Post #31 Fuel Efficiency for Cruise Ships

I like the ocean & have been a passenger on about 35 ocean cruises. My reference to “bluer” ocean cruising in this post means better for the ocean & kinder to marine life. Aiming for constant improvement there. Following are: some of my personal thoughts after research; your own thinking & conclusions are also necessary.

Burning less fuel overall is a great goal. Comment seen: cruise lines are investing in new technologies to improve fuel efficiency thus reducing environmental impact. Let’s learn a bit about greater fuel efficiencies. Some infos. I found (including progress) follow.

As with an automobile, the amount of fuel consumed by a cruise ship varies, even day to day “greatly depending on several factors”. Largest cruise ships like Royal Caribbean’s Oasis-class vessels (the newest one of these has capacity: approx. 10,000 people) might consume “up to 250 metric tons of fuel per day”. That much fuel sometimes (often?) necessary to propel such huge ships through the water plus generate electricity for all those aboard.

In the design stage: Hurtigruten, Norwegian cruise company: has revealed “an ambitious design for a *zero-emissions* cruise liner” [size: 500 passengers + crew]. To have “retractable ‘wing sails’, 16,000 sq. feet of solar panels, & 60 megawatt batteries”, & company aspires to have one “traveling the Norwegian coast by 2030”. When docked, the ship could recharge its batteries on Norway’s “98% renewable electricity grid”. Sounding impressive to me.

In the works: New Celebrity Cruises ship is to have their first “Flex Fuel Engine”. If/when using such tri-fueled engines which can run off of 3 different types of fuel including methanol “our ships will be ready to adapt & drive the industry forward to a more sustainable & net zero emissions future” said President & CEO of Royal Caribbean Group. Inaugural passenger cruise for this 5th Edge Class ship which appears to be the “Celebrity Xcel” which is currently scheduled for Nov., 2025.
For this Celebrity ship, Finnish engine manufacturer/technology group Wärtsilä is to deliver 2 converted 8-cylinder Wärtsilä 46F engines (are in Wärtsilä’s order book). Local emissions including “sulphur oxides (SOx), nitrogen oxides (NOx), & particulate matter” said to be significantly reduced. Per their President & CEO: “Wärtsilä has invested heavily into researching viable future carbon-neutral fuels for the marine industry, & methanol [is] one of the most promising candidates”.

Per a 2022 review article, the “Wärtsilä 31DF dual-fuel engine [was then] regarded as the world’s most powerful ship engine”, & that engine is/was said to have “a low level of exhaust gas emissions”. Reported: recent upgrades to this engine had then “lowered greenhouse gas emissions by near about 750 tons per annum”. This corresponded to “85,000 pounds of oil being saved in a day” in the case of that particular engine (compared to a diesel version).

Another engine (&/or series), made by MAN Energy Solutions, was analyzed by a reviewer a few months ago as the most fuel efficient engine(s): “the MAN B&W ME-GI & ME-LGI Series”. Per MAN’s website regarding the MAN B&W ME-GI series: “highest efficiency, lowest methane slip”. Also noted there:
– “The ME-GI series … suitable for LNG (Liquefied Natural Gas) .. The ME-LGI counterpart is designed to run on liquid gas fuels such as methanol, LPG, & dimethyl ether”; &
– Using cleaner fuels, “the ME-GI & ME-LGI engines produce significantly reduced CO2, NOx, & SOx emissions [&] particulate emissions are also minimal.”

& More possibilities/ideas: From research article “Reduction in greenhouse gas & other emissions from ship engines: Current trends & future options “, published Jan. 2023:
– “Several technologies [are] already capable of meeting present & future shipping emission regulations & with further development enable (near-)zero-emission shipping”.
– Immediate impact is achievable with solutions fitted into existing ships (or with retrofitting, because lifetime of ships is long). E.g.: “for methanol use, diesel engines can be retrofitted”.
– Other “potential future alternative options include: “hydrogen (fuel cells), ammonia, batteries & wind’.