Tuesday, February 19, 2013

Going to Gas: New Uses for LNG

By Jim Shaw

Federal Way, Washington-based TOTE’s recent announcement that it had contracted two LNG-fueled container ships from San Diego’s NASSCO shipyard is one in a growing number of such orders, although TOTE’s order for two 764-foot by 106-foot vessels represents the largest such LNG-burners ordered to date. In Europe the STX Finland shipyard at Turku floated out the 56,000-gt cruise ferry Viking Grace for Finland’s Viking Line in August, with the LNG-burning vessel to inaugurate service on the run between Turku and Stockholm later this month. The 715-foot by 104-foot ferry makes use of four duel-fuel Wärtsilä 8L50DF main engines driving twin fixed pitch propellers, with LNG to be the dominant fuel. Wärtsilä has also provided its LNGPac system to the Finnish newbuilding, which comprises an onboard LNG bunkering system as well as two storage tanks, both fitted on the aft deck, along with related handling and safety equipment. The 2,800-passenger ferry is expected to use about 20,000 tons of LNG each year which is equivalent to about 60 tons a day.

LNG Bunkering
LNG for Viking Grace will be provided by two Swedish units of Germany’s Linde Group, which have been collaborating on LNG fueling in Stockholm harbor. While Viking Grace was under construction, Linde’s AGA unit had contracted with Linde’s Gas Cryo AB division for a bunkering vessel that could deliver LNG to the new ferry. Norway’s Fiskestrand Verft was contracted to convert a retired car ferry for the purpose through the fitting of horizontal LNG storage tank of 180-cubic-meter capacity, or about 47,000 gallons, and pump-less LNG bunkering equipment supplied by Cryo. This vessel will provide LNG bunkers for Viking Grace at the Stockholm end of its run.

Seeing the potential of LNG as a marine fuel, Linde is building an LNG terminal in Lysekil, Sweden, close to Gothenburg, that will be capable of providing LNG to the transportation sector while a second terminal is being built at Hamburg where the German government has recently decided to exempt LNG from tax if it is used as ship fuel. The latter project is being spearheaded by the newly created joint-venture company Bomin Linde LNG that plans to cover the complete LNG value chain in Europe, from purchasing and transport through storage to distribution and refueling of ships at strategic points.

Gas-Only Ferries
In northern Norway, Barents NaturGass AS is supplying LNG to Torghatten Nord’s growing fleet of LNG ferries and is using LNG-fueled tanker trucks to do the job. Torghatten Nord, which has a ten-year contract to serve the Lofoten archipelago, is having a series of LNG-powered ferries built in Poland, the first two of which have already entered service.

The 96-meter by 17-meter boats are powered by gas-only rather than dual-fuel engines, the first two vessels making use of the new Bergen B35:40V12PG engine to give a maximum speed of 21 knots and a service speed of 19 knots. The second two ferries, to ply shorter routes, have been equipped with the Bergen C26:33L9 engine giving a service speed of 15 knots.

For fuel storage the ferries carry a single 150 cubic meter capacity Hamworthy tank located beneath the lower car deck and positioned just aft of the main engine room. A bunkering station is provided on the port side of the main deck and it takes three truck loads to fill the empty tank. The LNG bunkering procedure has been well tested on the growing number of LNG-powered ferries and offshore vessels now operating along the Norwegian coast.

In addition to its four new ferries, Torghatten Nord is having three older diesel-powered ferries converted to LNG. Barents NaturGass AS, which also supplies LNG to two LNG-burning Norwegian Coast Guard vessels, is establishing LNG distribution facilities at the ports of Bodø, Moskenes and Lødingen and has plans to eventually transport LNG along the coast by ship.