CO2

1. Carbon Capture and Storage
PRESENTATION TO THE PORTFOLIO COMMITTEE OF
ENVIRONMENT, TUESDAY 21 AUGUST 2007
CCS: 210807

2. Carbon Sequestration
• Carbon capture and storage (CCS) is an approach to
mitigating global warming by capturing carbon dioxide
(CO2) from large point sources such as power plants and
subsequently storing it instead of releasing it into the
atmosphere. Technology for capturing of CO2 is already
commercially available for large CO2 emitters, such as
power plants; however, capture is meaningless without
storage. Storage of CO2, on the other hand, is a relatively
untried concept and as yet (2007) no power plant operates
with a full carbon capture and storage system.

3. Worldwide large stationary
sources of CO2

4. CO2 storage
• Various forms have been conceived for
permanent storage of CO2. These forms
include gaseous storage in various deep
geological formations (including saline
formations and exhausted gas fields), liquid
storage in the ocean, and solid storage by
reaction of CO2 with metal oxides to produce
stable carbonates

5. Geological storage
• Also known as geo-sequestration, this method involves injecting carbon
dioxide directly into underground geological formations. Oil fields, gas
fields, saline formations, unminable coal seams, and saline-filled basalt
formations have been suggested as storage sites. Here, various physical
(e.g., highly impermeable caprock) and geochemical trapping
mechanisms would prevent the CO2 from escaping to the surface. CO2 is
sometimes injected into declining oil fields to increase oil recovery
(enhanced oil recovery). This option is attractive because the storage
costs are offset by the sale of additional oil that is recovered.
Disadvantages of old oil fields are their geographic distribution and their
limited capacity.

6. ……Storage
• Unminable coal seams can be used to store CO2
because CO2 adsorbs to the surface of coal.
However, the technical feasibility depends on the
permeability of the coal bed. In the process of
absorption the coal releases previously absorbed
methane, and the methane can be recovered
(Enhanced Coal Bed Methane recovery). The sale
of the methane can be used to offset the cost of the
CO2 storage.

7. ….. Storage
• Saline formations contain highly mineralized brines, and
have so far been considered of no benefit to humans.
Saline aquifers have been used for storage of chemical
waste in a few cases. The main advantage of saline
aquifers is their large potential storage volume and their
common occurrence. This will reduce the distances over
which CO2 has to be transported. The major disadvantage
of saline aquifers is that relatively little is known about
them, compared to oil fields. To keep the cost of storage
acceptable the geophysical exploration may be limited,
resulting in larger uncertainty about the aquifer structure.
Unlike storage in oil fields or coal beds no side product will
offset the storage cost. Leakage of CO2 back into the
atmosphere may be a problem in saline aquifer storage.
However, current research shows that several trapping
mechanisms immobilize the CO2 underground, reducing

8. ….. Storage
• For well-selected, designed and managed
geological storage sites, IPCC estimates that
CO2 could be trapped for millions of years,
and the sites are likely to retain over 99% of
the injected CO2 over 1,000 years.

9. ….. Storage
• Ocean storage
• Two main concepts exist. The 'dissolution' type
injects CO2 by ship or pipeline into the water
column at depths of 1000 m or more, and the CO2
subsequently dissolves. The 'lake' type deposits
CO2 directly onto the sea floor at depths greater
than 3000 m, where CO2 is denser than water and
is expected to form a 'lake' that would delay
dissolution of CO2 into the environment.

10. Dissolution and lake type storages

11. CCS v non-CCS
• CCS applied to a modern conventional power plant
could reduce CO2 emissions to the atmosphere by
approximately 80-90% compared to a plant without
CCS. Capturing and compressing CO2 requires
much energy and would increase the fuel needs of
a plant with CCS by about 10-40%. These and
other system costs are estimated to increase the
cost of energy from a power plant with CCS by 30-
60% depending on the specific circumstances.

12. • Storage of the CO2 is envisaged either in deep geological
formations, deep oceans, or in the form of mineral
carbonates. In the case of deep ocean storage, there is a
risk of greatly increasing the problem of ocean acidification,
a problem that also stems from the excess of carbon
dioxide already in the atmosphere and oceans.
• Geological formations are currently considered the most
promising sequestration sites, and these are estimated to
have a storage capacity of at least 2000 Gt CO2. IPCC
estimates that the economic potential of CCS could be
between 10% and 55% of the total carbon mitigation effort
until year 2100.

