To assess the energy operation level of various working groups (WGs) in reheating furnace, a novel approach for lean energy operation based on energy apporitonment model has been proposed in reheating furnace. This new approach mainly includes: i) The billet gas consumption (BGC) apportionment model; ii) The BGC equivalence value (BGCEV) model; iii) The BGC operation level evaluation model. A case study has demonstrated that: The average BGCEV (ABGCEV) of four WGs in the order of data size is: B Group (1.44 GJ/tons); C Group (1.40 GJ/tons); D Group (1.38 GJ/tons); A Group (1.37 GJ/ tons). Then, the BGC operation level of four WGs is evaluated as: excellent grade (A Group and D Group); good grade (C Group); poor grade (B Group). The model accuracy analysis shows that this novel appraoch (Model 2) had higher accuracy than traditional calculation method (Model 1). Then, the ABGCEV standard deviation analysis results show that the ABGCEV fluctuation degree is the most improtant factor determining the BGC operation level of each WG. Therefore, how to improve operation stability is an improtant way to achieve lean energy operation of reheating furnace, such as theoretical training, simulation training, skill training etc. (C) 2019 Elsevier Ltd. All rights reserved.