Bioethanol: time to stop comparing apples to oranges

What about using biofuels to replace fossil fuels? Let’s not be too hasty! From a strictly environmental point of view, this is not always a win-win process. Indeed, if we are to succeed in comparing like with like, many other factors need to be taken into account such as the reduction of greenhouse gases which is required by European regulation. If we want to objectively consider all the environmental impacts of biofuel, one method in particular seems appropriate: Life Cycle Assessment. Implemented by a chemical engineer at the University of Liege, this method has yielded informative results with regard to the use of bioethanol.

Perhaps you are familiar with “E 5”? This is the technical name for a mixture of petrol and bioethanol as used in several European countries including Belgium. A gasoline-powered car uses fuel which is composed of 95 % traditional petrol and 5 % bioethanol. Whatever the mixture may be (sometimes, the proportion of bioethanol can be as high as 85 %), bioethanol is most often produced from sugar beet. However, corn, wheat or sugar cane are also sometimes used, the latter being used in South America, in particular, where it grows in abundance. In fact Brazil has been one of the main producers of bioethanol in the world for more than forty years. Over there, motorists are able to get around thanks to a fuel mixture which is rich in “green” fuel. Biofuels (also called agrofuels) are also very popular in North America. In the US, plant fuel is mainly produced from corn and wheat. The same applies in Europe although over here we can add sugar beet to the list of raw materials most commonly used to produce biofuels.

The use of these non-fossil fuels is good for economies that are dependent on fossil fuel energy. It also represents an interesting alternative from an environmental point of view because it results in a reduction of greenhouse gas emissions. However, we will need to be very cautious if we are to succeed in this noble objective.  If we transform carbon-rich soils into areas for growing the raw materials for biofuel, the carbon can be released into the atmosphere and we do not reach the target levels. Even worse, we are doomed to failure, for example, if the fabrication process for factory-produced biofuel uses a lot of fossil fuel because this also contributes to high levels of greenhouse gas emissions (GHG). This is why the following important European regulation was passed: in order to be accepted for use in our tanks, biofuels must lead to a reduction of at least 35 % of GHG in relation to fossil fuels. A note of caution here: it is the entire life cycle of biofuels which is targeted here, including the fabrication procedure and direct land use change (LUC) resulting from the decision to grow the raw materials for these fuels.

This environmental condition, which is part of an EU directive, could also be extended to include other factors. This is because the impact of biofuel fabrication on the environment is far from being merely limited to greenhouse gases. Growing crops such as corn, wheat, sugar beet and sugar cane inevitably has consequences for water-use, the conservation of biodiversity or the emission of other pollutants not to mention the fact that industrial transformation requires the use of various chemical products. All these environmental impacts must be taken into account when the ethanol produced by plant fermentation is used for the fabrication of a fuel, but also when it is used for the fabrication of ethylene (1), the monomer necessary for the plastics industry which we refer to as the “bioplastics” sector.

From the sowing stage to incineration

This is where the work of Sandra Belboom, a teaching assistant in the Department of Applied Chemistry at the University of Liege, comes in. In her recent doctoral thesis (2), the young researcher wanted to pursue as far as possible – that is to say, from the most reliable data available at the current time- an analysis of the environmental impacts of the production of bioethanol and bioplastics. “My ultimate objective consisted of identifying the best possible use of bioethanol according to the type of raw material used. To do this, I used the “Life Cycle Assessment”, (LCA). Standardised by the ISO and guided by the European Union, this tool has the advantage of taking into account the entire life cycle of a product from the planting and cultivation of the plant concerned to the end product (for example incineration if it concerns a bioplastic), this includes factors such as transportation and transformation etc.”. 

The researcher modeled around fifteen different scenarios based on three elements: raw materials (wheat, sugar beet and sugar cane), the place of growth and transformation (Europe- more precisely Belgium and the Ukraine- on one hand, and Brazil on the other), and finally, the type of use of bioethanol (biofuel or bioplastics).  “The choice of Brazil was imposed by the fact that this country has a long tradition of sugar cane growing and because it has an important production capacity for the two types of use. In addition, given the growing demand for biofuels across the world, the countries of Europe could turn to this country in the future for the importation of finished products”. The choice of Belgium is an obvious one, to the extent that the European objective for biofuel use consists of maximizing the use of local resources and reducing the importation of raw materials to encourage increased energy independence. In addition, there is a sizeable amount of robust and reliable field information that has been validated by experts who were consulted by Sandra Belboom both at Gembloux Agro Bio Tech and at the Belgian Beet Research Institute (IRBAB). The choice of Ukraine was justified by the wish to compare the situation in Belgium with a European agricultural region reputed to have enormous areas of croplands but having low yields. 

