Second methanol engine for Stena Germanica

13 Nov 2015
The complex piping governing fuel supply at the cylinder heads of the methanol-MGO Wärtsilä engine on board 'Stena Germanica'

The complex piping governing fuel supply at the cylinder heads of the methanol-MGO Wärtsilä engine on board 'Stena Germanica'

Stena Rederi is to convert a second engine in its ground-breaking methanol fuelled ro-pax Stena Germanica, with the installation to be completed next month.

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 dual-fuel methanol engine has now been running for more than 700 hours, and a recent inspection by Wärtsilä confirmed that the engine’s condition and operation meant the second installation could proceed. Per Stefenson, marine standards advisor for Stena Rederi’s technical division, explained that the ship conversion took six weeks, but that subsequent conversions should take even less time.

“We can do a lot of what we did a little simpler next time,” Stefenson told delegates to 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.

In related news, the company is also considering other candidate vessels formethanol conversion. 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. Stefenson noted that 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.

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