Energy and economic analysis of the local hydrogen production via electrolysis for industrial port districts

Industrial port districts are facing tough challenges in the decarbonization of their industrial and transport activities. To meet environmental requirements while maintaining economic competitiveness, ports are following several strategies to reduce their carbon footprint, e.g. the electrification and automation of the vehicle fleet, the onshore power supply for vessel stay at quay, the exploitation of Renewable Energy Sources (RES), and the use of alternative fuels and energy carriers. The combination of the last two points is a promising solution to reduce the carbon impact of industrial port districts. However, to increase the power generation from RES, the imbalance between supply and demand due to the intermittency and unpredictability of RES must be efficiently addressed. Despite the electrochemical battery systems are widely use as electric energy storage for power produced from RES, they are unfit for seasonal energy storage because of energy self-discharged and volume per unit of energy [1]. To overcome these technical limitations, several authors have proposed Power-to-X technologies, i.e. the RES are used to produce energy carriers which, in turn, are used when/where it is needed. Accordingly, it could be possible to store and transport energy produced from RES on a seasonal basis [2,3]. In particular, the hydrogen produced using RES (i.e., green hydrogen) could be employed to decarbonize both hard-to-abate industry sectors and heavy-duty transport typically located in industrial port districts [4]. In fact, ports are usually contiguous to industrial areas (e.g. refineries, metallurgical industries and chemical industries) and require a significant amount of energy for the port equipment (e.g. yard tractors, reach stackers and cranes). Several ongoing pilot projects in industrial port districts worldwide demonstrate the interest on hydrogen use in ports. For example, the port of Hamburg and the port of Rotterdam suggest the concept of ports as hydrogen hubs, i.e. an infrastructure which supply hydrogen for both industrial and port users. The use of hydrogen as fuel for cargo handling equipment has also been proposed by the port of Seattle, the port of Los Angeles and the port of Valencia [5]. This study presents a comparison of different solutions for hydrogen-based decarbonization strategies applied to a typical Mediterranean port. At first, an overview of hydrogen production, transport, conversion, and utilization technologies is presented. A process simulation model developed by the authors in a previous study [6] is then improved and used to analyze and compare the levelized cost of hydrogen and the equivalent carbon emissions of different configurations of the energy systems, where hydrogen is (i) locally produced via RES-driven water-electrolysis, (ii) imported in its pure form via ship/trucks/pipelines, or (iii) imported as energy carrier (e.g. ammonia or LOHC) via ship/truck. The potential decarbonization of port vehicles and industrial hydrogen users is evaluated with reference to the conventional energy supply. For port cargo handling equipment and vehicles, hydrogen as fuel is compared with the electric vehicles in terms of costs and carbon impact reduction. Preliminary results suggest a levelized cost of local-produced hydrogen of about 9 €/kgH2. Hence, it emerges that, to date, the most mature and convenient way of importing hydrogen is via trucks in liquid or compressed forms (4-5 €/kgH2 [7]). Part of the electricity used for the electrolysis process should be purchased from the grid to meet the port hydrogen demand while maintaining the competitiveness of the hydrogen production system. This, however, implies that the locally produced hydrogen cannot reach a zerocarbon impact, although the model results show a potential reduction of the equivalent carbon emissions from port equipment of up to 70%.