In Depth: Forerunners Anticipate LNG Transition

Maritime companies preparing to start using LNG as a propulsion fuel are teaming up to establish safe and reliable on board installations and bunkering procedures. Innovation projects, a study excursion, Green Deal and innovation board support their achievements.

A decade of experience with installing, bunkering and certification of LNG propelled vessels is available in Norway. Yards, ship owners, suppliers and knowledge institutes from the Netherlands and Germany travelled to Oslo to learn. The group of thirty representatives out of 33 participating companies in the two- country innovation project MariTIM sailed the 600 person ferry Tidedronningen that maintains a service between the centre of Oslo and the opposing peninsula of Nesoddtangen. They eagerly inspected the on-deck installations for pressure control and the chimney for calamity boil-off gas release. Also the lower deck engine room was intensively inspected, with special attention for the safety measures around the tank and the explosion-resistant zone built to cover the vaporisers that transform liquid LNG into combustible natural gas.

The study trip participants are Dutch and German forerunners in the massive conversion to LNG propulsion that is foreseen in the next decade. Most of the companies present during the trip are partners in the MariTIM project, in which companies from the German region of Niedersachsen work together with companies from the north of the Netherlands to develop know-how for building innovative and environmentally sound vessels. The two regions share the Wadden Sea and the river mouth of the Ems as sailing areas. These waters, part of a marine natural park, may see a rapidly increasing fleet of vessels running on the fuel causing less emissions. Within the MariTIM project, research and development is going in the creation of various concepts: passenger vessels that run on LNG and benefit from other sustainable technologies for hotel function power supply as well, together with studies into the so called ECO2 inland barge and a short sea shipping vessel that is propelled by both wind and an LNG engine.

Emissions

Liquified Natural Gas as a fuel has environmental and financial benefits for ship owners. Engines running on LNG emit about 30% less carbon dioxide (CO2), about 90% less nitrogen oxide (SOx), virtually no sulphur and no soot as compared to engines running on diesel oil. Let alone heavy fuel oil, that contains even more environmentally hazardous chemicals. LNG has been available for decades, the fuel has been used as a marine propulsion fuel since as long ago as 1956. The offshore gas industry has been liquefying natural gas since the 1950s to be able to transport it. Tankers carrying the gas have used the boil-off from their tanks in dual-fuel or lean burn engines for over 50 years now. While an effective, widely available and less polluting fuel, a distribution network for bunkering vessels or filling vehicles with LNG has never evolved. Only since United Nations marine authority IMO have evoked rules minimising the maximum exhaust of sulphur from seagoing ships in the North Sea and the Baltic Sea, the marine industry embraces the possibilities of LNG as a propulsion fuel. The cleaner fuel poses the possibility to meet emission standards without having to install a costly scrubber installation aboard and with the relaxing notion that LNG as a fuel will possibly see a quite moderate price development, as still immense amounts of natural gas reserves are available. The promising perspective is that engines, fit to run on LNG, will run on Bio LNG in the future. LNG is the product of a fossil fuel and – although less – still causes CO2 emissions. But there is hope that in the next couple of decades the production of fuels from cattle dong and agricultural waste will grow to sufficient levels to be able to widely use it as a fuel. Then, emissions will be neutral because the amount of carbon and other greenhouse gasses from burning the Bio LNG have been in the ecosystem already. Until production of Bio LNG has grown, LNG is presented the ideal step towards carbon neutral transport.

LNG acceleration

That is why two ferry operators in the Wadden Sea – Doeksen, that maintains the line between Harlingen and Terschelling, and AG Ems, that connects the isle of Borkum with Eemshaven and Emden – plan to transfer to LNG. Doeksen is building a new ferry, AG Ems will refit the Ostfriesland to run on LNG. Norwegian Norlines, active cargo shipping company in the region, is planning to start using the fuel, too. They may bunker at the same LNG station that Groningen Seaports is planning to open at Eemshaven. Inland cruise company Princenhof from Eernewoude, on the Frisian lakes, provides trips through the natural reserve ‘Alde Feanen’. The company is planning to build a new passenger cruise vessel that incorporates a lot of energy saving new technologies and  will be a remarkable example of forward green technology. Dutch yard VeKa-Group is preparing the build of four LNG vessels: three tankers and an LNG propelled inland barge. Two tankers are designed for short sea LNG transport from large LNG terminals to smaller regional hubs. The third tanker will be both a tanker delivering fuel to riverside bunkering stations, and a bunkering ship. For propulsion, it will use the boil-off gasses that evaporate from the cold-stored LNG. Natural gas becomes liquid at 162 degrees Celsius below zero. That means that under normal conditions some fluid will become gassy. This is captured and used as the engine fuel. The inland ship Argonon is already navigating Dutch and German rivers, it was at its launch the first Dutch inland ship that is LNG propelled.

