Economic and Environmental Analysis of Hydrogen Production when Complementing Renewable Energy Generation with Grid Electricity

Abstract

Hydrogen (H2) can be a critical factor in achieving a more sustainable society reducing carbon emissionsworldwide in the long run. However, there are some challenges to be solved yet. One of these challenges isthat, right now, the economical competitiveness of electrolysis production strongly depends on the RenewableEnergy Sources (RES) availability. This paper analyzes the economic and environmental implications ofcomplementing the power supply of a H2 production plant that usually operates using only RES with gridelectricity during the time RES are not available. For performing this analysis, we proposed an assessmentmodel that incorporates Alkaline (ALK) and PEM electrolyzer technology features (such as the low dynamicload range of ALK electrolyzers, which is usually ignored when modeling H2 production). Moreover, weintroduce a new metric, named the LCOH&E, which captures the existing trade-off between reducing theLevelized Cost Of Hydrogen (LCOH) with more H2 production using grid electricity and increasing CO2emissions by producing more H2 with grid electricity. We illustrate the proposed assessment model with acase study based on real data from Chile. Our results show that the optimal fraction of grid electricity to beused in producing H2 may be different when minimizing the LCOH and when minimizing the LCOH&E becauseof the LCOH-CO2 emissions’ trade off. Moreover, it is remarkable that using only 10% of grid electricity inan ALK electrolyzer, it is possible to increase the H2 production in 25.7%, without significantly increasing theCO2 emission level.