Apart from a review of the abundant international literature relative to bioethanol (3), the work of Sandra Belboom has consisted in modeling the environmental impact of the principal stages of bioethanol production: planting, transportation of crops to the factory, transformation into hydrated bioethanol, the conversion of the latter into fuel or bioplastic and the end of life. Particular emphasis was placed on land use change, whether directly (for example, the transformation of a forest or grassland into crops grown for energy) or indirectly (shifting crops to other soils leading to land use change).  What emerges from this?  “From the perspective of greenhouse gas emissions and the exhaustion of fossil fuels, without taking account of direct and indirect land use changes, both the bioplastics sector and the biofuels sector are more advantageous than the traditional sectors (Editor’s note : that is to say fuels from fossil resources), and this applies regardless of what raw material is used (4). With regard to the bioplastics sector, high-density polyethylene (HDPE) produced from sugar cane is the most advantageous, despite the constraint of transporting this product from Brazil to Belgium. This is directly followed by the HDPE from Belgian crops. Among the latter, sugar beet is ahead of wheat because it makes it possible to produce more bioplastics per unit of surface area. On the other hand, if we take account of land use changes, local crops- in this case wheat and sugar beet- are to be preferred to sugar cane and crops grown in the Ukraine”.

Another conclusion can be drawn from this modeling: if we take account of impact categories other than GHG emissions and the exhaustion of fossil resources such as ecotoxicity, acidification of soils and eutrophication of water by waste pollution, it becomes clear that the fabrication of bioplastics leads to more damage to the environment than the traditional plastics sector. This applies regardless of the raw material in question.

No need to call BioWanze into question

Finally, we come to the third main category of results: the payback time for climate change. This is the number of years necessary so that a crop that is “economic” in greenhouse gas emissions compensates for its negative effect in terms of land use change. Therefore, if we take account of GHG emissions caused by deforestation linked to the cultivation of Brazilian sugar cane intended for use as biofuel, the payback time varies between 39 and… 152 years (in the event of indirect changes in land use). For Belgian crops used as biofuel, indirect changes in land use concern the transformation of grassland into land for the cultivation of wheat or sugar beet in other countries of the European Union  (on condition of obtaining a dispensation from the Common Agricultural Policy). Within this prospective framework, the payback times calculated are much shorter, that is to say, 14 years for wheat and 10 years for sugar beet.  In the case of bioplastics, the payback times vary between 26 and… 101 years for sugar cane (indirect changes here too). The payback times are 31 years for sugar beet from Ukraine and 8 years for Belgian sugar beet. For Belgian wheat it is 14 years. 

Such conclusions do not call into question the construction of production units for bioethanol such as the one for BioWanze, far from it indeed. In order to produce its 300,000 annual tons, this factory in the Mosane region uses strictly local sugar beet and cereals from an area within a radius of less than 300 kilometers. However, according to changes in the commodity market, the work of Sandra Belboom, extended to take account of the wider macroeconomic implications, could be useful for the various decision-makers. The history of biofuels which certain environmental organizations prefer to call agrofuels (thus distinguishing them from the protection of being labeled as “biological”), has certainly not been plain sailing.  The European Commission, for example, recently proposed to change the obligatory proportion of biofuel involved in transport from 10% to 5% by 2020.  Objective: to halt the worrying phenomenon of land-grabbing in Southern countries through which investors substitute energy crops for traditional crops causing an explosion in basic food prices and resulting in serious social problems for farmers.

Such considerations have evidently not been taken into account in the work of Sandra Belboom. “It is evident that the aspect I studied, which was strictly environmental, should ideally be completed from the perspective of sustainable development. We can well imagine that the same approach – life cycle assessment – serves as a back-up to economic and social analyses. Ultimately, a comprehensive analysis of this type should also be possible for second-generation biofuels (plant waste, sawdust from mills, etc.)” There is no doubt: given the energy and climate crises, that we have not heard the end of discussions about bio or agrofuels…

(1) By extracting a molecule of water from bioethanol- known as catalytic dehydration, we obtain bioethylene which can be used for the manufacture of plastic.

(2) “Assessing the environmental impact of bioethanol production from sugar cane, sugar beet or wheat by life cycle assessment. A comparison of the uses of biofuel and bioplastics.” 
(3) The literature on the bioplastics sector, which is quite new, is much more limited than the literature on biofuels.
(4) In this situation, we do not take into account the changes on international markets which could result from a decision to favor the production of plastic on a grand scale.