人类的生存发展离不开能源。当人类学会使用第一个火种时便开始了能源应用的漫长历史。几千年来,人类所使用的能源已经历了三代,正在向第四代能源时代迈进。主体能源的更替充分反映出人类社会和经济的进步与发展。第一代能源为生物质材,以薪柴为代表;第二代能源以煤炭为代表;第三代能源则是石油、天然气和部分核裂变能源。实际上,第二代和第三代能源都是以化石燃料为主体。第四代能源的构成可能是核聚变能、氢能和天然气水合物。天然气水合物的 Human survival and development are inseparable from energy. The long history of energy use begins when humans learn to use the first fire. For thousands of years, mankind has spent three generations of energy and is moving toward the fourth generation of energy. The replacement of main energy fully reflects the progress and development of human society and economy. The first generation of energy is biomass, represented by firewood; the second generation of energy is represented by coal; the third generation of energy is oil, natural gas and some nuclear fission energy. In fact, the second and third generations of energy are based on fossil fuels. The formation of the fourth generation of energy may be nuclear fusion energy, hydrogen and gas hydrates. Gas hydrate