Laminaria digitata - Algecenter Danmark
Laminaria digitata - Algecenter Danmark
Laminaria digitata - Algecenter Danmark
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Life Cycle Assessment of biogas<br />
production process from <strong>Laminaria</strong><br />
<strong>digitata</strong><br />
Merlin Alvarado�Morales<br />
Bioenergy Research group<br />
Department of Environmental Engineering<br />
Technical University of Denmark
� ... \Introduction<br />
� ... \Objective<br />
� ... \LCA framework<br />
� ... \ ○ Goal and scope definition<br />
○ Inventory analysis (LCI)<br />
○ Impact assessment<br />
○ Interpretation \<br />
� ... \ Conclusions<br />
….\Agenda to be followed<br />
2
�Objective<br />
….\Introduction<br />
The aim of this work was to perform a Life Cycle<br />
Assessment (LCA) of a biogas process from<br />
<strong>Laminaria</strong> <strong>digitata</strong> to identify bottlenecks and to<br />
improve the environmental aspects at various<br />
points in its life cycle.<br />
3
o ISO 14040 (ISO 2006)<br />
o ILCD Handbook (EU-JRC-IES, 2010)<br />
….\LCA framework<br />
4
�Goal and scope definition<br />
o Functional unit<br />
o System boundaries<br />
o Assumptions and limitations<br />
o Impact categories<br />
….\LCA framework<br />
5
�Inventory analysis (LCI)<br />
….\LCA framework<br />
o Inventory of flows from and to environment<br />
o Inputs of water, energy, and raw materials<br />
o Outputs to air, land, and water<br />
o Data flows are related to the functional unit<br />
6
�Impact assessment<br />
o Selection of impact categories (global<br />
warming, eutrophication, etc.)<br />
o Selection of characterization models<br />
o Impact measurement<br />
….\LCA framework<br />
7
�Interpretation<br />
o Identification of significant issues<br />
o Evaluation of the study<br />
... \ Completeness<br />
... \ Sensitivity analysis<br />
... \ Consistency check<br />
….\LCA framework<br />
o Conclusions, limitations and recommendations<br />
8
�Goal and scope definition<br />
Functional unit<br />
Cultivation and processing of one tonne of dry<br />
….\LCA framework<br />
seaweed biomass –<strong>Laminaria</strong> <strong>digitata</strong>– produced<br />
in Denmark for biogas production.<br />
9
�Goal and scope definition<br />
….\LCA framework<br />
To assess the potential environmental impacts of<br />
a seaweed-based biogas process as well as to<br />
identify hotspots in the life cycle where<br />
environmental performance of the system can be<br />
improved.<br />
10
�Goal and scope definition<br />
….\LCA framework<br />
o The impact assessment was performed based<br />
on EDIP2003 (Hauschild and Potting, 2003).<br />
o Impact categories: Global warming,<br />
Acidification and Terrestrial Eutrophication.<br />
11
�Goal and scope definition<br />
System boundaries – process system description<br />
….\LCA framework<br />
12
Assumptions<br />
�Goal and scope definition<br />
….\LCA framework<br />
o The investigated algae processing system was<br />
assumed to be located along the coastline in<br />
Denmark.<br />
o The seaweed cultivation site was situated at<br />
the open sea.<br />
o The biogas production facility was situated at<br />
the seaside on land.<br />
13
Assumptions<br />
�Goal and scope definition<br />
o The biogas produced is combusted in a gas<br />
engine with electrical efficiency of 42%.<br />
….\LCA framework<br />
o Heat is also cogenerated but used internally in<br />
the biogas plant.<br />
o The electricity generated is assumed to<br />
substitute coal-based marginal electricity.<br />
14
Assumptions<br />
�Goal and scope definition<br />
….\LCA framework<br />
o The digestate generated is used as fertilizer on<br />
agricultural land.<br />
15
�Inventory analysis (LCI)<br />
….\LCA framework<br />
Samples of L. <strong>digitata</strong> were collected in late March<br />
2011, at Ømo, Denmark.<br />
Arbona and Molla (2006) and Edwards<br />
and Watson (2011) , personal<br />
communication with fishermen<br />
Seaweed production<br />
16
�Inventory analysis (LCI)<br />
