Large cruise companies began running trials with biofuels two years ago, but their executives say they are far from being able to use it to power their ships regularly.
Instead, they are continuing to test and study biofuels as a drop-in fuel source in the short term while awaiting cleaner fuels like green methanol, green hydrogen or electric liquefied natural gas to become available at scale.
"It's a journey, right?" Jason Liberty, CEO of Royal Caribbean Group, told reporters in January while on the Icon of the Seas, Royal Caribbean International's first LNG-fueled ship. "It will take time for those fuels to come and be available."
Royal Caribbean is among the lines that have undertaken trials of biofuel use, which it did last year in Europe, but it faces a lack of biofuel, a supply issue that's facing not only the cruise industry but other sectors.
Cruise lines are under pressure, both from within the industry and outside of it, to reduce their greenhouse gas emissions. But the lack of sufficient alternative fuels has slowed progress toward CLIA's goal that the industry reach net-zero carbon by 2050.
CLIA has suggested that achieving that goal will happen in stages.
From now through 2030, cruise lines will have to maximize energy efficiency and use alternatives such as biofuel when they can. The decade after, newbuild ships must rely on fuels such as methane or methanol. From 2040 to 2050, reaching the net-zero target will mean using green hydrogen and bio-based feedstocks derived from renewable energy and electrolysis, the association said.
Meanwhile, the International Maritime Organization (IMO) wants the maritime industry to hit as much as 10% alternative fuel usage by 2030. And the European Union's Fit for 55 plan targets reducing the EU's greenhouse gas emissions by 55% by 2030, requiring the entire maritime sector, including cruise, to transition to 2% use of alternative fuels in 2025 and 6% by 2030.
The EU timeline is not aggressive enough, said Walter Nadolny, professor emeritus of marine transportation and global business at the State University of New York Maritime College.
"The science is telling us 2023 was the hottest year on record, and we ain't seen nothing yet," he said.
Biofuel is an easy answer for older ships because they are the easiest conversion, said Nadolny, who has served as a delegate to the IMO's marine environmental pollution committee. "All you do is put biofuels in your bunkers, and you're there."
Pilot programs test the waters
Across the cruise industry, 32 pilot programs are testing sustainable fuels, according to CLIA's 2023 sustainability report. Of those programs, 24 involve ships' trial use of biofuels, which are produced by purifying raw materials like waste oil and fats.
"We see biodiesel as a transition fuel, but we're really preparing and want to explore further on the long-term solutions like methanol," said Emily Bishop, senior director of environmental, social and governance (ESG) for Norwegian Cruise Line Holdings (NCLH).
NCLH conducted biofuel trials on seven ships last year, five from Norwegian Cruise Line and two from Regent Seven Seas, about 20% of the NCLH fleet. What the company learned was that it needed to further study the quality, availability at scale and the reporting associated with the use of biofuels, Bishop said.
Not only do the trials test how the fuel works on the ship, but they also test the supply chain and are "building the muscle" needed to make the use of alternative fuels possible and regular, said Angela Stark, senior vice president, assistant general counsel, securities, ESG and compliance for NCLH.
Bishop was among experts across the industry who said that availability is a significant problem for cruise lines and other sectors as they work to transition to cleaner fuel. While more biofuel manufacturers have launched, and the fuel is in demand, the challenge is the production and transport of the quantities needed, all at reasonable commercial rates, she said.
Carnival Corp. is on track to reach an 18% reduction in greenhouse gas emission intensity this year compared with 2019 levels. That's just 2 percentage points shy of the company's goal to reach a 20% reduction by 2030.
One of the ways the line has made those gains is by reducing fuel consumption by, for example, sailing more energy-efficient itineraries and employing technology like LED and smart lighting.
Using biofuel also helps, said Tom Strang, senior vice president of maritime affairs for Carnival Corp. The company conducted biofuel trials in 2022 and 2023, mostly in Europe -- including on Holland America Line's Volendam and the Aida Prima out of Rotterdam, Netherlands -- and on the Carnival Magic in the U.S.
The company plans to conduct more trials this year, Strang said, adding that doing so inside Europe helps Carnival Corp. keep within the carbon dioxide allowance under the EU's Emissions Trading System, which requires large cruise ships to pay for each ton of carbon dioxide emitted.
Strang said the lack of sufficient biofuel could be particularly problematic for ships on Norway itineraries, as the country plans to only allow ships using alternative fuels to sail its fjords beginning in 2026.
"We want to make sure that we've got all of our ducks in a row prior to us entering into these regulated areas," he said. "They're probably a bit more than trials ... but it's not like we're doing full utilization because, frankly, the availability of these fuels is not scaled yet."