Concepts for hydrogen storage and utilisation on-board ships

Abstract

Hydrogen is considered to be a promising candidate to replace petroleum products in tomorrow s transportation sector. To date, most research and development has been devoted to introducing hydrogen to the automobile industry. However, hydrogen may also be a good alternative for the marine sector. Norwegian shipping is today responsible for 40 % of the total domestic NOx emissions and 6 % of the total domestic CO2 emissions. It is evident that the shipping industry is an important benchmark for environmental policy. This thesis is part of a further development of the FellowSHIP project. The FellowSHIP project is a joint industry project with the goal of promoting the use of fuel cells onboard ships. In this thesis, hydrogen storage concepts and hydrogen utilization onboard ships is of the essence. Fuel cell technology for marine purposes is also investigated. The report is divided into two parts; a general and a specific part. The general part presents state-of-the-art storage concepts for hydrogen as well as fuel cell types for marine applications. The specific part makes use of an existing offshore supply vessel s operating profile to determine the appurtenant fuel cell profile. The ship in question will run on a high-temperature fuel cell. Fuel cells of this type are difficult to regulate, and the fuel cell should therefore run on constant load. For this reason, there will be periods where the fuel cell will produce more power than is demanded by the ship, and there will also be periods when the fuel cell will need auxiliary power to cover high ship loads. This problem may be solved by introducing a hydrogen circuit where the excess power from the fuel cell will be directed to an electrolyser to produce hydrogen during low ship loads. The produced hydrogen will be sent to intermediate storage. During high ship loads, the stored hydrogen will be used in a low temperature fuel cell to provide the ship with auxiliary power during high ship loads. The aim of the thesis is to determine the available excess fuel cell power and quantify hydrogen production and hence storage needs. The study demonstrates the need to further optimize the propulsion system onboard and its components. The study also emphasizes the strong need for optimization of load adjustment capabilities of high-temperature fuel cells.