A Polish case study for biogas to biomethane upgrading

The article presents the results of a theoretical pre-feasibility study for biogas upgrading to biomethane for a planned agricultural biogas plant with a capacity of about 10 million Nm3 of raw biogas production per year. Upgraded biogas to the quality of natural gas can be injected to the natural gas distribution network or used as a transportation fuel for natural gas vehicles (NGVs). Currently the agricultural biogas, as well as landfill gas and gas from sewage treatment plants, is mainly used in Poland to produce electricity and heat (CHP plants). The market for biogas upgrading to biomethane in Poland does not actually exist. A variety of factors affects this situation, including: high investment costs of upgrading units, the existing national incentive system promoting green electricity and heat production from biogas, lack of national standards for biomethane, limited awareness of the available technologies, and finally a small number of vehicles capable of using compressed biomethane (CBM). The aim of this study is to examine alternative options for biogas utilization compared to combined heat and power production. Several biogas upgrading technologies available on the European market (water scrubbing, chemical scrubbing, cryogenic upgrading) were compared in terms of their applicability and cost effectiveness. Estimation of the installation costs, operation costs and revenues was presented for two alternatives of biomethane application: injection into the gas distribution grid or use for transport purposes for NGVs. A profitability analysis of the two solutions was performed, taking into account possible incomes from renewable energy certificate system (for injecting to the gas grid option).