Understanding the biofuels opportunity

Mar 17 2022

Biofuels offer the potential of a zero carbon fuel which can be dropped into current ship fuel systems without any changes. There’s a bit more to it, but it is something shipowners can consider, we heard at an ABS webinar.

Biofuels offer the shipping industry the possibility of a fuel which can be dropped into their current fuelling systems and engines, which is zero carbon. There’s quite a bit more to it, but all the same, it is something which shipowners may wish to consider.


That could be a summary of a webinar held by ABS to explore the subject on Oct 8, together with representatives of the US National Biodiesel Board, a trade association representing biodiesel producers.


The biggest problem is availability of the biofuels. Biofuels are not available in large quantities now. The question is how much the supply chain could generate, should a market exist. But this is very difficult to answer without seeing what the market can do.


Biofuels may compete with other uses of agricultural products such as food. But also, they may not, some biofuels are made from agricultural and forestry waste.


The chemical properties can match existing maritime fuels, so they can be ‘dropped in’ with minimal or no changes. For land applications, a blend of 5-10 biofuel, the rest conventional fuels, is normally used, but a higher proportion of biofuel is possible.


With ammonia and hydrogen, the other possible zero carbon fuels, not likely to be available for 5, maybe 20 years, “biofuels are your best, most competitive option available today,” says Scott Fenwick, Technical Director, National Biodiesel Board.


The emissions picture is not straightforward. Biofuels still emit CO2 when combusted but can be considered carbon neutral because they absorb this carbon from the atmosphere while the plants are growing.


But this only counts if emissions are being assessed on a well (or farm) to wake basis, not a tank to wake basis, and IMO measures such as EEDI are based on tank to wake.


Also there are other emissions to consider in the equation, including emissions which would have been absorbed by plants growing on the land had there not been biofuel plants, and emissions from fuels used in making fertiliser, then transporting and processing the fuel.


The webinar only focussed on liquid biofuels, but there are also biogases such as methane being considered as fuels, for vessels equipped to run on liquefied natural gas.


Fuel availability

The current fuel demand of the global fleet for international trade has been estimated to be 200 to 215m tons a year, with a further 50m tonnes for domestic trade, an ABS spokesperson says.


This compares to the current production capacity of the two most likely biofuels, FAME (Fatty Acid Methyl Ester) with 50m tonnes a year, and HVO (Hydrotreated vegetable oil) being 4.2m tonnes a year. Most of this FAME and HVO is used in road transport.


However, the annual production capacity of biofuels is continuously increasing.


However, the maritime industry does not have much direct influence over availability and cost of biofuels. That is influenced by factors such as government land policies and regulations.


Basics of biofuels

Biofuels is a term for any fuel derived from biomass (plant or animal material), including waste.


The many different biofuels can be classed into fuels which can replace distillate maritime fuel oils, and biofuels which replace residual (heavy) fuel oils, said Meg Dowling, engineer with the Machinery, Electrical and Systems Engineering Department of ABS Technology.


Biofuels which can replace distillates include Fatty Acid Methyl Ester (FAME), Hydrotreated renewable diesel, and Fischer Tropsch diesel.


Biofuels which can replace residual fuel oils are vegetable oil, pyrolysis bio-oil, and hydrothermal liquefaction biocrude.


Many biofuels are named for their production process, she said. For example, “Fatty Acid Methyl Ester” is produced by a process called transesterification, and the feedstock is fats, oils, grease and vegetable oils.


For complex feedstocks, such as lignocellulosic biomass (plant dry matter) a chemical process is required, such as gasification and Fischer Tropsch synthesis, or “fast pyrolysis” (heating up to high temperatures in absence of air). “Hydrothermal liquefaction” is a process for a fuel which needs further liquefaction, under moderate heat and low pressure.


Different biofuels have differing combustion properties and other characteristics.


They can be compatible with existing bunkering infrastructure - so minimum changes may be necessary to use them.


There are some benefits of biofuels over conventional fuels. They have detergent properties, which means that they can help keep the fuel system clean – although this may also mean they “may at first require more frequent maintenance,” Ms Dowling said.


If there is an oil spill, they will degrade quicker than petroleum-based oils.



“The production specifications have shown that biodiesel quality across the globe is better than it’s ever been. It is better than petroleum fuel quality (in many cases),” said NBB’s Mr Fenwick.


A variety of emissions

All biofuels contain carbon and so emit carbon dioxide at the point of combustion. The big question is how much this is counterbalanced by CO2 absorbed when the plant is grown, and other CO2 impacts during the process.


A biofuel has a negative emission where it absorbs CO2 from the atmosphere while it is being grown or protects CO2 from otherwise being released.  But it has positive emissions where it has caused more emission, such as from forestry being cut down to make land to grow them.


There are emissions caused during the production and transport of the fuel, such as fuel for a chemical process. And there are emissions released in the combustion.


One of the most efficient biofuels from a CO2 standpoint can be “biowaste” such as forest residues, used cooking oil. This because any energy inputs into creating it have been accounted for elsewhere.


