Making the Case for Marine Biofuels

January 02, 2024

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by Michael Kass (Oak Ridge National Laboratory/Biodiesel Magazine) The maritime industry is one of the most important transportation sectors, with more than 80% of all goods shipped via large container or cargo vessels that are powered using residual heavy fuel oil (HFO). The global economy is, therefore, closely bound to heavy fuel oil and maritime transport.

Unlike the automotive industry, this sector has not received much regulatory attention until now. Sulfur reductions in residual fuel oils were imposed by International Maritime Organization starting in 2020, and emission control areas were established in the U.S. and northern Europe to reduce shoreline sulfur and particulate emissions from these vessels.

However, maritime transport also accounts for 2-3% of global emissions of CO2, which is significant, especially compared to global aviation. To mitigate marine CO2 emissions, the IMO seeks to reduce greenhouse gas (GHG) emissions from 2008 levels by 50% in 2050. To meet this challenge, the maritime industry is looking heavily at renewable fuels, including biofuels such as biodiesel, renewable diesel, pyrolysis oils, etc., and zero-carbon fuels like hydrogen and ammonia. Some of these fuels, such as methanol, can be synthesized via several routes, including biomass.

Because of the global nature of maritime transport, a multiple-fuel strategy is needed based on regional legislative initiatives, economies and unique bioresources. It’s not a one-size-fits-all approach and will likely mean a higher degree of fuel flexibility than what is currently available. To reduce infrastructure costs and pressure, biofuels have high potential to be used as drop-in candidates for HFO.

Fuels With Low Impact on Port and Shipping Infrastructures
The two most immediate drop-in candidates for HFO are biodiesel and possibly renewable diesel.

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The U.S. DOE’s Bioenergy Technologies Office is also exploring fast-pyrolysis (FP) and hydrothermal liquefaction (HTL) oils, which are collectively referred to as biointermediates, and produced from a large variety of feedstocks. These oils must be heavily upgraded in order to be a distillate drop-in. However, because the large two-stroke crosshead engines used to power the large cargo and container vessels can operate on lower combustion quality fuels, the level of upgrading (and hence cost) necessary to produce a suitable fuel is expected to be lower.

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The Barriers
Barriers can be broken down by technical feasibility, cost and availability.

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Biodiesel blends exceptionally well with residual fuel oils, whereas conventional diesel does not. As for renewable diesel, it shows a more mixed response to asphaltene precipitation. Raw biointermediates have not shown consistent suitability to be reliably blended with HFO; however, our studies have shown that moderate upgrading (hydrotreating and oxygenate removal) improves blend stability.

Aging is another hurdle, but not one we have looked at in high detail.

The second hurdle with regard to infrastructure is compatibility. Biodiesel and its blends with HFO are not expected to have serious incompatibilities with metal infrastructure components, but it would not be surprising if some seals and gaskets have to be replaced. A more serious issue is the high acidity of pyrolysis oils.

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Competition With Sustainable Aviation Fuel
Currently, a key concern is the availability of biomass for fuel production. Sustainable aviation fuel (SAF) is expected to be a large consumer of biomass. Incentives have been established for the production and use of SAF for the aviation industry, but there are none in place for the maritime sector. The maritime community is rightly concerned that most biomass production will be directed toward SAF.

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Biofuels as Pilot Fuels for Zero-Carbon Fuels
It is important to keep in mind that marine engines being developed for zero-carbon fuels require pilot ignition to ignite the main charge. Pilot ignition is currently done for methanol and liquified natural gas-fueled ships using a diesel-like distillate having a high cetane number. These pilot fuels can be up to 5-10% of the total fuel use (which is around 300 million metric tons per year). Therefore, in order to further reduce carbon intensity, biofuels—especially biodiesel and renewable diesel—are heavily being considered for pilot use. READ MORE

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Viewpoint: European marine biodiesel demand to firm (Argus Media)

Excerpt from Argus Media: Marine biodiesel bunkering demand in Europe could rise in 2024, as a result of the International Maritime Organisation's (IMO) first assignment of energy efficiency "grades" for vessels and the extension of the EU's Emissions Trading System to the shipping sector.

Market participants expects firmer marine biodiesel bunkering demand in the first half of 2024 on the back of the new regulations.

IMO's CII regulations means that vessels will be graded from A to E in 2024, which will represent their operational energy efficiency in 2023. Bunkering marine biodiesel can enhance a vessel's rating as it reduces the CO2 emissions from fuel consumption and allow non-compliant ships to avoid fines and increased refinancing costs.

In January 2024 the EU's Emissions trading system (ETS) will cover CO2 emissions from large ships. Using a biofuel component in a marine biodiesel blend will have an emission factor of zero under the EU ETS scheme, making it a lucrative option for shipowners looking to minimise their exposure to EU ETS regulations.

The marine biodiesel market is tiny compared with the conventional marine fuels market, but demand has stayed steady on the year in 2023 at around 520,000t, triple the volumes sold in 2021, according to data from the Port of Rotterdam. This compares with about 6.77mn t of conventional fossil bunker fuels sold at the port in the first nine-months of this year.

Some participants reported that demand for marine biodiesel may firm further in 2025 as shipping firms will have to use ETS allowances covering 70pc of their reported emissions, while allowance availability tightens. The FuelEU maritime initiative which is set to start in 2025, could also support demand.

But others expects a more marginal rise in marine biodiesel consumption on the back of thinning biofuels subsidy tickets values for the shipping sector in Amsterdam and Rotterdam.

New markets

An increasing number of suppliers in the northwest European bunkering hub of Amsterdam-Rotterdam-Antwerp (ARA) have been offering marine biodiesel blends, with a spot market emerging there and also the west Mediterranean.

This prompted the indexation of northwest European calculated biodiesel and very-low sulphur fuel oil (VLSFO) prices and the launch of the first market-led marine biodiesel blend price in the west Mediterranean.

B24 dob Algeciras-Gibraltar is a spot price assessment launched on 1 November, comprising a blend of 24pc used cooking oil methyl ester (Ucome) and 76pc very low sulphur fuel oil (VLSFO). READ MORE