Wind energy carries emission-free merchant vessels into the 21st century

Wallenius Marine is showcasing its concept for The Oceanbird, an automobile-carrying cargo ship with a capacity of 7,000 cars. The company is leading a government-funded team studying wind-powered ships, along with a Swedish consortium of the Royal Institute of Technology (KTH) Centre for Naval Architecture, and maritime tech developer SSPA, with a goal of designing a Wind Powered Car Carrier (WPCC) by 2021.

Per Tunell, COO, Wallenius Marine said the Wind Powered Car Carrier project “changes the prerequisites for oceangoing sea transportation."

"The industry faces enormous challenges in terms of sustainability and this type of solution with wind powered ships on the oceans is by far the most interesting solution for achieving truly sustainable shipping,” Tunell said.

RETRACTABLE WINGS
Oceanbird features vertical metal or composite wings to harness wind energy for propulsion. They will be raised and lowered telescopically and will be fully rotational and autonomously controlled. When fully extended, the wings will be much higher than the tallest point on traditional ships (high aspect ratio). The wings can be retracted in harbours and to get under bridges. The design features diesel engines for entering and leaving port, and to augment the sails to maintain schedules.

Wind-powered car carriers will be slower that the current fleet of 450 conventionally-powered car carriers in service today. For example, they currently take seven or eight days to cross the Atlantic, where the WPCC would take 12. But the tradeoff is a vastly reduced fuel costs and emissions. Contemporary car transporters burn about 40 tons of fossil fuel per day.

PARADIGM SHIFT
The International Maritime Organization (IMO) has established a goal of reducing overall merchant ship carbon emissions by half by 2050. But the WPCC team is aiming even higher.

“We are going much further and aiming for a reduction of 80-90 percent,” said Prof. Jakob Kuttenkeuler of the KTH Centre of Naval Architecture in Stockholm. “This entails a paradigm shift as today’s ships travel far too fast and with high fuel consumption. We are developing the world’s first emission free shipping concept in modern times.”

Kuttenkeuler said the design is a blend of aerospace and marine engineering. “The rigging should be aerodynamically optimized, robust, light and cheap to manufacture. It can be likened to designing sailing mechanics for an airplane that is going to be tossed about at sea.”

The Swedish Transport Administration is backing the WPCC research consortium with a US$3 million grant. The research effort will run until 2023.

OPTIMIZATION
KTH will provide aerodynamic and sailing mechanics expertise, including calculations of performance and route optimization, and fabrication of a seven-metre scale model for in-water testing.

Naval architecture students at KTH tested their model at Viggbyholm, north of Stockholm. According to lysse Dhomé, Project Supervisor at KTH, the “sea trials” were very useful. “Now we know more precisely how the boat will behave and we can calculate how to make it stable,” said Dhomé.

SSPA will utilize its tow tank facility in Gothenburg, Sweden to conduct hydrodynamic modelling and testing of a 1:25 scale model for validation of concepts and designs.

“We have done extensive computer simulations,” said Sofia Werner, Manager Strategic Research Hydrodynamics at SSPA. “Now we need to confirm these simulations with the experiments to get more accurate numbers of the performance and the forces acting on the ship.”

The consortium partners see a bright future. “We are creating a Swedish competence cluster of wind-powered vessel development and design. Together we are stronger!” said Vendela Santén, Senior Researcher & Project Manager at SSPA.

The team said the wind concept can be applied to other types of ships in the future.