Fast-Paced Strategies in the Race to Carbon-Neutral Shipping

March 18, 2024

With the IMO now having set a net-zero GHG target by or around 2050, and the EU’s emissions trading system which started to hit shipping this year, the race is now on for the industry to find ways of cutting its carbon footprint.

Regulation will be the main driver of change. Shipowners already need to comply with the IMO’s CII and EEXI regulations, and the EEDI for newbuilds, as well as the EU’s emissions trading system (EU ETS), and will need to prepare for compliance with the FuelEU Maritime regulation in less than a year’s time.

But the true zero-carbon options for shipping are still some way from maturity. Given this problem, what are the best strategies for moving quickly to reduce GHG emissions in the short term?

Vessel, Route and Speed Optimization

The first thing for a shipping company to get a handle on is how its current fleet is performing and where improvements can be made.

A wave of digitalization is now hitting the shipping industry, with new services emerging that can provide a much more detailed picture of individual ships’ energy consumption than was previously possible.

These services can come to a view on where, when and how quickly ships should be moving to maximize their energy efficiency and can deliver significant emission reductions as a result at little cost. This will pay immediate dividends in terms of both CII scores for the IMO and costs under the EU ETS for vessels trading in Europe.

Weather routing is another aspect of vessel optimization, predicting weather along ships’ routes to allow them to avoid conditions that would reduce fuel efficiency.

These services also often provide suggestions for where and when to bunker at the lowest price, generating extra savings.

Every aspect of a ship’s performance should be optimized, including its speed, its just-in-time arrival management, its trim, draft and ballast and its on-board power consumption.

Energy-Saving Technologies

Once shipping companies are satisfied that their fleets are consuming as little fuel as possible in their current state, the next stage is to look at what upgrades can be made to reduce consumption further.

This is another burgeoning industry set to bring in many more shipping customers over the remainder of the 2020s.

Air lubrication systems cut bunker use by putting bubbles of air between the bottom of a ship’s hull and the surrounding water, reducing friction.

Retrofits can be arranged to deliver power limitations, propeller optimization and improved hull designs to minimize drag.

Adding carbon capture systems to existing scrubbers may also be an emissions-reducing retrofit becoming available on a more widespread basis soon, although this part of the industry is in its infancy.

Anti-fouling technologies can deliver energy consumption reductions by reducing friction caused by sea life like algae and molluscs building up on ships’ hulls. These technologies include both anti-fouling paints and automated cleaning systems.

Wind-assisted propulsion systems are one of the most promising areas among fuel-efficiency technologies for shipping. A growing number of shipping companies are now installing these systems, which can either directly help with propulsion or generate electricity for use on board.

Some firms are also starting to experiment with solar power arrays on ships’ decks to provide further electrical power.

Any shipping company currently in the process of ordering new ships should be considering some or all of these technologies to add to them from delivery; they are rapidly becoming the norm for newbuilds, and those vessels without them may underperform in freight markets.

And when considering existing fleets, retrofits of these technologies need to be weighed up against the age of the ship, the likely improvement to CII scores or EU ETS costs and how much profit they can deliver over the remaining lifetime of the asset.


When it comes to the current global commercial fleet, one choice for reducing net GHG emissions and complying with FuelEU Maritime in the short term is switching to biofuel blends.

These are typically blends of up to 30% biofuel content mixed with conventional VLSFO, HSFO or MGO, with the GHG savings coming from the carbon absorbed by the biomass used to produce them before it was turned into fuel. The biofuel content is typically HVO or FAME.

Shipping companies have already considered and bunkered B100 (100% biofuels) in order to maximize GHG emissions savings.

Biofuel bunker blends require little or no modifications to existing engines to use, and while their cost is higher than for conventional fuels, they are gaining in popularity and are now available at most of the largest ports.

Shipping customers are also increasingly showing an interest in paying more for services running on biofuels to carry their cargoes, meaning at least some of the extra cost could be recouped from end-users.

Developing a Strategic Future-Fuel Plan

Beyond these more immediate ideas for cutting carbon emissions, shipping firms will also need to move quickly to come up with a plan for their future fleet.

LNG and biofuels are likely to be popular routes in the short to mid- term, with these taking on a growing share of the marine energy mix in the coming years, and bio- and synthetic LNG, methanol, ammonia and hydrogen are likely to gain traction towards the end of this decade. Even as we see more alternative-fueled ships at sea, biofuels will be relevant as a pilot fuel for those ships.

While the markets for zero-carbon synthetic methanol, ammonia and LNG have yet to emerge and mature, it is preferable for companies to make firm plans now for when they will be ordering ships running on these alternative fuels.

Picking one fuel and sticking to it may likely be more cost-effective; choosing methanol, ammonia or LNG and then switching to the other at a later date could result in costly retrofits, as well as missing the opportunity to lock in supply of one of the fuels at lower prices before demand shoots up.

For now, first movers are hedging their bets by opting for dual-fueled vessels that can run on conventional bunkers if their alternative fuel of choice proves to be unavailable at the ports they operate at, or too expensive. This would appear to be a sensible strategy for navigating the next few years while the future energy mix remains so uncertain.