Scrubbing up – energy-efficient cruise operations

Recently, the cruise industry has ramped up its commitment to reducing its well-documented environmental footprint.

Operators have made huge strides to lower emissions, increase energy efficiency and improve waste management, but there is still huge scope for change.

Despite increasingly stringent regulations, in many ways the drive for a greener industry is led by the cruise lines themselves. Firms have mustered a long list of accolades for their efforts in engineering sustainable technology, operational changes and collaboration with environmental agencies. Disney Cruise Line has designed a system that recaptures condensation for use in washing decks, saving 22.3 million gallons annually; Royal Caribbean has implemented a smoother hull coating on Oasis of the Seas that reduces fuel usage by up to 5%; and Norwegian Cruise Lines has launched the prototype 'Live Load' systems to recycle more than 35% of solid waste on board.

By its very nature, mobilising vessels weighing tens of thousands of tons is an energy-intensive exercise, but a look at the attributes of new cruise liners, as well as the technologies retrofitted in older models, offers tangible examples of how operators can drastically reduce their impact. From the bow to the stern, the engine room to the cabin, where they see an opportunity and business case to limit waste and pollution, they've demonstrated the appetite to do so.

Environmental challenges

Carnival Corporation is no stranger to tackling environmental challenges. With a 101-strong fleet, it is certainly in the line's best interests to improve efficiency, demonstrated by its commitment to reduce greenhouse gas emissions by 20% from its 2005 baseline by 2015. It was also awarded the title of Best Marine Solutions Company in The New Economy's 2013 Clean Tech Awards, primarily due to its $400-million investment into exhaust-gas cleaning technology, colloquially known as scrubbers. In a bid to improve transparency, it now produces annual corporate sustainability reports that track its environmental performance.

"If you look at the latest one, which looks at the 2012 fiscal year, there's a whole range of regulations that we have to meet, but while some companies look at these as a maximum, a ceiling, we see them as a starting point," says Jim Van Langen, Carnival's vice-president for management systems. "A lot of what we do goes way beyond the industry benchmark. The regulations for discharge of treated sewage, what's known as blackwater, is three miles from the shoreline, a statutory limit of the US and other places, but we've set a corporate standard of operating outside of 12 miles. It's just one example where we go beyond standard practice."

For Van Langen, when looking at where cruise liners can improve efficiency, its best to start from the top and work down. This inevitably means beginning with a ship's propulsion load, which usually accounts for more than half of its energy consumption. By vessel class, cruise liners are now the largest group to be fitted with the Azipod electric propulsion system, one of the most environmentally friendly devices available, with newer models able to save as much as 55,000L of fuel oil a week and operating with 10-15% more efficiency than conventional systems.

Carnival also commonly employs heat-recovery systems for recapturing waste energy released from the exothermic reactions of engines, using it to power other areas. Its ships typically make 70% of their fresh water out at sea, and this recaptured energy can be used to heat the evaporators, which make water suitable for drinking and bathing.

"It's already a common feature on a lot of ships, but we're looking at more ways of using it," says Van Langen. "The second area we would normally look at is heating, refrigeration, ventilation and air conditioning.

"We have refrigerators and freezers to store the vast quantities of food for the voyage, and we need to ensure that those systems and the equipment associated with them work as efficiently as possible. We also look at things as simple as opening and closing doors - how you design the spaces between interior and exterior public spaces can really affect the heat load."

Green giant

Though greener engines and ecological design are now standard practices in newbuilds, in older models, operators need to demonstrate more pragmatism when reducing emissions. The technology largely responsible for Carnival's victory in the Clean Tech Awards is its scrubbers, which are currently being installed in more than 70 vessels. Already widely used in factories and other vehicles, the emission abatement system scrubs exhaust gases with seawater to remove sulphur - in accordance with the IMO's regulatory limit - and drastically reduces fuel costs.

"Reducing the emissions and complying with the requirements for using low-sulphur fuel partly drove our commitment to use scrubbers, but our goal is to exceed the legal requirements," says Van Langen. "It's a long-term project and probably the most significant area of retrospective action for us.

"We're also looking at things like installations that measure fuel consumption. Historically, you'd only look at the total, but with these meters, you can assess each engine individually, so you know exactly what each individual component is using."

Carnival has made huge progress already in reducing company-wide emissions and is on course to meet its self-imposed 20% reduction by 2015, when it will re-evaluate and set new targets. Van Langen accepts that more can always be done and any movement towards sustainability will happen incrementally.

"It's a continual process, an ongoing evolution," he says. "We're a highly capitalised organisation, and we're not going to be able to suddenly change the technology in all of our ships; we experiment with new designs on a few at a time, and if the trials work, then we can begin to scale it up."

To some extent, operators' progress in sustainability is impeded by other industry stakeholders. The amount of power used by liners in ports contributes immensely to the infamous smog epidemics that plague areas such as the Los Angeles basin. As a result, many have resorted to 'cold ironing', where vessels are adapted to connect to shore for power, drastically reducing port emissions.

Though effective, only a handful of ports across the world possess the necessary infrastructure to accommodate these adaptations. Even then, the power has to come from somewhere, and there's no guarantee this will be from clean energy sources.

Operators' hands are also tied by the over-reliance on a restricted supply of green technology manufacturers. "Nobody in this market has a technical edge, as we're all dealing with the same technologies," says Van Langen. "There's a limited supply of shipbuilders, engine manufacturers and equipment suppliers providing cruisers with environmentally related technology.

"There's also a significant R&D investment into making greener technology; it's a huge commitment, so there has to be a positive economic equation to ensure it's going to reap benefits in years to come."

There will always be a sense that more can be done to reduce the industry's environmental footprint. As Van Langen says, to really make an impact, environmental regulations must be treated as a starting point, not a finish line.

It will require significant investment and closer collaboration between parties across the entire industry, but if this can be achieved, it'll be more than the environment that benefits.

"In a lot of cases, we exceed legal requirements," says Van Langen. "We're well on our way to meeting our own targets, and since we know this, we've started to establish the next round of goals and objectives. It just makes good business sense to do so."