Connecting the dots: The biogenic carbon footprint of power transmission across forested lands

水电是最大的可再生能源之一。加拿大东部的魁北克省是一个重要的水电生产国：在未来几年中，它打算通过加速其经济电气化来减少进口化石燃料的使用，并通过增加水电出口为美国东北部司法管辖区的脱碳做出贡献，这将需要付出巨大努力来增加魁北克省境内和邻近市场的电力传输能力。水力发电的温室气体（GHG）排放量被认为大大低于化石能源的排放量。尽管最近全球和国家对水电温室气体足迹的估计考虑了水库的排放，但它们通常忽略了输电系统对陆地的生物影响。在魁北克，输电网络覆盖了17万公顷，包括几种不同类型的高地森林生态系统，从产生大部分水力发电的北方森林到靠近需求中心的北方阔叶林。我们建议量化电力线对林地和植被的生物碳影响。为此，我们将研究现有电力线走廊及其毗邻森林内的土壤和植被中的碳储量和循环，并对魁北克和新英格兰各州未来规划电力线的地区进行预测。该项目将为改进水电生命周期分析迈出重要的一步，完善水电碳足迹的估算也将用于所有消耗水电的过程和产品的生命周期分析，从而直接提高温室气体量化评估的准确性，并最终提高魁北克及其出口市场的气候政策。此外，它将提供经验证据，以完善与森林转化为公用设施走廊和其他类型住区有关的省、国家和国际温室气体清单方法。

Hydropower is one off the largest sources of renewable energy. The province of Quebec, in eastern Canada, is an important hydropower producer : over the next years, it intends to reduce its use of imported fossil fuels by accelerating the electrification of its economy and contribute to the decarbonisation of jurisdictions of northeastern United States through increased hydropower exports, which will require significant efforts to increase electricity transmission capacity across the Quebec territory and into the neighbouring markets. Greenhouse gas (GHG) emissions from hydropower are thought to be significantly lower than emissions from fossil energy sources. Although the most recent global and national estimates of the GHG footprint of hydropower takes into account emissions from reservoirs, they usually ignore the biogenic impacts of the transmission system on the land. In Quebec, the transmission network covers 170 000 hectares, including several different types of mostly upland forested ecosystems from boreal forests where most hydroelectric power is produced, to northern hardwoods forests close to demand centres. We propose to quantify the biogenic carbon impact of power-lines on forest land and vegetation. For doing so, we will study carbon stocks and cycling in the soil and vegetation within existing power-line corridors and their bordering forests, and will make projections for areas on which future power-lines are planned in Quebec and across the American border in New England states. This project will provide an important step forward for improving the life-cycle analysis of hydropower, Refining the estimates for the carbon footprint of hydropower will also feed into life-cycle analyses of all processes and products that consume hydro-electricity, thus directly improving the accuracy of GHG quantification assessments, and ultimately climate policies of Quebec and its export markets. Moreover, it will provide empirical evidence for refining both provincial, national and international GHG inventory methodologies related to forest conversion to utility corridors and other types of settlements.