Meanwhile, Bimco president John Denholm is unconvinced. In a speech at the IMO’s World Maritime Day Symposium recently, Denholm blasted LNG as an unworkable eco-fantasy and “not an option” for most ships. He went on to express scepticism that sufficient refinery capacity low-sulphur Marine Diesel Oil (MDO) would be available.
Closed-loop scrubbers, however, whereby the pollutants removed from the exhaust are not merely dumped into the sea, present another option. Although regarded with uncertainty by shipowners, scrubbers theoretically allow for some of the cheaper, dirtier Heavy Fuel Oil (HFO) to be used without the air pollution it usually entails.
Recently, Langh Ship announced that it had tested its own in-house closed-loop scrubber system aboard its vessel Laura, using Heavy Fuel Oil (HFO) in the North Sea ECA zone where the limit on sulphur is 1%. “We requested quotations on scrubbers, but the offers we were getting were just too high to seriously consider installing them in used vessels,” said company managing director Hans Langh.
Seatrade Global asked Wärtsilä Ship Power, one companies leading the charge on scrubber technology, whether scrubbers presented a more viable alternative for retrofit applications than the installation of new dual-fuel engines. “In most cases scrubbers will be as you say a ‘more workable’ solution for retrofits, but there are also examples of the opposite,” said Sigurd Jenssen, director of exhaust gas cleaning, Wärtsilä Ship Power.
The biggest barrier to scrubber retrofit is space. In some cases, new kit is required to make the scrubber installation viable, with some ships requiring more significant investments such as replacement funnels. Not every vessel will have enough space to accommodate a scrubber system. “The choice of system will depend on a number of factors, space, power consumption, operating area, and vessel design, so it is difficult to generalise. The main benefits of the closed-loop system are of course the ability to operate in a zero-discharge mode, and that it works independently of the alkalinity in the seawater.”
“We are already delivering systems that are designed for both the 0.1% ECA limits entering into force in 2015, and the future 0.5% IMO and EU limits that enter into force in 2020. We see exhaust gas cleaning as a viable and attractive route to compliance for a large part of the world fleet, providing potential cost savings already today.”
While fuel costs are certain to rise, and particularly in the case of low-sulphur fuels, the rate at which they do so will ultimately determine whether closed-loop scrubber technology will be worth the investment.
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