Abstract: As the penetration of renewable energy in power systems increases, the uncertainty in its output poses significant challenges to grid operations. In response to the rapid growth of new energy installed capacity in the Gobi Desert and other arid regions, this study proposes methods to leverage the rapid regulation capabilities of thermal storage concentrated solar power plants (CSPP) to mitigate fluctuations in wind and solar generation. Additionally, it presents a bidding strategy for cross-regional bundled transmission that consider the uncertainty of new energy sources, with the aim of maximizing the total revenue of combined power plants in electricity and ancillary services markets. Firstly, this study analyzes the day-ahead market bidding methods and limitations for new energy bases with CSPP in the contex of high renewable energy penetration. Secondly, a new bidding model that takes into account the flexible resource regulation characteristics of CSPP is proposed. This model effectively reduces the deviation penalties caused by the uncertainty of new energy output under the harsh environmental and climatic conditions of the Gobi Desert and other arid regions, thereby enhancing the revenue of combined power stations. Finally, case studies validate that the utilization of CSPP's flexible resources can enhance the economic efficiency of day-ahead bidding for renewable energy bases. The consideration of two-stage uncertainty can effectively reduce penalties and increase the overall profit of the renewable energy base.