http://www.stockholmshamnar.se/en/For-Customers/LNG/LNG-at-Ports-of-Stockholm/

LNG bunkering of a full-size passenger ferry has never been done before. For this reason, logistics and safety procedures have been developed in close collaborations between AGA, the supplier of the gas, Viking Line, who invested in the new vessel, Ports of Stockholm and the relevant government agencies.

In addition to having been involved in the preparative work, Ports of Stockholm functions as the contact point for all who are involved in the bunkering process, and if any unexpected situation should arise.

Bunkering for Viking Grace

LNG is transported by tanker truck from the AGA LNG terminal at Nynäshamn to Loudden in Stockholm. When it arrives at Loudden the LNG is pumped from the tanker truck to the specially adapted bunkering vessel, Seagas.

Bunkering, which AGA and Viking Line are responsible for, is performed around six times each week using a purpose-built bunkering vessel, which draws up alongside Viking Grace. Bunkering vessel-to-vessel means that the ferry only has to remain in port for one hour. Bunkering from tanker trucks would not be possible in such a short time.

Aboard Viking Grace the natural gas is stored in liquefied form in two LNG tanks that are located outdoors on the quarterdeck, where they are monitored by reliable systems.

The environmentally friendly Viking Grace

Viking Grace is one of the world's greenest vessels. As the vessel runs on natural gas, emissions of environmentally harmful gases, acidic vapours and other gases with a negative impact on health, in addition to particle emissions, are reduced by an order of magnitude of 25 to 90 percent in comparison to oil-based fuels. Four energy efficient natural gas engines power generators that drive the propellers of the vessel via two electric motors.

Read more at The Viking Grace website (external link)