In order to analyze some of the reasons for the delays in the implementation and the beginning of the operation of transmission system projects in Brazil, this study considers the deadlines and definitions of the regulations of the MMA Ordinance No. 421/2011, Interministerial Ordinance No. 60/2015, MS/SVS Ordinance 01/2014, IPHAN RI 001/2015 and FCP RI 01/2018, applicable in the environmental licensing of energy transmission enterprises. The analysis focused on the simplified federal environmental licensing, deemed to have little potential for environmental impact by IBAMA and its interface with involved bodies FCP, IPHAN and MS/SVS. The regulations and their deadlines were applied in a developed schedule in the MS Project software and the result was that the simplified licensing process for energy transmission systems projects is controlled by the deadlines for the manifestation of the bodies involved and not by the deadlines of the environmental licensing body. Thus, despite efforts to seek a design of the energy transmission system with less socio-environmental impact and, therefore, be considered as an enterprise with little potential for environmental impact, the project schedule may not be compatible with shorter deadlines for simplified environmental licensing.