Energy State of the art of biogas technology - Examples from Germany October 2010, Jyväskylä, Finland Jens Giersdorf, German Biomass Research Centre (DBFZ)

Content  German Biomass Research Centre (DBFZ)  Biogas development in Germany  Biogas technologies  Economics of biogas production in Germany  Recent trends and challenges

Energy German Biomass Research Centre (DBFZ)

 DBFZ founded in 2008 as a non-profit company owned by the German Federal Ministry of Food, Agriculture and Consumer Protection (BMELV)  2009: 134 employees, 149 projects  Application oriented technical, economic and environmental R&D activities  Consultancies for private/public institutions  Policy assessment for federal ministries  Feasibility studies for bioenergy plants

Energy Biogas development in Germany

Number of biogas plants and installed electricity power Source: DBFZ 2010 Electrical power generation from biogas (2009): 10.5 TWhel (real), equals 34% of power generation from biomass in total, respectively 1.8 % of German brutto electrical power generation

Share of substrates (% FM) in German biogas plants Source: Biogasmessprogramm II, FNR, 2009 n = 413

Energy Biogas technologies

Scheme of processes in a farm-based biogas plant Source: Biogas – an introduction, FNR, 2009

Types of biogas digestors SystemContinuousDiscontinuous CategoryContinuous stirred- tank reactor (CSTR) Plug flow digestorBatch/Percolati on Symbol Example Substrate Characterist ics Liquid, 12% total solids Viscous, up to 40% total solids Solid, structured, stackable, humidification through sprinkling

Continuous stirred-tank reactor (CSTR) Source: Handreichung Biogas, FNR, 2009; DBFZ 2010

Continuous stirred-tank reactor (CSTR) Advantages  Cost-effective construction > 300 m³  Flexible flow-through/storage operation  Maintenance without reactor emptying Disadvantages  Cover sheet for large reactors is complex/expensive  Short circuit currents may occur, retention time insecure  Scum and sink layers may occur

Plug-flow digester Sources: Handreichung Biogas, FNR, 2009; Eisenmann AG 2010

Plug-flow digester Advantages  Cost-effective construction for small plants  Separation of fermentation steps in plug-flow  No scum nor sink layers, short retention time  Optimal retention time due to prevention of short circuit currents  Low heat losses due to compact construction form Disadvantages  Construction only for small plants feasible  Maintenance of stirring devices requires complete emptying of digester

Batch/percolation Source: Bekon 2010

Batch/percolation Advantages  Utilization of solid substrates  Modular construction, flexible adaption to demands, low investment  Few material handling equipment, reduced investment and maintenance costs, low process energy demand Disadvantages  Delayed operation of several modules for continuous production  Incomplete mixture: zones with reduced gas production may occur  Installation of security equipment required  Large quantities of inoculate needed for high biogas yields

Energy Economics of biogas production in Germany

Investment costs Investment costs depend on….  Technical equipment of the plant  Development costs of the property (road, canalization, etc.)  Access to energy grid, heat grid, manure storage tank if necessary  Substrate for digestion (biogenic waste treatment plants more expensive than energy crops due to higienisation)

Investment costs Source: Bundesmessprogramm II, FNR, 2009 Total investment costs [Mio €] Relative frequency Installed electr. capacity [kW el ] Specific investment costs [€/kW el ] Total investment costs: 1 – 1.5 mio USD Specific investment costs: 3,800 – 5,000 USD/kW el

Operating costs  Substrate costs  Costs for spreading of digestate  Maintenance costs  Labor costs  Process energy demand  Costs for consumables  Costs for depreciation and interest

Annual total costs DepreciationBase rate Purchase of energy crops Other direct costs Labor costs Maintenance contracts Other operating costs Relative annual expenditures [% of total costs] Source: Bundesmessprogramm II, FNR, 2009

Production costs for electrical energy Source: Bundesmessprogramm II, FNR, 2009 Production costs for electrical energy [€/kWh el ] Electrical utilization ratio [%]

Revenues  Revenues for electricity:  Feed-in-tariff  Substitution of expensive own consumption  Revenues from direct marketing/sales  Revenues for heat:  Constant heat demand, especially in summer  Costs for heat conduction  Alternative heat costs  Revenues for disposal:  Additional costs for treatment  Revenues free plant (without additional transport costs)  If applicable higher environmental regulations for the plant  Revenues for digestate (substitute for mineral fertilizer)

Composition of revenues Electr.Heat salesDigestateDigestate salesHeat savings Composition of revenues[€/a] Source: Bundesmessprogramm II, FNR, 2009

Important factors for success  Optimal choice of biogas plant location of major importance  Low substrate costs  Year-round demand for heat and electricity  Skilled employees with enthusiasm for the challenge „biogas plant“  Professional plant layout  Long-term financing

Energy Recent trends and challenges

Biomethane feed-in plants in Germany  About 38 biogas upgrading and feed-in plants operating (23,520 Nm³/h capacity)  High costs for upgrading of biogas to natural gas quality requires large plants (> 2 MW el )  Gas grid can be used as storage facility  Optimization of heat use and/or satisfaction of peak loads  Several feed-in plants planned, but development slowed down

Biomethane feed-in plants in Germany

Integration of bioethanol and biogas production Sources: Agraferm, 2010, Verbio AG, 2010

Challenges  Optimization (acceleration) of process biology  Improvement of heat utilization concepts  Optimization of „dry fermentation“ to increase use of ligno-cellulosic substrates (agricultural residues)  Reduction of biomass/methane losses during the production process  Promotion of biomethane application (esp. as transport fuel)

Energy Thank you for your attention! Deutsches BiomasseForschungsZentrum German Biomass Research Centre Torgauer Straße Leipzig, Germany Tel./Fax. +49(0)341 – 2434 – 112 / – 133 Contact: Jens Giersdorf