Optimizing the energy efficiency of higher education institutions Sergey Sergeev, Sergey Barykin, Olga Kalinina, Elena Naumova, Natalia Dedyukhina and Tatiana Dmitrieva E3S Web Conf., 244 (2021) 11029 Published online: 19 March 2021 DOI: 10.1051/e3sconf/202124411029