Wind-Powered Freighters Herald New Era
Prompted by the global trend toward reduction of environmental impact of ocean liners a Norwegian engineer has designed a cargo ship that is powered by wind and gas, dubbed the VindskipTM.
The concept highlight introduced by Mr Terje Lade, managing director of the company Lade AS, is that the hull of the freighter serves as a wing sail.
On the high seas, the VindskipTM cargo ship would benefit from free-blowing wind making it very energy efficient. For low-wind passages, in order to maneuver the ship on the open sea while also maintaining a constant speed, it is equipped with an environmentally friendly and cost-effective propulsion machinery running on liquefied natural gas (LNG).
With the combination of wind and liquefied natural gas as an alternative fuel to heavy fuel oil, the fuel consumption is estimated to be only 60 percent of a reference ship on average.
Carbone dioxide emissions are reduced by 80 percent, according to calculations by the Norwegian company.
In order to calculate the optimal sailing route, researchers from Fraunhofer Center for Maritime Logistics and Services CML, a division of Fraunhofer Institute for Material Flow and Logistics IML, have developed a customized weather routing module for VindskipTM.
Considering meteorological data the software for the new ship type uses a navigation algorithm to calculate a route with the optimum angle to the wind for maximum effect of the design.
“With our weather routing module the best route can be calculated in order to consume as little fuel as possible. As a result costs are reduced. After all, bunker expenses account for the largest part of the total costs in the shipping industry,” says Laura Walther, researcher at CML in Hamburg.
For the complex calculations, the researcher and her team apply numerous parameters, such as aero- and hydrodynamic data as well as weather forecasts from the meteorological services, such as wind speed and wave height.
“At angles close to headwind the wind generates a force in the ship’s direction that enable the ship to be pulled forward. Since the hull is shaped like a symmetrical air foil, the oblique wind on the opposite side – leeward – has to travel a longer distance. This causes a vacuum at the windward side that pulls the ship forward,” explains VindskipTM patent-holder Lade.
This makes the freighter move at speeds of up to 18 to 19 knots, hence just as fast as conventionally powered ships.
As explained, due to its very low fuel consumption, Vindskip™ can utilize liquefied natural gas (LNG) as fuel and still be capable – in the worst case – of 70 days of steaming between bunkering.