13. Geological storage options

15. conceptual plan for converting
methane gas into hydrogen
and CO2, then pumping the
separated CO2 offshore to
assist with efficient oil
production from the Miller
oilfield.

16. World CO2 emissions
The quantity has steadily increased
since the start of the industrial
revolution (1800's) and peaked late
in the last century. Worldwide,
emissions are still rising.

17. How does CO2 affect climate ?
The average temperature of the
Earth is rising, especially when
measured at the poles. Note that
the average Earth surface
temperature correlates well with
the amount of CO2 in the
atmosphere (i.e. as the CO2 levels
in the atmosphere have increased,
the surface temperature has gone
up at the same time).

18. How does CO2 affect oceans?
• About half of the extra CO2 from the
atmosphere will dissolve in the oceans, making
the water more acidic. The diagram shows how
acidic the oceans will become in the future, upto
the year 3000. To work this out, it was
necessary to:
• predict how CO2 emissions will change in the
future (the top of the diagram)
• calculate how this will change the amount of
CO2 in the atmosphere (middle part of the
diagram)
• finally work out how acidic the oceans will
become (bottom part of the diagram)
• The acidity is shown as a change in pH units.
The effects of this change on marine life is
unknown, but could be disastrous.
Diagram from Caldeira, K. & Wickett, M.E.
(2003) Nature, v. 425. p. 365

19. …CO2 and Oceans
The ocean already holds 400
Billion tons of fossil fuel CO2.
Consequently, the ocean is already
0.1 pH units more acid than before
industrial CO2 emissions. This
means nutrients for plankton in the
North Sea, and all shallow ocean
waters, are
changing rapidly. This is the base of the food chain for invertebrates,
shells and, eventually, economic fishing. By 2050 the ocean will be
five times more acid than at any time since glaciation (change pH
8.4 to pH

20. Cost of CCS
• Capturing and compressing CO2 requires much
energy, significantly raising the running costs of
CCS-equipped power plants. In addition there are
added investment or capital costs. The process
would increase the energy needs of a plant with
CCS by about 10-40%. The costs of storage and
other system costs are estimated to increase the
costs of energy from a power plant with CCS by
30-60%, depending on the specific circumstances.

21. …..Cost
• For the world scale,
estimates are commonly
about 2% of Global
Domestic Product. That
is one year of normal
growth.

22. CO2 transport
• After capture, the CO2 must be transported
to suitable storage sites. This is done by
pipeline, which is generally the cheapest
form of transport, or by ship when no
pipelines are available. Both methods are
currently used for transporting CO2 for other
applications.

23. Environmental effects
• A third concept is to convert the CO2 to bicarbonates
(using limestone) or hydrates.
• The environmental effects of ocean storage are generally
negative, but poorly understood. Large concentrations of
CO2 kills ocean organisms, but another problem is that
dissolved CO2 would eventually equilibrate with the
atmosphere, so the storage would not be permanent. Also,
as part of the CO2 reacts with the water to form carbonic
acid, H2CO3, the acidity of the ocean water increases. The
resulting environmental effects on benthic life forms are
poorly understood. Even though life appears to be rather
sparse in the deep ocean basins, energy and chemical
effects in these deep basins could have far reaching
implications. Much more work is needed here to define the
extent of the potential problems.

24. ….Environmental effects
• The time it takes water in the deeper oceans to circulate to
the surface has been estimated to be on the order of 1600
years, varying upon currents and other changing
conditions. Costs for deep ocean disposal of liquid CO2
are estimated at 40-80USD/ton (2002 USD). This figure
covers the cost of sequestration at the powerplant and
naval transport to the disposal site.
• The bicarbonate approach would reduce the pH effects
and enhance the retention of CO2 in the ocean, but this
would also increase the costs and other environmental
effects.

25. ….Environmental effects
• Leakage
• A major concern with CCS is whether leakage of stored
CO2 will compromise CCS as a climate change mitigation
option. For well-selected, designed and managed
geological storage sites, IPCC estimates that CO2 could
be trapped for millions of years, and are likely to retain over
99% of the injected CO2 over 1000 years. For ocean
storage, the retention of CO2 would depend on the depth;
IPCC estimates 30-85% would be retained after 500 years
for depths 1000-3000 m. Mineral storage is not regarded
as having any risks of leakage. The IPCC recommends
that limits be set to the amount of leakage that can take
place.

