GIZ (German Development Cooperation) hired AESA to carry out a first level energy assessment and a gap analysis to determine the scope and implementation degree of an Energy Management System (SGEn) in accordance with the ISO 50001 standard of the factories of Sánchez y Martín (Guadalajara), Bio Pappel (Durango) and Clariant (Ecatepec de Morelos). To that end, the main characteristics of the consumer centers, both thermal and electrical consumptions, were determined.