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Biomass CHP – best practice
Conclusions and recommendations
Anders Evald, Janet Witt, Kati Veijonen
Harrie Knoef, Johan Vinterbäck, Elvira Lutter
Vienna 9 March 2006
Project aims
• Promote biomass CHP in Europe and highlight plants
with the best operation
• Provide e.g. authorities and future plant owners with
information about typical plant performance and
about best available technologies.
• Enable benchmarking, identify the improvement
potential of the existing European CHP plants
• Replicate best practices
• Challenge: collect reliable data
Different technolgies covered
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19 biogas and landfill gas plants
4 gasification plants
10 CFB (circulating fluidized bed) plants
11 BFB (bubbling fluidized bed) plants
15 grate-fired steam boiler plants using
uncontaminated biomass
• 8 grate-fired steam boiler plants using municipal solid
• waste (MSW) as a fuel
• 1 dust fired steam boiler plant
Fuels covered
• Solid biomass
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Forest fuels
Forest industry by-products such as bark, sawdust etc.
Wood pellets
Agricultural residues such as straw, husk etc.
Municipal solid waste
Landfill gas
Manure etc. for biogas plants
• Fossil fuels
– Heavy fuel oil
– Natural gas
– Coal
Key performance indicators
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availability
utilisation period
total efficiency
fuel input: biofuels vs. fossil fuels
nominal efficiency vs. operational efficiency
own power consumption
total efficiency on monthly basis
Gasification plants
Utilization factor: the extent, to which installed power is utilised
Availability factor: the extent, to which the plant is available for operation
average utilisation factor & average
availability
Availability and utilisation factor
100%
80%
60%
40%
20%
0%
56
utilisation factor
23
54
availability
1
Nominal efficiency and operational efficiency
100%
efficiency
80%
60%
40%
20%
0%
operational electric efficiency
nominal electric efficiency
operational heat efficiency
nominal total efficiency
56
23
54
1
aug-05
jul-05
jun-05
maj-05
apr-05
Mar 05
feb-05
jan-05
Dec 04
nov-04
Oct 04
sep-04
aug-04
jul-04
jun-04
maj-04
apr-04
Mar 04
feb-04
jan-04
Dec 03
nov-03
Oct 03
sep-03
total efficiency per month
Total efficiency of individual plant over 24 month
120%
100%
80%
60%
40%
20%
0%
Gratefired boiler plants
Availability and utilisation factor
100%
80%
60%
40%
20%
0%
41
4
6
utilisation factor
20
60
14
57
82
availability
5
16
22
45
35
Nominal efficiency and operational efficiency
120%
efficiency
100%
80%
60%
40%
20%
0%
operational electric efficiency
nominal electric efficiency
operational heat efficiency
nominal total efficiency
Ranked to increasing capacity
Annual energy production and operational efficiency
heat production: 606
GWh/a
300000
100%
250000
80%
200000
60%
150000
40%
efficiency
average energy production
[MWh/a]
350000
100000
20%
50000
0
0%
41
power production
4
6
20
60
14
heat production
57
82
5
16
total efficiency
22
45
35
electric efficiency
41
4
6
20
60
14
57
82
5
16
22
45
aug-05
jul-05
jun-05
maj-05
apr-05
Mar 05
feb-05
jan-05
Dec 04
nov-04
Oct 04
sep-04
aug-04
jul-04
jun-04
maj-04
apr-04
Mar 04
feb-04
jan-04
Dec 03
nov-03
Oct 03
sep-03
total efficiency per month
Total efficiency of individual plants over 24 month
120%
100%
80%
60%
40%
20%
0%
35
Cross technology comparison
Plant size
Min./max. net power output of participating plants for six
conversion technologies
net power output [MWel]
100
80
Average
Max. value:
200 MWel
60
40
20
0
bio- and
landfill gas
plants
gasification
plants
CFB plants
BFB plants
grate fired
boiler plants
MSW grate
fired boiler
plants
Electric efficiency
Min./max. electric efficiency of participating plants for six
conversion technologies
40%
annual electric efficiency
Average
30%
20%
10%
0%
bio- and
landfill gas
plants
gasification
plants
CFB plants
BFB plants
grate fired
boiler plants
MSW grate
fired boiler
plants
Total efficiency
Min./max. total efficiency of participating plants for six
conversion technologies
annual total efficiency
100%
80%
60%
40%
20%
Average
0%
bio- and
landfill gas
plants
gasification
plants
CFB plants
BFB plants
grate fired
boiler plants
MSW grate
fired boiler
plants
Utilization
Min./max. electric utilisation factor of participating plants
for six conversion technologies
annual electric utilisation period
100%
80%
60%
40%
Average
20%
0%
bio- and
landfill gas
plants
gasification
plants
CFB plants
BFB plants
grate fired
boiler plants
MSW grate
fired boiler
plants
Availability
Min./max. availability of participating plants for six
conversion technologies
100%
annual availability
90%
80%
70%
Average
60%
50%
bio- and
landfill gas
plants
gasification
plants
CFB plants
BFB plants
grate fired
boiler plants
MSW grate
fired boiler
