发展燃料乙醇和生物柴油的碳排放效应综述

A review of carbon emissions caused by bioethanol and biodiesel

燃料乙醇和生物柴油最初被认为是"清洁能源"和"绿色能源",并在各国政府以"减排"为目标的相关政策支持下得到了快速发展;但近两年却有学者提出,发展生物燃料可能会导致更多的碳排放,对碳排放效应的认识发生了转折性分歧。文章基于燃料乙醇和生物柴油的碳排放效应,系统综述了其碳排放效应研究历程,结果表明:仅通过生命周期评价法对比燃料乙醇和生物柴油与化石燃料的生产流程,二者的确能够显著减少温室气体排放;但如将它们所带来的土地利用的变化考虑在内,就会产生更大的碳排放;尤其是改变森林、草地等碳储量高的土地利用方式,可能需要上百年的回收期。因此,未来制定燃料乙醇和生物柴油发展政策前,有必要将其带来的土地利用变化的碳排放效应考虑在内,以准确认识其综合碳排放效应。

Bioethanol and biodiesel were considered as ＂clean energy＂ and ＂green energy＂ initially,therefore,many countries introduced many policies to promote it in order to reduce greenhouse gas emissions.However,some scholars proposed that they may lead to more carbon emissions.Why the understanding about carbon emissions transformed so much. This article focused on the carbon emissions effect of bioethanol and biodiesel,systematically reviewed the related researches.It was concluded that if only compared manufacturing process of bioethanol and biodiesel and fossil fuels by life cycle assessment,they could indeed reduce greenhouse gas emissions significantly, however, once the change of land use caused by them were taken into account, bioethanol and biodiesel may lead to more carbon emission,especially in forest,grassland,etc,which had more carbon stock,and the use of them once changed may need hundreds of year to recovery.As a result,before the policy introduced,it was necessary to consider the effects of carbon emissions caused by the change of land use.