Techno-economic analysis of Flettner rotors onboard LH2 and LNG tanker ships

Abstract

The maritime sector is currently a transitioning toward carbon neutrality. The lower availability and higher cost of production of reduced carbon fuels, like hydrogen and natural gas, may exacerbate the need for fuel-saving measures. Wave and wind data are utilised to investigate the potential fuel and lifetime cost savings of a conceptual liquid hydrogen ship (the JAMILA) and a reference liquified natural gas (LNG) ship, along two shipping routes (Morocco-UK and Algeria-France). One such measure is the installation of Flettner rotors, which utilise the Magnus effect to produce lift in the presence of cross-winds. For the JAMILA ship with a single Flettner rotor installed, an annual fuel saving of 1.6% is estimated across both routes. There was generally a linear increase in fuel savings with each additional rotor installed, within the range of rotors considered. Seasonality, route selection and ship direction were observed to be major factors influencing fuel savings. Regardless, with optimal spin utilisation of the Flettner rotors, fuel savings were predicted in each voyage. Compared to the LNG case, the economic case for Flettner rotors was stronger for LH2, even when high rates of boil-off gas (BOG) utilisation was assumed, due to high production costs. This corresponded to a lifetime cost saving of $4.5 M - $ 20 M over 30 years. This therefore highlights the importance of utilising wind assisted propulsion technologies in shipping to mitigate the high cost of producing low carbon fuels.