Latest Gas Powered Ice Class Vessels Utilise Adaptive Drive Technology for Northern Sea Route

FINLAND – When any powered technology moves to a new type of fuel there are almost bound to be disadvantages as well as the advantages which prompted the shift in the first place. ESL Shipping made a conscious decision to move much of its fleet to liquefied natural gas (LNG) as opposed to conventional fuel oil and in the latter part of 2018 the company took delivery of two bulk carriers, the HaagaViikki.

At 160 metres and 25,600 dwt the ships emit less than 50% of CO₂ compared to their predecessors but even more significant is that both ships had to be prepared to face the ravages of the Northern Sea Route, a transit which again saves over 40% in noxious emissions compared to the conventional Panama Canal voyages.

When the Viikki was delivered from the Chinese Jinling yard ESL Chairman Aki Ojanen was at pains to point out that all fifty of the company fleet were ice strengthened, not just the two new gas powered arrivals. The new power source however made it necessary to look at exactly how that power was delivered as the sea ice can cause rapid changes in the main engine load. Therefore, the propulsion units need to be flexible, responsive and deliver optimal power per unit, while still meeting the most stringent environmental criteria.

The designers turned to WE Tech Solutions, whose variable frequency drive technology WE Drive™ and The Switch direct drive permanent magnet shaft generator, helps the vessels achieve Ice Class 1A propulsion, while still slashing fuel consumption, costs and emissions. WE Tech Solution Three which is implemented on these vessels allows mechanical energy from the propeller shaft to be converted to electrical energy, the most energy-efficient way to generate power in a vessel. Mårten Storbacka, Managing Director of WE Tech, explains:

“The solution delivered offers different operational modes according to the vessel’s needs. In Power Take Out mode WE Drive™ enables propulsion machinery to operate in combinator/variable speed, while the direct-drive permanent magnet shaft generator produces electrical power up to 700 kW for the vessel’s electrical network. This delivers significant savings by drastically decreasing the operating hours of the auxiliary generators, saving fuel and resulting emissions, as well as reducing maintenance requirements.

“For the most demanding conditions, Power Take In (PTI) mode can be selected. This converts auxiliary generator power to propulsion power by employing the direct-drive permanent magnet shaft generator as an electrical motor. In doing so, an added 1250 kW of mechanical power can be harnessed to boost the propulsion system, ensuring effective operation in Ice Class 1A.”

This technology allows the vessels to meet the Energy Efficiency Design Index (EEDI) requirements while still having sufficient power to sail in icy conditions. The permanent magnet machines at the heart of this solution generate energy for vessel systems in a way that matches with the shipping industry's push for less waste and increased efficiency. The mechanical energy from the propeller shaft is captured and converted to green electrical energy for the vessel whilst, as in the case with the Viikki, it can also be used to supplement engine power for the most demanding operations.

Photo: The Viikki, now operating in the Baltic Sea and which made her maiden voyage from China via Japan where she loaded ore bound for Finland via the Northeast passage.