The issue of energy security in the new development paradigm featuring dual circulation has been paid attention to by all sectors, but at present, there are few results from relevant quantitative analyses. With a focus on China’s actual energy trade, this research examines the core elements of energy security in international and Chinese cycles. In this context, the “gravity model” and “Allen substitution elasticity” are optimized and expanded. An integrated assessment methodology is developed as a result of this effort. This methodology consists of an international-cycle trade gravity model and a Chinese-cycle price elasticity model. Additionally, it empirically analyzes the effects of China’s renewable energy substitution from the perspective of the “dual cycles” of energy security, and illustrates the current state of China’s energy security through the analysis of energy substitution relationship data. The results show that Chinese renewable energy does have a buffer effect on imported coal in terms of trade efficiency, scale, and behavior, as well as performance, and the energy trade price has a direct guiding significance for this buffer function, but the enhancement function of economy-driven efficiency is indirect. Furthermore, as far as the absolute price elasticity and net price elasticity are concerned, although Chinese wind power generation is a substitute for imported coal, its price elasticity also confirms that Chinese wind power generation is not a “normal commodity”. Moreover, at present, Chinese photovoltaic power generation shows the attribute of a “normal commodity”, but it has a certain degree of complementarity with imported coal, although this complementarity will weaken in the near future with the trend of changing to substitution.