Cruises have been experiencing a real boom lately. Some travelers have a guilty conscience because the ships consume a lot of energy and emit pollutants. However, some shipping companies are emphasizing their efforts to protect the climate.
The large shipping companies are struggling to strike a balance between environmental and climate friendliness and what is economically feasible. Proudly announced new ocean liners promise to protect the sea, the air and the climate. Is there a dream destination: a cruise without a bad environmental conscience?
New generations of ships are at least reducing their harmful emissions, for example through an efficient energy mix of fossil fuels with battery storage or fuel cells. Many details in ship design and operation on board improve the climate balance. Sönke Diesener from the German Nature Conservation Union (NABU) speaks of “future-oriented solutions”.
Some shipping companies also optimized their existing fleet. “But the cruise vacation is not yet environmentally friendly,” says the NABU officer for environmental policy and transport. Dirty heavy oil still dominates the world’s oceans.
What is bad for the environment about boat travel?
Engines powered by heavy fuel oil damage the environment with the emission of sulfur oxide, nitrogen oxide, particulate matter and soot and contribute to the climate crisis with carbon dioxide emissions (CO2). Low-pollution fuels such as marine gas oil and marine diesel are more expensive and emit only slightly less CO2.
Even the less polluting liquefied natural gas LNG, which is considered a transitional solution to a climate-friendly cruise, only achieves a CO2 reduction of around 20 percent. And it also has disadvantages, as Katharina Koppe from the Federal Environment Agency explains: “During production, transport and operation, however, climate-damaging methane escapes, which reduces the CO2 advantage and sometimes even makes the climate balance worse than that of ships with marine diesel.” If fracking gas is used, the climate balance worsens even further.
Floating small towns also damage sensitive natural areas, for example in the Arctic, even if they drive with low emissions. It should not be forgotten that the crowds of guests from giant ships sometimes overran destinations such as Palma, Dubrovnik or Venice in times before Corona. Venice’s historical foundations were damaged by the water displacement of the giants in the canals. In the summer of last year, the Italian government decided to ban large cruise ships from entering part of the lagoon.
What are the shipping companies doing?
Some shipowners comply with the regulations of the UN organization responsible for shipping, the IMO, with exhaust gas cleaners (scrubbers), which, however, in turn increase energy consumption and the contaminated washing water from which is usually disposed of into the sea. In protected zones and when entering ports, ships powered by heavy fuel oil switch to less environmentally harmful but more expensive marine gas oil or marine diesel.
After all, thanks to scrubbers, nitrogen oxide catalysts and soot particle filters, six ships in the TUI Cruises fleet emit up to 99 percent less sulphur, 75 percent less nitrogen oxide and 60 percent less harmful particles from their chimneys and dispose of the residues professionally on land.
The goals are ambitious. In 2030, the first ships in the TUI fleet should be completely climate-neutral, TUI Cruises boss Wybcke Meier recently told the “Tagesspiegel”. However, there is one big unknown, according to Meier: the sufficient availability of biofuels. In any case, the “Mein Schiff 7”, which is scheduled to go into service in 2024, is being designed in such a way that it could also run on methanol.
Aida Cruises relies primarily on fossil LNG, which could one day be replaced by synthetic or biogenic fuel. Others such as Hapag Lloyd or Plantours use marine diesel. A ray of hope is currently shore power from renewable sources. The connection of the ships in the port makes the operation emission-free in time and reduces noise and vibration.
“Ecologically produced shore power will be very important in the environmentally friendly energy mix of the cruise,” says Harald Zeiss, Professor of Sustainability and Tourism at the Harz University. But while almost half of the ships will soon be capable of shore power or can be quickly converted to it, according to the Association of the Cruise Industry (CLIA), there are only 14 ports worldwide with the appropriate connections, including Hamburg, Kiel, Rostock-Warnemünde, Bergen, Trondheim and Southampton .
How else do cruise ships reduce environmental pollution?
Route changes and economical driving using sophisticated software and drag-reducing outer skin coatings on the hull reduce fuel consumption. New harmless techniques prevent marine growth on the cooling system. Many adjustments are also being made in hotel operations, which consume up to 50 percent of the ship’s energy.
The shipping companies’ environmental reports mention heat recovery, insulation, water treatment and sophisticated waste management with plastic reduction and disposal in recycling plants in the ports. “Some ocean liners have better waste disposal and wastewater treatment than a small municipality,” says NABU officer Diesener. Details such as biodegradable cleaning and care products, optimization of air conditioning systems or energy recovery from the braking energy of elevators and green, fair shore excursions are further steps towards more environmental protection and sustainability.
Norway is currently considered a pioneer on the way to climate-friendly shipping. The Hurtigruten ships run on marine diesel mixed with up to 20 percent biodiesel made from food waste. The shipping company wants to be able to offer emission-free cruises by 2030. The new competitor on the postal route, Havila Kystruten, relies on computer-controlled energy management from LNG plus battery. The ships can travel electrically for up to four hours.
Which routes pay more attention to the environment?
In international waters ships are allowed to sail with heavy fuel oil. For areas close to the coast and special areas designated by the IMO as endangered (Emission Control Areas, ECA), stricter rules apply with regard to the emission of sulfur and nitrogen oxides. This includes the Baltic Sea and North Sea, the coasts of the USA and Canada including the waters around Hawaii and the US Caribbean, some areas in China and generally all EU ports.
In the Antarctic and in the future in the Arctic, ships are not allowed to have any heavy fuel oil on board as a precautionary measure. But one thing is also clear: Anyone who has flown halfway around the world before embarking is already leaving a miserable CO2 balance on board the comparatively environmentally friendly small expedition ships.
What can environmentally conscious cruisers look out for?
There is no longer a current NABU ranking of which ship is the least harmful to the environment. Instead of the ships, as in the past, the nature conservation association now rates the shipping companies according to environmental and climate friendliness. The next ranking will be presented in August 2022. (Here the NABU cruise ranking 2020.)
As a rule of thumb, the newer a ship is, the more efficiently it uses energy. Hybrid forms such as marine gas oil or LNG with batteries or fuel cells are promising candidates. Blended biofuel should come from waste and not from crops. Ships that are connected to green shore power in the port protect the environment and climate. The cruise journalist Franz Neumeier suggests “short cruises in the vicinity and arrival by train” as an environmentally conscious cruise for vacationers.
In fact, long flights greatly ruin the CO2 footprint of the holiday. Then even sailing cruises, where a diesel engine is only used when there is no wind, come off badly. Cruisers can also reduce emissions through their choice of shore excursions. And they can voluntarily compensate for CO2 with an additional amount of money and thus offset the greenhouse gases emitted on their heads during the journey.