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Carbon Sequestration
SavePlanet EarthfromCO bombardment
Background• Greenhouse gases emission resulting from human activity are causing changes in the Earth’s temperature and weather systems
• carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and a group of chlorine and fluorine containing gases such as halo carbons (HF-C's) per-fluorocarbons (PFC) and sulfur hexafluoride (SF6).
• The main anthropogenic greenhouse gas is CO2.
Background (cont.)• In 2001 the IPCC predicted mean global temperatures to increase by between 1.4 and 5.80C over the coming century .Then what??????
• Global greenhouse gas emissions will rise by 52% by 2030, unless the world takes action to reduce energy consumption .
Implications• changes in the distribution of rainfall,
• changes in the frequency and intensity of extreme weather conditions
• sea level rise
• Africa already has a highly variable and unpredictable climate (including frequent droughts, floods and other extreme events).
. • Ecosystems, agriculture & forestry, water resources, human health and
industry are all sensitive to the planet’s climate.
Implications (cont.)• Poorest countries more vulnerable to global warming.• WHY?
• lack economic & social resources, meaning they are ill-equipt to adjust to rapid changes in long-term conditions.
• Local economic and social conditions in many parts of the Kagera Basin have driven poor people to marginal areas and forced them to exploit natural resources to support their livelihoods.
• Erode the quality of the natural resource base - without intervention this ill reinforce conditions of poverty.
Anticipated impacts of climate change on East Africa
• Decreased rainfall, increased temperature and evaporation in dry areas
• Frequent drought spells leading to severe water shortage
• Change of planting dates of annual crops
• Increased fungal outbreaks and insect infestations due to changes in temperature and humidity
Anticipated impacts of climate change on East Africa
• Decline in crop yields
• Increased risk of food shortage and famine
• Reduction in ecosystem integrity, resilience and decline in
biodiversity
• Increased potential of malaria transmission and burden on
the countries’ health care systems.
Carbon dioxide emission in top five countries
CHINA; 9700
USA; 5420
INDIA; 1970
RUSSIA; 1830
JAPAN; 1240
Million tonnes per annum
Netherlands Environment Agency
Carbon dioxide emissions per capitaDescription : Carbon dioxide emissions per capita Anthropogenic carbon dioxide emissions stemming from the burning of fossil fuels, gas flaring and the production of cement.Source : UN Common Database (CDIAC)Category : EnvironmentRanking : 54 (2002)
Unit of measurement: Metric tons per capita
INDIA
(Tons CO2 per person)
Sources of carbon dioxide emission
Man made sources Industries Transportation Land use change Soil cultivation Biomass burning
How can these increasing levels be reduced or stabilized?
• Reducing the demand for energy;
• Altering the way in which it is used;
• Changing the methods of producing and delivering energy.
How can these increasing levels be reduced or stabilizedDemand for energy can be influenced by a number of means
that include fiscal measures and changes in human behavior. • Improving energy efficiency; • Switching to low carbon fuel; • Switching to no-carbon fuels; • Preventing CO2 from fossil fuel combustion building up in
the atmosphere.
What is Carbon sequestration??
• Carbon sequestration refers to the capture and long term storage of carbon dioxide in forest, ocean or in deep geological formations to reduce the concentration of CO2 in the atmosphere
Ways that carbon can be sequestered
Geological sequestration: Underground
Ocean sequestration: Deep in ocean
Terrestrial sequestration: In plants and soil
Geological sequestration
Carbon extractedfrom a coal or otherfossil fuel…
is currently burned and emitted to air
• >CO2 is captured as concentratedhigh pressure fluid.
• >CO2is shipped as supercritical fluid via pipeline to a selected,permitted injection site.
>CO2 injected at pressure into pore space at depths below and isolated (sequestered)from potable water
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Terrestrial Sequestration
Terrestrial carbon sequestration is defined as either the net removal
of CO2 from the atmosphere or the prevention of CO2 net emissions from
the terrestrial ecosystems into the atmosphere.
