1. SETAC Conference 11-13 November 2013 Rome, Italy
The (Exergetic) Life Cycle Assessment ((E)LCA)
of microalgae production as feed for aquaculture:
an environmental sustainability analysis
Sue Ellen TAELMAN(a)
S. De Meester(a), L. Roef(b), M. Michiels(b), J. Dewulf(a)
(a) Research Group EnVOC, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
(b) Proviron Holding nv, G. Gilliotstraat 60, 2620 Hemiksem, Belgium

2. Introduction
Aquaculture: feeding fish to fish principle is not sustainable
Alternative for fish oil/meal production = ALGAE
Microalgae are unicellular, mostly photo-autotrophic organisms
They need water, light and inorganic nutrients to grow
Some advantages:
Very rich biomass
Able to live of waste streams
Higher photosynthetic efficiency
Marginal land is sufficient
Known disadvantages:
Low cell density cultivation -> reflection on harvesting and processing
Claimed to be a sustainable biomass resource -> correct? .

3. Research questions
Examining the environmental sustainability of algae production in the new ProviAPT system
Scenarios:
Pilot 2012 (based on actual production runs)
Two upscaling scenarios (2013 and 2015)
Determining the potential of microalgae as fish feed application + benchmarking with traditional fish feed

4. Methods Exergy analysis on process level
Thermodynamics: ‘all real processes generate entropy’
‘all real processes generate loss of work potential’
Quality/quantity measurement of material & energy flows
Process improvement
Life Cycle Assessment (LCA), ISO standards & 14040
Functional unit: 1MJex
System boundaries: cradle to gate
Foreground: provided by Proviron
Background: database ecoinvent v2.2
Climate change (IPCC,2007)
Resource consumption (CEENE, 2007)

5. Cultivation
Pilot 2012
240 m²
Michiels, M. 2009 : Bioreactor. EP

6. Foreground system pilot 2012
Centrate
Permeate

7. Forecast: First production scale 2015
Upscaling analysis (1)
Pilot 2012
Forecast:
Pilot 2013
Forecast: First production scale 2015
Scenario (generic)
Scale
240 m²
1320 m²
2.5 ha
Location
Belgium
Spain
Recycling of permeate and
centrate (process C and D) No
Yes, extra filtration on centrate
Photobioreactor
Area PBR
12 m²
26 m²
Reactive area PBR
7 m²
21 m²
Photosynthetic efficiency
1.2% on 12 m²
2.4% on 26 m²
Areal productivity
4.59 g/m²/d
15.1 g/m²/d
Volumetric productivity
0.53 g/l/d
1.25 g/l/d
Efficiency fan
25 %
35 %
80 % (a)
Efficiency circulation pump
11 %
80 % (b)
Source CO2
bottled
Flue gases
Heat
200 W/m², 50% of the year at 50% of the peak power
No extra heat necessary
(a) based on document UNEP, 2006a (b) based on document UNEP, 2006b (c) Piek et al., 2012 (d) Sheehan et al., 1998

8. Forecast: First production scale 2015
Upscaling analysis (2)
Pilot 2012
Forecast:
Pilot 2013
Forecast: First production scale 2015
Centrifuge
Type
Bowl centrifuge
Hydrostop centrifuge
Electricity consumption
15 kWh/m³
3.5 kWh/m³
0.95 kWh/m³(c)
Drying
Freeze dryer
Drum dryer
59 kWh/kg DW
13 kWh/kg DW /
Natural gas consumption
0.98 kWh/kg H2O(vapour)(d)
(a) based on document UNEP, 2006a (b) based on document UNEP, 2006b (c) Piek et al., 2012 (d) Sheehan et al., 1998

9. Forecast: First production scale (2015)
LCA: results (1)
Pilot plant (2012)
Forecast:
Pilot plant (2013)
Forecast: First production scale (2015)
Cumulative Energy Extraction from
the Natural Environment (CEENE)
MJex,CEENE/MJex DM
55.5
21.6
2.46
Renewable
0.58
0.18
0.11
Fossil
21.26
8.04
1.24
Nuclear
24.45
9.32
0.23
Metal ores
0.02
0.01
0.00
Minerals
0.17
Water
4.47
1.34
0.20
Land use
4.57
2.66
0.68
Atmosphere
Carbon Footprint (CF)
kg CO2,eq/MJex DM
1.76
0.64
0.09

10. LCA: results (2) CEENE (MJex,CEENE/MJex DM) IPCC (kg CO2,eq/MJex DM)
Pilot 2012
Forecast Pilot 2013
Forecast First Production scale 2015
IPCC (kg CO2,eq/MJex DM)
Pilot 2012
Forecast Pilot 2013
Forecast First Production scale 2015
*(Huysveld et al., 2011; Huysveld et al., 2013)

11. Conclusions and future research
Recycling of water/nutrients and savings on energy use show important routes to make the overall production more sustainable
Also upscaling, reactor design improvements, enhancement of photosynthetic yield and good choice of location contribute to an environmental progress
Although additional efforts are required to improve the carbon footprint, in the near future algae production can reach a lower resource footprint (2.46 MJex,CEENE/MJex DM) than traditional fish feed (7.70 MJex,CEENE/MJex DM)
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