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Guide to Green Shipping: Reducing Ship and Boat Pollution

Like every other industry, the shipping industry is under pressure to reduce its emissions and generally reduce its negative impacts on the environment. The move towards green shipping, much as in the car industry, has also been motivated by historically high fuel costs that have driven the search for efficiencies in fuel consumption. The happy by-product of this is lower emissions and less ship and boat pollution. So, what does green shipping look like these days, and how is it achieving the environmental goals set for it by regulators and concerned shareholders? Here’s a quick tour of what shipping operators and regulators are doing to promote green shipping, from hybrid propulsion and slow steaming to the introduction of ballast water treatment systems.

Green shippingPart 1 – Reducing carbon emissions

More efficient ship designs – Modern design techniques like CFD (computational fluid dynamics) create ships that slip through the water more efficiently. Less resistance means lower fuel consumption.

Lightweight materials – If a vessels weighs less for a given size, it needs less power to drive it. Steel is still the material of necessity for larger vessels, but aluminium and the increasing use of composite materials in smaller, high-speed craft are playing their part in green shipping.

Hybrid propulsion systems – Using diesel generators to make electricity that drives the propellers is a more efficient use of fuel than direct drive in some circumstances, particularly for workboats like tugs that idle their engines for long periods of time. Storing the energy in batteries also allows the ships to move with zero emissions when needed, such as when manoeuvring in harbours within cities. Hybrid systems are gradually being adopted, although they are currently more expensive than conventional alternatives.

Clean(er) fuels – LNG (liquefied natural gas) is much cleaner than fuel oil and diesel. Hydrogen is the Holy Grail of zero emission propulsion. Early days yet for these, but vessels using propulsion systems powered by these fuels are starting to be used, particularly on inland waterways. However, container ships and even cruise liners are getting in on the act. Find out more here.

Green shippingWind assisted propulsion – Sadly not a return to sailing ships, but the use of wind power to help drive vessels across the oceans has long been the subject of research. A number of different systems are being studied and, in some cases, trialled. Sails, kites and rotors are all being looked at as ways of supplementing traditional engine power, but the unpredictability of wind and the challenges presented by bringing back masts and running rigging make it a niche technology at present.

Going slow – It does save fuel, as anyone who drives a car knows. At times of high fuel costs, reducing steaming speeds – ‘slow steaming’ – can deliver big savings, particularly for large container ships. It also reduces emissions. Time is, however, money; introducing permanently lower speeds would require more vessels to maintain cargo volumes, leading to higher inventory costs.

Part 2 – The wider environment

Ballast water treatment systems – The drive to prevent invasive marine microorganisms hitching a ride from one ecosystem to another in ships’ ballast tanks takes a critical step forward in September 2017 when it becomes mandatory for (almost) all long-distance vessels to carry treatment systems that kill the microorganisms entering and / or leaving their ballast tanks. This is called the Ballast Water Management Convention and is a major victory in the battle to preserve the oceans’ biodiversity. Concerns do remain however that biofouling on ships’ hulls still gives microscopic plant and animal life a way to travel the high seas unimpeded.

Water and waste processing – The dumping of domestic and other ship waste products at sea is prohibited under various international and local regulations, although it can be hard to enforce, particularly in open ocean. Holding tanks for disposal ashore and onboard waste treatment systems ensure that a vessel does minimal harm as it moves through the sea.

Green shippingShip disposal – Breaking up and recycling ships at the end of their lives is dangerous and dirty work. It is often done in third world countries where health and safety regulations are not always rigorously enforced. Ships contain many hazardous materials that can pose a risk to both the environment and workers’ health. However, matters are improving as international standards are agreed, and owners realise the reputational risks of not acting responsibly.

Getting international agreement on a cleaner shipping industry is slow work, but good progress is being made, aided by responsible owners and new technology.