Most of the Dutch builders and ship owners with LNG plans participated in the early June study trip to Oslo. Experienced LNG shipping professionals like ferry captain Svein Hugo Nilsen from Norled and Stein Petter Eriksen from Gasnor explained about bunkering procedures and on board installations to secure safe day to day operation. “We do the bunkering for the ferries just some hundred metres away from the boarding platform of the ferry in the centre of Oslo”, Nilsen revealed. “A tanker truck comes to the quay we use for bunkering. We do not have extensive safety measures. First we attach electrostatic grounding. Then, tanks of the truck and the ship are connected. Pressure differences in the tanks are evened out. As a fuel, LNG tends to stay liquid, even though it is only liquid at minus 162 degrees. Therefore, pressure in the tanks is typically about the same as surrounding atmospheric pressure. Still, after the two week interval we have for bunkering, the pressure in the vessel’s tank may see some fluctuations because of occasional boil-off. Pressure levels in the tanks are monitored from the bridge. The tank aboard is well isolated to minimise boil-off and keep temperature low. The large quantity of LNG, 25 cubic metres in the ferry’s tank, maintains at its liquid state and temperature throughout the two weeks.”

Classification

During the visit of the captain’s ferry, delegates inspected the isolated tank and the Ex-class compartment that is built around the fuel exit of the tank and the vaporisers. Although natural gas – vaporised LNG – will only cause fire or an explosion at a five to 15 percent concentration in air and further seem inflammable, security to prevent accidents around the vaporising units is expedient. Henning Mohn from classification bureau DNV agreed with Nilsen and Eriksen that fire or explosion risk with LNG is lower then with gasoline. Yet, as natural gas is odourless and invisible, the risk of an explosion is eliminated by safety measures the classification society prescribes. Bunkering pipes through the ship and the engine room need to be double- sided stainless steel. In case of leakage, gas will stay inside the outer tube. DNV has come up with classification standards for LNG propelled vessels that can now be applied internationally.

In Norway, the first LNG propelled vessel sailed ten years ago. Nowadays, 16 car ferries, seven offshore supply vessels, three coast guard vessels and three passenger ships use LNG as a propulsion fuel. Introducing the delegates to the characteristics of LNG, Gasnor’s sales director Eriksen showed a short film in which a small amount of LNG is held in a drinking glass in a home kitchen. The liquid is poured out over a tray, from which it hissingly evaporates. Then the person in the film puts a burning cigarette in the second glass of LNG. The cigarette smothers. “When bunkering from a shore station,” Eriksen further showed, “we first cool down the connecting hoses using SO2, in order to have least possible boil-off of LNG during the bunkering process. As LNG is a fluid, we can just pump it like any fluid.”

Ambition

All this effort to transfer from diesel and HFO to LNG is stimulated by government. Early July, Dutch companies together with their government signed the Green Deal LNG, in which the companies dedicate themselves to finding green solutions for transport by using LNG, while the government promises to help fund the investments needed therefore. The aims are high: at the Green Deal ceremony, the ambition of 50-50-500 by 2015 was acclaimed. That means the partners in the Green Deal strive to have 50 seagoing ships on LNG in the Netherlands in 2015, as well as 50 inland barges and 500 trucks. A first bunkering station, Nobel Bunkering Services in the town of Zwijndrecht, the Netherlands, is being installed. In the town of Pesse, the Netherlands, the first LNG filling station for road transport is almost ready for operation under the name ‘Green Planet.’

Hans Buitelaar

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