Odyssa – a techno-economic evaluation framework for wind-assisted vessels with hydrogeneration

In this paper the modelling framework Odyssa is presented, which combines several aspects such as the performance of vessel and wind-assisted propulsion devices, powertrain modelling, operation optimization and route simulation with time-resolved weather data to analyse ship design, as well as operational and economic aspects. The framework is illustrated by a case study on a sailing bulk carrier operating between Hamburg and New York. The model ship is equipped with a Dynarig sail system and an electrified powertrain with a methanol genset and a battery. Additionally, two hydrogenerators are available to recuperate energy during high wind conditions. The case study is performed for two operational speeds and the results are compared with two baseline designs: the first based on a classical two-stroke HFO engine and the second additionally equipped with sails. Results indicate that Dynarig sails can enable 36% fuel savings at a constant speed of 10 kn and 49.3% fuel savings when instantaneous vessel speed is optimized without compromising on the average speed. When the average speed is reduced to 7 kn, hydro-generators are found to be particularly effective, unlocking a further 3.1% fuel savings on top of the results with speed optimisation. By reducing fuel costs and mitigating emission taxes the investigated wind ship designs without recuperation resulted in similar total costs of ownership compared to a conventional baseline ship, despite higher investment costs on the sails system. Adding a recuperation system resulted in moderately higher costs.