Do cruise companies’ green claims hold water? an article was published on Grist.
Carnival Cruise Line
Carnival Cruise Line’s latest ship is a behemoth. The Mardi Gras sports 20 decks, 5,200 rooms, and as if that wasn’t enough, a swooping outdoor roller coaster. Unlike most of the company’s fleet, it won’t be running on oil. The vessel, which first hit the water in Finland late last month, will run entirely on liquefied natural gas when it starts sailing from Florida to the Caribbean Sea this fall.
Cruise and cargo shipping companies are increasingly switching to super-chilled fuel, which produces much less air pollution compared with the dirty “bunker fuel” that previously powered most ships. By 2025, Carnival says it will have 11 vessels running on liquefied natural gas, or LNG, including the AIDANova, the world’s first LNG-powered cruise ship.
But the overall benefits of switching to natural gas aren’t entirely clear. A new study found that using the fuel may do little to curb the shipping industry’s greenhouse gas emissions in the coming decades. In certain cases, it might actually be worse for the climate than another conventional marine fuel, researchers said.
The report, by the International Council on Clean Transportation, or ICCT, adds to the debate about whether natural gas should play a role in the industry’s shift to cleaner fuels.
Costly distraction – LNG
Many environmental groups and academic experts argue that LNG is a costly distraction, one that siphons investment away from technologies that could cut a ship’s emissions to zero, and it locks ships into relying on fossil fuels at a time when climate scientists say we should leave them in the ground. For proponents, the fuel is one of few readily available alternatives to bunker fuel — the longtime industry favorite that is mostly banned from oceangoing ships. Compared to that sludgy old staple, LNG produces much less air pollution and carbon dioxide.
The main problem with LNG is methane, a potent greenhouse gas that traps significantly more heat in the atmosphere than carbon dioxide. The ICCT team found that high amounts of unburned methane can leak from some LNG marine engines. Extracting gas, liquefying it, and transporting the fuel also results in methane leaks and CO2 emissions. Added up over a 20-year period, LNG emits far more lifecycle emissions — between 70 and 82 percent — than “marine gas oil,” a common petroleum product, researchers said.
“That’s the missing part of the equation that [the industry] is not accounting for right now,” said Bryan Comer, a senior researcher in ICCT’s marine program who co-authored the report. “If you account for how much methane is escaping from marine engines, you get a much different picture of what the total climate impacts could be of using LNG as a marine fuel.”
The ICCT study, funded by environmental group Stand. Earth, builds on earlier reports that question LNG’s potential benefits. In 2018, researchers at the University College London’s Energy Institute found that “there is no significant CO2-equivalent reduction achieved through the use of LNG as a marine fuel,” in large part because of the “upstream” emissions from producing natural gas.
“It’s a dead-end,” said Tristan Smith, who researches low-carbon shipping technologies at the institute.
The global shipping industry moves trillions of dollars worth of goods every year and accounts for about 3 percent of total annual greenhouse gas emissions. That number is projected to soar in coming decades if vessels don’t use cleaner fuels. Cruise and cargo ships have historically contributed significant amounts of sulfur oxides and nitrogen oxides, which can damage people’s hearts and lungs, especially in waterfront communities.
In response, regulators have started clamping down on maritime pollution. Since the start of the year, the International Maritime Organization, a United Nations body, requires vessels to burn only low-sulfur fuels. Newly built ships must follow energy-efficiency design standards, while the industry as a whole is working to cut emissions in half by 2050 compared with 2008 levels.
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Source: Grist
