Department of Agricultural Economics, Purdue University, 403 West State Street, West Lafayette, IN 47907, USA; Joint Global Change Research Institute, Pacific Northwest National Laboratory, 5825 University Research Ct, College Park, MD 20740, USA.
Department of Agricultural Economics, Purdue University, 403 West State Street, West Lafayette, IN 47907, USA.
Sci Total Environ. 2021 Jul 20;779:146238. doi: 10.1016/j.scitotenv.2021.146238. Epub 2021 Mar 5.
Sustainable aviation fuels (SAFs) are expected to play an essential role in achieving the aviation industries' goal of carbon-neutral growth. However, producing biomass-based SAFs may induce changes in global land use and the associated carbon stock. The induced land use change (ILUC) emissions, as a part of the full life-cycle emissions for SAF pathways, will affect whether and to what extent SAFs reduce emissions compared with petroleum-based jet fuels. Here, we estimate the ILUC emission intensity for seventeen SAF pathways considered by the International Civil Aviation Organization (ICAO), covering five ASTM-certified technologies, nine biomass-based feedstocks, and four geographical regions. We introduce the SAF pathways into a well-established computable general equilibrium (CGE) model, GTAP-BIO, and its coupled emission accounting model, AEZ-EF, to study economy-wide implications of SAF production and estimate ILUC emissions intensity for each pathway. The estimated SAF ILUC emission intensities, using a 25-year amortization period, range from -58.5 g COe MJ for the USA miscanthus alcohol (isobutanol)-to-jet (ATJ) pathway to 34.6 g COe MJ for the Malaysia & Indonesia palm oil Hydrotreated Esters of Fatty Acids (HEFA) pathway. Notably, the vegetable oil pathways tend to have higher ILUC emission intensities due to their linkage to palm expansion and peatland oxidation in Southeast Asia. The cellulosic pathways studied provide negative ILUC emissions, mainly driven by the high carbon sequestrations in crop biomass and soil. Using the core life-cycle emissions established by ICAO, we show that fifteen of the assessed pathways have a lower full life-cycle emission intensity than petroleum-based jet fuels (89 g COe MJ), offering promising options to reduce aviation emissions.
可持续航空燃料（SAF）有望在实现航空业碳中和增长目标方面发挥重要作用。然而，生产基于生物质的 SAF 可能会引起全球土地利用变化和相关碳储量的变化。作为 SAF 途径全生命周期排放的一部分，诱导的土地利用变化（ILUC）排放将影响 SAF 相对于石油基喷气燃料减少排放的程度和程度。在这里，我们估计了国际民用航空组织（ICAO）考虑的十七种 SAF 途径的 ILUC 排放强度，涵盖了五项 ASTM 认证技术、九种生物质原料和四个地理区域。我们将 SAF 途径引入到一个成熟的可计算一般均衡（CGE）模型 GTAP-BIO 及其耦合的排放核算模型 AEZ-EF 中，以研究 SAF 生产的经济影响，并估计每种途径的 ILUC 排放强度。使用 25 年摊销期估算的 SAF ILUC 排放强度，从美国芒草酒精（异丁醇）-喷气（ATJ）途径的-58.5 g COe MJ 到马来西亚和印度尼西亚棕榈油加氢处理脂肪酸（HEFA）途径的 34.6 g COe MJ 不等。值得注意的是，由于与东南亚棕榈油扩张和泥炭地氧化有关，植物油途径往往具有更高的 ILUC 排放强度。所研究的纤维素途径提供负的 ILUC 排放，主要由作物生物量和土壤中的高碳固存驱动。使用 ICAO 确定的核心生命周期排放，我们表明，在所评估的途径中，有十五种途径的全生命周期排放强度低于石油基喷气燃料（89 g COe MJ），为减少航空排放提供了有希望的选择。
