Saving the fjords

Another major step towards marine environmental sustainability has been taken with Kongsberg Maritime’s development and deployment of an eco-friendly fuel gas supply system (FGSS) using liquefied natural gas (LNG).

The systems are our first green-fuelled cryogenic products. They are being fitted to a new fleet of zero emissions cruise ships that are helping to maintain the unique and precious environment of Norway’s beautiful but threatened fjords.

One of the ships, the Havila Capella, is the first delivery of four eco-friendly vessels for the operator Havila Kyrstuten. It made its maiden voyage to Bergen in November and is now in use on the cruising route along the Norwegian coast to and from Kirkenes.

Given the fragility of this compelling but environmentally sensitive area, it is essential that emissions and other impacts on the route are minimised. 

Kongsberg Maritime has been contracted to supply the motive power and propulsion technology for the four new Havila Kyrstuten vessels, all of which are scheduled for delivery during the rest of 2022. They are designed by HAV Design AS.

We estimate that greenhouse gas emissions from the engines on the Havila vessels will be 20 per cent lower than those from equivalent diesels. The Bergen LNG engines the new ships will use are reported to provide an impressive fuel efficiency rates of 50 per cent and maintenance cost reductions are estimated at 10 per cent.

In addition, the use of LNG reduces CO2 output by 25 per cent and NOx emissions by an unprecedented 90 per cent. The onboard battery packs – said by Havila Krystuten to be the world’s largest – provide up to four hours of silent, zero emissions operating time.

The system works by taking the fuel, which is at -160 degrees, and feeding it into a process where it is heated up. The pressure is controlled so that it can fuel the main engine on the ship. Generator sets also produce electricity for use on the vessel. 

“We have finished and industrialised our Cyrogenic Design Factory and we have fully established our supply chain, meaning that we can expand our marketing in this area. “We have the potential to go further on this,” says Ole Andre Gjerpe, Director of LNG Solutions and Alternative Fuels, Kongsberg Maritime.

Each ship has or will have two LNG FGSS units, meaning that eight prototypes have been built in parallel. All have been constructed in Turkey. 

THE FGSS on each ship consists of two LNG tanks, each of which is 185 cubic metres, along with two bunker stations and two process systems configured to supply four Bergen C-gas gensets and two LNG process control and safety systems. 

The LNG tanks are double walled and vacuum insulated and each has a diameter of five metres, a length of 16 metres and a dry weight of about 86 tons.

We have developed a FGSS based on experience from projects we have already delivered. We have been able to optimise the design of the process system without reducing requirements in terms of the operational safety, robustness and flexibility of the ships. Redundancy, too, has been optimised.

The Kongsberg Maritime system, while complex in design, is easy to maintain and service. “We had some issues with heat exchangers, fatigue and pressure drops and some challenges related to equipment,” says Audun Jetlund, Principal Engineer.  “But we do have quality components and the experience with those along with the right certificates.” 

“There have been stressful challenges, but I’m very happy it’s working,” adds Ole Andre. 

“The best thing we have heard is the gratitude from the Havila Capella crew,” says Maciej Plocki, Senior Engineer Green Fuel Solutions. “We were on the maiden voyage from Turkey to Norway and they told us that they are very happy with the system.

“They found it so easy to handle and it has a lot of different possibilities. They also really appreciate the built-in flexibility.”

Havila Krystuten has also drawn upon Kongsberg Maritime technology for the main propulsion units on its vessels. Havila Capella sets the standard with its Azipull-PM (Permanent Magnet) L-drive unit, noted for providing high levels of hydrodynamic and propulsive efficiency 

Our relationship with Havila Krystuten is a close one and is well founded. The company takes a large amount of pride in its eco-friendly and energy efficient credentials. 

Its commitment to a green future extends to a ban on the use of all unnecessary plastics and a shore-based recharging infrastructure for its vessels’ batteries using clean hydropower.

The Bergen gas engines and accompanying FGSS systems fitted to the Havila Capella and which will be installed in its sister vessels will help to minimise environmental impacts and will take into account the fragility of the fjords.