The production of utilities is essential for productive processes in the pulp and paper industry, due to thermal energy requirements for evaporation, drying and heating processes, and the intensive electrical power consumption of the mills. The possibility of combined steam and electricity production in cogeneration plants allows the pulp and paper industry to define operation modes of the facilities that meet the needs of internal consumers, enhancing the production and sale of electricity to the national grid. The present project aims to fulfil the difficulties reported in the decision-making process on the most appropriate operational alternatives for power generation at the Setúbal site of The Navigator Company. The analysis of the current situation allowed to identify the problem under study and the objectives of a potential solution, supporting the development and implementation of a decision support system for power generation, which: i) provides relevant information to the main decision-makers; ii) allows the simulation of process data for modelling the production of thermal and electrical power; iii) presents the simulated scenarios results in graphical and summarized forms. The development of an artefact, named Energy Decision Support System (EDSS), responds to the problem and objectives outlined, allowing the decision maker to select the most adequate alternative, respecting the pulp and paper process needs and boosting electricity sales and profits.