One litre of biodiesel costs 14,000 litres of water

Biofuels carry a heavy water footprint, although the size of that print varies widely from crop to crop, according to new research from the Netherlands’ University of Twente.

Researchers at the university analysed 13 crops to determine the optimal production regions for each based on water consumption and climate date. Their goal was to make it easier to prevent biomass cultivation from jeopardising food production in regions where water is already in short supply.

The researchers found, for example, that it takes an average of 14,000 litres of water to produce one litre of biodiesel from rapeseed or soya. However, the water footprint for rapeseed in Western Europe is significantly smaller than in Asia. For soya, India has a large water footprint, while the figures for countries such as Italy and Paraguay are more favourable.

Jatropha, which is increasingly used for biomass production, has an even less favourable water footprint of 20,000 litres of water on average for one litre of biodiesel.

Using whole plants to generate bioelectricity, on the other hand, requires a smaller water footprint than using crops to make biofuels. Even then, however, crop footprints vary. For example, the researchers found that, when used for bioelectricity, sugar beet has by far the smallest water footprint, while jatropha is 10 times less water-efficient.