26. Norway’s Sleipner gas field
• To further investigate the safeness of CO2 sequestration,
we can look into Norway's Sleipner gas field, as it is the
oldest plant that sequesters CO2 in an industrial scale.
According to an environmental assessment of the gas field
which was conducted after ten years of operation, the
author affirmed that geographic sequestration of CO2 was
the most definite way to store CO2 permanently.
• "Available geological information shows absence of major
tectonic events after the deposition of the Utsira formation
[saline reservoir]. This implies that the geological
environment is tectonically stable and a site suitable for
carbon dioxide storage. The solubility trapping [is] the most
permanent and secure form of geological storage."

27. …Example CCS projects
• As of 2005, three industrial-scale storage projects are in
operation. Sleipner is the oldest project (1996) and is
located in the North Sea where Norway's Statoil strips
carbon dioxide from natural gas with amine solvents and
disposes of this carbon dioxide in a saline formation. The
carbon dioxide is a waste product of the field's natural gas
production and the gas contains more (9% CO2) than is
allowed into the natural gas distribution network. Storing it
underground avoids this problem and saves Statoil
hundreds of millions of euro in avoided carbon taxes.
Sleipner stores about one million tonnes CO2 a year.

28. Statoil
•The Sleipner A project injects carbon dioxide into saltwater aquifers
deep beneath the sea floor off the Norwegian coast. The project
turns a profit due to the presence of Norway’s high carbon taxes.

29. …Example CCS projects
• The Weyburn project Weyburn started in 2000 and
is located in an oil reservoir discovered in 1954 in
Weyburn, Southeastern Saskatchewan, Canada.
The CO2 for this project is captured at the Great
Plains Coal Gasification plant in Beulah, North
Dakota which has produced methane from coal for
more than 30 years. At Weyburn, the CO2 will also
be used for enhanced oil recovery with an injection
rate of about 1.5 million tonnes per year.

30. …Example CCS projects
• The third site is In Salah, which like Sleipner
is a natural gas reservoir located in In Salah,
Algeria. The CO2 will be separated from the
natural gas and re-injected into the
subsurface at a rate of about 1.2 million
tonnes per year.

31. …Example CCS projects
• A major Canadian initiative called the Integrated CO2
Network (ICO2N) is a proposed system for the
capture, transport and storage of carbon dioxide
(CO2). ICO2N members represent a group of
industry participants providing a framework for
carbon capture and storage development in Canada.
• Currently, the United States government has
approved the construction of what they claim to be
the world's first CCS power plant, FutureGen.
• In the Netherlands, an 68 MW oxyfuel plant ("Zero
Emission Power Plant") is being planned and is
expected to be operational in 2009.

33. Global C storage in vegetation
In terms of quantity of
carbon stored, tropical and
boreal forests are visibly
outstanding. The values for
carbon storage in
vegetation in the tropics
reach a maximum of 250
metric tons per hectare.
Temperate forests and tropical savannas store less than the tropical
and boreal forests. Non-woody grasslands and drylands store less
than the forested areas, and sparsely vegetated and bare desert
areas have the least carbon storage potential.

34. Capturing carbon dioxide from small, mobile sources, such as cars,
would be more difficult. But with power plants comprising 40 percent
of the world's fossil fuel-derived carbon emissions, the potential for
reductions is significant.
Estimates of worldwide storage capacity range from 2 trillion to 10
trillion tons of carbon dioxide, according to the Intergovernmental
Panel on Climate Change (IPCC) in its report on carbon capture and
storage. Global emissions in 2004 totaled 27 billion tons, according
to the U.S. Department of Energy's Energy Information
Administration.
If all human-induced emissions were sequestered, enough capacity
would exist to accommodate more than 100 years' worth of
emissions, - IPCC.

