绿色公路技术LCA评价体系及效益分析

针对各类绿色公路技术难以横向比较的问题,文章从技术可行性、经济效益、节能减排效益等方面,提出建立绿色公路技术LCA评价体系,并以G312苏州西段工程为例进行综合效益分析,其综合效益最为显著,具备规模化、资源化、投资适宜的绿色公路技术;技术瓶颈问题的突破和创新,是推进绿色公路发展的根本动力;将绿色理念融入公路建设的全生命周期的前提,是因地制宜的前期规划布局研究,也是合理选择适宜绿色公路技术的基础。     

Effects of battery chemistry and performance on the life cycle greenhouse gas intensity of electric mobility

Lithium traction batteries are a key enabling technology for plug-in electric vehicles (PEVs). Traction battery manufacture contributes to vehicle production emissions, and battery performance can have significant effects on life cycle greenhouse gas (GHG) emissions for PEVs. To assess emissions from PEVs, a life cycle perspective that accounts for vehicle production and operation is needed. However, the contribution of batteries to life cycle emissions hinge on a number of factors that are largely absent from previous analyses, notably the interaction of battery chemistry alternatives and the number of electric vehicle kilometers of travel (e-VKT) delivered by a battery. We compare life cycle GHG emissions from lithium-based traction batteries for vehicles using a probabilistic approach based on 24 hypothetical vehicles modeled on the current US market. We simulate life-cycle emissions for five commercial lithium chemistries. Examining these chemistries leads to estimates of emissions from battery production of 194–494 kg CO₂ equivalent (CO₂e) per kWh of battery capacity. Combined battery production and fuel cycle emissions intensity for plug-in hybrid electric vehicles is 226–386 g CO₂e/e-VKT, and for all-electric vehicles 148–254 g CO₂e/e-VKT. This compares to emissions for vehicle operation alone of 140–244 g CO₂e/e-VKT for grid-charged electric vehicles. Emissions estimates are highly dependent on the emissions intensity of the operating grid, but other upstream factors including material production emissions, and operating conditions including battery cycle life and climate, also affect life cycle GHG performance. Overall, we find battery production is 5–15% of vehicle operation GHG emissions on an e-VKT basis.     

汽车轻量化技术的应用

应用汽车轻量化技术可实现减轻汽车质量,解决节能与环保问题。文章通过轻量化对促进汽车工业健康发展重要性的论述,阐明轻量化技术在汽车结构优化设计、轻量化材料开发应用及新工艺上实现的方法和主要作用,以及产品全生命周期评价列为轻量化技术之一的考虑,揭示汽车轻量化技术的主要应用方向和应用现状,强调轻量化技术在汽车轻量化中的重要作用与前景。     

Trends in life cycle greenhouse gas emissions of future light duty electric vehicles

The majority of previous studies examining life cycle greenhouse gas (LCGHG) emissions of battery electric vehicles (BEVs) have focused on efficiency-oriented vehicle designs with limited battery capacities. However, two dominant trends in the US BEV market make these studies increasingly obsolete: sales show significant increases in battery capacity and attendant range and are increasingly dominated by large luxury or high-performance vehicles. In addition, an era of new use and ownership models may mean significant changes to vehicle utilization, and the carbon intensity of electricity is expected to decrease. Thus, the question is whether these trends significantly alter our expectations of future BEV LCGHG emissions.To answer this question, three archetypal vehicle designs for the year 2025 along with scenarios for increased range and different use models are simulated in an LCGHG model: an efficiency-oriented compact vehicle; a high performance luxury sedan; and a luxury sport utility vehicle. While production emissions are less than 10% of LCGHG emissions for today’s gasoline vehicles, they account for about 40% for a BEV, and as much as two-thirds of a future BEV operated on a primarily renewable grid. Larger battery systems and low utilization do not outweigh expected reductions in emissions from electricity used for vehicle charging. These trends could be exacerbated by increasing BEV market shares for larger vehicles. However, larger battery systems could reduce per-mile emissions of BEVs in high mileage applications, like on-demand ride sharing or shared vehicle fleets, meaning that trends in use patterns may countervail those in BEV design.     

Comparison of coal-based dimethyl ether and diesel as vehicle fuels from well to wheel in China

With life cycle assessment (LCA) methodology, a life cycle model of coal-based vehicle fuels (CBVFs) including coal-based dimethyl ether (CBDME) and coal-based diesel (CBD) is established. Their primary energy consumption (PEC) and global warming potential (GWP) from well to wheel including feedstock extraction, fuel production, fuel consumption in vehicle and energy transportation are calculated and compared. Results show that the life cycle PEC and GWP of CBD pathway are 1.17 and 1.34 times as CBDME pathway. Based on the above results, CBDME will become a choice with great potential to replace conventional petroleum-based diesel (CPBD) in China.     

