Climate change threatens all parts of the US electric power system, from electricity generation to distribution. An important dimension of this issue is the impact on electricity demand. While many studies have looked at these impacts, few have tried to represent this effect at higher temporal resolutions (such as daily or sub-daily) or to analyze its seasonal aspects. Our study expands on previous work to improve our understanding of how climate change can affect patterns of hourly electricity demand, the differences in these effects over different seasons, and how this in turn could affect the operations of the power system. For this analysis, we combine a linear regression model, a simplified economic dispatch model, and projections from twenty different climate models to analyze how climate change may affect seasonal demand patterns and, consequently, power plants dispatch. We use this method to analyze a case study of the Tennessee Valley Authority (TVA). The results suggest that climate change can result in an average increase in annual electricity consumption in the TVA region of 6% by the end of the century and an increase in the frequency of peak demand values (the maximum quantity of electricity demanded during an hour). However, this increase is not uniformly distributed throughout the year. During summer, total electricity consumption can increase on average by 20% while during winter, it may decrease on average by 6% by the end of the century. Such changes in demand could result in changes in the typical dispatch patterns of TVA's power plants. Estimated summer time capacity factors would increase (8 to 37% for natural gas and 71 to 84% for coal) and winter time capacity factor decrease (3% to virtually zero for natural gas and 67 to 60% for coal). Such results could affect the decision-making process of planning agents in the power sector.