Can Cruising Achieve Net Zero by 2050?

As the cruise sector strives towards its unified objective of attaining net zero carbon emissions by 2050, a variety of new energy alternatives are being explored. Options include biofuels, synthetic fuels, batteries, hydrogen fuel cells, and solar power. Additionally, wind—the classic and natural source of energy—could increasingly supplement the power needs of both large and small cruise vessels.

“I have high hopes for wind energy in the future,” states Bill Burke, chief maritime officer of Carnival Corporation, the largest cruise company in the world, which operates nine brands including Carnival, Holland America Line, Princess Cruises, Cunard, and Seabourn. “I anticipate its implementation within the next decade,” Burke shares with Dinogo, discussing how wind power can help cruise ships reduce—and eventually eradicate—greenhouse gas emissions.

To achieve both short- and long-term climate objectives, the cruise industry will likely rely on a combination of emissions-reducing fuels and technologies. Cruise lines are investing billions into future methods for powering their vessels, actively anticipating green energy sources and potential obstacles that are still unforeseen. The rationale is clear: cruise ships are designed to last 25 to 30 years; those being launched now must be compatible with sustainable engine technologies and cleaner fuels that may not even exist or be perfected yet, to meet future expectations.

Upcoming Fuel Sources for Cruise Ships

At present, the cruise industry is concentrating on Liquefied Natural Gas (LNG), recognized as the cleanest burning fossil fuel available at scale. Over a dozen cruise ships utilize it as a “transitional fuel,” indicating that it can be easily replaced by greener bio or synthetic LNG once these sustainable alternatives become more widely accessible. According to the Cruise Line Industry Association (CLIA), 25 LNG-powered cruise ships are set to launch in the next five years.

LNG significantly reduces sulfur emissions, nearly all particulate emissions, and the majority of nitrous oxides. While it has faced criticism for methane emissions, this perspective may be outdated. Critics often overlook advancements in technology aimed at minimizing methane slip, as noted by Burke.

Carnival Corp. plans to add 11 LNG-powered vessels to its fleet by 2025, including eight that are already operational. The Royal Caribbean Group, encompassing Royal Caribbean, Celebrity Cruises, and Silversea, is also introducing LNG ships designed to explore fuel cell technology—specifically, the 728-passenger Silver Nova for ultra-luxury line Silversea, which launched last month, and the 7,600-passenger Icon of the Seas from Royal Caribbean, set to debut as the world's largest ship in January 2024.

Soon to join the fleet are seven ships equipped to be either methanol-ready or methanol-capable from brands like Norwegian Cruise Line, Celebrity Cruises, and Disney Cruise Line. These vessels will be able to transition to green methanol, enabling near climate-neutral operations once it becomes more accessible. According to Burke, Carnival Corp. is considering retrofitting existing ships for methanol and may order new methanol-ready ships in the future.

Regarding the choice between LNG and methanol, Burke states, “We don’t necessarily want to choose a favorite, so we’ll have ships powered by both.”

New fuel sources are crucial for decarbonization, yet their availability poses the greatest challenge for the cruise industry in achieving net zero by 2050. Cruise ships will face competition for green fuels not just from the maritime sector but also from aviation and various other industries.

As we look ahead to 2050, Burke emphasizes, “The primary challenge is green power.”

Alongside LNG and methanol, cruise lines are increasingly launching pilot programs to test alternative sustainable fuels on their currently operating ships. These greener fuels are molecularly identical to conventional marine gas oil, allowing them to be utilized in existing engines—meaning older vessels can adopt them too.

Carnival initiated the use of a biofuel blend combining marine gas oil with raw natural materials on AIDA’s 3,300-passenger AIDAprima in July 2022. In October 2022, Royal Caribbean’s Navigator of the Seas became the first ship in the U.S. to operate on renewable diesel.

Cruise lines are partnering with companies that produce biofuels from manure, vegetables, used cooking oil, tallow, and wood.

According to CLIA, there are currently 32 pilot projects and collaborative efforts underway between cruise lines and producers of sustainable fuels and engine manufacturers. Additionally, seven new cruise ships are in development, expected to operate on zero-carbon fuels—five aiming for green methanol and two for green hydrogen, including those from MSC Group’s new luxury line Explora Journeys.

However, the limited supply remains a challenge. Burke states, “We’ve experimented with various feedstocks and are satisfied with the outcomes. We will continue testing over the next couple of years, but generally, they are not available in large quantities today and are significantly more expensive than fossil fuel alternatives.”

On a four-day voyage in June, the 6,300-passenger MSC Euribia traveled from Saint-Nazaire, France, to Copenhagen to demonstrate that net-zero cruising is achievable today. The LNG-powered vessel utilized bio-LNG from Nordic energy company Gasum, a leading biogas producer, and employed technology to enhance energy efficiency.

Wind and solar are also part of the testing landscape. Consider it an open invitation for sustainable alternatives. There's even been discussion of ammonia, hydrogen, and nuclear power—though Burke expresses skepticism about their potential adoption in the cruise sector.

