Thermal energy storage (TES) systems allow concentrated solar power (CSP) producers to participate in a day-ahead market. Then, the optimal power scheduling problem can be posed, whose objective is the maximisation of profits derived from electricity sales. Most papers in literature use a mixed-integer linear programming (MILP) approach to solve this type of problems. This paper proposes a novel approach based on the use of two models: a detailed model and a MILP model. This approach combines MILP capabilities and the accuracy of a detailed model. The proposed approach is applied to a 50 MW parabolic-trough-collector based CSP plant with molten-salt-based TES. A detailed model available in literature and validated against operating plant data is used, but some improvements are included for its use in optimal scheduling problems. Moreover, the MILP model was developed to adjust as much as possible to the features of the detailed model. The improvements regarding other scheduling strategies for a specific example are shown. (C) 2016 Elsevier Ltd. All rights reserved.