The cruise industry and the environment

There has been a lot of press recently regarding the environmental impacts of cruise ships.

The cruise and shipping industry are looking to innovate and seek best practice when it comes to being environmentally conscious. Things are changing rapidly, with the lines designing ships to be more efficient and environmental sustainable. So let’s take a look at some of the initiatives being developed and delivered to improve the impact of ships.

Alternative fuels

A lot of ships currently utilise a mixture of different heavy oil fuels, depending on whether they are in port or at sea, which produce differing levels of emissions (particularly sulphur dioxide and other particulates).  Addressing this is a significant challenge and the industry is looking to move away to more sustainable fuels, with older ships being retrofitted with new technology and new ships being built with it in mind from design outset.

Many ships already employ solar energy to power many of the systems on board, for example the lighting, which in turn reduces the need to burn as much fuel.  Whilst this may not seem much remember some of the ships we are talking about look after thousands of guests and the size of small towns, so it all makes a difference.

One upcoming example of fuel for the industry is Liquified Natural Gas, or LNG.  This is a rapidly growing market as LNG tends to be cleaner and more efficient than existing diesel counterparts.  Currently the downside is the cost of storing, transporting and production, however this is changing rapidly and LNG hybrid cruise ships are already in use by Aida Cruises, the AidaPrima and AidaPerla.  More LNG-powered ships are set to be delivered in the coming years by most parent cruise companies, including Carnival, MSC, NCL and Royal Caribbean.

One other source which will be utilised on ships in the near future is the application of fuel cell technology on board.  This is where hydrogen is used in a chemical reaction to produce energy, where importantly there are very few byproducts, of which the main one is water.  Royal Caribbean are looking to trial this technology on existing ships from 2017 and deploy it to its newest ships in the next few years, with the eventual aim to remove the need for a funnel entirely.

Emission scrubbing

Over the past few years the cruise industry has taken an active role in looking to address existing emissions from ships.  One such mitigation is installing scrubbing equipment within the exhaust systems of ships.  This is a neat solution as lines are able to retrofit their existing fleet to bring down emissions.

Scrubbers, or Advanced Emissions Purification Systems, take the exhaust from the ships engines and cleans it.  Jets of salt water are sprayed into the exhaust and the particles of sulphur dioxide react with the water to form sulfuric acid, which is then neutralized by the salt water. The water also causes other debris to drop from the smoke. This water is then treated by filtering and centrifuge to remove the added chemicals and particulates. These systems are or have been installed on a number of ships and multiple lines are looking to do this across the industry. It has been shown that this can reduce more than 97% of sulphur dioxide emissions.

Ship Design

Whilst changing the fuel is one way to address emission concerns, a more intrinsic look needs to be taken at how ships are designed that can help to reduce emissions.  Cruise lines are always looking to develop ships that are more efficient and ultimately burn less fuel.  This is for a number of reasons, including cost, efficiencies and of course environmental protection.  The design of cruise ships is rapidly changing, with hull structures being completely rethought in order to enable it to travel using less energy.  For instance, a number of new ships coming out in the coming years will employ variations of what is known as the inverted bow.  As the name suggests the bow appears to be upside down and significantly increases efficiencies.

The design of a cruise ship hull is understandably complex, and there are many other ways which will look to reduce consumption and emissions overall.  One such innovative system to note is what is called an Air Lubrication System.  This relative newcomer is being rolled out across the industry, where a cushion of air is projected under the ship.  This reduces the friction between the ship and the water enabling it to travel more efficiently through it, in turn reducing the need to utilise energy to propel the ship.  This can significantly improve efficiencies and reduce CO2 emissions up to 10-15%, along with significant fuel savings.

Shore power

One major issue issue for the industry is when ships come into ports and have to continue to use their engines to generate power, potentially producing emissions in the vicinity of populated areas.  Some of the above solutions could be employed to reduce emissions in ports, but one solution that is available now is shore power.

As the name suggests, this is where the ship effectively plugs into the main power grid of whatever port it is in, and so enables the ships to turn off their engines whilst in the port.  This is a great idea, however, the delivery of such a solution has been very slow with only a handful of ports and ships able to provide this.  Principally this is for three reasons, firstly there is no industry standard or regulation for the power interface so ships may or may not be compatible. Secondly it is a very costly process not only for the port but cruise lines as well, and thirdly that there may very well not be the availability of power to support the ship (or that the power would still come from unsustainable sources). However despite this, there is significant potential in its application.

Water treatment 

One area Dispatches focussed on was the discharge of grey or impure water, particularly when ships are at sea.  This has been a big issue in the past, with several lines having been fined heavily for this activity, but it is again something the industry is working to try and address.

Many ships and lines now employ what is called an Advanced Wastewater Purification System.  This advanced systems cleans the wastewater generated on board, with the aim that cleanliness exceeds any wastewater discharge standards.  The way the system does this varies, but can include biological treatment, filtration, disinfection and advanced oxidation. Once the water has been through this process it is recycled through the ship or discharged safely.  Any remaining impurities/sludge are pumped into a holding tank for subsequent drying/incineration or appropriate disposal at land-based facilities.


In order to achieve a standard that excels for the industry there is a need for physical measures as highlighted above, but also appropriate industry, company and ship board policies and regulations to be in place to ensure environmental impact is kept to a minimum and best practise/innovation is embraced.

An example of company policy is through the Royal Caribbean Save the Waves programme.  The sustainability programme is founded through four key principles:

  • Reduce, reuse, recycle – reduce the generation of waste material, reuse and recycle wherever possible, and properly dispose of remaining wastes
  • Practise pollution prevention – It is strictly forbidden to throw anything overboard
  • Go above beyond compliance – Do more than regulations require
  • Continuous improvements – Change is the only constant.  Innovation is encourages and rewarded

It can be easy to fob-off programmes such as this as corporate jargon, but embedding this responsible culture in an organisation can influence its entire business model, as well as customer and staff behaviours which in turn can look towards reducing the impact the industry has on the environment. Influencing behaviour has to be one of the core principles of this change.


This is just a quick canter through some of the schemes that are being undertaken across the industry.  There are many more initiatives being undertaken which collectively will look to create a sustainable industry in the future.



Leave a Reply

Scroll to Top