Carbon Sequestration- Curbing Global Warming

Before starting up with the topic let us see what is Carbon Capture and Storing. Carbon capture and storage (CCS) is an approach to mitigate the contribution of fossil fuel emissions to global warming. It is based on capturing carbon dioxide (CO2) from large point sources such as fossil fuel power plants. It can also be used to describe the scrubbing of CO2 (A CO2 scrubber is a device which absorbs carbon dioxide) from ambient air as a geoengineering technique. The concept of geoengineering is usually taken to mean proposals to deliberately manipulate the Earth's climate to counteract the effects of global warming from greenhouse gas emissions. The captured carbon dioxide can then be permanently stored away from the atmosphere. Carbon dioxide is been extensively used for crude oil EOR operations in US.
Carbon sequestration is the storage of carbon dioxide through biological, chemical or physical processes, for the mitigation of global warming. Mitigation of global warming involves taking actions to reduce greenhouse gas emissions and to enhance carbon sinks aimed at reducing the extent of global warming. A Carbon Sink is a natural or manmade reservoir that accumulates and stores carbon containing chemical compound for an indefinite period.
1. The main Natural sinks are:-
· Absorption of CO2 by the oceans.
· Photosynthesis by plants and algae.

2. The main Manmade sinks are:-
· Landfills- A landfill, also known as a dump is a site for the disposal of waste (here waste is CO2 ) materials by burial and is the oldest form of waste treatment.
· Carbon capture and storage proposals.
Carbon capture and sequestration begins with the separation and capture of CO2 from power plant flue gas and other stationary CO2 sources. At present, this process is costly and energy intensive, accounting for the majority of the cost of sequestration. However, analysis shows the potential for cost reductions of 30–45 percent for CO2 capture. Post-combustion, pre-combustion, and oxy-combustion capture systems being developed are expected to be capable of capturing more than 90 percent of flue gas CO2.
The next step is to sequester (store) the CO2. The primary means for carbon storage are injecting CO2 into geologic formations or using terrestrial applications. Geologic sequestration involves taking the CO2 that has been captured from power plants and other stationary sources and storing it in deep underground geologic formations in such a way that CO2 will remain permanently stored. Geologic formations such as oil and gas reservoirs, unmineable coal seams, and underground saline formations are potential options for storing CO2. Storage in basalt formations and organic rich shales is also being investigated.
Terrestrial sequestration involves the net removal of CO2 from the atmosphere by plants and microorganisms that use CO2 in their natural cycles. Terrestrial sequestration requires the development of technologies to quantify with a high degree of precision and reliability the amount of carbon stored in a given ecosystem.
In September 2008, a Coal-fired power plant in Spremberg, Eastern Germany, became the world's first coal using plant to capture and store carbon dioxide. The Swedish electricity provider Vattenfall has invested 70 million Euros in this project. The idea is simple. Carbon dioxide is captured, turned into liquid and transported hundreds of kilometers. It is then stored 3,500 meters underground in natural gas caves. But this project has been heavily criticized by environmentalists. This new technology needs more coal to produce the same amount of electricity as with conventional means. And no one is sure whether the stored CO2 may not cause an increase in the temperature underground.