Increasing amounts of hydropower are being exported from Canada to the northern United States. Recently proposed projects would increase transmission capacity to U.S. population centers without increasing generation. This avoids generation-side impacts from hydroelectric development and introduces power to the U.S. energy mix that is dispatchable, unlike wind and solar, with greenhouse gas emissions generally lower than those of fossil fuels. There is, however, a lack of analysis comparing high upfront capital costs to social benefits and controversy over valuation of social costs of hydropower from existing generation given the negligible marginal cost of production. This analysis evaluates direct and indirect costs in comparison to alternatives for a 1250 MW transmission line from Canada to New York City currently under development to replace the recent loss of ∼15 TWh year^–1 of nuclear generation. For the case study considered, we find that long-distance transmission avoids $13.2 billion ($12.1–14.4 billion) in total social costs by 2050. This includes $4.2 billion ($3.4–5.1 billion) from premature mortality in disproportionately Hispanic and African American or Black counties (roughly 306 avoided deaths). In an extensive sensitivity analysis, results are robust to all modeling choices other than the cost assigned to hydropower: the nominal dollar value of hydropower imports (payments from buyer to seller) commonly used in cost–benefit analysis leads to substantial underestimates of net benefits from transmission projects. The opportunity cost of these imports (e.g., environmental benefits foregone in alternative export markets) is a better metric for cost but is difficult to estimate.

中文翻译：

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长距离水力发电的社会总成本和收益

越来越多的水电从加拿大输出到美国北部。最近提议的项目将在不增加发电量的情况下增加到美国人口中心的输电能力。这避免了水电开发对发电方面的影响，并为美国能源结构引入了可调度的电力，与风能和太阳能不同，温室气体排放量通常低于化石燃料。然而，由于生产的边际成本微乎其微，缺乏对高额前期资本成本与社会效益进行比较的分析，以及对现有发电水电社会成本估值的争议。^–1的核能发电。对于所考虑的案例研究，我们发现到 2050 年，长距离传输可避免 132 亿美元（121-144 亿美元）的社会总成本。这包括 42 亿美元（3.4-51 亿美元）因不成比例的西班牙裔和非裔美国人或黑人过早死亡县（大约避免了 306 人死亡）。在广泛的敏感性分析中，结果对于除分配给水电的成本之外的所有建模选择都是稳健的：通常用于成本效益分析的水电进口的名义美元价值（买方向卖方付款）导致大大低估了来自水电的净效益传输项目。这些进口的机会成本（例如，替代出口市场放弃的环境效益）是一个更好的成本衡量标准，但很难估计。