Relevance of Optimized Low-Scale Green H2 Systems in a French Context: Two Case Studies

Hydrogen has been identified as a very promising vector for energy storage, especially for heavy mobility applications. For this reason, France is making significant investments in this field, and use cases need to be evaluated as they are sprouting. In this paper, the relevance of H-2 in two storage applications is studied: a domestic renewable electricity production system connected to the grid and a collective hydrogen production for the daily bus refill. The investigation consists of the sizing of the system and then the evaluation of its performance according to several criteria depending on case. Optimizations are made using Bayesian and gradient-based methods. Several variations around a central case are explored for both cases to give insights on the impact of the different parameters (location, pricing, objective, etc.) on the performance of the system.Our results show that domestic power-to-power applications (case 1) do not seem to be competitive with electrochemical storage. Meanwhile, without any subsidies or incentives, such configuration does not allow prosumers to save money (+16% spendings compared to non-equipped dwelling). It remains interesting when self-sufficiency is the main objective (up to 68% of energy is not exchanged). The power-to-gas application (case 2, central case), with a direct use of hydrogen for mobility, seems to be more relevant according to our case study, we could reach a production cost of green H-2 around 5 (sic)/kg, similar to the 3-10 $/kg found in literature, for 182 houses involved. In both cases, H-2 follows a yearly cycle, charging in summer and discharging in winter (long term storage) due to low conversion efficiency.

Automated summary

Hydrogen is considered a promising vector for energy storage, particularly in heavy mobility applications. This paper examines the relevance of hydrogen in two storage applications and uses optimization methods to evaluate their performance. The study finds that hydrogen is not competitive with electrochemical storage in domestic power-to-power applications, but is more relevant and cost-effective in power-to-gas applications for mobility.