Impacts from decommissioning of hydroelectric dams: a life cycle perspective
Impacts from decommissioning of hydroelectric dams: a life cycle perspective
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DOI：
10.1007/s10584-007-9261-4
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发表时间：
2007-05
期刊：
影响因子：
4.8
通讯作者：
S. Pacca
中科院分区：
文献类型：
--
作者：
S. Pacca
水电站大坝的温室气体（GHG）排放通常被水电行业描述为不存在，并且在全球不同电力来源的比较中基本上被忽视。然而，任何水电厂的生命周期评估（LCA）表明，温室气体排放发生在电厂生命的不同阶段。这项工作考察了退役水电站大坝在温室气体排放中的作用。水库中积累的沉积物含有明显的碳含量，这些碳可能在大坝退役后释放到大气中。对美国十大水力发电厂中的六个进行了沉积物堆积率和沉积物体积调查。估算了大坝退役时刻（建成后100年）沉积物的数量和各自的碳含量。释放的碳被划分为co2和ch4排放，并使用全球变暖潜势（GWP）方法转换为co2当量排放。由于大坝退役导致的全球变暖效应（GWE）被归一化为每个发电厂在生命周期内产生的总电力。估计发电厂的GWE在128-380克二氧化碳当量之间。当总有效沉积物有机碳（SOC）的11%矿化且co2当量在35至104克之间时，/kWh。当总SOC的3%矿化时，/kWh。尽管这些数值低于燃煤电厂的排放系数（890克二氧化碳当量）。/kWh)，大坝退役时沉积物排放的温室气体量是一个不容忽视的显著数量，在考虑水电大坝的建设和再许可时必须予以考虑。
Greenhouse gas (GHG) emissions from hydroelectric dams are often portrayed as nonexistent by the hydropower industry and have been largely ignored in global comparisons of different sources of electricity. However, the life cycle assessment (LCA) of any hydroelectric plant shows that GHG emissions occur at different phases of the power plant’s life. This work examines the role of decommissioning hydroelectric dams in greenhouse gas emissions. Accumulated sediments in reservoirs contain noticeable levels of carbon, which may be released to the atmosphere upon decommissioning of the dam. The rate of sediment accumulation and the sediment volume for six of the ten largest United States hydroelectric power plants is surveyed. The amount of sediments and the respective carbon content at the moment of dam decommissioning (100 years after construction) was estimated. The released carbon is partitioned into CO2and CH4emissions and converted to CO2equivalent emissions using the global warming potential (GWP) method. The global warming effect (GWE) due to dam decommissioning is normalized to the total electricity produced over the lifetime of each power plant. The estimated GWE of the power plants range from 128–380 g of CO2eq./kWh when 11% of the total available sediment organic carbon (SOC) is mineralized and between 35 and 104 g of CO2eq./kWh when 3% of the total SOC is mineralized. Though these values are below emission factors for coal power plants (890 g of CO2eq./kWh), the amount of greenhouse gases emitted by the sediments upon dam decommissioning is a notable amount that should not be ignored and must be taken into account when considering construction and relicensing of hydroelectric dams.