Long-term sustainability assessment of fossil-free fuel production concepts

Report, 2018

The number of possible combinations of feedstock, feedstock pre-treatment, and downstream processes for large-scale production of different types of biofuel is substantial. Different production
routes will obviously perform very differently with respect to profitability and carbon footprint. Furthermore, large-scale production of biofuels requires substantial strategic investment decisions, requiring a prospective assessment approach. Evaluation of future biorefinery concepts using today’s conditions can be heavily misleading, and it is therefore essential that possible future conditions and related uncertainties are taken into account. This work explores methodological choices and assumptions of Techno-Economic Assessment (TEA) and Life Cycle Assessment (LCA) methods and tools used in four research groups in Sweden for assessing the long-term economic and carbon footprint performance of large future biorefinery concepts.

The report presents an in-depth analysis of the methods and tools used in the participating groups, and clearly establishes the need for increased collaboration and data exchange between biorefinery process developers, value chain modellers, TEA and LCA practitioners and large-scale energy and material system modellers. The work presented constitutes a significant step in this direction by clearly establishing the potential strength of prospective TEA and LCA in combination with scenarios describing possible future developments of the background energy system in which future biofuel production systems will operate. The report presents new results for one of the bio-methane production routes investigated in the “METDRIV - Methane as vehicle fuel – a well-to-wheel analysis” study conducted by Börjesson et al (2016) with respect to energy, greenhouse gas emissions (GHG) and cost performance. The input data used in the original METDRIV study were based on average prices/costs and GHG emission factors valid at the time of the study. In this work, new input data is adopted that reflects possible energy market development pathways generated by the ENPAC energy market scenario tool developed at Chalmers. For the selected production route, the results show that assumptions for costs and greenhouse gas emission factors related to increased use of biomass are of utmost significance, and that there is a clear need for further work in this area.

Finally, the report discusses some of the major challenges that remain to be addressed when developing scenarios for the “background” energy system to be used in prospective assessment studies of future biorefinery concepts:

• Handling the possible consequences of future limited biomass availability on biomass feedstock prices and emission factors.
• Handling future development of the electric power grid, as well as other large-scale grid energy systems (e.g. district heating) in a carbon-constrained world
• Integration issues: large-scale biorefinery concepts are likely to be co-located at existing industrial sites, which will also evolve in reaction to policy instruments, thereby affecting opportunities for integration of material and energy flows.