Which are the most sustainable biofuels?

Advanced biofuels are in the news as the EU considers the role of biofuels in transport post 2020. The Commission recently published ‘A European Strategy for Low-Emission Mobility’ 1, which confirmed the need for biofuels for de-carbonising transport, particularly aviation and heavy-duty transport into the future. The phase-out of food-based biofuels was confirmed although it will be ‘gradual’ with the aim that advanced biofuels take their place.  They also acknowledged that the development of advanced biofuels would need to be incentivised, as without support they can’t compete with other biofuels. A blending mandate for advanced biofuels has been suggested.

The Commission’s thinking about food and advanced biofuels has been set out in the ILUC amendment to the Renewable Energy Directive (‘ILUC Directive’)2  .  Advanced biofuels are perceived as more sustainable.  So, as Europe aspires to replace food-based biofuels with advanced biofuels, lets look closer at their sustainability credentials.

Defining advanced biofuels

The ILUC Directive loosely defines advanced biofuels as those with low indirect land-use change (ILUC) impacts and high greenhouse gas (GHG) emissions savings. A positive list of feedstocks and fuels is included in Annex IX of the Directive, clarifying what advanced biofuels can be made from. These are mainly industrial and agricultural wastes and residues, but also included are algae, bacteria and energy crops plus ‘renewable’ fuels made from e.g. hydrogen or waste carbon dioxide providing the energy input is renewable. 

Interestingly, there is also a declaration in the ILUC Directive that not all food-based biofuels actually cause ILUC.  This is an admission that the situation is not black and white. Better farming practices such as yield increases and intercropping can produce food-based biofuels with no ILUC. Neither does the cultivation of under-used land for food-based biofuels cause ILUC. In these cases, the extra economic incentive of biofuel production has encouraged farmers to increase yields and bring unused land into production. These biofuels can also have high GHG savings.

In summary, some food-based biofuels do not produce ILUC and have high GHG savings, just like advanced biofuels.

Sustainability is key

The attributes of advanced biofuels and the best food-based biofuels can be similar as discussed above. We should therefore focus more on sustainability criteria. It would be logical to promote and incentivize biofuels according to their sustainability, rather than using an imperfect categorization between ‘advanced biofuels’ and the rest. 

The most important sustainability criteria of biomass and biofuels are:

No deforestation or destruction of highly bio-diverse or high carbon stock areas

High greenhouse gas emissions savings 

Protection of the wider environment 

Respect for people’s land and labour rights

Does not cause ILUC

Lets look at each of these criteria to see how advanced biofuels score relative to food-based biofuels.

No deforestation or destruction of highly bio-diverse or high carbon stock areas is a key concern. Direct land-use change like this is already covered in the original Renewable Energy Directive (RED), which prohibits conversion of these types of land after 1st January 2008. The rule applies both to crop based biofuels e.g. food and energy crops and agricultural and forestry wastes. It is a key pass/fail criterion for sustainability certification. Increasing availability of satellite tracking technology means that direct land-use change can be verified more easily. Conversion of bio-diverse and high carbon stock land is a high risk in countries which have large areas of primary forest or highly bio-diverse grassland. As the rule against conversion of this type of land rightly applies equally to both crops and agricultural wastes/residues, it is a key sustainability risk for some advanced biofuels. Feedstocks such as waste fats and oils or municipal waste are not directly associated with land based production so are free from this risk. However intermediate type of wastes e.g. PFAD (palm fatty acid distillate) which is produced from palm oil processing, is arguably providing economic returns to the palm industry and could be associated with deforestation.

Some feedstocks for advanced biofuels carry a risk associated with deforestation, which is a key pass/fail for sustainability certification.

Greenhouse gas emissions savings: The raison d’être for biofuels is to save GHG emissions. Germany is already incentivizing biofuels based on their GHG savings and it would make sense for other European countries to do the same.  Incentives in the US and California also encourage biofuels with high GHG savings.

Surprisingly there is no figure in the ILUC Directive for the greenhouse gas emissions savings that advanced biofuels should achieve. They just need to achieve the same savings as other biofuels, which will be 60% for new facilities and 35% rising to 50% for existing ones. The reason for this omission is not clear. Perhaps it is because some advanced biofuel processing routes are multi-step and can be relatively greenhouse gas intensive. Also, advanced biofuel processes are just being commercialized, so that yields have not yet been optimized. Low yields are bad for GHG savings. Conversely, food-based biofuels can have high GHG savings where cultivation and processing are optimised. The best sugarcane ethanol can achieve 80%-90% savings or higher (or 65% -75% after subtraction of ILUC factors). 

