Which crop has the highest bioethanol yield in the United States?
Which crop has the highest bioethanol yield in the United States?
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DOI：
10.3389/fenrg.2023.1070186
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发表时间：
2023-02
期刊：
影响因子：
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通讯作者：
Tzu‐Shun Lin;H. Kheshgi;Yang Song;C. Vörösmarty;Atul K. Jain
中科院分区：
文献类型：
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作者：
Tzu‐Shun Lin;H. Kheshgi;Yang Song;C. Vörösmarty;Atul K. Jain
2021年，美国生物乙醇的年产量（主要由美国中西部的玉米淀粉生产）上升至570亿升，达到了2007年《能源独立与安全法案》（EISA）规定的常规生物燃料目标。与此同时，美国没有达到790亿升的纤维素或先进生物燃料目标。生物能源草的生长（例如，芒草和柳枝稷）有潜力提高纤维素生物乙醇的产量，如果成功的话，还可以增加可再生燃料的产量。然而，水消耗和气候变化及其极端情况是玉米和生物能源草生产力的关键问题。生产生物燃料需要有潜在生产力的土地和水，这使这些问题更加复杂。这是粮食-能源-水系统（FEWS）关系的一个基本挑战。我们应用计算框架来估计美国各地潜在的生物能源产量和转化为生物乙醇产量，通过对玉米、芒草和柳枝稷两个品种（Cave-in-Rock和Alamo）的田间试验和转化技术分析，目前的研究确定了美国中部和东部每种作物产量最高的地区。虽然种植生物能源草需要比玉米更多的水，但它们作为生物乙醇来源的一个优势是，它们相对于玉米控制了氮的浸出。生物能源草在极端气候条件下也保持稳定的高生产力，例如2012年美国中西部的干旱和热浪，因为常年生长季节和更深更密的根可以改善土壤水分胁迫。虽然潜在的乙醇产量可以使用能源草提高，但它们在成为乙醇产量的潜在来源方面的实际成功仍然受到社会经济和运营限制以及与粮食生产竞争的问题的限制。
Annual U.S. production of bioethanol, primarily produced from corn starch in the U.S. Midwest, rose to 57 billion liters in 2021, which fulfilled the required conventional biofuel target set forth by the Energy Independence and Security Act (EISA) of 2007. At the same time, the U.S. fell short of the cellulosic or advanced biofuel target of 79 billion liters. The growth of bioenergy grasses (e.g., Miscanthus and switchgrass) across the Central and Eastern U.S. has the potential to feed enhanced cellulosic bioethanol production and, if successful, increase renewable fuel volumes. However, water consumption and climate change and its extremes are critical concerns in corn and bioenergy grass productivity. These concerns are compounded by the demands on potentially productive land areas and water devoted to producing biofuels. This is a fundamental Food-Energy-Water System (FEWS) nexus challenge. We apply a computational framework to estimate potential bioenergy yield and conversion to bioethanol yield across the U.S., based on crop field studies and conversion technology analysis for three crops—corn, Miscanthus, and two cultivars of switchgrass (Cave-in-Rock and Alamo). The current study identifies regions where each crop has its highest yield across the Center and Eastern U.S. While growing bioenergy grasses requires more water than corn, one advantage they have as a source of bioethanol is that they control nitrogen leaching relative to corn. Bioenergy grasses also maintain steadily high productivity under extreme climate conditions, such as drought and heatwaves in the year 2012 over the U.S. Midwest, because the perennial growing season and the deeper and denser roots can ameliorate the soil water stress. While the potential ethanol yield could be enhanced using energy grasses, their practical success in becoming a potential source of ethanol yield remains limited by socio-economic and operational constraints and concerns regarding competition with food production.