Traditionally, for complicated systems, such as a gas turbine power plant, maintenance cost and online availability are two of the most important concerns to the equipment owner. However, in the deregulated electric power market, cost and reliability are not the only concerns. The ultimate goal is to maximize plant profitability, and this requires the evaluation of many different factors, including system performance, the aging and reliability of equipment, maintenance practices, and market dynamics accounting for the price and availability of fuel as well as the generation of revenues in competing markets. Thus, gas turbine power plant planning optimization is a complex problem, and comprehensive operational modeling and optimization methods are required. In this paper, a profit-based power plant outage planning approach is presented that reflects the new challenges posed by deregulation. Specifically, particular attention is paid to modeling power plant aging, performance degradation, reliability deterioration, and, importantly, the energy market dynamics. A multiple time-scale method is developed for coupled short-term, long-term generation scheduling and outage planning for this profit-based outage planning approach. The procedure is implemented for a base load combined cycle power plant with a single gas turbine, with the results demonstrating the feasibility of the proposed approach.