Life cycle assessment of bituminous pavements produced at various temperatures in the Belgium context

Bituminous mixture is the premier material for road construction in Belgium. Innovative technologies to improve energy efficiency of pavement constructions are necessary. Warm mix asphalt may provide significant energy savings to the asphalt industry, but the environmental impact of the total life cycle has to be investigated. The use of additives may counteract the reduced environmental impact due to energy savings. This paper presents the results of an environmental impact assessment of four wearing course test sections. Using life cycle assessment, hot mix asphalt is compared to a cold asphalt mix with emulsion and warm mix asphalt with two types of additives: a synthetic zeolite and an organic Fischer–Tropsch wax. Neither hot nor warm mix asphalt could be preferred based on the results of this study, because the additive has a major influence on the environmental results. It was seen that the production of bitumen, the transport and energy in order to generate heat mainly contribute to the total environmental impact. The results from the sensitivity analyses show that the total environmental impact of the life of the pavement can vary significantly based on the choice of the specific data source and service life.     

基于 LCA 的轨道交通车站 碳排放分析

建筑业作为碳排放最大的行业之一,每年排放的 CO2 约占世界总排放量的 25%,而建筑物化阶段和运营 阶段是建筑全生命周期中排放量最大的阶段,因此对这部分碳排放量化具有重要的研究意义。以某轨道交通车站 为案例,将建筑物化阶段进行分解,建立单元工序的碳排放计算模型,再对运营阶段的能耗进行分析,最后集成 得到整个工程的碳排放计算模型。通过案例分析发现,建筑物化阶段中钢材的碳排放量占总材料碳排放的 50.84%; 机械碳排放中柴油占比最大,为 70.62%;而在人员碳排放中垃圾处理的碳排放所占比例达到 78%,在车站运营 阶段通风空调系统碳排放占比最大,为 48.2%。根据计算结果,从机械使用、施工方式、能源来源、运营方式等 给出节能减排措施。     

The limits of partial life cycle assessment studies in road construction practices: A case study on the use of hydrated lime in Hot Mix Asphalt

Extensive published literature shows that hydrated lime improves Hot Mix Asphalt (HMA) durability. Its impact on the environmental impact of HMA has not been investigated. This paper presents a comparative Life Cycle Assessment (LCA) for the use of HMA without hydrated lime (classical HMA) and with hydrated lime (modified HMA) for the lifetime of a highway. System boundaries cover the life cycle from cradle-to-grave, meaning extraction of raw materials to end of life of the road. The main assumptions were: 1. Lifetime of the road 50 years; 2. Classical HMA with a life span of 10 years, maintenance operations every 10 years; 3. Modified HMA with an increase in the life span by 25%, maintenance operations every 12.5 years. For the lifetime of the road, modified HMA has the lowest environmental footprint compared to classical HMA with the following benefits: 43% less primary total energy consumption resulting in 23% lower emissions of greenhouse gases. Partial LCAs focusing only on the construction and/or maintenance phase should be used with caution since they could lead to wrong decisions if the durability and the maintenance scenarios differ. Sustainable construction technologies should not only consider environmental impact as quantified by LCA, but also economic and social impacts as well. Avoiding maintenance steps means less road works, fewer traffic jams and hence less CO₂ emissions.     

Evaluation on contribution of steel products to environmental improvement from life cycle assessment perspectives

High functionality given to steel products results in incremental environment loads at the steelmaking stage. However, at the stage of utilization, high-functional steel products prove more environment friendly than their conventional counterparts in many cases. Therefore, evaluation on contribution of steel products to environmental improvement requires an integrated approach that considers the product over its entire life cycle — life cycle assessment (LCA). This paper discusses the relationship between the improvement of steel products performance and environmental impact from the entire life cycle perspectives. The LCA method to calculate and assess contribution of high-functional steel products during the life cycle to environmental improvement is explained. Two case studies of Baoshan Iron &; Steel Co., Ltd. (Baosteel for short) are given to show that LCA is a scientific and systematic method for eco-materials evaluation or eco-design: ? in a power transformer, using silicon steel B30P110 to replace B30G130 can reduce carbon dioxide emissions in the region of 15.1% over the life cycle of the power transformer; ? tinplate steel of Baosteel for two-piece steel cans experienced six times thickness reduction from 0.280 to 0.225mm, which results in 14.5% emission reduction over the life cycle of two-piece steel cans. It is a systematic and scientific method for evaluating on products environmental performance from life cycle perspective.     

基于能源链的纯电动公交车全生命周期CO2减排效果研究

为准确量化纯电动公交车CO₂减排效果,更好地推动纯电动公交车在城市公交领域的推广应用,本文从能源链角度对纯电动公交车全生命周期的CO₂减排效果进行了研究.基于能源消耗数据,构建了基于能源链的纯电动公交车全生命周期CO₂排放模型;采用单因素敏感性分析法对排放模型的主要影响因素进行了分析,并基于此采用情景分析法建立了CO₂ 减排效果分析方法;通过实际案例及情景设置分析了现阶段及不同场景下纯电动公交车的CO₂减排效果.结果表明：在相同运营环境下,相比柴油公交车,纯电动公交车能源链全生命周期每百公里可以实现CO₂减排61.20%;在设定的不同情景下,2025年,2035年,2050年纯电动公交车的使用将分别实现每天CO₂减排134 712.36 t,253 566.80 t,326 323.74 t.