article is given by the fact that consistency and comparability improve the quality of the sustainability reporting. Without consistency and comparability the information's relevance is very low.Energies 2018, 11, 3456 2 of 24 to two studies [13,14] investigating in 1999 and 2017 the sustainability reports published by 250 companies included in the G250 35% of the companies disclosed information on social, environmental and economic issues (commonly referred to as corporate social responsibility-CSR) in 1999 and 93% in 2017.As there are almost 400 reporting instruments in place [15], a major issue which appears regarding the environmental reporting is the consistency and comparability of the information. The most comprehensive and used guidelines in the area are the ones issued by the Global Reporting Initiative (GRI) [14]. Thus, the objective of our research is to analyse the consistency and comparability of environmental performance indicators (EPIs), especially the ones related with energy and emissions issues, published by the European companies included in the International Integrated Reporting Council's (IIRC) Pilot Program using the GRI guidelines. Consistency assesses that the information is constantly disclosed in time while the comparability evaluates the disclosure of the information from one company to another. By analysing all the EPIs as opposed to only the ones related with energy and emissions, we emphasize better the importanc...