The remarkable significance of a new marine diesel technology just announced by Wärtsilä is that the low pressure, dual-fuel (gas/liquid fuel) benefits that are already available to 4-stroke engines, can now be applied to 2-stroke engines as well, thus making the technology available to the broader merchant shipping market.
The test engine: Photo courtesy of Wärtsilä
Wärtsilä, having announced the successful full scale testing on gas of an RT-flex50DF engine, say that the marine industry is already showing significant interest, evidenced by the fact that more than 130 industry executives from 89 leading shipping companies attended the recent introductory event in Trieste, Italy.
In his opening speech at the event, Jaakko Eskola, Senior Executive Vice President and President, Wärtsilä Ship Power, stated: “Dual-fuel engine technology is the future; it is a tide that cannot be turned back. Gas is certain to play an increasingly important role in merchant shipping - for both economic and environmental reasons. The introduction of Wärtsilä’s 2-stroke, dual-fuel, low-speed engines is a historic landmark in this process.”
Compared to other technologies, studies have shown that Wärtsilä’s low pressure DF engines offer capital expenditure (CAPEX) reductions of 15-20 per cent. Such a saving is achieved through a substantially simpler and lower cost LNG and gas handling system operating at pressures below 10 bar, and by the fact that no further exhaust gas cleaning systems are needed to meet future emission regulations. The new engines are to be IMO Tier III emissions compliant in gas mode, and the minimum Tier II level is achieved with liquid fuel.
Gas supply pipework to the engine: Photo courtesy of Wärtsilä
While using LNG fuel there are no sulphur emissions and close to zero particulate emissions, and the pilot fuel consumption is extremely low at just one per cent of the fuel used. Furthermore, the technology enables LNG fuel to be used at all engine loads, so there is no need to switch to diesel at low loads – when manoeuvring or in port – as is the case with other DF technologies. This has an obvious impact on the vessel’s exhaust emissions, as well as on operating costs.
According to the manufacturers the first engine utilising this technology, the Wärtsilä RT-flex50DF, will be available for delivery in the third quarter of 2014. Other engines from the company's new Generation X series will follow and are to be available for delivery during 2015 and 2016. In due course their entire portfolio of 2-stroke engines will be available as low pressure dual-fuel (DF) versions.