Techno-economic analysis of wind-powered green hydrogen production to facilitate the decarbonization of hard-to-abate sectors: A case study on steelmaking

Green hydrogen is among the most promising energy vectors that may enable the decarbonization of our society. The present study addresses the decarbonization of hard-to-abate sectors via the deployment of sustainable alternatives to current technologies and processes where the complete replacement of fossil fuels is deemed not nearly immediate. In particular, the investigated case study tackles the emission reduction potential of steelmaking in the Italian industrial framework via the implementation of dedicated green hydrogen production systems to feed Hydrogen Direct Reduction process, the main alternative to the traditional polluting routes towards emissions abatement. Green hydrogen is produced via the coupling of an onshore wind farm with lithium-ion batteries, alkaline type electrolyzers and the interaction with the electricity grid. Building on a power generation dataset from a real utility-scale wind farm, techno-economic analyses are carried out for a large number of system configurations, varying components size and layout to assess its performance on the basis of two main key parameters, the levelized cost of hydrogen (LCOH) and the Green Index (GI), the latter presented for the first time in this study. The optimal system design and operation logics are investigated accounting for the necessity of providing a constant mass flow rate of H2 and thus considering the interaction with the electricity network instead of relying solely on RES surplus. In-house-developed models that account for performances degradation over time of different technologies are adapted and used for the case study. The effect of different storage technologies is evaluated via a sensitivity analysis on different components and electricity pricing strategy to understand how to favour green hydrogen penetration in the heavy industry. Furthermore, for a better comprehension and contextualization of the proposed solutions, their emission-reduction potential is quantified and presented in comparison with the current scenario of EU-27 countries. In the optimal case, the emission intensity related to the steelmaking process can be lowered to 235 kg of CO2 per ton of output steel, 88 % less than the traditional route. A higher cost of the process must be accounted, resulting in an LCOH of such solutions around 6.5 €/kg.