The analysis of Power Quality issues and/orthe integration of renewable energy into the grid requiresthe use of different tools, among which the use of computersimulation applications stands out. The basic objective isto obtain a model of the electrical system under study thatallows for knowledge, with a reasonable degree of preci-sion, of its behavior under different operating conditions.The benefits of these tools are manifold, since they allow usto understand the response of the system, both in transientand steady-state conditions, to situations that are difficultto reproduce in practice: short circuits, failures in gen-eration, transmission and distribution infrastructures, etc.Additionally, these tools can be used as platforms for opera-tor training and network planning. Currently, a wide varietyof commercial tools that are de facto standards can be foundon the market. Some of these tools have a high cost andcannot be used by students outside the academic environ-ment. In parallel, and thanks to the efforts of the scientificcommunity, simulation tools have been developed that areavailable free of cost under several licensing models. Thiscontribution analyzes some of the available tools, with spe-cial attention to those that are published under several opensource and academic non-commercial software licenses thatare available to the academic community free of cost.