Biogasnalia biogas plant in Villalonquéjar (Burgos)

The Biogasnalia plant has a biogas output of around 1 MWe with a reactor of just 2,600 m3, which represents an enormous improvement in the efficiency of the process. It has now been demonstrated that the facility is capable of producing sufficient gas in a stable manner to drive a 500 kWe engine with just 1,300 m3 of reactor volume in use, when over 4,000 m3 was normally required. The average service volume of digesters at 500 kWe facilities is around 5,000 m3. AGF’s aim was to make the biogas profitable without subsidies and the first step was to increase the efficiency of the process.

In mid-November, AGF completed the construction and commissioning of the biogas plant built on a turnkey basis for Biogasnalia at the latter company’s facilities in the Villalonquéjar Industrial Park in Burgos, Spain. The contract entered into by the two companies encompassed the design, construction and commissioning of the AFG compact biogas plant described in this article.

Under the terms of the contract, the biogas plant had to comply with biogas output and process stability requirements. Compliance with these requirements was necessary in order to secure the final project payment, a significant proportion of the overall financial consideration.


These requisites were comfortably met and exceeded by the biogas plant, which has a very high potential biogas production capacity. Therefore, it was deemed that the terms of the contract had been complied with and the facility is now operating normally. Biogasnalia is responsible for operation of the plant, while monitoring and control is carried out by AGF.

Commissioning of the process

AGF had participated in the commissioning of many industrial plants in the United Kingdom but his was the first occasion on which it certified and commissioned a plant fully designed by the company itself.

The commissioning of the biogas plant was carried out over a period of 60 days, with 6 days of filling, 4 days of acclimatisation and 50 days of gas supply to the steam generator. It was in this latter period that compliance with the terms of the contract was achieved: stable sufficient production, or production in excess of consumption, over a period of 30 days was required to enable delivery of the plant. After the first week, in which the main work involved the filling of an inoculum volume, biogas was generated in accordance with a commissioning plan specifically designed by AGF at its laboratory in La Lapa, Badajoz.

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Published in: FuturENVIRO #46 December 2017 – January 2018