Calculating the footprint of biofuels

How to measure and ensure that biofuels fight climate change

Experts estimate that a reduction in the order of magnitude 45 Gt CO₂emissions by 2030 is needed to keep the global temperature increase below 2 degrees. With sustainable production processes, biofuels can contribute significantly to this goal.

Estimating the carbon footprint of biofuel is complicated. To establish a strong platform for the sustainability of biofuels, there is a need to distinguish between different contributions to the carbon footprint and to optimize their calculation methods.

One thing to consider is the cradle to gate LCA of the production, transportation and processing of feedstock. This is built from technical data and although there is some uncertainty regarding default values for fertilizers and N₂O emissions, there is general agreement about carbon footprint results. This is where farmers, ethanol producers and technology providers can make a real impact, so it is important  to optimize the relevant GHG calculation methods in this area.

Another important factor is the impact of land use change on soil. This is harder to calculate, since it is related to scientific studies, soil types and climate, and changes taking place over many years. So far most calculations have been based on IPCC tier 1 guidelines, but there is a need for more advanced modeling. Knowing how to calculate this impact is critical; not only to get the carbon footprint right, but also to help develop agricultural practices that favor carbon binding of soils. Such practices are important for both biofuels and the overall carbon footprint of agriculture.

The impact of indirect land use change (ILUC) is another piece of the puzzle, and is very different from the others. It builds on economic equilibrium modeling of market mechanisms, as well as assumptions about yield development and forest replacement rates. Furthermore, the individual players in the biofuel production value chain have no influence on the result. This is the contribution which is most heavily debated and it is generally accepted that the calculation methods must be improved before exact biofuel carbon footprint figures can be obtained.

The ILUC issue is prominent in the public biofuels debate. We support improved processes but do not believe that carbon footprint calculation is the most efficient means of preventing indirect land impacts. In our rush to solve the ILUC challenge, we should not forget the more basic elements of the carbon footprint calculations. Let’s ensure resources for their optimization, as they are important for improving GHG performance.

By:  Karen Margrethe Oxenbøll, Sustainability Manger, Novozymes

Retrieved from: Novozymes