Offshore Supply Vessel Goes Hybrid

By Bo Svensson 

Wärtsilä has completed the installation of a hybrid energy system on board the offshore supply vessel Viking Princess. The Norwegian vessel is now uses batteries to reduce the number of generators aboard the ship. Viking Princess completed sea trials and the system was handed over to customer Eidesvik Offshore in early October.

The new energy storage solution is designed to improve engine efficiency, generate fuel savings and reduce greenhouse gas emissions. The contract to replace one of the four engines on Viking Princess with battery power was signed in May.

Corvus Energy, Richmond, Va., is the supplier of lithium ion based energy storage systems (ESS). The Orca Energy ESS battery racks are installed on the vessel in a hybrid arrangement, replacing one Wärtsilä LNG genset. The battery capacity is 511 kWh and is built up by 5 racks for a total number of 90 battery modules. The battery racks are installed in a deckhouse (container) located behind the wheelhouse. The deckhouse was fitted with the battery, a transformer and a charger pre-installed before sending it to the shipyard. The dimension of each of the five battery racks is 28. 4 ft. (8.65 m), long, a depth of 23.3 ft. (7.10 m) and a height of 6.1 ft. (1.87 m). The total weight of the battery is 14,660 lb. (6650 kg).

The remaining Wärtsilä dual fuel engines, diesel/gas, are two model 34DF engines generating 2510 kW each, and one 20DF engine producing 1014 kW electricity.

“There is significant potential to save fuel through improved engine efficiency, as the operating profile of supply vessels is highly variable,” said Cato Esperø, sales director, Wärtsilä Marine Solutions & Services. “When using energy storage system on board Viking Princess, the fuel saving potential can be up to 30% in various operations and the CO₂ emissions can be reduced by up to approximately 13 to 18% per year, depending on operational conditions and requirements.”  Esperø also said the hybrid solution will provide a more optimal load on the engines, while the intervals between engine maintenance can be extended.

“Viking Princess now runs on a combination of the battery pack for energy storage and the three LNG-fuelled Wärtsilä engines. The new energy storage solution provides balancing energy to cover the demand peaks, resulting in a more stable load on the engines,” said Esperø. “The technology is similar to that used in hybrid vehicles: it prevents the engine load from dipping, and uses the surplus to re-energise the battery, which can be charged as needed.”

The Viking Princess’ battery system at the moment does not allow for external harbor charging. The control system and the electrical system are by Wärtsilä, and the company’s remote monitoring and operational advisory services are supporting the daily operation of the vessel.

“Eidesvik and Wärtsilä’s partnership dates back to 2003, when our ship, the Viking Energy, became the first offshore supply vessel powered by LNG fuel,” said Vermund Hjelland, president, Technical Department, Eidesvik Offshore. “Now, together, we are again introducing a world’s first, with the Viking Princess becoming the first offshore vessel in which batteries reduce the number of generators aboard the ship.”