35. Safety smarts
• The goal of carbon sequestration is to store the carbon
dioxide permanently, i.e. very, very long-term, geological
time periods.
• The greatest concern surrounding carbon dioxide storage
is the potential for it to leak. The obvious worry is that
leakage would lead to more global warming, defeating the
purpose of storage in the first place. But studies have
shown that leakage, if it happened at all, would be
insignificant. The IPCC reported that 99% retention of the
carbon dioxide that is stored would be ''very likely'' over
100 years and ''likely'' over 1,000 years. If done right,
selecting the site correctly and monitor, it can be near
permanent.

36. …..Safety smarts
• Of greater concern to the researchers are the
potential risks of carbon sequestration to
human health, mainly through asphyxiation
and groundwater contamination. The threat
of asphyxiation-or suffocation due to carbon
dioxide displacing oxygen-is very low,
because of the unlikelihood of a rapid
leakage, which would have to occur to cause
a problem.

37. …..Safety smarts
• Drinking water contamination is the more
probable danger. For example, if carbon
dioxide enters the groundwater somehow, it
can increase the water's acidity, potentially
leaching toxic chemicals, such as lead, from
rocks into the water. To address these risks,
scientists are studying reservoir geology to
better understand what happens after
injecting carbon dioxide underground.

38. …..Safety smarts
• Carefully selecting places that will not leak, and
doing a good job of engineering the injection
systems and paying attention to where the carbon
dioxide is actually going required.
• While a thorough technical understanding of the
risks will reveal best practices, the scientists also
stressed the need for good management to see
that proper procedures are followed.

39. 'A family of solutions'
• 'A family of solutions'
• Critics of carbon sequestration argue that the technology will divert
attention from research on long-term clean energy options, such as
renewable power. Worse, they fear it will prolong fossil fuel use, if
fossil fuels from some stationary sources can be used more cleanly.
• Continual emphasis on the need to adopt other technologies in
addition to carbon sequestration needed
• Geological sequestration be one of a family of solutions for
addressing the greenhouse gas issue.
• Energy efficiency and renewable energy are already feasible today
and also can define the long-term energy picture.
• Carbon dioxide sequestration is only a bridge technology.

40. What if we do nothing?
• The longer we wait, the worse it gets. Most scientists believe that the
evidence of high CO2 levels and hot climates in the past is compelling.
• Like all preventive medicine, it's easier to put off the fateful day. But when
that day arrives, it causes you more pain, and costs more, compared to
early actions. Its important to realise that, even if we act now, the climate
will carry on warming for another 3 or 5 degrees Centigrade. Potential for
areas to dry and heat up to become uninhabitable desert.
• By acting now, we have a chance to limit that rise to less than 5
Centigrade, by keeping atmospheric CO2 less than 550 parts per million.

41. Overview
• Carbon capture and storage (CCS) in geological structures is
technically feasible, although further development is needed to
optimise it.
• CCS potentially offers carbon emissions reduction at costs similar to
offshore wind and nuclear power.
• CCS offers a low-carbon way to use fossil fuels to ensure security of
electricity supply.
• Enhanced oil recovery in the North Sea could reduce the cost of CCS
and could also act as a lesson.
• Under present economic conditions CCS may not be financially viable.
Creating incentives for CCS forms part of the wider debate on
economic strategies to reduce CO2 emissions.
• CCS could play a key role in reducing future emissions from the
developing world like South Africa

42. Acknowledgements
• IPCC Special Report, 2005: CO2 Capture and Storage
• IPCC Special Report, 2000: Methodological and Technological Issues in Technology
• Transfer
• IPCC Special Report, 2000: Emissions Scenarios
• IPCC Special Report, 2000: Land Use, Land Use Change and Forestry
• IPCC National Greenhouse Gas Inventories Programme, 2000
• Good Practice Guidance and Uncertainty Management in
• National Greenhouse Gas Inventories
• Cooperative Research Centre for Greenhouse Gas Technologies
www.co2crc.com.au
• Cooperative Research Centre for Coal in Sustainable Development
www.ccsd.biz
• International Energy Agency (Carbon Dioxide Capture and Storage)
www.co2captureandstorage.info
• IPCC, 2003: Good Practice Guidance for Land Use, Land-use Change, and Forestry.
Institute for Global Environmental Strategies, Havana.
• Oremland, R., Marsh, L. M. and Polein, S. (1982). Methane production and simultaneous sulfate
reduction in anoxic marsh sediments. Nature, 296, 143-145.

43. END
Thank you for your kind attention