Approach to defining the object of energy efficiency assessment in industry Natalia Verstina, Natalia Solopova, Tatiana Meshcheryakova, Natalia Taskaeva and Natalia Shchepkina E3S Web Conf., 263 (2021) 05042 Published online: 28 May 2021 DOI: 10.1051/e3sconf/202126305042