The aging and lack of maintenance of the thermoelectric plants of the National Electric System and electric grids during the special period caused considerable damages and as a consequence a generation deficit that did not allow covering the demand of the users, in order to guarantee the electric service without affecting the generation, it is necessary to acquire diesel generators. In addition, it would force to take restrictive measures that affect national productions and the development of the country. In the development of the present work, the post investment study will be elaborated taking into account the indispensable requirements that appear in Decree 327/2014, which will allow evaluating the results from the technical-economic point of view of the investment Installation of 33.6 MW in MTU Engines in the municipality of Cabaiguán.