The rise of biogas opens the door to new models for the management and recovery of livestock excrement

The Biogas Plan for Catalonia 2023-2030, presented a few days ago at the BIT Congress in Vic, aims to triple the number of biogas plants in the country as a whole in seven years in order to significantly increase the production of this renewable energy source. In regions such as Osona, with significant livestock and meat activity, centralised biogas plants are emerging as one of the most viable collective strategies for treating, managing and recovering the high surplus of livestock excrement and organic waste generated. It is estimated that in Osona only 50% of livestock excrement can be applied as organic fertiliser on crop fields, so it is necessary to find other ways of management, treatment and, if possible, recovery.

Osona currently has two disimpact plants that manage a significant volume of slurry and at the same time apply electrical and thermal cogeneration through the combustion of natural gas. However, the economic viability of these plants is conditional on government subsidies for slurry management and thermal and electrical cogeneration. However, there is every reason to believe that in the coming years these plants will cease to receive the premiums, which will most likely lead to their closure. Faced with this reality, several experts from the BETA Technology Centre of the University of Vic – Central University of Catalonia (UVic-UCC), with the collaboration of Xavier Flotats, professor emeritus at the UPC, and with the support of the Osona County Council and Creacció, have worked on the theoretical definition of a new model of centralised biogas plant for the management of slurry and other organic waste that fits the reality of Osona.

A technical conference on 18 April

This plant model, designed to meet the specific needs of this region, will be presented at a technical conference to be held on Tuesday 18 April at 10 a.m. in the Segimon Serrallonga Hall of the Masia Torre dels Frares at UVic-UCC, in collaboration with Clúster Bioenergia Catalunya. At the conference, the group of experts who have worked on the proposal will show the main lines of the project from which the actual implementation phases could begin to be specified.

The conference will include the participation of several companies that have developed similar plants in other places, who will share their experience. Apart from presenting the results of the work that has been carried out so far, the aim of this meeting is to reach as many actors as possible in the biogas value chain (developers, livestock farmers, investors, marketers, distributors, consumers, etc.) and political representatives of the territory.

Aspects of the future plant

The group of experts has worked on the compilation of data and identification of the reality that has been carried out by the Table for the Sustainable Management of Livestock in Osona, in recent years technically coordinated by the BETA TC and presided over by the Osona County Council. The diagnosis has made it possible to identify and quantify the types of organic waste and by-products generated in Osona that could potentially be recovered in the proposed new plant. In this sense, it is not only livestock excrement but also other organic waste that can significantly increase the potential for recovery: meat waste, sewage sludge, and whey from the dairy sector or municipal organic waste, among others.

The report on which the experts have been working addresses such relevant issues as the possible location of the centralised biogas plant in Osona. Bearing in mind that current regulations and the orography of the area mean that there are practically no areas available in this region to build a new plant, “one option that has been explored is the feasibility of reconverting facilities that already have a permit to treat livestock waste”, explains Ricard Carreras, researcher at BETA TC and coordinator of the project for the new model of biogas plant in Osona.

Another aspect that has been put on the table is the technological scheme that this future biogas plant should follow. The central nucleus would be anaerobic digestion or biogasification, a biological process that takes place without the presence of oxygen, in which part of the organic matter in organic waste is transformed, by the action of microorganisms, into a mixture of gases. This process would make it possible to generate biogas that could later be used to replace natural gas or to generate electricity and heat. Moreover, according to Carreras, “the plant should also incorporate, in a well-dimensioned way, digestate treatment processes such as drying and pelletisation, as well as evaporation or condensation, which would make it possible to generate various types of fertiliser products with high added value”.

The objectives of the Biogas Plan

The Osona biogas plant model is part of the Biogas Plan for Catalonia 2023-2030, which was presented at the BIT Congress in Vic, the benchmark congress in Catalonia for the Bioeconomy, Innovation and Technology. The Biogas Plan aims to install 90 more plants by 2030, in addition to the 47 that already exist today, of which 30 are in wastewater treatment plants, 12 recover livestock waste, and 5 are in urban waste treatment plants. The Catalan Biogas Plan forecasts that biogas production in 2030 could reach 3.3 TWh per year, equivalent to 13% of current natural gas consumption.

Apart from biogas production itself, one of the reefs that remains to be resolved is the connection to the natural gas distribution networks, based on the transformation into biomethane. At the moment, only two of the current 47 installations are connected in this way.