Avaliação técnico econômica e ambiental da planta de produção de hidrogênio usando fontes renováveis (H2V): diagnóstico, otimização, avaliação dos impactos ambientais

Abstract

Population growth and industrialization present the challenge of providing more energy with fewer greenhouse gas emissions. In this context, hydrogen stands out as one of the most promising energy carriers, in addition to being essential for the production of ammonia, methanol, steel, glass industry products, among others. This study aims to analyze the technical, economic, and environmental potential of hydrogen production from renewable energy sources in the state of Minas Gerais. The first process analyzed was biomass residue gasification. For this, the 66 microregions of Minas Gerais were considered in the analysis of nine selected types of residues, under different gasifying agent conditions and with the possibility of gas upgrading. A chemical equilibrium model based on Gibbs free energy minimization was developed for this purpose, validated under gasification conditions with air, pure oxygen, and air-steam mixtures. Additionally, a Monte Carlo simulation was applied for the economic analysis, along with a life cycle assessment (LCA) of the gasification process. The second process evaluated was proton exchange membrane (PEM) electrolysis powered by renewable sources. The electrolysis process was modeled and, after model validation, sensitivity analyses were carried out to determine the operating points that maximize hydrogen production. With the maximum production points defined for both the electrolysis and gasification processes, an economic analysis was performed using the Levelized Cost of Hydrogen (LCOH) as a metric. The main results indicated that, in the case of gasification, the highest theoretical hydrogen production potential in Minas Gerais was obtained from sugarcane residues, representing 82% of the total. Only nine microregions concentrated about 80% of this potential. The economic potential was evaluated under three residue collection and usage scenarios, with Frutal and Uberaba standing out as the regions with the best economic prospects, reaching LCOH values below US$3/kg of hydrogen under optimistic waste utilization conditions across all gasifying agent scenarios. In the Monte Carlo simulation, the input parameters that most influenced the LCOH in gasification were: minimum attractive rate of return (MARR), residue recovery factor, capital expenditures (CAPEX), Chemical Engineering Plant Cost Index (CEPCI), and local taxes. The life cycle assessment indicated that using the purge gas from the PSA (Pressure Swing Adsorption) process in gasification is environmentally necessary, and that the process emissions were below 2.44 kgCO₂eq/kgH₂, which is considered low according to Law 14,948 of 2024, from the Brazilian code. For electrolysis, it was found that hydrogen purity requirements considerably increase the levelized cost. Furthermore, the addition of electrolysis modules showed a more significant economy of scale effect at lower production capacities. It was also found that self-generation of electricity cannot compete with auction-based tariffs from the same renewable sources (solar and wind), as these benefit from economies of scale, resulting in lower costs.