Conversion of an existing diesel depot into an on-site hydrogen refuelling station for heavy-duty vehicles: A multi-objective optimisation

Transport is one of the energy segments belonging to the so-called hard-to-abate sectors. Despite several EU directives promote its decarbonisation, heavy-duty mobility still shows increasing emissions, due to the continuous raise in road freight activity and reliance on low-efficiency internal combustion engines powered by fossil fuels. Hydrogen fuel cell electric trucks represent one of the most valuable solutions for the long-haul transport segment greening. However, the current lack of economy of scale and paucity of refuelling infrastructure represent a significant hint to the widespread deployment of hydrogen mobility. This paper presents a design methodology for converting a diesel depot into an on-site green hydrogen refuelling station dedicated to fuel cell electric trucks. To do so, 150 eligible capacities of photovoltaic plant, electrolyser and low-pressure storage system have been dynamically simulated in the MATLAB/Simulink environment. Thereafter, by means of a multi-objective optimization, based on Pareto Front and Utopia Point, the optimal solutions have been identified. By maximising the hydrogen production and simultaneously minimising the levelized cost of hydrogen, solar energy excess and compressor energy utilisation the components size can be determined. The main outcomes of this study show that the most suitable electrolyser/photovoltaic plant capacity ratio is 44.1%. By comparing on-site with off-site hydrogen refuelling stations, the hydrogen production, distribution and transmission cost equal to 7.70 €/kg is the break-even point between the two stations typologies. Converting diesel pumps into hydrogen refuelling stations can reduce capital expenditure by 30–50% compared to greenfield hydrogen stations.