Efficient and carbon negative biojet fuels, is it possible? - potentials, costs

In production processes for biofuels (eg aviation fuels) from biomass, only a limited fraction of the biomass' carbon atoms end up in the product. In most processes, a non-negligible proportion of the carbon atoms are emitted as carbon dioxide directly. In the short term, this means that the climate benefit of biofuels decreases because it contributes to the “carbon debt” that gives rise to a large part of the debate that exists about the sustainability of biofuels. In a longer perspective, emissions of carbon dioxide in the manufacturing process mean that the biomass is used more inefficiently than if all biogenic carbon atoms were included in products that replace e.g. fossil fuels. The technologies of the future for the conversion and utilization of biomass are expected to have a high utilization of the biomass of the biomass in order to be legitimate and competitive.

Capturing and storing some of the biomass raw material's carbon also provides an opportunity to produce carbon dioxide-negative bio-jet fuels. For air transport, carbon-negative fuels can also have a special significance due to the high-altitude effects which in some cases can have as great a climate impact as carbon dioxide emissions. Switching to renewable fuels does not affect the part of the climate impact caused by high-altitude effects, which means that flights with “normal” biofuels can sometimes only reduce the climate impact by half. With carbon dioxide-negative bio-aviation fuels, an opportunity is obtained to compensate for these high-altitude effects as well and thus achieve air transport with potentially no or little total climate impact.

This project aims to increase knowledge, quantitatively as well as qualitatively, about opportunities and challenges linked to increasing carbon efficiency in bio-aviation fuel production for a more efficient use of biomass and reduced climate impact. The project evaluates technical and economic possibilities and conditions for carbon dioxide storage (so-called BECCS, bio-energy carbon capture and storage) or carbon dioxide use (so-called BECCU, bio-energy carbon capture and utilization). Both thermochemical and biochemical production pathways are considered, as well as commercial as well as new technologies for carbon dioxide separation and biofuel production. The results will be relevant for pin-pointing technologies that are competitive in the long term. The data from the project is relevant in the short term (before implementation of BECCS / BECCU) to avoid the choice of technologies that do not have the opportunity to develop to high carbon efficiency.