The Future Agricultural Biogas Plant in Germany: A Vision

Abstract

After nearly two decades of subsidized and energy crop-oriented development, agricultural biogas production in Germany is standing at a crossroads. Fundamental challenges need to be met. In this article we sketch a vision of a future agricultural biogas plant that is an integral part of the circular bioeconomy and works mainly on the base of residues. It is flexible with regard to feedstocks, digester operation, microbial communities and biogas output. It is modular in design and its operation is knowledge-based, information-driven and largely automated. It will be competitive with fossil energies and other renewable energies, profitable for farmers and plant operators and favorable for the national economy. In this paper we discuss the required contribution of research to achieve these aims.

What Could China Give to and Take from Other Countries in Terms of the Development of the Biogas Industry?

“…Comprehensive and precise monitoring of biogas plant cannot be guaranteed in China because of the low-quality instrumentation used to detect technical and chemical parameters. Correspondingly, up-to-date measurement technologies have been employed in several biogas plants in Germany, such as spectral techniques [64].…”

Effect of a Profound Feedstock Change on the Structure and Performance of Biogas Microbiomes

“…In 2012, an upper maize limit of 60% was introduced which was further reduced to 50% in 2017 [5,6]. However, the transition to a circular bioeconomy is required, in which anaerobic digestion (biogas production) is a keystone for providing base load power which can be supplied on demand and serves as a sustainable residue management strategy [1]. Manifold residues from agricultural crop production, livestock husbandry, and landscape management, as well as from organic wastes from food processing, food consumption, and from the organic fraction of municipal solid waste might be appropriate feedstocks for anaerobic digestion [1].…”

“…However, the transition to a circular bioeconomy is required, in which anaerobic digestion (biogas production) is a keystone for providing base load power which can be supplied on demand and serves as a sustainable residue management strategy [1]. Manifold residues from agricultural crop production, livestock husbandry, and landscape management, as well as from organic wastes from food processing, food consumption, and from the organic fraction of municipal solid waste might be appropriate feedstocks for anaerobic digestion [1]. Consequently, plant operators will be forced to use a broad range of different feedstocks which are chemically very heterogeneous, variable over time, and often available only in small quantities.…”

“…Consequently, plant operators will be forced to use a broad range of different feedstocks which are chemically very heterogeneous, variable over time, and often available only in small quantities. This will lead to a more inhomogeneous feedstock supply and sometimes to rapid feedstock changes, which might cause problems for the microbial community in the biogas reactors as the available nutrients and the bioaccesibility may differ [1,7].The production of biogas is a complex process where several different microorganisms using different metabolic pathways work together to degrade organic matter into biogas. The process can be divided into four main steps: the hydrolysis, the acidogenesis, the acetogenesis, and the methanogenesis.…”

“…Consequently, plant operators will be forced to use a broad range of different feedstocks which are chemically very heterogeneous, variable over time, and often available only in small quantities. This will lead to a more inhomogeneous feedstock supply and sometimes to rapid feedstock changes, which might cause problems for the microbial community in the biogas reactors as the available nutrients and the bioaccesibility may differ [1,7].…”