By next month, Stena Rederi is to convert a second engine to methanol fuelled ro-pax Stena Germanica. Stena hopes to have all four engines converted for methanol in the beginning of 2016. The conversion of the ship – including a methanol tank in the vessel’s double hull, a gas-tight pump room and an overhaul of engine control systems – took place at Remontowa’s yard in Gdansk at the beginning of the year – along with the conversion of the first of four Wärtsilä engines.
The first engine conversion had resulted in an almost 100% decrease in SOx and particulate matter emissions, while NOx levels are reduced to around 60% of the emissions caused by running diesel. The first dual-fuel methanol engine has now been running for more than 700 hours and Wärtsilä confirmed that the engine’s condition and operation suggested the second installation could proceed. The ship conversion took six weeks, but that subsequent conversions should take even less time.
Stefenson told delegates in The Motorship’s Gas Fuelled Conference earlier this week, during a technical visit to the Germanica, “When you do something the first time around you have to stick to known technology in some areas, you can’t have all the balls in the air at once.”
At present the vessel can run on a fuel mix of 95% methanol and 5% MGO at full engine load. At half load, the mix is around 10% MGO and 90% methanol. Key to the conversion is an injector developed by Wärtsilä that comprises four separate hydraulic circuits – including circuits for methanol, MGO, a sealing oil to prevent methanol leaks and a cooling system.
At present the Stena Germanica takes on methanol bunker in Gothenburg. The company has considered investment in a methanol bunkering barge, but Stefenson explained that at least one more methanol-fuelled vessel would be needed to make a barge viable.
Once all four engines are converted, the Stena Germanica’s fuel consumption is expected to be around 24,000 tonnes of methanol and 2,000 tonnes of MGO a year.
Source: The Motorship