Biogas Plants as Hydrogen Production Facilities and Greenhouse Gas Sinks: Technology Comparison, Challenges and Potentials for Carbon Negative Hydrogen Production (HyBECCS)

Abstract

The biological transformation of industrial value creation aims to provide solutions with regard to the ecological challenges of our time. Concerning climate change, the most critical transformation area is the energy sector. Alternatives to fossil energy supply as well as the active removal of carbon dioxide (CO2) from the atmosphere are considered the most important challenges that technology must provide solutions for. A promising approach in this context is the carbon-negative hydrogen production from biogenic sources (HyBECCS). This approach can be implemented on the basis of existing biogas plants. Technology alternatives for retrofitting these plants to HyBECCS facilities are elaborated and their respective strengths, weaknesses, opportunities and threats are derived in this paper. Further, taking the example of Baden-Wuerttemberg in Germany, the ecologic potentials concerning hydrogen (H2) production and greenhouse gas (GHG) reduction are estimated. The current total H2 demand of 1.8 TWh/a in this area could be fully covered if 1/7 to 1/4 of existing biogas plants were retrofitted for H2 production. The substitution of gray H2 can avoid GHG emissions of 2.2-3.7 million t CO2 per year. In addition, capture and storage or long-term use of the resulting biogenic CO2 can enable negative emissions of 2.5-6 million t CO2 per year.