Explorative economic analysis of a novel biogas upgrading technology using carbon mineralization. A case study for Spain

This paper studies the potential application of a novel biogas upgrading technology called alkaline with regeneration (AwR). This technology uses an alkaline solution, along with carbon mineralization, to remove and store CO2 from biogas in order to create biomethane, a substitute of natural gas. Three different applications of biogas were explored for their potential economic benefits along three different biogas generation capabilities of landfills in Spain (250 Nm3/h, 1000 Nm3/h and 5000 Nm3/h). The scenarios include upgrading biogas using AwR and injecting the biomethane into the natural gas grid, or selling the gas as a vehicle fuel. The third reference scenario assessed directly burning the biogas for the production of electricity. The latter showed an annual profit of 0.2–5 million €2012 while upgrading the biogas to obtain biomethane showed an annual loss of 3–50 million €2012. This was due to the operational costs involved in AwR, namely the cost of NaOH (principal reagent) and the treatment of wastewater. Increasing revenue can help obtain an annual profit. In order to break-even it would be necessary to raise CO2 credits to 99 €2012/t or, through feed in tariffs, increase the price of the sale of biomethane to 0.25 €2012/kWh.