One ideal feedstock for biofuel is “silvergrass”, which can grow quickly on marginal land, so does not take land use away from other purposes, and “absorbs carbon rapidly when growing”.


A change in land use may be not directly associated with emissions, but there can be indirect emissions, such as a change in carbon content of the soil, or chemicals used.


The more that fuel needs to be transported before loading onto a vessel, the bigger the transport related emissions.


All of this needs to be calculated. Biofuels end up with a wide range of overall CO2 emissions over their lifecycle, Ms Dowling said.


Matt Herman, Director of Environmental Science with the US National Biodiesel Board, recommends that shipping companies do due diligence on their biofuel supplier to find out what the emissions actually are. They can ask for an International Sustainability Carbon Certification (ISCC) or some other form of government certification.


The “Roundtable on Sustainable Biomaterials” (RSB) is a voluntary standard that can be certified by ISCC, to prove the biofuels are sustainable. Sustainable is defined with metrics such as a “significant” reduction in CO2, not impairing food security, minimising pollution and following applicable laws.


Biodiesel and renewable diesel are generally expected to achieve at least a 50 per cent GHG reduction,” Mr Herman said.


Regulatory pressures

There are regulatory pressures to drive use of biofuel, such as the US Renewable Fuel Standards and the European Union Commission Renewable Energy directive (RED) II.


For example, RED II states that a minimum of 14 per cent biofuels or other renewable fuels for transport shall be used in every EU Member State by 2030, while also encouraging use of advanced biofuels, minimising direct land use, Ms Dowling said.    


However, the European and US policies are not consistent, said Scott Fenwick, Technical Director, National Biodiesel Board (NBB). This may cause shipping companies challenges with vessels going from one region to another.


There's a really big opportunity for us as fuel producers and consumers to sit down and work on standardising the environmental assessment,” said NBB’s Mr Herman.


“Groups like the Global Emissions Logistics Council have started to have the discussion, to understand how a carbon intensity which we’re so familiar with in the biofuel industry, can be translated to that industry.”


“Once we solve that, there's going to be a lot more excitement about this.”


Biofuels on ships

When considering biofuels for ships, the important consideration is the actual emission saving and how it compares to other options, and the technical requirements.


The shipping industry uses the jargon “well to tank” to describe the emissions caused in getting the fuel from its source to a ship’s tank. [Although for biofuels the fuel does not come from a well, it comes from land].


The well to tank emissions are calculated by adding up all of the emissions along the chain, which is a complex calculation the fuel supplier should do.


Then the term “tank to wake” is used for the combustion emissions at the ship engine.


Many companies are using the Greenhouse Gas Protocol reporting standard for emissions. This segments emissions from any company into Scope 1 (emissions they directly control), and Scope 3 (emissions from their value chain – purchases and customers). [Scope 2 is mainly grid electricity purchases which shipping companies would only do in a port.]


Under this definition, a shipping company’s tank to wake emissions are “Scope 1” and its well to tank emissions are “Scope 3”.


The list of emissions which could potentially be considered as Scope 3 can be infinite, so in practise shipping companies would set a ‘materiality threshold’, said Matt Herman, Director of Environmental Science, National Biodiesel Board. The emissions they will be most concerned about will be those from production and transport of fuel.


A ship using biofuel can include this in their EEDI calculation under MARPOL Annex VI regulation 22, Ms Dowling said. This includes a factor for the amount of CO2 released by the fuel the vessel is using.


Onboard a ship, biofuel emissions must also comply with IMO’s MARPOL ANNEX VI Regulation 18 for fuel quality, including NOx emissions limits (as for petroleum fuels) and rules on sulphur content. There is still some uncertainty about how this rule will be applied to biofuel, an ABS spokesperson said.


There are some unknowns on how the greenhouse gas footprint of fuels will be captured in future (this is an issue for every fuel). So far, most applications are being done as trials, and discussion with the flag state administration to confirm acceptance and the right carbon factor to use in reporting.


Technical issues for ships

One the technical side, “a lot of shipping companies, engine manufacturers have already done the work behind the scenes to prove that biodiesel works in their engines,” said Scott Fenwick of NBB.


“To date we haven't seen any technical roadblocks from a level of performance, assuming you’re using biofuels that meet current standards.”


“Engine manufacturers have noted that the use of biodiesel in main engines and auxiliary engines do not cause any operational issues, as long as the fuel is managed properly onboard the vessel.”


“Renewable diesel is a hydrocarbon, it is indistinguishable when blended into a (hydrocarbon) fuel.”


Biofuels are being used in the US in vehicles and off-road, onshore applications, without being blended with fossil fuels at all, and at as little as 2 per cent blend, he said.


Biofuels can emit more NO2 per unit energy than hydrocarbons, which may limit the amount of biofuel you can blend with conventional fuel, such as to 50 per cent, Mr Fenwick said.


The move to very low sulphur fuel oil (VLSFO) on a wide scale in the maritime industry in 2020 means that maritime oils have become closer in specification to many biodiesels, which means that there are fewer fuel compatibility issues, he said.


However, it is important that tanker operators pay attention to fuel specifications, and to fuel handling, he said.



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