Abstract

The reliance on petroleum derivatives and the increasing trend of fuel consumption in the transport sector have brought attention to biofuels as a measure to reduce greenhouse gas (GHG) emissions, enhance energy security and boost economic development. The incentive for utilizing biofuels is their potential to reduce carbon dioxide (CO₂) emissions compared to fossil fuels. Biofuels are considered to be carbon-neutral, regarding the direct CO₂ emissions associated with their combustion, on the grounds that the carbon dioxide absorbed by the plants through photosynthesis is equivalent to the CO₂ released during their combustion. However, a part of the carbon of biofuels may have a fossil origin and therefore, it is responsible for “non-neutral” CO₂ emissions. This was recognized by the Intergovernmental Panel on Climate Change (IPCC) in its guidelines for greenhouse gas inventories. Nevertheless, specific guidance of how to estimate fossil CO₂ emissions per each type of biofuel, in order to facilitate the work of emission inventory compilers and practitioners, is neither available in the IPCC guidelines nor in the scientific literature. The purpose of this paper is to define a higher tier method to estimate the associated CO₂ emissions with the fossil carbon content of biofuels, aiming to cover all possible biofuel types that are mainly used nowadays to replace diesel and gasoline.

摘要

对石油衍生品的依赖以及交通运输部门燃料消耗的增长趋势已经引起人们对生物燃料作为减少温室气体（GHG）排放、加强能源安全和促进经济发展的措施的关注。使用生物燃料的动机是与化石燃料相比，它们具有减少二氧化碳 (CO _{2 ) 排放的潜力。}生物燃料被认为是碳中性的，就与其燃烧相关的直接 CO ₂排放而言，因为植物通过光合作用吸收的二氧化碳与其燃烧过程中释放的 CO _2相当。然而，生物燃料中的一部分碳可能来源于化石，因此它是“非中性”CO _2的原因排放。政府间气候变化专门委员会 (IPCC) 在其温室气体清单指南中承认了这一点。然而，IPCC 指南和科学文献中都没有关于如何估算每种生物燃料的化石 CO _{2排放量的具体指导，以促进排放清单编制者和从业者的工作。}本文的目的是定义一种更高层次的方法来估算与生物燃料的化石碳含量相关的 CO ₂排放量，旨在涵盖目前主要用于替代柴油和汽油的所有可能的生物燃料类型。