Stepping towards a low-carbon economy. Formic acid from biogas as case of study

Abstract

The European Union has set an ambitious plan for addressing the Global Challanges in the coming years. One of these challenges is the use of biomass and the production of biomass-derived products following the spirit of a circular economy. Biogas obtained from biomass anaerobic digestion could play a pivotal role in this strategy. Herein an innovative strategy for synergizing biogas upgrading to biomethane and formic acid production from CO2 is presented. A profitability analysis of the combined biogas upgrading – CO2 utilization process was conducted to assess the economic viability of this novel approach. The profitability study focuses mainly on net present value and profitability index. Even though the process is environmentally favourable, negative profitability results are obtained. To revert the negative outputs, out of the market formic acid prices (1767–3135 €/t) would be needed to achieve a net present value equal to zero. The alternative of feed-in tariffs biomethane subsidies needs high values (121.1–269.4 €/MW) to reach profitable scenarios. These unsuccessful profitability results are ascribed to high consumables costs, mainly associated with the catalytic conversion of a CO2-rich feedstock. A 80% reduction of catalysts costs can considerably improve net present value up to 50%. This result indicates that further research is needed to find econimocally appealing catalysts to perform this process. The effect of biomethane subsidies as percentage of investment was also considered, evidencing encouraging results for small scale plants.