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Solar power: here comes the sun


5 March 2012


Abi Millar asks Royal Caribbean’s Jamie Sweeting how much scope there is for the use of renewable energies at sea.


In November 2008, Celebrity Solstice set sail on its maiden voyage through the Caribbean. The first vessel in the luxury-tier Solstice Class, the ship was an arresting sight: elegant and imposing, with half an acre of plush grass on the upper deck and sun motifs strewn liberally throughout.

But it wasn't on the basis of its size or style that the ship piqued industry attention. Rather, the vessel made headlines for its eco-friendly credentials, with trailblazing features marking it out as one of the greenest at sea. The hull boasted a breakthrough design, with the passenger space created to fit its specifications rather than the other way round. Modelled for optimal efficiency, Celebrity Solstice was subjected to extensive tests with a view to reducing drag.

Elsewhere on the ship, the goal of sustainability loomed large. From the high-glazed window glass to eco-friendly refrigerants, each element was selected to trim energy consumption. Lighting, for example, came courtesy of low-watt LED lightbulbs, a fixture on all Celebrity's ships, even before such bulbs were commercially available.

"Celebrity Solstice became the first-ever cruise vessel to feature solar panels on board, with 216 photovoltaic (PV) panels installed across five areas."

However, Solstice was not content to rest on its laurels, positioning itself not just as a flagship for its class, but as a flagship for sustainable cruising. It became the first-ever cruise vessel to feature solar panels on board, with 216 photovoltaic (PV) panels installed across five areas.

Spotlight on solar

The idea of using renewable energy on cruise ships is certainly enticing. With the downsides of bunker fuel well documented, the race is on to find sustainable alternatives, and cruise companies are working hard to redress the industry's tarnished environmental record.

"We've made a conscious decision to build a reputation for innovation and continuous improvement, and while we know we aren't perfect, we're committed to being even better tomorrow than we are today," says Jamie Sweeting, vice-president of environmental stewardship at Celebrity's parent company Royal Caribbean Cruises. "We have a maniacal focus on minimising air emissions, as well as fuel consumption and related costs."

As oil reserves continue to dwindle and environmental targets grow more stringent, renewable resources look like a reliable long-term bet. Moreover, with fuel prices capricious and near impossible to predict, non-bunker-based energies present a ship with a useful hedging strategy, mitigating the need to levy additional charges on passengers.

So far, results are promising, but Celebrity's solar panels do have a downside. Rather than contributing significantly towards ships' energy demands, the panels barely scratch the surface of what's required. Cumulatively, they generate just enough energy to operate the elevators, or 7,000 LED bulbs.

Hanging in the balance is an uncomfortable question: were these PV panels genuinely worth installing, or are they sheer gimmickry; a tokenistic show of commitment to the environmental cause?

"Hanging in the balance is an uncomfortable question: were these PV panels genuinely worth installing, or are they sheer gimmickry?"

Sweeting concedes that, for the time being, the benefits may seem negligible.

"We know they don't produce an enormous amount of power, but we initiated the project in the interest of 'future proofing'," he says. "We are beginning on a smaller scale in order to benefit our future efforts." He admits it would be unrealistic to run a cruise ship on solar power alone. While solar radiation on a clear day is roughly 1,000kWh/m², cruise ships consume around 10MW during their average station in port, with many additional energy costs incurred when they set sail. There simply would not be the physical space to install the requisite number of panels.

Solar energy is also expensive, perhaps prohibitively so. In these financially straitened times, a technology that takes so long to achieve return on investment is unlikely to commend itself to operators. To see its purpose, they have to look beyond the pressing aim of cutting costs in the here and now.

Sweeting, however, does not think that the eco-friendly option has to be bad for business. "Sustainability makes good business sense and solar energy is likely to become more effective," he says.

By the time more efficient solar panels are patented, Solstice will have no need for retrofitting, as the infrastructure will already be there. They will simply need to rip off the old panels, and install the new ones in their place. Other cruise ships, catching on to a good thing, will require a larger structural overhaul.

Energy giants

This logic is spreading rapidly through the industry. The three other ships in the Solstice Class (Equinox, Eclipse and Silhouette) include PV panels as standard, with a fifth vessel, Reflection, slated for this year. Meanwhile, the cruise industry at large is starting to pose questions about the scope for renewable energies.

In 2009, Royal Caribbean International launched Oasis of the Seas, followed by Allure of the Seas a year later. The two largest ships in the world, these leviathan vessels feature UNI-SOLAR laminates installed by BAM Solar of Miami. The panels cover 2,000m2, produce 111,108kWh of energy a year and are used to supply electricity to the ships' shopping districts.

"The first Oasis Class ship, Oasis of the Seas, has had such positive feedback for using solar that we knew we had to do it again with our Oasis sister ship Allure of the Seas," said Rasmus Norling, manager of R&D environmental technologies and environmental stewardship at Royal Caribbean Cruises. "Royal Caribbean is devoted to environmental protection and is the industry leader in our commitment to energy sustainability. Solar is one part of that mission."

"Oasis of the Seas has had such positive feedback for using solar that we knew we had to do it again with Allure of the Seas."

Solar power can also prove useful for ships docked in port. A 1MW solar power system was installed in the Port of Los Angeles in 2010, giving ships stationed between cruises an alternative to their diesel generators. According to port authorities, the system will save around $200,000 a year in electrical costs.

Renewable options

Of course, the sun is not the only source of renewable energy. Looking at other options, the most obvious contender might be wind power. While this has long been floated as a possibility - there is not, after all, a lack of wind at sea - Sweeting does not think that there is much scope for using turbines on a ship.

"We have tested wind via Helix wind turbines and it simply was not effective," he says.

Another alternative energy option is nuclear. Unfortunately, while this may present a valid possibility technologically, it is unlikely to prove acceptable among guests or port authorities, many of whom have reservations about its safety. More promising are sustainable biofuels, which eventually ought to become available at a price the industry can sustain.

Regarding solar, the real hope is that the panels will become smaller over time. Using an analogy with computer chips, this is precisely the trajectory that can be expected: Moore's Law stipulates that technologies double in efficiency approximately every two years.

Now and beyond

Tiny, hyper-efficient solar panels are still a long way off, but the promise glitters alluringly on the horizon. For now, the task is to find a balance between future proofing and the needs of the present day.

"Tiny, hyper-efficient solar panels are still a long way off, but the promise glitters alluringly on the horizon."

What does Royal Caribbean have in the pipeline? Sweeting is circumspect, but with its commitment to renewable energies established, the company's first tentative steps in this arena may soon become bold strides.

"We are unable to reveal any specifics, but based on our history of innovation, you can count on us for continued progress," he says. "We leave no stone unturned."