aerial view of a container ship

Decarbonising container ships: win big instead of losing large with these five tips

Follow these five top tips from a Wärtsilä expert to help make sure your container shipping business doesn’t get left behind in the race to decarbonise.

It can be hard to know where to start with decarbonising your shipping operations. And if you own or operate container vessels, hesitation can really hold your business back. The sector’s big players are steaming ahead with big investments based on solid, long-term decarbonisation plans. What decisive action are they taking, and how can you make sure your container business doesn’t get left behind?

The container industry is forging ahead with its decarbonisation efforts, and here's some evidence to prove it:

  • As of 2023, 84% of the global orderbook measured in TEU for newbuild container ships is alternative-fuel capable, with liquefied natural gas (LNG) and methanol leading the way.
  • A.P. Moller – Maersk, a container industry giant, aims to transport a minimum of 25% of ocean cargo using green fuels by 2030, compared to a 2020 baseline. In 2023 the company ordered six mid-size container vessels with methanol-capable dual-fuel engines.
  • Seaspan and Hapag-Lloyd have plans to retrofit as many as 60 ships to run on methanol.


Why is container shipping taking decisive action to decarbonise?

If international shipping was a country, it would be the sixth biggest emitter of CO2 in the world. That’s according to a 2017 report from The International Council on Clean Transportation. Beyond the pressing need to decarbonise shipping in general, the container shipping industry has some specific drivers of its own.

  • Container shipping customers are placing tougher demands on shipping providers as they look to reduce the indirect emissions from their value chain (known as Scope 3 emissions). A number of shipping customers are willing to pay a little extra for more sustainable transportation because the increasingly environmentally aware consumers they serve are themselves willing to absorb the extra cost.
  • Fuel costs are not as big a pain point for container operators compared to other shipping segments. In terms of OPEX, fuel can account for as little as 10% of costs compared to 40–50% for bulk carriers and tankers. This makes more expensive alternative fuels like methanol a more viable option for container ships.

You can learn all about the advantages of methanol as marine fuel and the issues that you should consider before adopting methanol in this Insights article: Methanol as marine fuel – is it the solution you are looking for?


Don’t want to be left behind? Here are five ways to stay competitive

There are several operational and technical options open to you to help make sure you keep pace rather than getting left behind. Resident expert Figosta Zhou, General Manager, Technical Sales at Wärtsilä runs down his top five ways.

  1. Many container shipping industry leaders have embraced digitalisation and data-based decision making to help them minimise waste and maximise efficiency. Doing so can free up money to invest in energy-saving technologies that will further improve your vessel’s performance.

    Wärtsilä’s Fleet Optimisation solution (FOS) can, among other things, help you sail safely on the most efficient route as well as monitor the condition and performance of your assets. It also supports just-in-time arrival, which saves fuel and costs by avoiding idling outside ports while waiting for your docking slot to open up.

  2. If your container ship is has a 2-stroke engine designed for higher speeds than today’s market demands, the engine is likely operating at low load. This means it will consume far more fuel and producing much more CO2 than it needs to.

    Radical derating solutions, which involve reducing the engine bore size, can make your engine 10–15% more fuel efficient. One such solution is Wärtsilä Fit4Power, which cuts both fuel consumption and greenhouse gas emissions.
  3. You don’t need to build a new container ship if you want to adopt sustainable fuels that generate lower carbon, SOx and NOx emissions. Instead, you can convert the engines on an existing vessel to take advantage of fuel flexibility.

    For 2-stroke main engines, the Wärtsilä Fit4Fuels conversion platform can help you switch away from fossil diesel to more sustainable alternatives like LNG and eventually methanol or ammonia. This kind of retrofit can extend your ship’s Carbon Intensity Indicator (CII) compliance by as much as five years.
  4. Energy-saving technologies are a popular choice with many container ship operators because they can keep ships productive and competitive for longer and at a far lower CAPEX than investing in a completely new vessel.

    Rudder, propeller and bow enhancements to improve ship efficiency are common in the container ship segment along with hull air lubrication. For example, Wärtsilä EnergoPac includes propeller installation, a streamlined fairing cap and a rudder system with an efficiency bulb. The integrated propeller and rudder design improves your ship’s propulsion efficiency, reducing fuel consumption and emissions.
  5. Why use your auxiliary engines to generate electricity when you can generate it from your main engine and propeller shaft instead? A shaft generator system can improve your vessel’s energy efficiency by between three and five per cent.

    When your container ship is in port, with a shore power connection you can plug into the onshore electricity grid instead of using auxiliary engines to generate power. In many ports in the EU, 50% of the electricity supply is generated from fully renewable sources like wind, solar and hydro.

“The best advice I can give container ship operators is to focus on the low-hanging fruit as a first step,” says Zhou. “This means operational efficiency improvements that are quick and relatively economical to implement. Then look to plan and implement the most appropriate combination of solutions from engine derating, fuel conversions and energy-saving technologies during future drydock visits.

“Decarbonisation cannot be achieved in one shot. It’s a journey that demands incremental investment over the long term,” Zhou continues. “The best course of action is to gather as much real operational data as you can and engage an expert partner like Wärtsilä to help you build a tailored decarbonisation roadmap.”

How can you discover the real CII status of your vessels? How can you plan your path to CII compliance and secure your long-term competitiveness? This white paper has all the answers: Discover the real CII status of your vessels - and how to improve it.

Written by
Charlie Bass

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