• Storage of C in soils and plants has the potential to offset CO2 emissions
to the atmosphere in the coming decades while new ‘clean’ energy
production and CO2 sequestration technologies are developed and
deployed.
The following ecosystemsoffer significant opportunity for carbon sequestration:
Forest lands
Agricultural lands
Biomass croplands
Deserts and degraded lands
Wetlands and peat lands
Benefits of Soil Carbon Sequestration
Improved agricultural performance
Increased soil fertility
Healthier ecology
Improved soil structure
Less erosion
Better water use and storage
Improved biodiversity
Ocean Sequestration
Carbon is naturally stored in the ocean via two pumps, solubility and biological and there are analogous
man made methods, direct injection and ocean fertilization, respectively.
At the present time, approximately one third of human generated emissions are estimated to be
entering the ocean.
Ocean Sequestration
CO2 is soluble in ocean water, and oceans absorb and emit huge amounts of CO2 into the atmosphere through natural processes. Ocean Sequestration has huge potential as a carbon storage sink, however, enough R&D have to be carried out to understand about the physio-chemical processeswhich occur between seawater and pumped CO2.
Storage of CO2 in deep oceans has been suggested as a means of reducing inputs of greenhouse gases to the atmosphere.
MAJOR STORAGE SITES IN THE WORLD• Sleipner, Norwegian North Sea• Altmark, Germany• Weyburn, Canada• In Salah, Algeria• Miranga, Brazil• Hontomin, Spain• Hastings, Texas, USA
ADVANTAGES• CCS applied to a modern conventional power plant could reduce CO2
emissions to the atmosphere by 80-90 % compared to a plant without CCS.
• the solvents used to capture CO2 from the flue gases will remove some nitrogen oxides and sulphur oxides.
DISADVANTAGES• Increase significantly the emissions of acid gas pollutants.
• Capturing and compressing C02 requires much energy and would
increase the fuel needs of a coal-fired plant with CCS by 25-40%.
• These and other system costs are estimated to increase the cost of
energy from a new power plant with CCS by 21-90 %.
• CONT
• Water consumption, however, may be an issue for carbon capture systems which rely on solvents to remove CO2 from flue gases.
• This increase in water consumption may make these systems less suited to dry regions.
CARBON CAPTURE: ENVIRONMENTAL IMPACTS
• In ocean storage carbon dioxide reacts with water to form acid, so the oceans could become significantly more acidic .
• Another difficulty is that the CO2 would also eventually return to the atmosphere.
• In addition to the global climate change impact of CO2 returning to the atmosphere, leakages pose local risks to health and ecosystems.
• For storage sites under water, there are concerns about chronic exposure
of marine ecosystems to raised CO2 levels, such as might occur near injection sites.
• For CO2 storage sites on land, there are concerns that large scale leakage could harm people and wildlife in the immediate vicinity.
REFERENCES• Gibbins, J., Chalmers, H. (2007). Preparing for global rollout: A ‘developed country first’ demonstration programme for
rapid CCS deployment. Energy Policy. doi:10.1016/j.enol.2007.10.021.
• Tzimas, T., Mercier, A., Cormos, C. and Petevas, S.D. (2007). Trade-off in emissions of acid gas pollutants and of carbon
dioxide in fossil fuel power plants with carbon capture. Energy Policy. 35 (8):3991-3998.
• Bickle, M., Chadwick, A., Huppert, H. E., et al. (2007). Modelling carbon dioxide accumulation at Sleipner: Implications for
underground carbon storage. Earth and Planetary Science. 255, 164–176.
• Johansson, M., Mattisson, T., Lyngfelt, A. et al. (2008). Using continuous and pulse experiments to compare two promising
nickelbased oxygen carriers for use in chemicallooping technologies. Fuel. 87 :988-1001.
• Race, J.M., Seevam, P. N., Downie, M.J. (2007). Challenges for offshore transport of anthropogenic carbon dioxide.
Proceedings of OMEA2007, 10-15 June, 2007, San Diego, CA,USA.
Thank You