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14th September 20101
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Life Cycle Assessmentof biomethane public transport
Jan Paul Lindner
Dept. Life Cycle Engineering (GaBi)
Chair of Building Physics (LBP)
Universität Stuttgart
14th September 2010, Brussels
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Life Cycle Assessment methodology– Product systems– Multitude of environmental impacts
Biomethane from an environmental point of view– Overview– Feedstock generation– Digestion– Upgrading– Distribution– Use
Outline
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„Cradle to grave“ approach– Resource extraction and processing– Materials production, product assembly– Use phase– End-of-life
Modular inclusion of other product systems
LCA – product systems
OutputInput
OutputInput
OutputInput
OutputInput
OutputInput
Life cycleinventory
CO2
CF4
CO
N2O
CH4
NOX
SO2
HCl HF NOX
NH3
NH4+
PO43–
...
Impactassessment
Climate change, resource consumption, acid rain, summer smog, overfertilisation...
Potential impact
Intermediatesproduction
Resourceextraction
Productassembly
Usephase
Disposal/recyclingLife cycle
LCA – product systems
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LCA – product systems
Process 1 Process 2 Process 3
InputOutput
Input Output
System boundary
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LCA – product systems
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„Environment“ more than just climate
Impact categories in Biogasmax– Global Warming Potential (GWP100)– Eutrophication Potential (EP)– Acidification Potential (AP)– Photochemical Ozone Creation Potential (POCP)– Fossil Primary Energy Demand (PEfossil)
Presentation limited to climate impacts– Full report coming soon
LCA – environmental impacts
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Biomethane – overview
Feedstock Digestion Upgrading Distribution Use
Waste
Sludge
Biomass
Digestion
Water scrubbing
Chemical absorption
Pressure swing
adsorption
Vehicles
Truck
Pipeline
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Environmental impact (climate)
Feedstock Production Upgrading Distribution Use
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Environmental impact (climate)
Feedstock Production Upgrading Distribution Use
Tail pipe emissions
Life cycle emissions
Negative emission?
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Municipal organic waste– Life cycle accounted for in original product system– Waste considered “burden free” in biomethane system
Sewage sludge– Same as municipal waste
Dedicated biomass production– Feedstock produced exclusively for digestion to biogas– Environmental burden of production attributed to
biomethane
Feedstock generation
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Environmental impact (climate)
Feedstock Production Upgrading Distribution Use
Environmental impact (climate)
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Feedstock Production Upgrading Distribution Use
Biogenic CO2 = part of the natural carbon cycle
Environmental impact (climate)
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Feedstock Production Upgrading Distribution Use
Biogenic CO2 = part of the natural carbon cycle
Environmental impact (climate)
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Feedstock Production Upgrading Distribution Use
Biogenic CO2 = part of the natural carbon cycle
Release of same amount of CO2 to atmosphere
Fixing of CO2 from atmosphere
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Heat management– Dry matter content of slurry defines heat demand– Impact depends on type of fuel, combustion conditions
Biogas slip from digester– Potentially important GWP and POCP contribution
Residue valorisation– Fertiliser– Combustible– Filler material
Digestion
Environmental impact (climate)
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Feedstock Production Upgrading Distribution Use
Sludge thickening
Environmental impact (climate)
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Feedstock Production Upgrading Distribution Use
Environmental impact (climate)
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Feedstock Production Upgrading Distribution Use
Methane slip?
Environmental impact (climate)
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Feedstock Production Upgrading Distribution Use
Residue valorisation
Environmental impact (climate)
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Feedstock Production Upgrading Distribution Use
Residue valorisation
Environmental impact (climate)
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Feedstock Production Upgrading Distribution Use
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District heating– Mostly waste heat from industry considered
“renewable”
Landfill gas– Contains ca. 40% methane and lots of impurities– Combustion for heat rather than upgrading– Landfill emissions allocated based on revenue
shares generated from waste disposal and gas sales
Digestion
Environmental impact (climate)
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Feedstock Production Upgrading Distribution Use
Renewable heat source
Environmental impact (climate)
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Feedstock Production Upgrading Distribution Use
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Water scrubbing, PSA– Electricity consumption decisive
Chemical absorption– Heat consumption decisive
Methane slip– Important GWP and POCP contribution– Several mitigation measures exist
Conditioning– Addition of fossil materials reduces advantage
Upgrading
Environmental impact (climate)
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Feedstock Production Upgrading Distribution Use
Methane elimination
Environmental impact (climate)
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Feedstock Production Upgrading Distribution Use
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Pipeline transport– Little influence on overall result– Methane slip potentially important GWP, POCP contribution
Truck transport– Higher impact than pipeline transport
but no dominant factor in life cycle
Filling stations– Impact sensitive to power grid mix– Methane slip potentially important GWP, POCP contribution
Distribution
Environmental impact (climate)
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Feedstock Production Upgrading Distribution Use
Environmental impact (climate)
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Feedstock Production Upgrading Distribution Use
Methane slip?
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Vehicles– Busses– Heavy duty vehicles, e.g. garbage trucks– Cabs, private cars
Use
Environmental impact (climate)
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Feedstock Production Upgrading Distribution Use
Biogenic CO2
Engine emissions, e.g. NOX, CO
Environmental impact (climate)
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Feedstock Production Upgrading Distribution Use
Environmental impact (climate)
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Feedstock Production Upgrading Distribution Use
Environmental impact (climate)
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Biomethanetotal
Environmental impact (climate)
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Biomethanetotal
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Climate/carbon neutrality of Biomethane– Low climate impact, though not 100% climate neutral– Considerable improvement potential (technology just
stretching into market)
Critical points for climate impact– Reduction of methane slip at every stage– Valorisation of by-products
Presentation limited to climate impacts– Other impacts may (and do) behave differently
Conclusion
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Dipl.-Ing. Jan Paul Lindner
Dept. Life Cycle Engineering (GaBi)
Chair of Building Physics (LBP)
University of Stuttgart
Hauptstr. 113
70771 Echterdingen
Germany
Tel. +49-711-489999-25
Fax +49-711-489999-11
E-mail jan-paul.lindner@lbp.uni-stuttgart.de
Contact
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