一种水电站水足迹改进计算方法

A New Water Footprint Calculation Method for Hydroelectricity

传统水足迹计算方法在评价水电开发中水资源消耗时,未考虑水电站建设前河流天然状态下已有水量蒸发,一定程度上会高估水力发电水足迹。改进传统水足迹计算方法,将水库库区水面年蒸发量E改为年新增蒸发量ΔE,更能直观反映水力发电能耗比。以澜沧江中下游6座已建成水电站为案例,对比水足迹传统及改进计算方法,评估水电开发的水资源消耗,结果显示:传统方法求出平均水足迹为2.38 m3/GJ,改进方法为1.93 m3/GJ;改进计算方法考虑了建坝前河流天然状态下已有水量蒸发,水力发电水足迹计算结果更准确;水电站建设前后水面面积改变程度是影响计算结果改进程度的关键因素。

The commonly used water footprint calculation methods have ignored the evaporative water loss prior to the building dam,leading to an inaccurate assessment of water consumption of hydroelectric power plants. A new method is introduced in this study,in which gross water consumption（ E） is replaced by net water consumption（ ΔE）. Therefore,the ratio between benefits of hydropower plant construction and cost of its energy and water consumption can be reflected more clearly. We compare the water footprint of 6 cascade hydropower stations in middle and lower reaches of the Lancang River by applying the new method and traditional methods. The results show that the average water footprint is larger with the traditional method（ 2.38 m^3/GJ） than that with the new method（ 1. 93 m^3/GJ）. The traditional methods might overestimate the hydroelectric footprint of hydroelectric power. The degree of water surface area change is the key factor that affects the improved performance of water footprint calculation by applying the new method.