Big plans for big ships lead to a greener future

English

Overcapacity, challenging economic conditions and stricter emissions regulations are forcing the shipbuilding industry to rethink how vessels are built, powered and operated.

Fibreship, a consortium of 18 partners from the private sector, universities and innovation centres from 10 EU countries, is addressing some of the challenges and technology gaps in conventional shipbuilding. It's exploring the use of fibre-reinforced polymer (FRP) composite materials in the construction of commercial ships of more than 50m in length.

FRP could cut the structural weight of vessels by 30-40% and increase cargo capacity by 12%, said Raul Salinas Mullor, head of research at Madrid-based Tecnicas y Servicios de Ingenieria, a Fibreship partner. This in turn could lead to fuel savings of 10-15%, help reduce emissions, and shave 7% off operating costs for medium-sized container ships, or 3% for larger vessels, he said.

Another advantage is that FRP ships would not suffer from corrosion, so their working lives could be extended, and maintenance costs could be a third lower than for steel or aluminium ships, added Mullor.

Composite ships might also offer fluid dynamics qualities that reduce friction, according to Dominic Hudson, Shell professor of ship safety and efficiency at the University of Southampton, which is not part of the Fibreship consortium. As friction accounts for 70% of a containership’s resistance, or 80-85% for bulk carriers and oil tankers, companies such as Mitsubishi Heavy Industries and Silverstream Technologies have developed air lubrication systems. The technology forms small air bubbles on the bottom of the vessel that reduce friction between the hull and seawater, said Hudson, adding that air lubrication techniques could deliver fuel savings of 7-10%.

Greener, cleaner and smarter

There is also the emergence of autonomous, electric cleaning vessels, such as the HullBUG, which removes biofilm from the underwater portion of ships. Reduced maintenance requirements of composite ships make them particularly suitable for autonomous operation, said Bjørn Haugland, chief sustainability officer at maritime classification group DNV GL, which is not part of the Fibreship consortium. And, if ships were also electric, the need for crews to carry out maintenance would be further reduced, delivering additional cost and emissions reductions, he said.

The world's first fully electric and autonomous containership, the YARA Birkeland, will be launched in Norway next year.

Haugland predicts that electric ships, whether powered by batteries or hydrogen fuel cells, will become increasingly popular, especially on inland waterways and along coastal routes. Besides their fuel savings and emissions reduction potential, electric engines are more responsive than diesels, he said. This makes vessels easier to manoeuvre in difficult conditions, he said, pointing to the experience gained with offshore supply ship Viking Lady, the only commercial vessel to use fuel-cell technology.

For now, Fibreship is not considering alternative means of propulsion, as the consortium is focusing on ship design and on methods to reduce fire risk, which is a big challenge for composite vessels. But much research is ongoing elsewhere into the use of liquefied natural gas as an alternative to heavy fuel oil, as well as into auxiliary systems such as sails, kites and wind-powered rotors.

The next step could then be a holistic approach that brings together new materials, propulsion technologies and control systems – to make ships more efficient and more environmentally friendly.

Share

Source: 
imeche
Top