Development of a numerical optimization model for sizing hydrogen refuelling stations: application to a case study

Abstract

Interest in hydrogen as a transportation fuel is growing. Fuel cell electric vehicles fed by hydrogen are expected to play a key role in the decarbonization of the transportation sector. Its impact will depend upon the existence of reliable and cost-effective fuelling stations. Numerical simulation allows sizing hydrogen refuelling on-site stations in order to identify the most cost-effective solution for a specific utilization pattern. This study aims to define a numerical optimization model for a hydrogen refuelling station to supply both light and heavy vehicles. The objective function is to minimize the total storage volume, taking into account the number of vehicles to be refuelled. The pressure at each storage skid is considered a decision variable, as well as the hydrogen mass that is provided at each vehicle filling. The model considers the hydrogen properties and the physical constraints to size the station prior to its construction. Additionally, a cost analysis based on the capital expenditure concept was developed. The hydrogen refuelling station must be able to supply 300 kg/day of hydrogen. The station includes four main systems: the hydrogen production equipment, an electrolyzer, and a system that can store hydrogen to feed the compression cascade. The station should be able to fill 10 heavy vehicles at 350 bar (H35), considering 2 skid pressure levels and a supplied mass of 30 kg and 30 light vehicles at 700 bar (H70), considering 3 skid pressure levels, dispensing 4.2 kg of hydrogen each. At all vehicle fillings, a pressure differential of 50 bar between the high-pressure skid and the vehicle tank is mandatory so the refuelling can be validated. The results show that it is possible to refuel 10 heavy vehicles considering a total storage volume of 36.9 m3, whereas, for light vehicles, it is possible to refuel 30 vehicles with a total volume of 22.9 m3. Based on capital expenditure, the most representative capital costs are the production equipment (30%), high-pressure storage unit (20%) and the hydrogen compression system (18%).