Can the largest cruise ship in the world really be climate-friendly?

In a ceremony that naturally involved a soccer ball, Argentine soccer superstar Lionel Messi pressed a button and smashed a bottle of champagne against the bow of Icon of the Seas on Tuesday, christening the world's largest cruise ship in its home port. from Miami. Like an A-list celebrity stepping onto the red carpet, the arrival of Royal Caribbean's 250,800-ton ship has captured the world's attention, with some marveling at its cutting-edge features such as the largest water park at sea , while others criticized the ship's enormous potential to damage the environment.

With a capacity to carry almost 8,000 people, the 20-deck, 350-metre-long ship – whose first cruise with paying passengers departs on January 27 – is the size of a small town. There are eight “neighborhoods” packed with amenities, including a 55-foot waterfall, six water slides and more than 40 restaurants, bars and entertainment venues.

According to Royal Caribbean, the ship, which is registered in the Bahamas, also sets a new standard for sustainability with the use of energy-efficient technology designed to minimize the ship's carbon footprint and move closer to the company's target come: the introduction of a net zero current. ship by 2035.

“We live by a single philosophy, which is to provide the best vacations responsibly,” said Nick Rose, vice president of environmental management at Royal Caribbean Group. “And to do that, we build with the core principles of preserving our planet and communities.”

For decades, the cruise industry has been criticized for its negative impact on the environment. A 2021 study published in the Marine Pollution Bulletin found that, despite technical advances, cruising remains a significant source of air, water and land pollution, affecting sensitive habitats and human health.

While environmental groups have welcomed some of Icon of the Seas' features, such as its advanced water treatment system, some say building such enormous ships runs counter to the cruise industry's long-term goals of sustainability and conservation.

“The ships are getting bigger and that's the wrong direction for the cruise industry,” said Marcie Keever, director of the Oceans and Vessels Program at the environmental organization. Friends of the Earth. “If you really thought about sustainability and not about your bottom line, you wouldn't build a cruise ship with a capacity of almost 10,000 people.”

With more than five different brands, Royal Caribbean has a fleet of 65 cruise ships of various sizes. Icon of the Seas was built to meet demand and deliver experiences consumers were looking for, the company said, adding that all its ships follow the same sustainability principles of energy efficiency and advanced waste and water management.

Here's a look at some key features that Royal Caribbean says make Icon of the Seas more sustainable and how they stack up.

Transition to alternative energy sources

Icon of the Seas is Royal Caribbean's first ship to be powered by liquefied natural gas, or LNG, a fossil fuel touted by the cruise industry as a cleaner alternative to the commonly used heavy fuel oil.

“LNG is currently the fossil fuel available at a scale that provides the best performance in reducing atmospheric emissions,” Cruise Lines International Association, the industry trade group, said in its report. Environmental Technologies and Practices Report 2023, with reference to analysis of Marine LNGan industrial coalition promoting the benefits of LNG as a viable marine fuel.

But environmental analysts worry about LNG's long-term problems. Despite emitting about 25 percent less carbon dioxide than conventional marine fuels, they say LNG is largely methane, a powerful gas that traps more heat in the atmosphere over time than carbon dioxide.

According to a 2020 greenhouse gas study According to the International Maritime Organization, the United Nations body that regulates global shipping, the use of LNG as a marine fuel increased by 30 percent between 2012 and 2018, resulting in a 150 percent increase in methane emissions from ships.

Bryan Comer, maritime program director at the International Clean Transport Council, The reason methane emissions have grown faster than LNG use is that ships are switching from steam turbines to dual-fuel combustion engines. “They are more fuel efficient, but emit large amounts of unburned methane into the atmosphere in the form of engine 'methane slip,'” he said, pointing out ICCT research that predicts that demand for LNG will triple between 2019 and 2030, as will methane emissions.

“Even if ships used 100 percent renewable LNG bio or e-fuels, methane emissions from ships would still double between 2019 and 2030 due to methane slippage,” he added.

Royal Caribbean says LNG was the most viable alternative fuel available when decisions were made to build Icon of the Seas more than a decade ago.

