Hydrogen (H${}_2$) can be a critical factor in achieving a more sustainable society reducing carbon emissions worldwide in the long run. However, there are some challenges to be solved yet. One of these challenges is that, right now, the economical competitiveness of electrolysis production strongly depends on the Renewable Energy Sources (RES) availability. This paper analyzes the economic and environmental implications of complementing the power supply of a H${}_2$ production plant that usually operates using only RES with grid electricity during the time RES are not available. For performing this analysis, we proposed an assessment model that incorporates Alkaline (ALK) and PEM electrolyzer technology features (such as the low dynamic load range of ALK electrolyzers, which is usually ignored when modeling H${}_2$ production). Moreover, we introduce a new metric, named the LCOH&E, which captures the existing trade-off between reducing the Levelized Cost Of Hydrogen (LCOH) with more H${}_2$ production using grid electricity and increasing CO${}_2$ emissions by producing more H${}_2$ with grid electricity. We illustrate the proposed assessment model with a case study based on real data from Chile. Our results show that the optimal fraction of grid electricity to be used in producing H${}_2$ may be different when minimizing the LCOH and when minimizing the LCOH&E because of the LCOH-CO${}_2$ emissions’ trade off. Moreover, it is remarkable that using only 10% of grid electricity in an ALK electrolyzer, it is possible to increase the H${}_2$ production in 25.7%, without significantly increasing the CO${}_2$ emission level.

氢气（H${}_2$) 从长远来看，这可能是实现更可持续的社会减少全球碳排放的关键因素。然而，还有一些挑战需要解决。这些挑战之一是，目前电解生产的经济竞争力在很大程度上取决于可再生能源 (RES) 的可用性。本文分析了补充 H 供电的经济和环境影响。${}_2$在可再生能源不可用期间，通常仅使用可再生能源和电网电力运行的生产工厂。为了执行此分析，我们提出了一种评估模型，该模型结合了碱性 (ALK) 和 PEM 电解槽技术特征（例如 ALK 电解槽的低动态负载范围，在建模 H${}_2$生产）。此外，我们引入了一个名为 LCOH&E 的新指标，它捕捉了降低氢气平均成本 (LCOH) 与更多 H 之间的现有权衡${}_2$ 使用电网电力和增加二氧化碳的生产${}_2$ 通过产生更多的 H 来排放${}_2$与电网电力。我们通过基于智利真实数据的案例研究来说明提议的评估模型。我们的结果表明，用于生产 H 的最佳电网电力比例${}_2$ 由于 LCOH-CO，当最小化 LCOH 和最小化 LCOH&E 时可能不同${}_2$排放的权衡。此外，值得注意的是，在 ALK 电解槽中仅使用 10% 的电网电力，就可以增加 H${}_2$ 25.7% 的产量，而不会显着增加 CO${}_2$ 排放水平。