In 2013, Centro Nacional de Control de Energia (CENACE), which is Mexico's power system operator, updated its short-term hydrothermal coordination planning (STHTCP) tool. CENACE utilized commercial software to solve mixed-integer programming models for the unit commitment and economic dispatch of thermal units, such as gas, coal-fired, and combined-cycle plants. In an earlier paper that we reference, authors of this paper describe the mathematical model for the thermal unit commitment (TUC) problem, which is a sub-problem in the STHTCP process. The new STHTCP tool, which uses a mixed-integer programming-based TUC approach, has enhanced the modeling and solution quality compared to the Lagrangian relaxation-based TUC approach. The new tool has improved CENACE's operations for managing its existing infrastructure, including power stations and transmission lines, and establishing the marginal prices needed to make energy trades. From the beginning of 2013 to the end of 2014, CENACE saved $2.2 million annually, which it attributes to better management of its thermal units. Over 10 years, it anticipates that these savings will represent more than $20 million in total savings.