It would be fair to say that the cruise industry’s response to the International Maritime Organization’s (IMO) MARPOL Annex VI regulations has been cool at best. The initiative, introduced to curb air pollution from ships, stipulates that operators are required to switch to fuels with a sulphur content of less than 0.1% by 2015.

While it has long been in the interest of operators to evince their green credentials, in conforming to the mandate, cruise lines have been forced to overhaul their engine room strategies. Namely, this concerns both sourcing and adapting to eco-friendly alternatives, which are more costly than traditional bunker fuels due to limited availability.

Furthermore, the regulatory countdown is now in full swing. In August, the North American Emission Control Area (ECA) – which states that all ships operating within 200 nautical miles of the US and Canada coastline must use marine fuel with a sulphur content below 1% – will come into play, much to the consternation of many.

"Cruise lines are turning to retrofitting as a means of ramping up engine performance and efficiency in line with new MARPOL legislation."

Last year, Carnival Cruise Lines UK CEO David Dingle lambasted the measures as being "badly researched" and "the biggest single threat to the cruise industry", while Royal Caribbean International CEO Adam Goldstein, speaking at Cruise Shipping Miami’s State of the Industry panel in March, conceded that "it is not clear we’re going to be able to access that [low-sulphur] fuel".

The general consensus also appears to be that it is a case of poor timing. As well as forever being at the mercy of unstable fuel prices, the spectre of financial austerity still looms conspicuously over the entire industry. So, one may ask, what exactly does this mean for ship propulsion systems?

Put simply, as the rate of newbuild orders continues to subside in line with restricted budgets, cruise lines are turning to retrofitting as a means of ramping up engine performance and efficiency in line with the MARPOL legislation; however, according to Brian Swensen, senior vice-president of technical operations and refurbishment at Norwegian Cruise Line, engine room retrofitting is not a novel recourse.

"Although there is a heightened awareness today in line with IMO regulations, I would say that the push really began in 2003-04," he says. "While some of the operators pursued newbuilds back then, it is now certainly more a case of looking into new technologies, even if the industry as a whole has been slow to react due to complications associated with making these modifications."

Scrubbing technology

One such solution is the implementation of compact scrubber technology. Akin to installing a shower facility within the stack of a ship, scrubbers are air pollution control devices that are able to wash emissions from the engine room and remove up to 90% of sulphur particles. Several operators are piloting both closed-loop scrubbers, which recycle water, as well as open-loop scrubbers, which purify water before releasing it back into the ocean.

"As the rate of newbuild orders continues to subside in line with restricted budgets, cruise lines are turning to retrofitting."

The most notable exponent of this has been Royal Caribbean International, which in July announced that it had successfully installed a compact MARPOL-compliant exhaust scrubber on Liberty of the Seas. But as the group’s vice-president of environmental stewardship Jamie Sweeting admitted to Travel Weekly in March, despite being a more desirable alternative to newbuilds, such technology is far from cheap.

"These are multimillion-dollar investments," he said. "It’s not like buying a toaster oven from Walmart." Swensen corroborates Sweeting’s statement, while adding that retrofitting also posits some unique practical challenges, particularly for older vessels.

"We are under no illusion that it is going to take millions," he says. "If you go in the direction of scrubbers, it’s also going to require additional power, which could be a problem for older ships. Another concern I have is that operators are going to invest a lot of money in short-term solutions when, in fact, the long-term solution over the next five years or so is probably going to be the increased use of LNG."

LNG: a specialist option

The use of LNG on cruise ships has long represented a salient, if arguably still moot, talking point among operators. While its low-sulphur content and economic feasibility – the price per energy content is lower than oil – makes it a viable option, it requires specialised LNG engines, which in turn necessitate more space in the engine room.

"With natural gas, there is a tremendous amount of money to be saved, but at the same time, it’s going to require tremendous investment by operators," says Swensen. "In terms of the engines operating on natural gas, we are not quite there yet. The question mark still lingers over how to store them onboard. In order to do this, we, as an industry, will most probably have to do it in steps."

"Scrubbers are air pollution control devices that wash emissions from the engine room and remove up to 90% of sulphur particles."

Presently, the short-term answer lies in a dual-engine concept, in which ships are able to switch from heavy fuel oil (HFO) to LNG on entering an ECA, such as the aforementioned North American space.

"That first step I mentioned may well be a move towards dual engines," says Swensen. "This means that when you enter an eco-zone, you are able to switch over to LNG, and while you are docked, you can also refuel and have enough container space for what you need. The final goal will obviously then be to operate the whole voyage on natural gas."

Such ideas have clearly gathered momentum of late. But, as Swensen admits, "the marine industry has always moved in a slow and methodical way".

Are operators on schedule to implement the right technology in time, or is it still in its theoretical stages?

"While we can only really speak for ourselves at Norwegian, we have various projects going on right now," he says. "We are in the process of studying how we can take our existing engine rooms and modify them for the future. Recently, we have also invited outside think tanks to explore new technologies to see not only where we will be in 2015, but beyond to 2020-25.

"I am sure, however, that our competitors are making similar investments, particularly on the scrubber side. Initiatives are starting to be put into place as everyone is concerned about the impending rules and regulations."

IMO deadlines inevitable

It would be blinkered to assume that the initial misgivings concerning the looming IMO deadlines have subsided, with Swensen echoing Dingle and Goldstein’s earlier objections – "it sometimes feels like a case of putting the cart before the horse".

"LNG requires specialised engines, which necessitates more space in the engine room."

There appears, however, to be an air of acceptance among players that the inevitable can no longer be delayed. And while retrofitting throws up its own set of complexities, it is likely to remain prevalent for some time to come.

"A lot of operators don’t like to be the first to make the move," says Swensen. "From a regulatory perspective, I suppose you have to ask yourself if there is ever a good time. I would say, probably not. It’s simply something that has to be done because we know what’s down the road and staring us in the face. As a result, I think we will see some dramatic changes in the technology we implement in the next couple of years."