In the last years the greenhouse effect has been significantly intensified due to human activities, generating large additional amounts of Greenhouse gases (GHG). The fossil fuels are the main causes of that. Consequently, the attention on the composition of the national fuel mix has significantly grown, and the renewables are becoming a more significant component. In this context, biomass is one of the most important sources of renewable energy with a great potential for the production of energy. The study has evaluated, through an LCA (Life Cycle Assessment) study, the attitude of alfalfa (Medicago sativa) as “no food” biomass alternative to maize silage (corn), in the production of biogas from anaerobic digestion. Considering the same functional unit (1 m³ of biogas from anaerobic digestion) and the same time horizon, alfalfa environmental impact was found to be much comparable to that of corn because it has an impact of about 15% higher than corn considering the total score from different categories and an impact of 5% higher of corn considering only greenhouse gases. Therefore, the analysis shows a similar environmental load in the use of alfalfa biomass in energy production compared to maize. Corn in fact, despite a better yield per hectare and yield of biogas, requires a greater amount of energy inputs to produce 1m³ of biogas, while alfalfa, which requires less energy inputs in its life cycle, has a lower performance in terms of yield. The results show the possibility to alternate the two crops for energy production from an environmental perspective.

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苜蓿和玉米用于农场生产沼气的生命周期评估分析

在过去的几年中，由于人类活动，温室效应大大增强，产生了大量额外的温室气体（GHG）。化石燃料是造成这种情况的主要原因。因此，对国家燃料结构成分的关注已大大增加，可再生能源正变得越来越重要。在这种情况下，生物质是最重要的可再生能源之一，具有巨大的能源生产潜力。该研究通过生命周期评估（LCA）研究评估了苜蓿（Medicago sativa）在厌氧消化生产沼气中作为“无食物”生物质替代玉米青贮饲料（玉米）的态度。考虑相同的功能单元（1 m ³厌氧消化产生的沼气）和相同的时间范围，发现紫花苜蓿对环境的影响与玉米相当，因为考虑到不同类别的总得分和5％的影响，它对玉米的影响比玉米高约15％仅考虑温室气体，玉米的含量更高。因此，分析表明，与玉米相比，苜蓿生物量在能源生产中的环境负荷相似。实际上，尽管每公顷产量和沼气产量更高，但玉米需要更多的能量输入才能生产1m ³的沼气，而苜蓿在其生命周期中需要较少的能量输入，但其产量却较低。 。结果表明，从环境角度看，两种作物交替生产能源的可能性。