Researchers at the University of Twente have demonstrated that the production of biodiesel from rapeseed in Europe does not currently offer a sustainable solution to the energy problem. In large areas of Europe, production actually consumes more energy than it yields, the researchers concluded. Farmers use so many fossil fuels and artificial fertilizers for the cultivation of rapeseed that the process is not energy efficient. If they refrain from using them, then the rapeseed yield is low and results in too little energy. Moreover, the researchers found that the most favourable areas for cultivating rapeseed as an energy crop are precisely those areas that are important for food production.
Rapeseed is used for the production of biodiesel on a wide scale, particularly in Europe. The researchers at the UT looked into where the most favourable conditions for the cultivation of rapeseed in terms of energy efficiency are to be found. Energy returns compared to energy investment were low across the whole of Europe.
Energy efficiency can be expressed in terms of Energy Return on Energy Invested (EROEI). Researchers at the University of Twente gathered data on the EROEI values for every EU country and also Switzerland. They did this using expected yields extrapolated from maps showing the suitability of areas for rapeseed cultivation. In Europe, rapeseed biodiesel is produced with EROEI values of 2.2 or lower, while a value of 3 or more is viewed as being the only practicable option.
Competition with food producers
The areas in which rapeseed can be cultivated with the highest levels of efficiency are important areas for food production. A large part of the area that is suitable for rapeseed cultivation in Italy is used for the production of risotto rice, for example, and in Germany farmers use the areas with relatively high energy efficiency values for rapeseed production for the cultivation of wheat and sugar beet.
UT researcher Iris van Duren suggests that the plans for the cultivation of rapeseed need to be supplemented with EROEI maps. "Where rapeseed will be able to grow is not the only relevant factor," explains Van Duren. "We should also be looking at where the cultivation of rapeseed for bio-energy can be efficient. In areas that in theory are suitable for rapeseed cultivation, 37.6% of the area will only be able to produce rapeseed for biofuels with a loss of energy. So in the end, you are actually wasting more energy than you are producing." According to Arjen Hoekstra, another big disadvantage of using rapeseed for energy production is the fact that the water footprint for rapeseed is extremely high.
