## 1 Introduction to Redispatch Models in Real-Time Operation  
The expansion of solar and wind generation has been positioned for more than two decades in an energy market with high marginal costs, and in recent times, in the market of ancillary services that use bidding and auction mechanisms linked to conventional hydrothermal generation [1]. However, the higher the penetration of renewable energies, the greater the uncertainty caused by economic mismatches in real-time operation, leading the system operator to quickly switch on/off plants by means of an economic merit list and, in the worst-case scenario, to execute a dispatch action randomly without mathematical support, based only on plant start/stop times. The system operator uses unit commitment models prepared with information prior to the effective operating day. Unit commitment allows the mitigation of demand deviations, frequency variations due to the uncertainty of renewable generation and other externalities such as generation restrictions due to high emissions from fossil fuel power plants [2, 3]. The problem for the system operator is the real-time operation where mismatch scenarios occur in the generation, transmission, and demand system that are not foreseen in the unit commitment model, leaving the unit commitment model expired and unable to support the system operator's decisions. In several countries in South America, Europe, and Asia, the economic merit list is used as a substitute for unit commitment to reduce the cost overrun gap between scheduled and real-time operation [4; 5]. However, there are more sophisticated mathematical models such as real-time redispatch, which allow the replacement of the inefficient methods of random plant dispatches and the use of the economic merit list, given the uncertainty of renewable generation [6], the overload in the transmission system and generation failures [7]. The redispatch model is the main support for the system operator that helps to optimally execute economic decisions in accessible times for their timely elaboration, modeling, and execution [8]. Therefore, implementing a redispatch is a novel proposal. A complete redispatch model must be able to dimension the technical and economic constraints and other characteristics of the market, such as the integration of renewable energies, ancillary services, and inertia modeling. In this context, designing a redispatch model is essential to face the environmental security restrictions, because the economic consequences and the stability of the system can be detrimental due to the retirement of thermal power plants if it does not adapt an adequate renewable generation park in its replacement. The importance of renewable generation in terms of system dynamics and stability is fundamental [9]. Consequently, if current redispatch models do not integrate the uncertainty of renewable generation, the economic effects will be negative [10]. It is important that the redispatch development can resolve in advance the technical and economic consequences that could be caused in real time by the uncertainty of solar-wind generation due to forecast errors and meteorological adversities such as cloudiness and extreme winds [11]. For the system operator, the redispatch model should have an anticipatory role and predominate over other scheduled operation models such as the unit commitment and the economic merit list. Finally, the main considerations in this redispatch model are the profitability for all available generation plants that supply the demand (Figure 1) and to integrate a modeling of the gas stock storage for those combined cycle thermal power plants through a correct optimization of the gas resource to avoid monopolistic use by the generating companies. The redispatch model optimizes fuel consumption, which in many of the traditional models is equated to an economic merit list at the maximum value of the power generated as a linearized variable cost, which is why it does not faithfully reflect the variable cost of generation of thermal power plants.