Waste and residue based biofuels processed using established technology have very good GHG savings (greater than 80%-90%) as, unlike crops, they are assumed to have a zero GHG intensity at the point they are generated. GHG intensity due to transport and processing are the key inputs to their overall GHG intensity. However some processing and agricultural residues may have to carry a proportion of the GHG intensity of the upstream processes into the future as policy evolves, leading to a reduction of their GHG savings.

Food-based biofuels can have high GHG savings and the GHG savings of advanced biofuels can be reduced by multi-step processing and inclusion of some upstream emissions. 

Protection of the wider environment, people’s land and labour rights are aspirations in the RED, which are not reflected in concrete requirements. Although these aspects are largely covered by other European legislation, they may not be protected in other parts of the world. A recent appraisal of the Commission’s oversight of biofuel sustainability   by the European Court of Auditors 3 criticized the omission of these sustainability criteria. They are equally important for energy crops and agricultural wastes.

Preservation of soil quality and carbon content is also a key sustainability consideration for agricultural and forestry residues. Leaving some residues on the soil can improve soil quality and increase the soil carbon-stock. Excessive removal should be avoided. There is currently no requirement for this to be monitored. 

Advanced biofuels from energy crops and agricultural wastes carry a risk of impacting the wider environment and people’s rights. 

Does not cause ILUC: The push towards using wastes and residues for biofuels is at the heart of the Commission’s strategy to avoid ILUC. However, some bio-wastes and residues already have uses in other industries e.g. for animal feed or for chemicals. Something that is a waste in one region of the world may not be elsewhere. So, if the existing use has to be replaced from another source this could generate ILUC or be satisfied by a fossil based source of carbon. On the other hand, the ILUC Directive describes food-based biofuels from increased production and intercropping that are ILUC free.

So some advanced biofuels from wastes and residues may cause ILUC and there are ILUC free food-based biofuels.

Sustainability verification

Sustainability verification of biofuels is carried out by Voluntary Sustainability Schemes, together with EU countries’ own systems. The biofuels with the highest risk of falling short on sustainability are from countries where EU Standards of human and worker rights, environmental, forest and biodiversity protection are not necessarily upheld. Focusing on advanced biofuels made from processing residues, municipal waste and agricultural and forestry residues may reduce these risks, but it won’t eliminate them. If agricultural straw or energy grasses take the place of cereals or sugars for bioethanol then shouldn't we also examine the conditions on the farms where they are produced?  The best Voluntary Sustainability Schemes, typically those that are multi-stakeholder and NGO approved, robustly audit all of these aspects. Unfortunately, these Schemes currently certify a minority of biofuels. 

As the focus shifts to wastes and residues, and these have the advantage of designated zero GHG intensity (and extra incentivisation), then it will become even more important to verify that biofuels are verified and labeled correctly. At the bottom of the supply chain, how easy will it be able to distinguish between ethanol from straw and ethanol from a cereal, for example? This places even more emphasis on tracing waste materials up the supply chain and ensuring that all Sustainability Schemes have the highest auditing standards. 


There is an acknowledged role for biofuels to decarbonize transport post 2020, particularly for aviation and heavy-duty road transport and Europe is looking to ‘advanced’ biofuels to fulfill this role. Europe should promote and incentivize biofuels according to their sustainability.

Limiting ILUC is important and low ILUC food-based biofuels should also be able to play their part in de-carbonising transport. Those food-based, low ILUC biofuels that achieve high GHG saving should be incentivised, as high GHG savings are the ultimate goal.

The protection of the wider environment, people’s land and labour rights should be included as required sustainability criteria for all biofuels including those from energy crops and agricultural wastes.

This article was first published in Biofuels International.

[1] http://ec.europa.eu/transport/themes/strategies/news/doc/2016-07-20 decarbonisation/com(2016)501_en.pdf


[3 ] http://www.eca.europa.eu/en/Pages/NewsItem.aspx?nid=7172

Published: 13 September 16

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