Technical-economic feasibility analysis of green hydrogen production in Patagonia through wind energy, and transport to Italy for the decarbonisation of steel industry

The work carried out in this thesis aims to evaluate the technical and economic feasibility of producing low-cost green hydrogen in Patagonia Argentina, exploiting wind energy, and ocean shipping to Italy to satisfy the demand of the national steel industry. Two production scenarios have been evaluated, related to the hydrogen demand needed to decarbonise the Direct Reduced Iron production process. The first scenario assumes the replacement of 30 % of Natural Gas with pure Hydrogen. The annual hydrogen demand is 143.144 tonnes. In the second scenario is assumed the total replacement of Natural Gas with pure Hydrogen, to completely abate CO2 emissions. The annual hydrogen demand rises to 355.702 tonnes. Two carriers for storage and transport have been studied and compared; ammonia, synthesised via the Haber-Bosch process and liquefied at a temperature of - 33 °C, and liquid hydrogen, which requires a temperature of - 253 °C to be liquefied. Maritime transport is carried out by dedicated ships, designed to keep the carriers in cryogenic conditions. For both carriers, the Levelized Cost of Hydrogen (LCOH) has been calculated, which considers the costs of production, storage, transport and, in the case of ammonia, also reconversion into hydrogen. For the design and economic calculations related to the production phase, four configurations have been considered, the first involves the production of hydrogen in an off-grid alkaline plant, the second involves grid integrated alkaline electrolyser. The third and fourth configurations involve the production of hydrogen by means of a PEM electrolyser, in the third case off-grid, while in the fourth case it is fed by a grid-wind mix providing a 100 % capacity factor. The results obtained show that the value chain of LH2 provides a lower LCOH than NH3, although the ammonia is characterised by more competitive storage and transport costs. The biggest drawback of ammonia is the high cost and inefficiency of cracking and purification, in addition to a more complicated production process compared to liquid hydrogen, which arrives at the destination terminal as final product. None of the two carriers provides a competitive final hydrogen cost [$/kgH2]. Ammonia is an attractive carrier that provides competitive storage and transport costs for applications requiring NH3 as final product. Sensitivity analysis has been performed for each scenario analysed, studying the variation of the LCOH in relation to the most relevant parameters influencing the cost of hydrogen, such as the wind and grid energy costs, the capacity factor, and the CAPEX of the electrolyser.