Many parameters can affect the choice of the best technology in terms of economic and technical aspects but also comfort and expected navigation areas are relevant.  In order to take into proper account these many parameters, the Thermochemical Power Group (TPG) at University of Genoa has developed a tool that calculates all the main properties for each technology suggesting the most suitable for the desired application: HELM (Helper for Energy Layouts in Maritime applications).

The core of the tool resides in a strong database, developed through a deep and detailed market investigation and private communication by different companies, considering both storage systems and power units. From this database, specific maps have been created correlating the main parameters (such as weights, volumes and costs) with the size required by the system.

The main inputs are the power required by the ship and the operational hours without docking. In this phase, the power required has to be intended as the maximum power necessary for a proper operation of the boat. This is a conservative choice since in the real operation, the maximum power will not be required continuously, but there will be operational time-dependent profiles where the maximum value is the maximum power considered in this phase. Multiplying these values, the energy required by the ship is obtained. Dividing this energy by the system efficiency, the amount of fuel needed is calculated and then used as input in the dedicated storage map reporting its parameters (weight, volume, cost). For what concerns the power unit, the size is given by the power required, therefore this value can be directly inserted in the dedicated power unit map to obtain the power unit parameters. Furthermore, the emissions are evaluated using maps for each configuration where the input is the amount of fuel consumed depending both on fuel and power unit.

HELM gives an evaluation of the most suitable technology for the scenario considered; this evaluation is represented by the score of each technology: the best application obtains the highest total score. The total score for each solution is the sum of single scores obtained for the four evaluation categories: volume, weight, cost and emissions. For each category, the score goes from a minimum of 1 up to a maximum of 10.

Since each application has specific requirements (i.e. a ship mainly used for navigation in ECAs will consider emissions as the most relevant parameter), the resulting score is affected by the relevance parameters initially set, depending on the application considered. The score for each technology is multiplied by the corresponding relevance (i.e. if weight relevance is 3, the maximum score for the weight category is 30 points). Once the calculation is completed, the tool also provides automatic limitations concerning the ship size initially selected (small, medium, large depending on the application). Hence, taking into account the ship’s dimensions, the tool highlights the parameters that are not feasible for the chosen application.

HELM can be used in a preliminary design phase. Both in case of new applications or renovation of existing ships. Every boat is strictly characterized by the scenario of application. Therefore it is necessary to choose accurately the relevance parameters in order to properly analyze the scenario. All the varieties of ships can be studied with this tool, from small to large size. Therefore yachts, ferries and cruises of different size can be analyzed. Furthermore it is possible to analyze and simulate the cases where only energy for services (such as hotel services) or the overall power, propulsion included, are taken into account.

Clean energy production by PEM Fuel Cells on tourist ships: A time-dependent analysis

M. Rivarolo, D. Rattazzi, T. Lamberti, L. Magistri

Abstract. This manuscript presents a clean energy solution for marine applications, investigating both the choice of the most promising production and storage technologies and, in a second step, the best operational management in order to satisfy a ship’s energy demand. The case study subject of the analysis is a ferry, with a capacity up to 200 people, operating on the artificial lake of Itaipu hydroelectric plant (on the border between Brazil and Paraguay). In the framework of new international rules, aimed at clean and sustainable solutions, in particular in Emission Control Areas, PEM fuel cells are a promising technology for onboard power generation. In this paper a PEM fuel cell system is investigated in detail, analyzing the best operative strategy in terms of energy efficiency, CO2 emissions and costs, in comparison with the state-of-the-art solution for ships (fuel oil ICEs). The analysis is performed with two dedicated software tools, both developed at the University of Genoa: the first is a tool modeled to support the preliminary design and the choice of the most promising solutions for maritime applications; the second is a software program for thermo-economic analysis of energy systems in time-dependent conditions, aimed at determination of the best operative strategy, minimizing operative costs.
The proposed approach has general validity thus it can also be applied to different kinds of ships, even considering different technologies for energy generation and storage.