….\LCA framework<br />
Data on biogas potential were generated through<br />
batch experiments at 52 °C for 30 days.<br />
mLCH4/gVS<br />
250<br />
200<br />
150<br />
100<br />
50<br />
Anaerobic digestion<br />
0<br />
S. latissima*<br />
L. <strong>digitata</strong>*<br />
P. palmata*<br />
U. lactuca**<br />
U. fusca**<br />
17
Assumptions<br />
�Impact assessment<br />
o The impact assessment was facilitated in<br />
SimaPro 7.2.4 LCA software (Pre, 2010).<br />
….\LCA framework<br />
18
Assumptions<br />
�Impact assessment<br />
Impact Potentials<br />
200<br />
100<br />
0<br />
-100<br />
-200<br />
-300<br />
-400<br />
-500<br />
-600<br />
-700<br />
Characterized Environmental Impact Potentials<br />
Global Warming<br />
(kg CO 2 -eq)<br />
Seaweed Production (SWP)<br />
Mechanical Pretreatment (MP)<br />
Anaerobic Digestion (AD)<br />
Total<br />
Acidification x 10<br />
(m 2 )<br />
Terrestrial Eutrop.<br />
x 10 (m 2 )<br />
….\LCA framework<br />
19
Assumptions<br />
�Interpretation<br />
….\LCA framework<br />
o Important benefits for all impact categories<br />
due to savings linked to both the avoided<br />
fertilizer and energy production.<br />
o In fact, 555 kWh of electricity per functional<br />
unit are recovered and delivered to the grid,<br />
thereby displacing coal-based marginal<br />
electricity production somewhere else in the<br />
energy system.<br />
20
Assumptions<br />
�Interpretation<br />
….\LCA framework<br />
o Electricity consumption was estimated to be:<br />
118 kWh per one tonne of dry seaweed.<br />
o Electricity production was estimated to be:<br />
555 kWh per one tonne of dry seaweed.<br />
o Net electricity production: 437 kWh per<br />
functional unit.<br />
21
Assumptions<br />
�Interpretation<br />
….\LCA framework<br />
o “Electricity, hard coal, at power plant/NORDEL<br />
S”: 0.851 kg of CO 2 per kWh of electricity<br />
produced.<br />
o Therefore, ca. 372 kgCO 2 per tonne of dry<br />
seaweed are avoided.<br />
o 8, 9 and 37 kg of N, P, and K per one tonne of<br />
dry seaweed.<br />
22
Assumptions<br />
�Sensitivity analysis<br />
Impact Potentials<br />
0<br />
-100<br />
-200<br />
-300<br />
-400<br />
-500<br />
-600<br />
-700<br />
-800<br />
-900<br />
Sensitivity Analysis Results<br />
Base case S1 S2 S3<br />
Global warming (kg CO2-eq)<br />
Acidification x 10 (m2)<br />
Terrestrial Eutrophication x 10 (m2)<br />
S1: Energy consumption in SWP (-10%)<br />
S2: LCH4/gVS (+10%)<br />
S3: LCH4/gVS (+42%)<br />
….\LCA framework<br />
23
�Conclusions<br />
o Sensitivity analysis showed that the system<br />
….\LCA framework<br />
has potential for technological development<br />
and consequently significant improvements.<br />
o Improve the biodegradability of the feedstock<br />
by different pretreatments.<br />
o Metal content in the digestate needs to be<br />
evaluated.<br />
24
Life Cycle Assessment of biogas<br />
production process from <strong>Laminaria</strong><br />
<strong>digitata</strong><br />
Merlin Alvarado�Morales<br />
Bioenergy Research group<br />
Department of Environmental Engineering<br />
Technical University of Denmark<br />
www.capec.kt.dtu.dk
�Inventory analysis (LCI)<br />
….\LCA framework<br />
Resource<br />
consumption<br />
Unit<br />
Seaweed<br />
production<br />
Mechanical<br />
pretreatment<br />
Anaerobic<br />
Digestion<br />
Diesel L 30<br />
Petrol L 30<br />
Electricity kWh 30 38 50<br />
Heat kWh (GJ) 512 (1.84)<br />
Water L 2380 3439<br />
Stock nutrients solution L 0.03<br />
Plantlet nutrients g 189<br />
26
�Conclusions<br />
….\LCA framework<br />
o Production of different biofuels has their own<br />
benefits, risks and uncertainties.<br />
27
�Conclusions<br />
o In order to ensure net societal benefits of<br />
….\LCA framework<br />
biofuel production, governments, researchers<br />
and companies need to work together to carry<br />
out comprehensive assessments, map suitable<br />
and unsuitable areas, and define/apply<br />
standards relevant to the different<br />
circumstances of each country.<br />
28