“People will say LNG is not the long-term fuel, and we agree with that and see it as a transition phase,” Mr Rose said. “We built the ship to be adaptable to future fuel sources.”

The company is preparing to debut next year the Celebrity fuels to become carbon neutral. the sailing.

Shore power options

When cruise ships dock at ports, their engines and diesel generators often run on fuel, releasing carbon dioxide into populated areas. Icon of the Seas is built to operate in ports on shore power, a cleaner alternative to fuel, and hopes to become one of the first cruise ships to plug into the local electrical grid at Port Miami when shore power facilities are ready. available in the spring.

Three ships can safely and simultaneously call at the port on any given day, including Icon of the Seas, a Port Miami spokeswoman said.

“When it comes to sustainability, there is no silver bullet and we want to leverage every lever we can,” said Royal Caribbean's Mr. Rose. “So if we can come into a port that has cleaner shore power options, we want to connect that so we don't use fuel.”

The problem is that most ports don't provide shore power: according to CLIA, only 2 percent of the world's ports currently offer it to cruise ships. Royal Caribbean says it is working with ports and other cruise lines to promote its use.

Converting waste into energy on board

Expanding its 30-year history The 'Save the Waves' programwhich aims to keep waste out of landfills and the ocean, Royal Caribbean has built what it says is a first-of-its-kind waste management system on board Icon of the Seas that converts waste into energy.

The microwave-assisted pyrolysis technology, known as MAP, takes food, biowaste and cardboard waste and turns them into small pellets. The pellets are then heated to produce a gas that is converted into steam energy that Royal Caribbean said would be used to power the ship's water park. The system also produces biochar, which can potentially be used as a fertilizer.

The company said it will gain a better understanding of the system's output in the coming months while the ship is in full operation, but so far approximately 25 kilowatts of electricity are required to operate the system at an output of 200 kilowatts .

“It won't take much energy to run the system,” Mr. Comer said ICCTbut, he added, “It also won't produce much energy for the ship.”

Advanced water treatment

Icon of the Seas is equipped with an advanced purification system designed to treat all wastewater on board, from toilets and showers to kitchen galleys. More than 93 percent of the ship's fresh water will be produced onboard through a reverse osmosis system, which removes pollutants from the water, the cruise line said.

Ms. Keever of Friends of the Earth said Royal Caribbean deserves credit for its treatment systems. “They are installing the most expensive and best sewage treatment technology on their ships, and that is important because they are the largest cruise line and they are showing the industry that they can do it, they will pay for it and they should,” she said.

Fuel cells

In his 2023 promotional video seriesMaking an Icon, Royal Caribbean said Icon of the Seas would be the “first ship to feature fuel cell technology,” which would be used to power parts of the ship such as the air conditioning and elevators.

But it won't happen yet.

Fuel cells combine hydrogen and oxygen to make electricity without combustion. Their byproduct is water, which means they don't emit as many greenhouse gases as traditional fossil fuels. Although Icon of the Seas was built to house fuel cells, the batteries have not yet been installed, according to Bloom Energy, the fuel cell manufacturer partnering with Royal Caribbean. Due to the size and scope of the project, Bloom Energy said it was experiencing issues with third-party suppliers.

Bloom Energy is now focused on solving the problems with larger fuel systems planned for Royal Caribbean's 5,668-passenger Utopia of the Seas, which will enter service next year. Suminder Singh, the vice president of navy at Bloom Energy, said the next opportunity to fit Icon of the Seas with the cells may not come for another five years, when the ship goes to dry dock. Royal Caribbean says it may not last that long and that the decision will depend on the success of the technology on Utopia.

ICCT's Mr Comer said while fuel cells would be a good option, they have similar life cycle emissions to conventional oil-based fuels if made on land using natural gas. “We need hydrogen made from renewable electricity,” he said. “And if we have that and use that in fuel cells, then you would basically have zero life cycle greenhouse gas emissions.”

Follow New York Times Travel on Instagram And sign up for our weekly Travel Dispatch newsletter for expert tips on smarter travel and inspiration for your next holiday. Are you dreaming of a future getaway or are you just traveling in an armchair? Check out our 52 places to go in 2024.