Boosting manure-biogas through
external carbon inputs
- Environmental consequences and system
perspectives on how to prioritize the
biomass ressources
Lorie Hamelin
[email protected]
Nordic Biogas Conference, Reykjavik, August 2014
Outline
• WHY biogas is a good idea
• WHEN biogas is a good idea
• HOW biogas is a good idea
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Context
• Extremely interconnected world
• Strategic research: Must quantified in a future
perspective:
– Decisions are taken TODAY, but will generate consequences
in the FUTURE
3
The future
• Background conditions for possible futures:
–
–
–
–
More people to feed
More meat & dairy on the menu
Increased demand for land-dependant bioenergy
Uncertainty prospects for yield increase (P accessibility,
pollinator decline, climate change impacts, etc.)
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System Integration
Agricultural /
land system
Energy system
(Organic) waste
system
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System Integration
Agricultural /
land system
Energy system
BIOGAS
(Organic) waste
system
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1) The land system (why)
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Global outlook on land use (today)
13 Gha of land area on Earth:
•4.89 Gha agricultural land
 1.53 Gha arable land;
 3.36 Gha pastures
•4.04 Gha forest
 3.76 Gha natural forest;
 0.28 Gha plantations
Uncultivable
19%
Rest
12%
Arable
land
12%
Pasture
26%
Forest
31%
•4.09 Gha other land
 2.50 Gha uncultivable (tundra, ice, desert);
 1.59 Gha rest (built-up land, savannah, etc.)
(FAOSTAT, retrieved in 2012; FAO 2010; Kampman et al. 2008; Kok et al. 2008)
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Land use changes
DLUC
LUC
Food/feed crop
Energy crop
ILUC
LUC
Nature
Cropland
Intensification
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2) The energy system (why/when)
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The challenge of fluctuating
renewables
Circles:
surplus wind
In pink:
wind not
enough
Electricity produced from wind power vs demand. Modelled as 2008 capacity + 3000 MW (to represent
2020), for January (744 hours). Adapted from Hansen (2011).
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3) Case study example (HOW)
- external C co-substrates to boost manure-based
biogas (in Denmark)
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Context
• Ambition (DK): 50% of the manure produced
to be digested by 2020
• Carbon rich co-substrates necessary to ensure
economical sustainability
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Aim
Goal: investigating environmental consequences of different co-substrate
strategies for drastic increase in manure-biogas
FU: 1 ton manure ex-animal
1.002 ton
manure exhousing
Energy
crops
(maize
silage)
Straw
Household
biowaste
Commercial
biowaste
+
Garden
waste
Sourcesegregated
solid
manure
None
(Monodigestion)
=>: 7 baseline scenarios
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LCA System boundary
- Energy crop (maize silage)
Greener agriculture for
a Bluer Baltic Sea
28-08-2014
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LCA System boundary
- Energy crop (maize silage)
Greener agriculture for
a Bluer Baltic Sea
28-08-2014
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LCA System boundary
- Energy crop (maize silage)
ILUC
Greener agriculture for
a Bluer Baltic Sea
28-08-2014
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Lost alternatives
1.002 ton
manure exhousing
Energy
crops
(maize
silage)
LUC
Straw
Household
biowaste
Combustion
Commercial
biowaste
+
Garden
waste
Compost
Sourcesegregated
solid
manure
None
(Monodigestion)
Ref. manure mgmt
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Selected LCA results
- Global Warming
1018
ILUC
Impacts
2000
1000
0
-1000
-143
-101
-32
-128
-313
-2000
-3000
-1256
AVOIDED REFERENCE MANURE
MANAGEMENT
Savings
kg CO2 eq. per FU
3000
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Conclusions
• In a 100% RES, biomass is the only source of C.
• The environmental cost (GHG-wise) of biomass is potentially very high
• Biogas, because it is storable and versatile, allows to use biomass
efficiently
• Significant environmental benefits of avoiding reference manure
management, whenever this is possible
• Biogas strategy based on energy crop: important to remember why we
produce biogas at the first place
• Straw and biowastes better used for manure-biogas than for their other
uses (not universal for all substrates, though!)
• C recycling: biogas is also a key for maintaining soil C balances
• Biogas as a key to integration between land and energy systems: Any
strategy allowing to minimize land use is a must for a “sustainable” future.20
Questions & Discussions
[email protected]
For more details:
•Hamelin L, Naroznova I, Wenzel H (2014). Environmental consequences of different carbon
alternatives for increased manure-based biogas. Applied Energy 114, 774-782.
•Hamelin L. (2013) Carbon management and environmental consequences of agricultural
biomass in a Danish renewable energy strategy. PhD Thesis, University of Southern Denmark,
Odense, Denmark.
The correspondence for all references cited in this presentation can be found
in the above-mentioned PhD thesis.
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