Cold commissioning of large-scale biomethane plant scheduled for autumn
One year after the groundbreaking ceremony, construction of the combined biogas and gas upgrading plant for Biogas Västra Skaraborg AB (BVS) in Vara, Sweden, is progressing according to schedule. EnviTec Biogas is supplying and installing the entire biogas plant technology, including the EnviThan gas upgrading system. The gas upgrading system has successfully passed its Factory Acceptance Test (FAT) and has since been installed on site. “With the installation work completed, we have laid the groundwork for cold commissioning, which is scheduled for autumn,” reports Project Manager Michael Ogundare.
Significant construction work has now been completed at the site in the province of Västergötland. The feedstock feeding system has been delivered and installed. All concrete tanks have been constructed by EnviTec's subsidiary EnviTec-Greten. The internal installation work in the tanks has been completed, and the first air blown double-membrane gas holders have been installed. The heat exchanger unit has also been delivered and integrated into the plant. While piping and electrical installation work is already underway, further mechanical installation work is being carried out in parallel.
For the subsequent biological start-up, the plant's tanks will be filled with substrate. BVS will source the required substrate from surrounding biogas plants. “We have planned the filling process in detail in advance and will closely supervise it together with BVS, including biological support and a defined start-up and ramp-up plan,” explains Maurice Markerink, Managing Director of EnviTec Anlagenbau.
The tank trailers are unloaded inside a dedicated technical building, from where the liquid substrate is pumped through pipes into the intake tank before being transferred to the digesters. In the next step, solid feedstock is introduced into the digesters using the feeding system and thoroughly mixed with the liquid substrate. “This creates the conditions for a consistent feedstock supply and stable biogas production,” says Ogundare.
The biogas produced at the plant will be upgraded to biomethane using EnviTec's EnviThan membrane technology. The gas quality will be adjusted to meet the requirements of the downstream liquefaction plant. The biomethane will then be transferred directly to the Bio-LNG production facility provided by the customer.
The industrial-scale plant operated by BVS, an association of around 100 farmers, will process pig and cattle slurry as well as manure from the surrounding region. The facility is designed to process approximately 370,000 tonnes of feedstock per year. These regional agricultural residues will be converted into renewable gas for subsequent Bio-LNG production.
“Close coordination with EnviTec Biogas is crucial for the next steps. The key technical details and interfaces have been clarified, allowing us to move into the decisive phase of the project together,” says Tomas Carlmon of Biogas Västra Skaraborg AB. In addition to the close coordination of technical interfaces, several solutions contribute to the plant's energy-efficient operation. The heat recovery system, for example, uses heat from the digestate to preheat the incoming liquid substrate. This allows process heat to be reused within the plant.
Designed for Swedish weather conditions
The specific climatic conditions at the site have also been taken into account during the planning and construction phases. The enclosures housing the technical equipment installed on the digesters are designed to withstand the snow and wind loads typical of Swedish winters. An officially appointed expert monitors and inspects the individual construction phases to ensure compliance with the applicable technical and structural standards.
Commissioning of the biogas plant, gas upgrading system and downstream liquefaction plant will be coordinated in stages. Initial biomethane production is scheduled for January 2027. Once operational, the facility is expected to supply up to 70 GWh of biomethane per year for Bio-LNG production, making an important contribution to the decarbonisation of the transport, shipping and industrial sectors in Sweden and Northern Europe.
