Assessing Bioenergy Potentials in Rural Landscapes Oludunsin
Tunrayo Arodudu Alexey Voinov Iris van Duren
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INTRODUCTION Depletion of global fossil fuel reserves Climate
change challenges Shortage of fossil fuel supply
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Research Problem Developing a more holistic approach for
assessing bioenergy potential under an SEA framework Known measures
of bioenergy potential Available land Some biomass are not grown on
land Biomass yield Not a function of energy obtainable Energy yield
Energy invested not considered Money invested and gained
Susceptible to political and market mechanisms
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ALTERNATIVE APPROACH: NEG/EROEI Net Energy Gain (NEG) NEG =
Energy Output - Energy Input Net Energy Gain becomes a loss when it
is less than 0 & Energy Return on Energy Invested (EROEI) EROEI
= Energy Output / Energy Input Energy production activity becomes
incapable of supporting continuous socio-economic function when
EROEI is less than 3
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SCOPE OF THE STUDY (RURAL LANDSCAPES) Crop residues Farm manure
Surplus pasturelands Natural grasslands WHY? Relative benignity and
favourability in terms of existing policy constraints: Food
security Nature conservation: soil, water, biodiversity Competitive
use of biomass and well being of the local people
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Reasons for choice of crop and animal For crops (Scarlat et al,
2010): Corn, Rye, Triticale, Wheat, Barley, Oat, Rapeseed
Availability in commercial quantity Good Crop to Residue Yield For
animal (Fehrs, 2000): Beef Cattle, Dairy cattle, Pig, Chicken large
Population of animal % collectable on barns and hard surfaces For
Grasses on Surplus pasturelands (Prochnow et al, 2009)- Alfalfa
Prevent a total change in ecosystem structure Meet future fodder
needs
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Factors influencing potential availability of biomass for
bioenergy production For Crop residue (Scarlat et al, 2010) Use for
soil conservation purposes Use as substrates for mushroom (Wheat)
Use for animal beddings For Animal waste (Fehrs, 2000) %
collectable on barns and hard surfaces For Grasses (van Vuuren et
al, 2010) Use for animal beddings and animal feed
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Method: Combination of Life Cycle Inventory (LCI) and GIS From
the LCI: List of energy inputs and outputs, biomass and energy
conversion models and coefficients Estimation of Potential Biomass
and Biomass Potentially available for Bioenergy Production
Estimation of Energy Input and Output of the different bioenergy
production options Estimation of NEG and EROEI of the different
bioenergy production options From the GIS: Estimation of area under
natural grassland using GIS coverages (LGN 6 Land cover map)
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RESULTS: PERCENTAGE COMPOSITION Biomass typePercentage (%)
Manure89.56 Crop residue9.99 Natural Grassland0.44 Surplus
pasturelands0.01 Manure by far has the largest biomass and
bioenergy potential
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RESULTS: FARM MANURE Large NEG, not necessarily high EROEI
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RESULT: CROP RESIDUE Biomass type NEG (TJ)EROEI Corn
6684.7816.68 Rye 6.939.23 Triticale 7.758.52 Wheat 44.809.59 Oat
1.427.91 Barley 33.968.96 Rapeseed 2.559.04 Corn residues: most
energy efficient : High EROEI most energy profitable: High NEG
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Results: Choice of grass harvest for bioenergy production
Biomass typeNEG (TJ)EROEI Natural Grassland : Early Harvest (<
12cm) 153-2567.44 Intermediate Harvest (15-20cm) 216-36111.62 Late
Harvest (>25cm) 136-22813.09 Surplus Pasturelands: Early Harvest
(< 12cm) 2.472.12 Intermediate Harvest (15-20cm) 4.714.09 Late
Harvest (>25cm) 3.347.06 Natural grassland (Intermediate
Harvest): Natural Grassland Management Policy in the Netherlands
Surplus Pasturelands (Late Harvest): Highest energy efficiency
value (EROEI).
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Comparison of EROEI levels
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Form of energy Bioenergy target (60PJ) Conversion Efficiency of
biogas Bioenergy potential NEG-66PJ Net Gain to EU targets
elsewhere Transport fuel 23PJ96%23PJ- Heat (CHP) 13PJ70%28PJ+15PJ
of heat Electricity (CHP) 14PJ35%14PJ- Industrial raw material
10PJAs liquid fertilizer 5.94PJ-3.06PJ Evaluation of Overijssels
bioenergy potential Extra 2PJ of biogas still exists.
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Conclusions NEG/EROEI approach is quite holistic: Opens up room
for broad analysis of bioenergy potential issues Alternatives :
minimizing constraints and maximizing energy gains Unconventional
biomass sources Farm scale wet anaerobic co-digestion technology
Better animal management options and farm structures Energy
efficiency component: EROEI Accurate evaluation of bioenergy
targets: NEG Basis for stakeholder interactions