Cruise ships are big. The biggest, Royal Caribbean’s 7,600-passenger Icon of the Seas, is 1,198 feet long and has a gross tonnage of 248,336. This floating hotel features 20 decks and offers endless prepared food; large, airconditioned spaces; huge, clean swimming pools; and other passenger comforts that require a lot of energy.
According to Popular Science, each floating hotel can burn up to 250 tons of fuel a day. They are the worst in an industry that accounts for 2.9 percent of global carbon dioxide emissions. Yet, the cruise industry is embracing sustainability tactics. Members of the industry’s trade group, the Cruise Lines International Association (CLIA), have committed to NetZero carbon emissions by 2050.
More cruise lines are expanding their energy strategy and incorporating multifuel engines, testing new fuel cell technology, and adding wind and photovoltaic solutions, including power-shaving battery storage. Lines are testing new propulsion technologies as well as using liquified natural gas to power ships. They are also studying alternative fuel sources looking to run on renewable fuels, including biofuels and synthetic carbon fuels.
https://www.asme.org/topics-resources/content/infographic-cruising-toward-sustainability