Batteries, Fuel Cells, and Wind Energy

Batteries and fuel cells will also play a crucial role in achieving net-zero goals by 2050. Some cruise lines, including Norway's Hurtigruten and France's Ponant, already operate vessels capable of running for several hours on battery power and/or hydrogen fuel cells, reflecting trends seen in the automotive industry, where there is a significant push for more electric vehicles (EVs) and, to a lesser degree, in the airline industry.

Major cruise lines like Royal Caribbean, Viking, and MSC Cruises are equipping their ships with hydrogen fuel cells that can supply power for brief intervals or act as auxiliary power systems, helping to decrease fuel usage. Meanwhile, Carnival Corp. is experimenting with a 10-megawatt battery on the AIDAprima. “This could enable peak shaving, allowing operations at more efficient speeds or reducing engine run hours,” Burke explains.

CLIA reports that 15 percent of new ships entering service over the next five years will feature battery storage and/or fuel cell technology.

“We believe that fuel cell systems and battery technology can enhance some of the primary energy needs for operating our ships,” stated Jason Liberty, chairman of Royal Caribbean Group, in the company’s annual sustainability report published in April (based on 2022 insights). “This innovative and complex approach is transforming how energy has traditionally been generated and distributed on cruise ships.”

Wind technology is also on the horizon. The first passenger cruise ships utilizing SolidSail technology, developed by French shipyard Chantiers de l’Atlantique, are set to debut in 2026 and 2027. These 100-passenger vessels, commissioned by Orient Express, will represent the luxury hotel company's entry into the cruise market and will feature a foldable, large rigid sail made from composite materials.

For its wind energy initiatives, Carnival Corporation is exploring a “vertical rotor-type component,” says Burke. This will likely be placed atop the ship near the exhaust stacks and is expected to be incorporated into a newbuild rather than an existing vessel.

The Future of Cruise Ships

Some cruise lines are pushing the boundaries of design, aiming to unveil net-zero ships within the next seven years.

Ponant is targeting a zero-greenhouse gas emissions ship by 2030. The prototype 200-passenger vessel will operate on wind, solar power, low-temperature hydrogen fuel cells, and high-temperature fuel cell carbon capture technology.

Hurtigruten is also aiming for a 2030 launch of a ship powered by wind from retractable sails, solar energy, and batteries. Some of the intended technology is still in early development, while other aspects have “reached a relatively advanced stage,” as stated by the cruise line. This prototype will accommodate 500 passengers.

Royal Caribbean Group plans to construct a ship by 2035 capable of achieving net zero for all operational aspects “without emitting air pollutants like sulfur dioxides and nitrogen oxides.” The company is exploring various green concepts, including LNG, methanol, and ammonia.

Minimizing Fuel Consumption

As new sustainable fuels and energy sources become available, cruise lines must continue to reduce fuel consumption to manage costs, since sustainable fuels are more expensive than traditional marine fuels.

Many vessels have upgraded their HVAC (heating, ventilation, and air conditioning) systems for improved efficiency and have transitioned to LED lighting to lower their energy demands.

Other innovative approaches in the cruise industry to reduce fuel consumption include specialized hull coatings designed to decrease drag. Some ships utilize air-lubrication systems that create a layer of millions of microscopic bubbles to help them glide more efficiently and save fuel. Additionally, improved route planning and reducing speed can further cut fuel usage, according to Burke.

Connecting to Shore Power

Cruise lines are increasingly investing in shoreside electricity, allowing ships to turn off their engines while docked, significantly cutting emissions. This approach is most effective when the local power grid relies on green energy.

Depending on the energy mix, connecting to shoreside power—which involves using large electrical plugs—can reduce emissions by as much as 98 percent, according to various studies, including those by the U.S. Environmental Protection Agency. As per CLIA’s latest environmental data report, 120 out of 292 member ships are now equipped for shoreside electricity, marking a 48 percent increase since 2022, and 86 percent of CLIA member ships set to launch between now and 2028 will have plug-in capabilities.

However, there is a significant challenge to this initiative. While the number of cruise ships with plug-in capabilities is projected to reach 210 by 2028, only 32 ports—less than 2 percent of global cruise ports—currently have at least one berth equipped for plug-in power. The European Union’s Fit for 55 green program mandates that all major European ports must offer shoreside power by 2030, highlighting the need for expanded plug-in infrastructure at ports worldwide.

Vision for 2050

CLIA and its member cruise lines are urging for enhanced support of research initiatives to achieve the sustainability targets set for 2050.

“With appropriate backing from governments and international bodies to promote the swift advancement of technology and the availability of renewable fuels, the industry can reach net-zero emissions cruising by 2050,” remarks Michele Francioni, senior vice president of optimization for MSC Group's cruise division.

Is the industry equipped to meet its 2050 objectives? “I believe we’re in a strong position,” Burke states, though he concedes that a long journey lies ahead.

“I think the train has left the station, and we’re committed to making it happen,” he adds. “We genuinely aspire to achieve net zero, but many factors must align for this to occur.”