A clean energy generation system, comprising at least one energy generation unit, each of which comprises a wind tunnel, an air/gas turbine, a generator, at least one heating device and an air/gas compressor. The wind tunnel includes a contraction section, a test section and a diffuser section. The air/gas turbine is located in the test section or the diffuser section and is coupled to the generator. The at least one heating device is located in the contraction section for preheating the air/gas flowing through the at least one heating device. The air/gas compressor is for compressing the air/gas flowing through the air/gas compressor and is located in the diffuser section or in the contraction section between the at least one heating device and the air/gas turbine. The air/gas turbine is driven by the preheated and compressed air/gas such that the generator is driven to generate electricity.