New biogas concepts for increasing the overall economy of biogas production Hinrich Uellendahl Section for Sustainable Biotechnology A.C. Meyers Vænge 15, 2450 Copenhagen hu@bio.aau.dk, ph +45 99 40 25 85

Biogas research Denmark @ Aalborg University Copenhagen (AAU Cph) From March 1, 2019: Biogas research group Hochschule Flensburg University of Applied Sciences www.hs-flensburg.de Germany @ Hochschule Flensburg, Germany Section for Sustainable Biotechnology Department of Chemistry and Bioscience Aalborg University Copenhagen (AAU) www.sustainablebiotechnology.aau.dk Hinrich Uellendahl Biogas Research on: Process optimization by Reactor design & configuration Process control Biomass pretreatment Biogas as part of biorefinery

27 Centralized biogas plants Biogas research with respect to full-scale operation 27 Centralized biogas plants Capacity: 20 – 600 kton/year Full-scale biogas plants in Denmark WWTP Industry Waste disposal Centralized plant Farm-scale plant Production (TJ/year) (MW) 0.7 – 3.2 3.2 – 12.7 Under construction New plant

Full-scale biogas plants in Denmark - Recent trends: LARGE SCALE Capacity ≥ 500 kton/year Combined with biogas upgrading for use in natural gas grid or as transportation fuel Biogas plants as nutrient banks Biogas to counteract fluctuating renewable electricity production - Power-to-gas technologies - Flexible biogas production Maabjerg Biogas (2012)

Full-scale biogas plants in Denmark - Challenges: CHP plant + BioGAS Manure as main feedstock Additional organic waste with high biogas yields is limited Increasing shares of solid (lignocellulosic) biomass - straw, deep litter, grass, biowaste etc. Digestate as valuable fertilizer product Biogas upgrading has significant costs Adaptation to flexible biogas production Biogas Upgrading ≥ 75% Manure ≤ 25% Organic waste, Solid biomass Natural Gas Grid Digestate Fertilizer N,P,K

Full-scale biogas plants in Denmark - Challenges: Manure as main feedstock - High water content, Additional organic waste with recalcitrant fibers high biogas yields is limited Increasing shares of solid - Treatment for enhanced (lignocellulosic) biomass hydrolysis necessary - straw, deep litter, grass, biowaste etc. Digestate as valuable fertilizer - Separation and distribution product of nutrient fractions Biogas upgrading has significant costs - New upgrading technologies Adaptation to flexible biogas production - Process control

Biogas potential of solid waste biomass Biogas plant Clover grass Sugar beets Majs/corn Sugar beet tops OFMSW Aquatic biomass Garden waste Road-side biomass Non-cultivated fields Nature areas Catch crops Straw Ind. Organic waste 50% Manure Organic fraction of municipal solid waste Agricultural residues

Improving the biogas plant economy Increasing biogas yields of manure - Solid-liquid separation to and nutrient management lower transportation costs Increasing biogas yields of - Improved process, new lignocellulosic biomass process concepts, integration of pretreatment Biogas as part of a biorefinery - Extraction of high-value biomass fractions before biogas production

New concepts to increase the biogas yield per ton of biomass supplied Solid-liquid separation at farm – only manure fibers to biogas plant Manure Biogas plant BioGAS Manure fibers Mixing tank 6-8%TS 15-30%TS

New concepts to increase the biogas yield per ton of biomass supplied Increasing the biogas yield of manure fibers Manure Biogas plant BioGAS Manure fibers Mixing tank Enhancing hydrolysis by Increasing HRT (DK: 15-30 d, DE: 100 d), several reactors in series Increasing the temperature (from 37°C to 52°C) Pretreatment of lignocellulosic biomass

New concepts to increase the biogas yield per ton of biomass supplied Pretreatment methods for lignocellulosic biomass Physical/mechanical Thermal Chemical Biological Grinding, milling, maceration, ultrasound etc. Steam explosion, Wet oxidation @ 150-180ºC, +/- O2 Addition of acid, base etc. Fungi, hydrolytic bacteria and their enzymes

Change in biogas potential New concepts to increase the biogas yield per ton of biomass supplied Effect of pretreatment dependent on content of lignocellulosic biomass Increase of biogas yield by mechanical maceration of manure Change in biogas potential after maceration (%) Biogas potential of influent (L-CH4/kg-VS)

New concepts to increase the biogas yield per ton of biomass supplied Effect of pretreatment dependent on content of lignocellulosic biomass Increase of biogas yield by pretreatment in combination with TS increase

Digested fiber fraction Pretreated digested fibers New concepts to increase the biogas yield per ton of biomass supplied Pretreatment of the digested fiber fraction Separation Digested fiber fraction Liquid fertilizer Pretreatment Pretreated digested fibers Manure Biogas plant BioGAS Manure fibers Mixing tank 51 m3 /tonfeed 35 43 + Pretreatment + Recirculation

Biomass Biogas as part of a biorefinery Biogas Organofinery project: Biorefinery for organic protein feed, fertilizer & energy Mechanical Fractionation Green Juice Organically grown Biomass Brown Juice Protein precipitation Press cake Biogas Protein concentrate Biogas plant Organic Fertilizer Organic Feed

Biogas as energy storage buffer Energy storage of fluctuating excess electricity Power-to-gas Using H2 to convert CO2 into CH4 or other products Flexible electricity production from biogas

Biogas as energy storage buffer XEL2Gas project: Acetic acid as a storage molecule for excess electricity Combination of H2 utilization and biogas upgrading

Main conclusions for improved biogas concepts Increasing yield per m3: Combination with solid-liquid separation Reactor design and configuration: Process parameters (OLR, HRT, temperature) dependent on biomass characteristics and if biogas yield or productivity should be increased Pretreatment: specifically on recalcitrant fraction, combination with solid-liquid separation, pretreatment of digested manure fibers Higher valorization/New biomass options for integration with other biorefinery processes Utilization of excess electricity combined with biogas upgrading Flexible biogas production vs. larger gas storage capacity

New biogas concepts for increasing the overall economy of biogas production Vielen Dank für Ihre Aufmerksamkeit! Tak for opmærksomheden! Thank you for your attention! Hinrich Uellendahl