The cruise industry finds itself at a crossroads as it seeks new sources of energy and propulsion that will allow it to achieve its zero-emissions goal by 2050.

The sector’s challenge is compounded by having to develop several new types of fuel while continuing to operate its existing ships that rely on traditional fuels.

Cruise lines will tell you there is no silver bullet that will eradicate the toxic gases ships discharge. However, they will highlight the lengths to which they are going to achieve zero-emission operations.

Some specialists are even looking into suction wings, Flettner rotors and hard sails to propel their sustainability ambitions to even greater heights. Hurtigruten’s Sea Zero concept and Ponant’s Swap2Zero design are two of the more outlandish efforts in the works.

Outlook ’very fragmented’

Trade body Clia, though, has identified sustainable fuels as being the most fruitful avenue, describing them as “a critical element in the industry’s decarbonisation strategy”.

The cruise sector will need these fuels to meet a number of targets like the European Union’s Fit for 55, which mandates 2% use of alternative fuels by 2025, rising to 6% by 2030, in an effort to reduce greenhouse gases (GHGs) by at least 55%.

“It will be very fragmented over the next 10-15 years,” Royal Caribbean Group’s vice-president of environmental stewardship Nick Rose tells TTG. “You’ll have traditional, gaseous and alcohol-based fuels, plus biofuels. Flexibility is key.”

So, what are the fuel types of the future that may, one day, replace fossil fuels?

Clia Europe director general Marie-Caroline Laurent is excited by the level of cruise line investment in hydrogen. Explora Journeys has ordered two hydrogen ships, slated to launch in 2027 and 2028.

“This is actual money Explora has given to the shipyard,” she reiterates.

Clia believes hydrogen will be the fuel of choice between 2040 and 2050 as the sector nears its zero- emissions deadline. But Laurent cautions: “The challenge with hydrogen is that the volume you need to power a vessel is 10 times more than traditional fuels.”

’Increasingly clear pathways’

One source, which has the potential to be a long-term decarbonisation option, is methanol. According to Clia, seven ships – either methanol-ready on delivery or methanol capable – will launch over the next five years.

However, like all fuel types, methanol is not a perfect solution. Methanol fuel tanks must be watertight due to the potential fire risk, and are around 2.5 times larger than oil tanks.

Clia, though, says that once methanol is available at scale, thanks to collaborative work between fuel suppliers and cruise lines, it will make operations almost climate-neutral.

As ever, there is a caveat. “Low-carbon fuels – including hydrogen and methanol – aren’t yet viable at scale for continuous development on cruise ships,” says Linden Coppell, vice-president of sustainability and ESG at MSC Cruises. “However, there’s an increasingly clear pathway to widespread usage.”

Laurent believes the best option is advanced biofuel, which requires only “a small adaptation” to existing ship engines before it can be used. However, she notes: “While it has an equivalent chemical fuel to ordinary fuel, we don’t have it at scale right now.”

Powered by biofuel, MSC Cruises’ Euribia operated the world’s first net-zero cruise from Saint-Nazaire in France to Copenhagen last summer. Ahead of the four-day sailing, Laurent reveals MSC bought 400 tons of bio-liquefied natural gas (LNG) from Swedish firm Gasum – all of its available stock – highlighting the supply issues.

But Laurent adds: “There were no emissions during that sailing. As an industry, we’re looking to achieve this by 2050. I was really impressed.”

’Time for agents to take an interest’

Today, LNG has become the go-to transitional fuel for cruise lines following heavy recent investment in LNG-powered ships. There are currently 15 LNG ships in operation, with 13 more on order through 2028.

In January, Royal Caribbean will launch Icon of the Seas, its first LNG ship. Coppell explains LNG reduces levels of sulphur and nitrogen oxides to “very close” to zero, and reduces greenhouse gases by 20%, making it the cleanest marine fuel presently available to lines at scale.

“Perhaps even more crucially, it’s a transition fuel, so the onboard hardware can also be used for the next generation of low-carbon fuels,” she adds.