Abstract: The Turkish power sector achieved a rapid growth after the 1990s in line with economic growth and even beyond. However, this development was not supported by domestic resources and therefore culminated in a high dependency on imported fossil fuels. Over and above, the governments were slow of the mark in introducing policies for increasing the share of renewable energy. Nevertheless, even late actions of the government, as well as significant decreases in the cost of wind and especially solar technologies, have recently brought the Turkish power sector in a promising state. In this study, a large-scale generation expansion power system model (TR-Power) with a high temporal resolution (hours) is developed for the Turkish power generation sector. Several prospective scenarios (high penetration of renewable resources, limiting constraints on GHG emissions, and changes in subsidy schemes on renewable and local resources) were analyzed for assessing their environmental and economic impacts. The results indicate that a transition to a low-carbon power grid with around half of the electricity demand satisfied by renewable resources over a 25-year period would be possible with annual investments of 4.25 to 7.10 Billion 2019 US$. Moreover, TR-Power indicates that the shadow price of CO₂ emissions in the power sector will be around 13.8 and 34.0 $/per tCO₂ by 2042 under 30% and 40% emission reduction targets relative to the reference scenario.