What is the environmental footprint of a ship?

07 Jun 2023 The Navigator

The Nautical Institute’s Head of Safety and Environment, Captain Jeffrey Parfitt, FNI looks at how our environmental awareness has changed over the years, and what makes up a ship’s environmental footprint, shipyard to scrapyard

According to the Organisation for Economic Co-operation and Development (OECD), around 90% of the word’s traded goods are transported by sea, enabling us to enjoy the essentials of living, as well as the more exclusive luxuries on offer. However, global shippingis also responsible for almost 3% of all greenhouse gases (GHG). While sea transport is infinitely more environmentally sound than air transport, it still needs to clean up its act. By adopting an environmentally forward thinking philosophy, ship owners and operators can assist in making our planet a better place to live for everybody - and navigators have a role to play in that.

Welcome to the Fourth Industrial Revolution

We are now in the fourth industrial revolution. This term is often bandied about, but what exactly does it mean? Previous industrial revolutions have brought a seismic change to society. Steam engines transformed the world and we went from sail to engine power. We ushered in new innovations, such as electricity and changes in modern transport. Then came advances in science and mass production, followed by the huge technological expansion – all of these accompanied by social change. Now, we are looking at the next wave of seismic changes, in the form of artificial intelligence and green energy.

Thinking back to my early days at sea, the changes from how we were back then to how we are now are quite astonishing. Back in the mid 1970’s, life at sea hadn’t really changed much for at least 50 years. We were still navigating with sextants, windup chronometers (listening to a daily time signal on the BBC) and log tables – there were no calculators. Some of the ships were from the 1950’s and were derivatives of vessels from the 1940’s, such as T3 tankers (they were good fun though!). Radar targets were hand-plotted and it wasn’t uncommon for a passing ship mid-ocean to request an update on their position. With the technological explosion came daylight radar displays, ECDIS, GPS, dynamic positioning, automation, power management, satellite communication, variable pitch propellers, etc. – advances that you probably take for granted. However, the fundamental method of propulsion hasn’t changed – power-driven vessels still require either steam or diesel engines to turn the large fan and that currently needs fossil fuels. Further, ship construction has become increasingly reliant upon less environmentally-friendly materials that do not break down over time. Plastics and synthetic oils in particular are increasingly used in precision engineering. 

Green shipping

So what does the future look like for green shipping? We already know that the IMO has set a target to cut GHG emissions from ships by 50% by 2050. However, it is anticipated that the IMO will make a further announcement this summer that may see this target revised to 100% by 2050 – across the whole lifecycle of the ship, not just what comes out of the funnel. We need to take a more holistic viewpoint and look at a ship’s carbon footprint, shipyard to scrapyard – cradle to grave.

In the shipyard

There is really no such thing as a zeroemission ship – unless we can return to the age of sail with wooden vessels and equipment and rigging made of iron and natural fibres. But we can do better than we are doing now. Ship owners need to consider a strategy that mitigates emissions through the vessel’s entire life, from construction to recycling. This involves compiling a Life Cycle Assessment (LCA) that would include such elements as: steel production, welding, cutting, blasting, transport of materials, coating and anodes. From such an assessment, all phases of the vessel’s life can be assessed, and the total cost of ownership and the vessel’s projected carbon footprint estimated.

You may ask – yet another book? We already have so many operational environmental log books to maintain on
board: Oil Record Books, Emission Record Book, Cargo Record Book (Noxious liquid substances in bulk), Ballast Water Record Book, Biofouling Record Book, MARPOL Seal Logs and Garbage Record Books. However, an LCA is compiled before the vessel is built.




In operation

There are new technologies being developed to improve environmental and economic benefits. Improvements on ship design inevitably follow, such as hull form and propeller/rudder efficiency. Fuel consumption is high on the priority list, with new greener alternative fuelled ships starting to be built and software monitoring programmes to gauge emissions. The two ‘front runners’ in alternative fuels are currently methanol and ammonia. Such fuels bring huge savings to GHG emissions, although they are not completely emission-free. “Air lubrication” is an interesting concept using a layer of air covering the hull surface to reduce resistance – this is particularly applicable to high-speed vessels.

Recycling: The Green Passport

Many of you will have heard of a ship’s “Green Passport”. This is a document listing all the potentially hazardous
materials utilised on board the vessel, in its construction, equipment and systems [IMO resolution A.962 (23) IMO Guidelines on Ship Recycling 05/12/03]. It is granted to a ship when it is built and accompanies the ship throughout its operational life. Successive owners are required to recordany changes, to maintain the accuracy of the document. Finally, the document is delivered along with the ship to the recycling facility, so that recyclers know what is on board and how to handle it appropriately. Apart from the usual ship particulars, the inventory of potentially hazardous materials should include location, as well as approximate quantity and volume.

Particularly Sensitive Sea Areas (PSSAs)

All these considerations steer us on into the world of practical operations and toward Particularly Sensitive Sea Areas (PSSA’s). What are they? 

PSSA is an area that needs special protection through action by IMO because of its significance for recognised ecological, socio-economic or scientific reasons and which may be vulnerable to damage by international maritime activities [IMO.org].

In other words, your vessel may not be allowed to navigate within these areas and / or special attention should be paid to any restrictions, which may involve SOx emissions or type of cargo carried and local reporting requirements. There are currently 14 designated PSSAs, including Australia’s Great Barrier Reef and the Archipelago of Sabana-Camaguey in Cuba.

This brings us full circle to my earlier comment on times past. Back in the day, we merrily cruised around throwing everything “over the wall” from general garbage to tank washing slops, including crude oil wax sludge manually dug out from VLCC tank bottoms, regardless of location and ignorant of any impact to the environment (as well as the impact to our own health and safety!). Thankfully, those days are permanently over and we are more aware.

Nowadays, people are being educated to be more aware of humanity’s global impact on our fragile planet from an early age. As such, it is incumbent upon the next generation to challenge and improve upon current practice and, in so doing, reverse the damage already inflicted by previous generations and restore nature to its balance. The mission is yours to accept.