The term “biofuels” suggests that fuels produced from renewable raw materials are per se environmentally friendly and ecologically compatible. A comparison of their environmental footprints throughout their lifecycles reveals that not every biofuel is more ecological than petrol or diesel.
The use of fuels made from biomass, so-called biogenic fuels, is climate-neutral since these fuels generate no additional carbon dioxide (CO2). To be able to compare their overall burden on the environment with that caused by fossil fuels such as petrol and diesel, however, the cultivation and processing of raw materials must also be taken into account. Researchers at Empa use life-cycle analyses (LCAs) for this purpose.
80 per cent less CO2 than petrol
Most fuels made from biomass generate up to 80 per cent less greenhouse gas than petrol. Biogenic fuels from waste materials prove to be significantly more environmentally friendly overall than so-called agrofuels. This is the case because the largest proportion of greenhouse gas emissions takes place during the agricultural cultivation of the raw materials, for instance through the pro- duction of fertilisers, the use of agricultural machinery or woodland clearance.
Heavy environmental footprint of agrofuels
Ecological life-cycle assessments reveal that agri- cultural cultivation with pollution caused by the overfertilisation of groundwater, soil acidification or loss of biodiversity is of great consequence. Many agrofuels place an even heavier burden on the environment than petrol. Biogenic fuels from waste materials, however, come off best with a 30-50 per cent smaller environmental footprint. The environmental impact caused by transport is low in terms of both greenhouse gas emissions and life-cycle assessments, provided that efficient means of transport such as ocean-going tankers or pipelines are used.
From cultivation to consumption
Life-cycle analyses (LCAs) enable researchers to compare the overall burden placed by different fuels and production processes on the environment. They take into consideration the entire production chain from the cultivation of raw materials to consumption. The results mentioned here are based on the state of the art of 2004 and must therefore be checked regularly. At present, LCA does not consider economic and social factors for the assessment.
