In a bid to meet the European Union political target for energy and climate, biogas production will play a critical role owing to its flexibility and storability as an energy carrier, a wide range of biological sources that can be implemented for its synthesis, and its established implementation in an array of applications. The implementation of anaerobic digestion for biogas production is still widespread as a critical bioenergy production path reference to its robustness in design arrangements.
Anaerobic digestion serves several applications. It offers a treatment pathway for minimizing huge amounts of complex organic matter, converting a good number of these molecules into monomers, for example, carbon dioxide and methane, which can be used in the energy sector. Above all, the nutrient-rich digestate produced from the anaerobic processes can be recycled on farmlands as organic fertilizers as alternatives to chemical fertilizers that cause eutrophication of fresh water bodies.
The choice of substrates used in the production of biogas has been discussed extensively, particularly, in relation to the use of energy crops. Negative economic and environmental issues related to the use of cultivated energy crops for bioenergy production has been reported in literature. Therefore, these substrates will definitely fall out favor as primary feedstock considered for biogas anaerobic digestion process, and thus alternative sources are required.
Agricultural production residues can be incorporated with the EU directive on the use of energy from renewable sources sustainability criteria. In contrast to the existing literature on the topic, researchers led by Professor Jens Bo Holm-Nielsen at Aalborg University in Denmark focused on the biomass and biogas energy potential from a collection of particular agricultural residues that have been documented to enhance in biogas yield when co-digested in biogas production. Their research work is published in Biomass and Bioenergy.
The main aim of their study was to forecast and map the biogas and biomass energy potential from particular potentially sustainable agricultural residues that have been documented to enhance in biogas yields when co-digested in the production of biogas for the EU28 in the year 2030. The authors considered residual types including, animal manure, excess grass from permanent and rotational meadows and grasslands, and straw byproducts from cereal production.
The research team projected energy potential from grass, manure and straw to be in the range of 1.2×103-2.3×103PJ/y for the European Union in 2030. The United Kingdom and Germany were identified to have the highest energy potential. The outcomes of the study indicate that there is a huge base for agricultural residues well suited for co-digestion all over Europe that are perfect substitutes to energy crops.
The study found that co-digestion of animal manure incorporating straw and grass is a potential that will enhance the efficiency and economic feasibility of the European Union biogas production in 2030. More technological development and implementation may be necessary if the biomass resources are to be used efficiently. Acquisition and processing of the selected biomasses are challenges that must be addressed before realizing a full potential. However, production of energy based on these residues is a more sustainable and economically viable method for developing the EU biogas industry keeping in mind the potential issues in relation to sustainability.
A.K.P. Meyer, E.A. Ehimen b, J.B. Holm-Nielsen. Future European biogas: Animal manure, straw and grass potentials for a sustainable European biogas production. Biomass and Bioenergy, Available online 1 June 2017.Go To Biomass and Bioenergy