Technology group Wärtsilä has engineered, delivered, and installed the biogas upgrading solution to a new biogas seven tons per day liquefaction plant in Hjørring, Denmark. The contract was awarded to Wärtsilä in 2022, and the official start-up took place in June 2023.

The facility is one of two biogas plants owned and operated by GrønGas A/S in Denmark. The other plant, located in Vrå, also features a Wärtsilä biogas upgrading solution. The plant in Hjørring has an annual production capacity of more than 6,200 tons of bioLNG. Denmark is a world leader in biomethane development, and these plants are seen as being an important element in securing the country’s green energy future.

The Wärtsilä Mixed Refrigerant (MR) liquefaction unit alone has an exceptionally low power consumption of <0.75 kWh per kilogram of bioLNG liquified. This, in combination with Wärtsilä’s Puregas CA technology for biogas upgrading & polishing, with a total methane loss of less than 0.1 percent, makes it extremely energy efficient. The Puregas CA at Hjørring is equipped with the patented VAC (vacuum) option that offers greater flexibility in delivering heat to the upgrader, heat sources down to a temperature of 95 degrees C are possible to use.

The Hjørring plant transforms manure-based biogas into bioLNG, representing annual CO2 savings of approximately 41,000 tons when replacing natural gas.

“Biogas is a renewable energy source that can be stored, and it is of great significance as Denmark seeks to combat the effects of climate change. The trust and efficiency of the Wärtsilä solutions selected for our two sites is central to these efforts,” says Allan K. Olesen, CEO, GrønGas.

“We at Wärtsilä are proud to contribute to a decarbonised future, and we congratulate GrønGas on the opening of this important new plant. Their plants are doing a great job in reducing greenhouse gas emissions, and we are pleased to support them. Our biogas solutions are designed to take advantage of energy integration, which optimises their performance and minimises the overall energy costs,” says Goran Gajski, Sales Manager Biogas, Denmark/Norway, Wärtsilä Gas Solutions.

The full Wärtsilä scope for the Hjørring installation includes the Puregas CA biogas upgrading and polishing unit, with the patented Wärtsilä VAC solution, the Liquefaction unit based on Mixed Refrigerant technology, a 250 m3 bioLNG storage tank, bioLNG export station to tank-truck and instrument air.

Wärtsilä has a 24/7 emergency support agreement with GrønGas covering the Hjørring plant, and a service agreement covering the 24/7 on-call, maintenance and optimisation of the Vrå plant.

Wärtsilä Gas Solutions is a market leader with innovative systems and lifecycle solutions for the gas value chain. Our main focus areas are the handling of gas in seaborne transport (storage, fuel, transfer and BOG management), gas to power, liquefaction and biogas solutions. We help our customers on their journey towards a sustainable future through a focus on lifecycle performance, innovation and digitalisation.