Several cruise lines are testing expanded biofuel use on their older ships, marking a new chapter in the cruise industry's exploration for fuel sources to help them decarbonize amid climate change.
Royal Caribbean International is the latest line to experiment with larger-scale biofuel use. In late October, the line's 20-year-old Navigator of the Seas sailed a three-night cruise to Ensenada, Mexico, from Los Angeles with one engine powered by 30 tons of biodiesel.
"That's what's great about biofuel: it can be used in our existing engines," said Laura Hodges Bethge, Royal Caribbean Group's executive vice president of shared services operations. "These engines were never intended for this, but we've done a lot of things that were never intended for something, and technology changes and the world develops new and amazing things."
The biodiesel, supplied by World Fuel Service, is a cocktail of products such as waste vegetable and frying oils, animal fat and corn. Their use greatly reduces carbon emissions compared to the burning of the fossil fuels used in marine gas oil.
If after a month the test on the Navigator goes well, Royal will expand the biofuel to power two engines to see how the ship performs, said Bethge. Over time, she said believes the line will be able to run an entire ship on biofuel, which is processed through an oil refinery and is molecularly identical to diesel.
This test will last three months, but even if it's successful, the main hurdle for Royal and the industry at large is a lack of sufficient biofuel in the market to support a permanent shift to its use.
"We're trying our very best to get as much in front of the line all the time to buy biofuel," said Jason Liberty, CEO of Royal Caribbean Group, who said that making biofuels work for the cruise industry is like "solving a Rubik's Cube," due to its short-term viability because ships can burn biofuel with their current engines but still face the challenge of finding enough of it to bunker in ports around the world. Bethge hopes the current test by Royal, one of the world's largest cruise companies, will signal to the market a need for more biofuels and thus spur production.
To reduce emissions currently, 61% of new cruise capacity is being built to use liquefied natural gas, or LNG, according to CLIA. Commonly referred to as a transition fuel, it results in 95% fewer particulate matter emissions, nearly eliminates sulfur emissions and reduces nitrogen emissions by 85%, reducing greenhouse gas emissions by up to 20%. LNG, however, is not a long-term solution for the cruise industry because it still produces carbon dioxide (CO2). Alternative fuels to accomplish the goal of net-zero carbon cruising are still being explored or are not widely available.
However, CLIA envisions a future where LNG-ready ships can adapt to a new generation of sustainable marine fuel, such as biofuels, methanol, ammonia and hydrogen, which would reduce the carbon emissions directly associated with causing climate change.
The transition to sustainable marine fuels is paramount to the industry meeting its goal of reaching net-zero carbon cruising by 2050, according to CLIA. The association is urging governments to support research to find innovative solutions.
Meanwhile, cruise lines are trying to get ahead of where the technology currently is.
Carnival Corp. brands Holland America Line and Aida Cruises conducted two biofuel pilots this summer in partnership with GoodFuels, a producer and supplier of sustainable biofuels for the transportation industry. HAL ran a long-term shipboard test on the Volendam, which ended with the ship using 100% biofuel for 15 days, and according to GoodFuels, seeing a 78% decrease in life cycle CO2 emissions compared to marine gas oil emissions. Aida, meanwhile, ran a blended biofuel test onboard the AidaPrima.
"With the successful start of biofuel usage, we have proven that gradual decarbonization is possible even on ships already in service," said Felix Eichhorn, president of Aida.
Norwegian Cruise Line is one of the few major cruise companies to resist building ships powered with LNG but has begun testing biofuel blends, the line said. It did not, however, reveal what the tests were or on what ships they were taking place. NCL is sniffing out a different fuel source; it signed a deal with MAN Energy Solutions in October to explore the feasibility of retrofitting an existing engines to operate with both diesel and methanol, another option the maritime industry is exploring.
Johanna Jainchill contributed to this report.