能源植物木薯规模化利用的温室气体减排潜力研究

Fossil fuel shortages and environmental pollution problems are worsening, while globally, countries are actively seeking alternative energy sources. As an important renewable new energy, bio-fuel (including bio-fuel ethanol and biodiesel) has attracted extensive attention of governments and enterprises throughout the world. China’s biofuel industry is witnessing rapid development. However, the development of biodiesel industry is still faced with many uncertainties, among which the accurate estimation of the potentiality of raw material supply, net energy production and greenhouse gas (GHG) emission reduction are the most crucial issue. . In recent years, many methods including Life Cycle Analysis (LCA) have been widely used in bio-energy assessment studies. However, previous studies mainly limited to calculate the unit mass or unit area of bio-fuel life cycle based on laboratory dataset, i.e. 'GHG emission reduction efficiency'. Regional total GHG emission reduction potentials were simply considered as 'efficiency times total yield'. Spatio-temporal variation of environmental factors, such as solar radiation, temperature, soil, and water, were neglected in previous studies. . The main objective of this project is to establish a operational method for comprehensive evaluation the GHG emission reduction potential from large-scale cultivation of energy plant Cassava, by combining LCA with ecosystem process model. LCA is used to evaluate the energy consumption and GHG emission from Cassava plantation, yield acquisition, production, and product use through to post-processing. Meanwhile, ecosystem process model, EPIC model, is adopt to estimates fluxes and storage of energy, water, carbon, and nitrogen for the Cassava and soil components of terrestrial ecosystems. The parameters, including factors for LCA and EPIC model, will be tested and localized according to field survey and sampling information in the Energy plantation experimental demonstration base in Fo Gang county and Guang Zhou city, Guang Dong province.. First, the potentiality, degree and spatial distribution of marginal land resources suitable for planting Cassava will be determined. Next, LCA-based analytical model of net energy production potential and GHG emission reduction potential of fuel bioethanol from Cassava produced from Cassava will be established. By this means, the analysis and appraisal of maximum net energy amount and GHG emission reduction potential of fuel bioethanol from Cassava can be achieved, thus offering technical methods and typical cases for analysis of development potentials and environmental benefits of biofuels derived from energy plants.

温室气体减排潜力是评价能源植物开发利用前景的重要依据。国内外现有评价方法大多是以单位体积或质量液体燃料为研究对象的“减排效率”，应用到较大范围的区域尺度时，往往采用全区平均的方法，不能充分反映光温水热等要素空间异质性带来的减排潜力的空间差异。本项目拟以能源植物木薯为例，结合试验区的测试和分析工作，发展一种耦合能源植物生长过程模型与LCA的技术方法，对基于木薯发展生物乙醇的GHG减排潜力进行准确评估。其中，能源植物生长过程模型拟选择EPIC模型，在前期研究基础上，利用我国木薯种植示范基地多年的实地数据进行改进和本地化。项目将真正实现区域尺度能源植物减排潜力的准确估算，为区域可再生能源发展、温室气体减排目标和相关产业政策的制定提供科学依据。

基于能源植物的生物液体燃料具有可再生、清洁和安全等优点，是解决能源危机和保护生态环境的有效途径。温室气体减排潜力是评价能源植物开发利用前景的重要依据。国内外现有评价方法大多是以单位体积或质量液体燃料为研究对象的“减排效率”，应用到较大范围的区域尺度时，往往采用全区平均的方法，不能充分反映光温水热等要素空间异质性带来的减排潜力的空间差异。本项目的主要研究内容是以能源植物木薯为例，以广东、广西等南方区域为研究区，结合试验区的测试和分析工作，发展一种耦合能源植物生长过程模型与LCA的技术方法，对基于木薯发展生物乙醇的GHG减排潜力进行准确评估。. 项目提出了边际土地资源识别及适宜性分析方法，筛选了能源植物生长过程模型（选择EPIC模型）在前期研究基础上，利用我国木薯种植示范基地多年的实地数据进行改进和本地化；在前期研究基础上，结合试验区的测试分析工作，发展了一种耦合能源植物生长过程模型（EPIC）与生命周期分析（LCA）的理论方法，在精细网格单元上，建立完整的木薯生命周期净温室气体（GHG）排放评估模型，该方法在时间上涵盖木薯生物乙醇的整个生命周期，在空间上适应公里网格—区域多级尺度，真正实现从单点的“减排效率”到区域尺度减排潜力的科学估算。利用该方法，对我国木薯主产区的能源潜力和减排潜力做了准确估算。. 利用项目研发的边际土地资源识别及适宜性分析方法，建立了多因子综合评价模型，结合地形、气象、土壤、能源植物生态习性及国家相关政策要求等因子进行边际土地适宜性分析，建立了全国1km栅格宜能边际土地资源时空数据库、我国主要能源植物生态习性要素空间数据库、全国木薯能源潜力数据集（包括能源潜力、减排潜力等）。. 项目研究成果真正实现了区域尺度能源植物减排潜力的准确估算，准确评估了我国适用于规模化发展能源植物的边际土地资源潜力（质量）、空间分布和动态变化，为区域可再生能源发展、温室气体减排目标和相关产业政策的制定提供了科学依据。