It is well known that the CO 2 emitted by fossil energy is one of the major reasons that result in global warming. It is still an open question about how to reduce CO 2 emission by the implementation of an investment plan for clean power systems. In this paper, we propose a clean power trading method among neighboring regions such that we can reduce CO 2 emission in a large region and reduce the imbalance between the power demand and supply in a region caused by the fluctuation of clean energy. With the five states with rich wind energy in America as an example, we use the quantitative computation results of the five states (from a modeling framework designed by ourselves) to show that our proposed clean power trading method can help reduce CO 2 emission and realize balance.