The Litomyšl Agricultural Cooperative has started trial operation of its new biomethane plant. It produces renewable gas from biogas derived from animal and crop agricultural waste and then injects it into the existing Gasnet gas network. The project also includes a compressed natural gas (CNG) filling station at the adjacent site in the village of Dolní Újezd. The entire investment worth more than CZK 50 million was carried out by Hutira – Brno and Hutira green gas. This is the first biomethane production technology in the Czech Republic that is connected to an agricultural biogas station, CNG filling station and gas injection into the gas network.

A test run of the new biomethane plant was launched in October. It is an innovation of the existing biogas plant on the cooperative’s premises, whose output in the form of biogas may no longer be used only for cogeneration of electricity and heat. In addition to the upgrading of the biogas to natural gas quality, the biomethane plant now also includes a unit that injects the biomethane into the high-pressure gas pipeline. The biomethane can also be used in a CNG station located couple kilometres away.

The normal operation is scheduled to start in December this year. Biogas is produced in the digesters of the agricultural biogas plant in stable quality, so there are no significant fluctuations in the input in terms of the methane content in the biogas. The amount of methane in biogas in Litomyšl is around 53 percent. The technology for purification to biomethane is thus simpler compared to waste processing AD plants.

The newly commissioned technology includes a set of several devices. The raw biogas first goes to a pre-treatment unit where it is stripped of moisture and sulphate. From there, it goes to an upgrading unit with a three-stage membrane separation, which converts the biogas into natural gas-quality biomethane. The biogas upgrading unit purifies the biogas to a concentration of at least 95% methane content using membrane separation technology in a processed volume of 160-360 Nm3/h of biogas.

The biomethane obtained is then directed to an injection station where the biomethane composition and quality are measured. If it is satisfactory, the treated gas is injected with odorant into a high-pressure gas pipeline with an excess pressure of 2,3-2,5 MPa. It is the injection of the biomethane into the gas network that is of primary interest to the agricultural cooperative.

The biomethane plant should process 30.6 million cubic metres of biogas over 10 years of operation, i.e. about 3 million cubic metres of biogas per year, which means a production of 1.7 million cubic metres of biomethane per year. The cooperative decided to build the biomethane plant in 2019. The main reason was to maximise the use of biogas energy. “Cogeneration has an efficiency of only about 35%in terms of electricity production. Another 30% is then in heat, for which we have no use during summer. Now that biomethane is going into the gas grid, our customers will use much more of our energy,” said Jan Pechanec, chairman of the cooperative.