In spite of the very large hydropower potential given from the melting snow and ice of Himalayas, Nepal’s population has little hydropower production. The high use of fossil fuels and biomasses results in measurable air pollution, even in the mountain areas. Hydropower planning and implementation, in the face of the changing climate, is therefore paramount important. We focus here on Nepal, and particularly on the Dudh Koshi river basin, with a population of ca. 170,000 people, within an area with large potential for hydropower production. Our main objectives are to (i) preliminarily design a local hydropower grid based on a distributed run of river ROR scheme, and (ii) verify the resilience of the grid against modified hydrology under perspective climate change, until the end of the century. To do so, we set up and tune the Poli-Hydro semi-distributed glacio-hydrological model, mimicking the complex hydrology of the area. We then modify a state of the art algorithm to develop and exploit a heuristic, resource-demand based model, called Poli-ROR. We use Poli-ROR to assess the (optimal) distribution of a number of ROR hydropower stations along the river network, and the structure of the local mini-grids. We then use downscaled outputs from three general circulation models GCMs (RCPs 2.6, 4.5, 8.5) from the Intergovernmental Panel on Climate Change IPCC AR5, to assess the performance of the system under future modified hydrological conditions. We find that our proposed method is efficient in shaping ROR systems, with the target of the largest possible coverage (93%), and of the least price (0.068 € kWh−1 on average). We demonstrate also that under the projected hydrological regimes until 2100, worse conditions than now may occur, especially for plants with small drainage areas. Days with energy shortage may reach up to nf = 38 per year on average (against nf = 24 now), while the maximum daily energy deficit may reach as high as edef% = 40% (against edef% = 20% now). We demonstrate that our originally proposed method for ROR grid design may represent a major contribution towards the proper development of distributed hydropower production in the area. Our results may contribute to improve energy supply, and living conditions within the Dudh Koshi river. It is likely that our approach may be applied in Nepal generally. Impending climate change may require adaptation in time, including the use of other sources which are as clean as possible, to limit pollution. Our Poli-ROR method for grid optimization may be of use for water managers, and scientists with an interest in the design of optimal hydropower schemes in topographically complex catchments.

中文翻译：

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气候变化下喜马拉雅山区河流计划的水电潜力：尼泊尔 Dudh Koshi 盆地的案例研究

尽管喜马拉雅山的冰雪融化提供了非常大的水电潜力，但尼泊尔的人口几乎没有水电生产。化石燃料和生物质的大量使用导致了可测量的空气污染，即使在山区也是如此。因此，面对不断变化的气候，水电规划和实施至关重要。我们在这里专注于尼泊尔，特别是 Dudh Koshi 河流域，人口约 170,000 人，位于具有巨大水电生产潜力的地区。我们的主要目标是 (i) 初步设计一个基于分布式河流 ROR 方案的地方水电电网，以及 (ii) 验证电网在预期气候变化下对修改后的水文的恢复能力，直到本世纪末。为此，我们建立并调整了 Poli-Hydro 半分布式冰川水文模型，模拟该地区复杂的水文。然后，我们修改了最先进的算法来开发和利用启发式、基于资源需求的模型，称为 Poli-ROR。我们使用 Poli-ROR 来评估沿河网络的多个 ROR 水电站的（最佳）分布，以及当地微型电网的结构。然后，我们使用来自政府间气候变化专门委员会 IPCC AR5 的三个大环流模型 GCM（RCPs 2.6、4.5、8.5）的缩减输出来评估系统在未来修改后的水文条件下的性能。我们发现我们提出的方法在塑造 ROR 系统方面是有效的，目标是尽可能大的覆盖率 (93%) 和最低的价格 (平均 0.068 € kWh−1)。我们还证明，在预计到 2100 年的水文状况下，可能会出现比现在更糟的情况，尤其是对于流域面积较小的植物。能量短缺的天数平均每年可能达到 nf = 38（现在 nf = 24），而最大的每日能量赤字可能高达 edef% = 40%（现在对抗 edef% = 20%）。我们证明，我们最初提出的 ROR 电网设计方法可能代表对该地区分布式水电生产的适当发展的重大贡献。我们的结果可能有助于改善 Dudh Koshi 河内的能源供应和生活条件。我们的方法很可能普遍适用于尼泊尔。即将发生的气候变化可能需要及时适应，包括使用尽可能清洁的其他来源，以限制污染。