20世纪两次石油危机给西方国家的经济带来了沉重的打击,同时也大大促进了全球范围内可再生 能源的发展。从20世纪70年代开始,尤其是近年来,可再生能源已逐渐成为常规化石燃料的一种替代 能源,世界上许多国家或地区将可再生能源作为其能源发展战略的重要组成部分。美国的加利福尼亚, The two oil crises of the 20th century brought a heavy blow to the economies of western countries and at the same time greatly promoted the development of renewable energies around the world. Since the 1970s, and especially in recent years, renewable energy has gradually become an alternative energy source for conventional fossil fuels. Many countries in the world regard renewable energy as an important part of their energy development strategy. American California,