Integrating life cycle assessment and emergy synthesis for the evaluation of a dry steam geothermal power plant in Italy
Integrating life cycle assessment and emergy synthesis for the evaluation of a dry steam geothermal power plant in Italy
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DOI：
10.1016/j.energy.2015.04.048
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发表时间：
2015-06
期刊：
影响因子：
9
通讯作者：
E. Buonocore;L. Vanoli;A. Carotenuto;S. Ulgiati
中科院分区：
文献类型：
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作者：
E. Buonocore;L. Vanoli;A. Carotenuto;S. Ulgiati
温室气体排放、气候变化和不断增长的能源需求目前被视为最关键的环境问题。本文以意大利托斯卡纳地区的一座20 MW干蒸汽地热发电厂为例，对其进行了生命周期评价（LCA）和能值评价（EMA）。该发电厂能够利用当地可用的可再生资源以及非再生资源的适度支持来发电。这使得地热资源有资格生产可再生电力。然而，直接利用地热流体会向大气中释放二氧化碳、硫化氢、汞、砷和其他化学物质，这些化学物质会高度促进气候变化、酸化潜力、富营养化潜力、人体毒性和光化学氧化。以及是否存在需要进一步关注的步骤和/或组件。能值综合法的应用为生命周期评价提供了一个补充视角，突出了自然资本和生态系统服务对电厂建设和运营的直接和间接贡献，并将地热发电厂的环境影响与可再生能源和化石燃料发电厂的环境影响进行了比较。所调查的地热发电厂的CO2当量排放量（248 g kWh−1）低于化石燃料发电厂，但仍高于太阳能光伏发电和水力发电等可再生能源技术。此外，与地热发电厂相关的SO2当量释放量（3.37 g kWh−1）与化石燃料发电厂相当。结果表明，需要进一步研究其他地热方案（例如二元系统），以减少对环境的影响，同时最大限度地利用地热资源。
Greenhouse gas emissions, climate change and the rising energy demand are currently seen as most crucial environmental concerns. With the exploration of renewable energy sources to meet the challenges of energy security and climate change, geothermal energy is expected to play an important role.In this study a LCA (Life Cycle Assessment) and an EMA (Emergy Assessment) of a 20 MW dry steam geothermal power plant located in the Tuscany Region (Italy) are performed and discussed. The plant is able to produce electricity by utilizing locally available renewable resources together with a moderate support by non-renewable resources. This makes the geothermal source eligible to produce renewable electricity. However, the direct utilization of the geothermal fluid generates the release into the atmosphere of carbon dioxide, hydrogen sulfide, mercury, arsenic and other chemicals that highly contribute to climate change, acidification potential, eutrophication potential, human toxicity and photochemical oxidation.The study aims to understand to what extent the geothermal power plant is environmentally sound, in spite of claims by local populations, and if there are steps and/or components that require further attention. The application of the Emergy Synthesis method provides a complementary perspective to LCA, by highlighting the direct and indirect contribution in terms of natural capital and ecosystem services to the power plant construction and operation.The environmental impacts of the geothermal power plant are also compared to those of renewable and fossil-based power plants. The release of CO2-eq calculated for the investigated geothermal plant (248 g kWh−1) is lower than fossil fuel based power plants but still higher than renewable technologies like solar photovoltaic and hydropower plant. Moreover, the SO2-eq release associated to the geothermal power plant (3.37 g kWh−1) is comparable with fossil fuel based power plants.Results suggest the need for further investigation of other geothermal options (e.g. binary systems) in order to reduce the environmental impacts while taking the maximum advantage of the geothermal resource.