Biofuels: Lighting the way to carbon neutrality

Jan. 19 2021

The shift from fossil fuels to carbon-neutral alternatives is underway, as the shipping industry strives to meet the International Maritime Organization’s (IMO) fast-approaching 2030 emissions reduction target[1].

Among carbon-neutral fuel alternatives available today[2], one option is already proving its sustainable credentials across the transportation industry: biofuels.

Biofuels are a sustainable form of energy derived from the harvesting and processing of different types of biomass, including waste, charcoal, wood, fishery and agricultural products. Burning biofuels can have a net-zero carbon impact on the environment[3], and greatly reduces emissions of greenhouse gases (GHG) such as sulfur, methane and ozone.

However, uptake in the marine industry has been slow, with under 1% of the global fleet currently running on biofuels[4]. As this renewable source becomes steadily more available, ship owners, operators and managers will need to consider its pros and cons as an alternative marine fuel.

What kinds of biofuels can ships use?

  • Liquid biofuels such as biodiesel and bioethanol are derived from biomass, and are the most commonly used type of biofuels for ships.
  • Biogas is naturally produced from the decomposition of biomass, which releases a blend of gases, including methane, which can fuel ships.
  • Synthetic fuels, such as synthetic natural gas (SNG), which are created by reforming biomass feedstock using (preferably renewable) electricity, can also be considered biofuels.

Exploring the benefits of biofuels

Biofuels offer a range of advantages for ship owners, operators and managers looking to use a more sustainable fuel source.

First, biofuels are already compatible with modern ship engines.
They can be used to power large or small vessels, whether gas-fueled or liquid-fueled. Deep-sea or short-sea trading vessels can use biofuels, whether fitted with two- or four-stroke engines. Importantly, burning biofuels requires no technical adjustments, added safety measures or design changes to existing ships, making switching to biofuels an immediately actionable solution[5].

Second, biofuels are a convenient alternative fuel source.
Biofuels require no region-specific resources and little specialized infrastructure, and can be produced in any location. Moreover, densely populated areas produce high levels of second-generation biofuels (e.g., food residue, human waste), providing a constant source of biomass. This enables biofuels to be produced locally, minimizing the time required to deliver to port and limiting emissions from transportation and distribution.

Finally, biofuels are likely to benefit from a supply chain with fewer emissions.
Biofuels depend on the production of resources such as crops, forests and waste, sectors whose green credentials are frequently scrutinized. Sustainable farming and forestry, responsible land use and waste management are increasingly expected along the agricultural supply chain.
Biofuels benefit from these earlier stages of production, participating in an environmentally conscious supply chain.

What are the first, second, and third generation biofuels?

  • 1st generation biofuels or “conventional” biofuels are unprocessed, organic materials grown for fuel production purposes. The sugar, starch and oils obtained from these resources are converted into biodiesel or bioethanol.   
  • 2nd generation biofuels are either the byproducts of other biomaterials (e.g. solid waste, agricultural residue) or the products of non-arable land intended for use as biofuels.
  • 3rd generation biofuels come from microorganisms such as algae; oil is extracted from these organisms for use as biofuel, a process that offers high yields and requires little maintenance.

Where biofuels need to improve

Many marine stakeholders hesitate to use biofuels, seeing it as only a partial solution for meeting IMO’s sustainability targets. Current predictions hold that biofuels could supply fuel for at most 30% of the global fleet, due to factors like cost, production levels and sustainable production.

For the moment, biofuels are more expensive than fossil fuels and may remain so in the short-term. Numerous factors can affect the price of biofuels, including operating costs, production scale, availability of infrastructure, feedstock prices and the cost of local resources[1]. Until biofuel production becomes more uniform and common, it will be difficult to achieve competitive costs.     

Assessing the sustainability of biofuels is another hurdle, as there is currently no globally agreed-upon certification or standard for verifying the end-to-end green production of biofuels. Fuel traceability in Europe is largely determined using the EU RED II framework, which outlines sustainability and GHG emission criteria for the transport of bioliquids.

While this is a good start, proving biofuels’ green credentials across the complete supply chain remains an elusive goal. Verifying traceability and renewable feedstock – using a blockchain approach, or holistic certification systems like the ISSC – will be paramount to cementing biofuels as a clean future fuel.

Ship managers also need to account for a handful of biofuel-specific technical challenges such as oxidation stability, cold flow properties, and the risk of microbial growth. Also, for certain types of engines, ship managers may need to choose a different lube oil.


Hopper dredger, ALEXANDER VON HUMBOLDT classed by Bureau Veritas, is the first to sail 2,000 hours on 100% sustainable marine biofuel, Credit: Jan de Nul


Starting strong with mixed fuels

For maritime stakeholders who are uncertain about committing to biofuels as a fuel solution, mixed fuels are another possibility. By mixing traditional carbon fuels with biofuels or synthetic fuels, known as “drop-in” fuels, ship owners can take a pragmatic step towards lowering their emissions.

Ships can burn mixed fuels without encountering technical, safety or regulatory difficulties, and ship operators can avoid questions of port-by-port biofuel availability. As part of mixed fuels, biofuels can provide a workable entry point into carbon-neutral shipping for ship owners, operators and managers.

Building the bridge to 2030

Marine stakeholders have a little less than a decade to reach IMO’s first major sustainability milestone, and market pressure is pushing ship owners to adopt biofuels well before 2030.

While many long-term renewable solutions are under development – including ammonia, hydrogen, fuel cells and batteries – biofuels are one of the only carbon-neutral fuels readily available today. And with 15% production increases expected in the next five years, and key market growth in Asia, biofuel availability will only improve in ports worldwide[1].

Though biofuels may never be the shipping industry’s dominant fuel, they are an indispensable stepping-stone on the path to decarbonization. For ship owners looking to advance their fleets into the next stage of the energy transition, biofuels offer an accessible, carbon-neutral solution.


Head of the Energy Department

Jan de Nul

On the technical side, we’re confident in biofuels; engine inspections after 2,000 hours running on 100% biofuel did not show any difference compared to running on marine gas oil. But from a commercial perspective, you have to take things day-by-day, as the cost of biofuels is hard to predict – especially in the current low-price environment for fossil fuels. This makes the real challenge with biofuels convincing clients to choose a sustainable path in an uncertain pricing environment.


[1]At least a 40% reduction of CO2 emissions per transfer work per ton-mile traveled compared to 2008.
[2] Carbon-neutral when produced sustainably throughout the supply chain
[3] The CO2 biofuels release is reused to grow the next generation of biofuels sources
[4] Backing biofuels: will the shipping industry ever get on board?, ShipTechnology.com, October 2018
[5] Once certain operational points are accounted for (e.g., microbial growth, inferior cold flow properties, risk of oxidation)
[6]Advanced Biofuels – Potential for Cost Reduction, IEA Bioenergy, 2020
[7] Transport Biofuels – Tracking Report, International energy Agency, June 2020