plants
Conclusions and recommendations
1. Bigger is better
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Higher efficicency
Lower own consumption
Better availability
Lower specific investment
But constrained by heat marked, and not necessarily true
for biogas plants
Capacity and utilization
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Plants are bigger than simply justified by the heat market
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Plants built for the future
Plant nominal capacity is too optimistic – very few plant
perform anywhere near their anticipated (nominal) efficiency in
practical operation
Economic optimization
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High electricity price
Optimizing tariff income
Heat accumulator
Not too small
Not too big
Low utilization = poor payback on invested capital
CHP or not CHP
• Many plants are not 100% dependent on heat market
(combined heat and power only as a fraction)
• German biogas plants produce very little heat, and
they don’t meassure it
• Premium price for electricity not allways require full
combined production
– Incentive for RE, but not for the most efficient RE
• Large plants (MSW) cannot connect enough heat
demand
Balancing heat and power
• Energy efficiency: electricity is the premium product;
heat is a by-product
• Valid also money-wise
• But not allways: nordic heat markets show high value
for heat
• Industrial facilities might see steam as the main
product and electricity as a byproduct
Choosing the right technology
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Large difference in electric efficiency
Low electric efficiency is compensated by more heat
Heat market set the framework
Steam cycles: go for high steam data
Retrofitting old equipment to improve efficiency and
reduce own consumption
Industrial systems
• A more fragile heat market
• Industries change
• Operated according to steam demand – less power
and low utilization
Reducing own consumption
• Big difference depending on choice of technology
• Option for improvement in old plants
• Low efficiency lead to high own concumption
Operational problems
• New challenges for plant operators
• Fuel quality problems (feed systems, moisture
content, flue gas fans etc.)
• Sintering bed material
• Fouling heat transfer surfaces
– Decrease efficiency and high temperature corrosion
• Result: lower efficiencies, higher maintenance
• Exchange experience!
Some concluding remarks [1]
• Technology implemented must be mature
– Proven prototype models
– Long-term duration tests
• Adequate infrastructure
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Local manufacturing capacity
After-sale service
Training facilities
Sustainable feedstock supply
• Motivated & skilled labor
– Operators, Management
– Incentives
Some concluding remarks [2]
• Information & knowledge exchange
– Performance, limitations, opportunities
– Evaluation with competing options
– Set-up monitoring program of successes in India, China
• Clear regulations
– Permitting procedures
– Emission according to “ALARP”
– Health, Safety & Environment
• Sale of electricity and heat
– Any legal obstacle should be removed
– Long-term fixed price is prerequisite
Some concluding remarks [3]
• Product quality must meet client specifications
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Technical performance
Financial/economic performance
Operational performance
Gaining confidence
• Certification
– stimulation
– product must meet defined quality standards
• Scale-up, demonstration, replication, optimization
– Economy of numbers (instead of economy of scale)
– Reduced capital costs
– Improvement from learning by doing
Some concluding remarks [4]
 Do not repeat the mistakes from the past
– learning by doing and not by a scientific approach
(cooperation is prefered)
– too optimistic approach of the economics, efficiency and
availability, projections: 7000 hrs of operation in 1st year
– no optimal cooperation of the ownership-consortium and
conflicting interests (who is responsible for what).
• Manufacturer versus plant owner
• Plant owner/technology supplier versus permitting
authority
Health, Safety & Environment
www.gasification-guide.eu
Success stories CHP gasifiers [1]
• More than “5 installed” systems:
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Bioneer [district heating]
Co-firing [at power stations]
Biomass engineering, UK
Eqtec, Spain
Xylowatt, BE
Mothermik, DE
Pyroforce, CH
Güssing concept, AT
Volund (DK, DE, Japan, Italy))
India, China (thousands, but unfavourable emissions)
Success stories [2]
8000
7000
hours of operation
6000
gasifier
engine
5000
4000
3000
2000
1000
0
2002
2003
2004
2005
2006
2007
Success stories [3]
Thank you for your attention!
Harrie Knoef
BTG biomass technology group BV
www.btgworld.com
[email protected]
Ph: +31-53-4861190