Energy

State of the art of biogas technology - Examples from GermanyOctober 2010, Jyväskylä, Finland

www.german-renewable-energy.com

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)

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

0

1000

2000

3000

4000

5000

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010*

An

lag

enza

hl

[-]

0

500

1000

1500

2000

2500

Inst

alli

erte

ele

ktri

sch

e L

eist

un

g

[MW

el]

> 500 kWel davon > 1 MWel

70 bis 500 kWel davon 70 bis 150 kWel

< 70 kWel install. el.Leistung [MWel]

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

6%3%

4%

48% 2%

2%

24%

9%

Pig liquid manure

Cattle liquid manure

Cattle solid manure

Other manure

Maize silage

Grass silage

Grains

Whole plants silage grains

Grass

Other energy crops

Water

Manure (37%)

Man

ure

Energy crops (63%)

Ene

rgy

crop

sSource: 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

System Continuous Discontinuous

Category Continuous stirred-tank reactor (CSTR)

Plug flow digestor Batch/Percolation

Symbol

Example

Substrate Characteristics

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 €]

Re

lati

ve

fre

qu

en

cy

Installed electr. capacity [kWel]

Sp

ec

ific

in

ve

stm

en

t c

os

ts [

€/k

Wel]

Total investment costs: 1 – 1.5 mio USD

Specific investment costs: 3,800 – 5,000 USD/kWel

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

Depreciation Base rate

Purchase of energy crops

Other direct costs

Labor costs

Maintenance contractsOther operating costs

Re

lati

ve

an

nu

al

ex

pe

nd

itu

res

[% o

f to

tal

co

sts

]

Source: Bundesmessprogramm II, FNR, 2009

Production costs for electrical energy

Source: Bundesmessprogramm II, FNR, 2009

Pro

du

cti

on

co

sts

fo

r e

lec

tric

al

en

erg

y

[€/k

Wh

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 sales Digestate Digestate salesHeat savings

Co

mp

os

itio

n o

f re

ve

nu

es

[€/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 MWel)

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 CentreTorgauer Straße 11604347 Leipzig, Germany

www.dbfz.deTel./Fax. +49(0)341 – 2434 – 112 / – 133

Contact:Jens Giersdorfjens.giersdorf@dbfz.de