An increasing number of passenger ship operators are selecting LNG as a marine fuel. We look at the engine options available to them.
So impressed is Spanish ferry group Baleària with the performance of its new liquefied natural gas (LNG) powered auxiliary engine in 190m long Abel Matutes, plying between Barcelona and Palma de Mallorca, that it has decided to invest €320 million in three new “smart ships” driven entirely by natural gas.
Embodying the biggest commitment to date in natural gas propelled passenger vessels working the Mediterranean, the new ships will be launched in late 2018 and 2019. The flagship will be 232m long with a 30m beam and will accommodate 1,730 passengers and 331 vehicles. It will be powered by four dual gas and fuel powered engines.
Environment-conscious Baleària, whose fleet comprises 12 cruising ferries and seven fast ferries (30 knots and more) is the first Spanish shipping line to use LNG. The group’s landmark adoption of LNG in the Mediterranean is also reflected elsewhere in Europe, as passenger lines take a long look at the benefits of gas power in response to tougher emissions regulations as well as to popular demand. Now that passenger lines have witnessed the increasingly rapid adoption of LNG by tug boats and cargo ships, they are growing more confident about using it on their own vessels.
“LNG makes good sense for passenger ships including cruise ships,” Oscar Kallerdahl, Rolls-Royce Marine’s business development and sales manager, told Passenger Ship Technology. “It is increasingly seen as a competitive advantage by the cruise industry because it creates a clean environment.”
That is why Rolls-Royce is fielding a lot of enquiries for its four-stroke LNG powered gas turbine engines, which produce between 1,500kW and 9,600kW – a power range suitable for medium-sized passenger ships that do not have to travel at high speeds. “The technology is very simple – similar to a petrol engine in a car. It is easy to control and it is fuel efficient,” added Mr Kallerdahl. “It is just pure gas. You do not have to add anything to it.” For larger vessels, two-stroke engines are the preferred choice.
Another company that has seen the benefits of LNG is Norway’s Torghatten Nord. The Brønnøysund-based group has commissioned shipbuilder Vard to build two 130m long hybrid gas-electric ferries at a total cost of US$70 million (€62.4 million). MAN Cryo, MAN Diesel & Turbo’s marine LNG fuel gas system manufacturer, which is building the onshore supply systems, believes the time has arrived for LNG. “We see a clear trend in the market with an increasing number of enquiries for fuel-gas systems,” said the unit’s managing director Mikael Adler.
“LNG is increasingly seen as a competitive advantage by the cruise industry because it creates a clean environment,” Oscar Kallerdahl (Rolls-Royce)
Onshore supply systems are proliferating, too, and crews are becoming more experienced in their technicalities. For instance, Torghatten Nord’s MAN-installed fast-charging unit comprises a 175cm³ vacuum-insulated storage tank plus auxiliary equipment such as an LNG vapouriser, pressure build-up unit, and bunker station.
Once crews overcome their initial concerns and get used to gas, they wish they had done it earlier, according to feedback that Rolls-Royce receives from client companies. The engineroom is oil-free. The chemicals used to keep it clean are much less powerful – in fact, similar to standard household products. And the air is purer.
When they are launched towards the end of 2018, Torghatten Nord’s ferries will join a growing LNG-powered fleet in the region. Equipped with four Rolls-Royce BV12PG engines, Egersund, Norway-based Fjord Line’s 170m long flagship ferries, Bergensfjord and Stavangerfjord, were the first and biggest ferries in the world to be driven solely by gas. They also took the top two positions in the World Ports Climate Initiative’s Environmental Ship Index, an increasingly important measure. Because the BV12PG engines do not use oil for pilot injection, they emit zero oxides of sulphur, reduce oxides of nitrogen by 98 per cent and cut carbon dioxide emissions by 23 per cent.
Another compelling factor for the growing adoption of gas is the determination of port authorities to keep the air clean. “This is an important catalyst,” noted Mr Kallerdahl. In fact, there are financial incentives available, according to industry sources. Baleària, which runs its LNG-powered engine on Abel Matutes when the vessel is in port, reportedly earns substantial discounts on harbour charges for doing so.
Adding further pressure to shipowners, in mid May the International Association of Ports and Harbors took a tougher stance against greenhouse gas emissions at its 30th world conference in Bali, Indonesia, where it announced a “world ports sustainability programme.” More will be revealed at the official launch in Antwerp, Belgium in March 2018.
Another factor influencing the swing to LNG is the rapid growth in onshore infrastructure, in part because it is contributing to a steady fall in the landed cost of the fuel. Receiving terminals in the Baltic, the Caspian Sea and the eastern Mediterranean are multiplying in number, with yet more on the drawing board. Poland’s Świnoujście LNG import terminal may soon expand with the installation of a third tank. Lithuania’s floating terminal at Klaipėda Seaport began small-scale reloading earlier this year. Norway has a terminal at Snøhvit and Sweden one at Brunnsviksholme. A further five are either under construction or at the planning stage.
And in a joint effort with Fjord Line, the busy port of Hirtshals in Denmark is building its own LNG production plant to make itself independent of imports. According to the Hirtshals authorities, home-produced LNG will be about 25 per cent cheaper than imported gas. That alone will do much to combat the collapse in the price of crude that, until recently at least, slowed down the adoption of LNG by the passenger ship industry.
That said, it may not be price that determines the future of LNG powered vessels, but the enforcement of emissions regulations.
Silent sailing under batteries
Norway’s Color Line is taking the plunge into hybrid power. In early 2017 it signed a letter of intent with Ulstein Verft to build what is billed as the world’s largest battery-hybrid ferry, a 160m long vessel capable of carrying 2,000 passengers and 500 cars on a route between Sandefjord and Strømstad. The ferry will switch to electric-only power in Sandefjord and when docking at both ends of the route. The battery, which can power the ferry for about half an hour, can be recharged on the dock and by the diesel engine.
Simultaneously, the all-important infrastructure to accommodate electrically and hybrid powered vessels is being deployed more widely. Because today’s batteries cannot run even a small ferry all day on just one charge, they need to be charged up quickly when the vessel stops to take on passengers and vehicles.
That is why there is considerable interest in Wärtsilä Marine Solutions’ wireless – or inductive — charging system. This is similar to the one used for cars, buses and trains, but much more powerful. According to Wärtsilä, the system can transfer 1MW of charge within a range of 15cm-50cm, or 300 times more than electric installation stations for vehicles. Prototyped during 2016 on a car ferry in partnership with engineering and automation group Cavotec, it is a world first that will be rolled out during late 2017. At present batteries are charged by conduction – that is, using heavy physical cables that are run from the port to the ship. As a bonus, the system will be paired with an automatic vacuum mooring process suitable for coastal ferries.
“Renewable energy, battery solutions and performance are improving and getting cheaper all the time. There is no reason not to implement them in coastal shipping,” said Ingve Sørfonn, a research and development expert at Wärtsilä. He sees the system as important in autonomous coastal transportation networks in the future.
Meanwhile Leclanché has unveiled a new lithium-ion battery system, a fully-certified modular product with a capacity of 4.3MWh. The system will be installed on a new all-electric passenger and car ferry in Denmark scheduled for launch at the end of 2017. Leclanché chief executive Anil Srivastava enthused about “the huge opportunity for marine vessels across the world to reduce their harmful emissions and cut their operating costs by leveraging battery storage technology.”
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Source: Passenger Ship Technology