1. Renewable / Alternative / Sustainable Energy : Analyzing the options
Carbon Sequestration
By means of
Ocean Iron Fertilization
Igal Levine, Alon Henson and Yotam Asscher
June 2010

2. What is Ocean Iron Fertilization?
Could this be a solution ?
Introduction
Carbon sequestration by means of Ocean Iron Fertilization

3. Goals
Perform a CO2 emissions analysis to Ocean Iron Fertilization (OIF).
Examine the global potential of Ocean Iron Fertilization
Introduction
Carbon sequestration by means of Ocean Iron Fertilization

4. Methodology Introduction Life Cycle Analysis
Raw Materials
Manufacture
Distribution
Product use
Closing the loop
Life Cycle
Analysis
Introduction
Carbon sequestration by means of Ocean Iron Fertilization

5. Iron Life cycle scheme CO2 Analysis Ore Extraction Pre-treatment
Iron Fertilization
Ore Extraction
Pre-treatment
CO2 Removal
Transport
CO2 Analysis
Carbon sequestration by means of Ocean Iron Fertilization

6. How much Iron is needed per Carbon?
Fe/C molar ratio
Green : mixed layer phytoplankton
Red : suspended biogenic particles
Brown : sinking biogenic particles
Blue : remineralization of particles
A-E : different regions
ML mixed layer
Value used in LCA : 4x10-4 , From the subantartic ocean
Directions Mesoscale Iron Enrichment Experiments : Synthesis and Future P. W. Boyd, et al. Science 315, 612 (2007)
Introduction
Carbon sequestration by means of Ocean Iron Fertilization

7. Iron ore production CO2 Analysis Value used in LCA : 10 kg CO2e/ton
Journal of Cleaner Production Volume 18, Issue 3, February 2010, Pages
CO2 Analysis
Carbon sequestration by means of Ocean Iron Fertilization

8. Overall reaction energy [kJ/mol] Average specific energy [kJ/ton]
Pretreatment - From Iron ore to Iron sulphate
Reaction
Overall reaction energy [kJ/mol]
Specific Energy
[kJ/ton]
Fe2O3 + 2H2SO4 → 2FeSO4 + 2H O2
297.7
5.3x106
FeO + H2SO4 → FeSO4 + H O2
157.6
2.8x106
Fe3O4 + 3H2SO4 → 3FeSO4 + 3H2 + 2O2
258.4
4.6x106
Average specific energy [kJ/ton]
CO2 e [kg]
4.2x106
1.3x103
But what about the process?
CRC handbook chapter 5 section 12
CO2 Analysis
Carbon sequestration by means of Ocean Iron Fertilization

9. Modeling the process CO2 Analysis Fe2O3 + 4SiO2 + 11C → 2FeSi2 + 11CO
Overall reaction energy
Specific Energy
CO2 e [kg]
1.6x103 [kJ/mole]
2.9x107 [kJ/ton]
8.7x103
Overall ferrosilicon production
2.2x104 [kg CO2 e]
Reaction / Production
40%
Overall pretreatment
1.3x103x2.5=3.2x103 [kg CO2 e]
Int J Life Cycle Assess (2009) 14:480–489
CO2 Analysis 9
Carbon sequestration by means of Ocean Iron Fertilization

10. Transportation Value used in this LCA : 36g CO2e/ton-km CO2 Analysis
Carbon sequestration by means of Ocean Iron Fertilization

11. Transportation Transportation distance : 10,000km CO2 Analysis
Carbon sequestration by means of Ocean Iron Fertilization

12. CO2 sequestered / CO2 emitted ~ 103
CO2 Balance
Quantity of Iron
1 ton
Transportation distance
10,000 km
Production
Transportation
Pretreatment
Total
10 [kg CO2]
3.6x102 [kg CO2]
3.2x103 [kg CO2]
3.6x103 [kg CO2]
CO2 Sequestered [kg]
2x106
CO2 sequestered / CO2 emitted ~ 103
CO2 Analysis
Carbon sequestration by means of Ocean Iron Fertilization

13. Global Potential of Ocean Iron Fertilization
Upper Limit of ocean carbon uptake
Phosphate and Iron demand for ocean iron fertilization
Global potential
Carbon sequestration by means of Ocean Iron Fertilization

14. What will be the best location for Ocean Iron Fertilization?
Plate 3a shows the magnitude of the seasonal difference for
phosphate integrated over the top 100 m of the ocean and
multiplied by a C:P ratio of This map represents spring-
summer new production
GLOBAL BIOGEOCHEMICAL CYCLES, VOL. 14, NO. 3, PAGES , SEPTEMBER 2000
Global potential
Carbon sequestration by means of Ocean Iron Fertilization

15. How much carbon can we sequester up to 2100?
Phosphorous net annual production in Southern oceans
6.6x1011 mole of Phosphorous
Phosphorous available until 2100 assuming linear correlation
6.0x1013 moles of Phosphorous
Redfield molar ratio for carbon : phosphorous
1 Carbon : 106 Phosphorous
Carbon sequestration until 2100
6x1015 moles of carbon
Global potential
Carbon sequestration by means of Ocean Iron Fertilization

16. How much Iron will we need?
Global maximum uptake of CO2 – theoretical model (Caldeira 2010)
6x1015 moles of CO2
Amount of Iron needed for maximum theoretical uptake
1.4x108 ton
Global amount of Iron production per year (2007)
1.1x109 ton
Global amount of Iron production until 2100
1.0x1011 ton
Plate 3a shows the magnitude of the seasonal difference for
phosphate integrated over the top 100 m of the ocean and
multiplied by a C:P ratio of This map represents spring-
summer new production
Iron needed / Iron production
0.1%
CO2 emitted due to fertilization process
5.1x1011 Kg = 1.2x1013 moles of CO2
Journal of Climatic Change “Can ocean iron fertilization mitigate ocean acidification?” L. Cao, K. Caldeira 2010
Global potential
Carbon sequestration by means of Ocean Iron Fertilization

17. A big improvement? Global potential Results (year 2100) model
Atm. CO2 [ppm]
Atm. Change in carbon storage
[PgC]
Ocean. Change in carbon storage
Pre-industrial
280.0
A2_emis
965.3
1457.1
540.9
A2_emis+OIF
832.6
1175.8
822.2
change in atmosphere and/or ocean carbon storage is relative to the pre-industrial values
2.8x1017g = 6x1015 moles of CO2
Journal of Climatic Change “Can ocean iron fertilization mitigate ocean acidification?” L. Cao, K. Caldeira 2010
Global potential
Carbon sequestration by means of Ocean Iron Fertilization

18. Summary
LCA of iron fertilization shows that carbon emitted in the process of fertilization is ~1000 times less than the carbon sequestered by fertilization between the years (Caldeira).
The estimates done in the LCA were done using the most stringent Fe/C uptake ratio, hence in terms of CO2 emissions, the process is favorable.
Further research should be done in order to asses the ecological impact of iron fertilization in the southern ocean.
(Acidification of deep ocean, Nutrient depletion)
OIF reduces atmospheric concentration but does not eliminate the CO2 problem.
Summary
Carbon sequestration by means of Ocean Iron Fertilization

19. The end… Questions? Acknowledgments Prof. David Cahen Dr. Ron Milo
Alon Shepon
Prof. Uri Pick
Dr. Hezi Gildor
Questions?
Summary
Carbon sequestration by means of Ocean Iron Fertilization