Carbon capture and storage

Carbon capture and storage (CCS) is an approach to mitigating global warming based on capturing carbon dioxide (CO₂) from large point sources such as fossil fuel power plants and storing it instead of releasing it into the atmosphere. Although CO₂ has been injected into geological formations for various purposes, the long term storage of CO₂ is a relatively untried concept. The first large-scale CCS power plant will begin operating in September 2008 in the eastern German town of Schwarze Pumpe in the hope of answering questions about the long-term prospects of 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 [IPCC, 2005] "IPCC special report on Carbon Dioxide Capture and Storage". Prepared by working group III of the . Metz, B., O.Davidson, H. C. de Coninck, M. Loos, and L.A. Meyer (eds.). Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 442 pp. Available in full at [http://www.ipcc.ch/activity/srccs/index.htm www.ipcc.ch] ] . Capturing and compressing CO₂ requires much energy and would increase the fuel needs of a coal-fired plant with CCS by about 25%. These and other system costs are estimated to increase the cost of energy from a new power plant with CCS by 21-91%. These estimates apply to purpose-built plants near a storage location: applying the technology to preexisting plants or plants far from a storage location will be more expensive.

Storage of the CO₂ is envisaged either in deep geological formations, in deep ocean masses, 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 (currently, 30 Gt per year of CO₂ is emitted due to human activities [cite web | title = Volcanic Gases and Their Effects | url=http://volcanoes.usgs.gov/Hazards/What/VolGas/volgas.html| accessdate=2007-09-07 ] ). IPCC estimates that the economic potential of CCS could be between 10% and 55% of the total carbon mitigation effort until year 2100 (Section 8.3.3 of IPCC report).

Cost of CCS

The increased energy requirements of capturing and compressing CO₂ significantly raises the operating costs of CCS-equipped power plants. In addition there are added investment or capital costs. The process would increase the fuel requirement of a plant with CCS by about 25% for a coal-fired plant and about 15% for a gas-fired plant. The cost of this extra fuel, as well as 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.

Costs of energy with and without CCS (2002 US$ per kWh)

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 risks are comparable to those associated with current hydrocarbon activity. CO₂ could be trapped for millions of years, and well selected stores 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.

It should also be noted that at the conditions of the deeper oceans, (about 400 bar or 40 MPa, 280 K) water–CO₂(l) mixing is "very" low (where carbonate formation/acidification is the rate limiting step), but the formation of water-CO₂ hydrates is favorable. (a kind of solid water cage that surrounds the CO₂). [3]

To further investigate the safety of CO₂ sequestration, we can look into Norway's Sleipner gas field, as it is the oldest plant that stores CO₂ on an industrial scale. According to an environmental assessment of the gas field which was conducted after ten years of operation, the author affirmed that geosequestration of CO₂ was the most definite way to store CO₂ permanently. [4]

"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." [4]

Phase I of the [http://www.ptrc.ca/access/DesktopDefault.aspx?tabindex=8&tabid=81 Weyburn] Project in Weyburn, Saskatchewan, Canada has determined that the likelihood of stored CO₂ release is less than one percent in 5,000 years. [Allan Casey, "Carbon Cemetery", Canadian Geographic Magazine, Jan/Feb 2008, p. 61]

CO₂ Reuse

A potentially useful way of dealing with industrial sources of CO₂ is to convert it into hydrocarbons where it can be stored or reused as fuel or to make plastics. There are a number of projects investigating this possibilityNew Scientist No2645, 1st March 2008.] .:

ingle Step methods: CO₂ + H₂ → Methanol

A proven process to produce a hydrocarbon is to make methanol. Methanol is rather easily [http://en.wikipedia.org/wiki/Green_Methanol_Synthesis synthesized] from CO₂ and H₂. Based on this fact the idea of a methanol economy was born.

ingle Step methods: CO₂ → Hydrocarbons

At the department of Industrial Chemistry and Engineering of Materials at the University of Messina, Italy there is a project to develop a system which works like a fuel-cell in reverse, whereby a catalyst is used that enables sunlight to split water into hydrogen ions and oxygen gas. The ions cross a membrane where they react with the CO₂ to create hydrocarbons.Fact|date=September 2008

2 Step methods: CO₂ → CO → Hydrocarbons

If CO₂ is heated to 2400°C, it splits into carbon monoxide and oxygen. The Fischer-Tropsch process can then be used to convert the CO into hydrocarbons. The required temperature can be achieved by using a chamber containing a mirror to focus sunlight on the gas. There are a couple of rival teams developing such chambers, at Solarec and at Sandia National Laboratory, both based in New Mexico. According to Sandia these chambers could provide enough fuel to power 100% of domestic vehicles using 5800 km², but unlike biofuels this would not take fertile land away from crops but would be land that is not being used for anything else.

Example CCS projects

As of 2007, four industrial-scale storage projects are in operation. Sleipner [http://www.iku.sintef.no/projects/IK23430000/] is the oldest project (1996) and is located in the North Sea where Norway's StatoilHydro strips carbon dioxide from natural gas with amine solvents and disposes of this carbon dioxide in a deep saline aquifer. 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. Since 1996, Sleipner has stored about one million tonnes CO₂ a year. A second project in the Snøhvit gas field in the Barents Sea stores 700,000 tonnes per year. Allan Casey, "ibid", p. 63]

The [http://www.ptrc.ca/access/DesktopDefault.aspx?tabindex=8&tabid=81 Weyburn project] is currently the world's largest carbon capture and storage project. Started in 2000, Weyburn is located on an oil reservoir discovered in 1954 in Weyburn, southeastern Saskatchewan, Canada. The CO₂ for this project is captured at the [http://www.dakotagas.com/Companyinfo/index.html 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. The first phase finished in 2004, and demonstrated that CO₂ can be stored underground at the site safely and indefinitely. The second phase, expected to last until 2009, is investigating how the technology can be expanded on a larger scale. [Allan Casey, "ibid", p. 59]

The fourth site is [http://www.co2captureandstorage.info/project_specific.php4?project_id=71 In Salah] , which like Sleipner and Snøhvit 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.

A major Canadian initiative called the Alberta Saline Aquifer Project (ASAP) [http://www.albertaasap.com ] is a consortium of 34 compaies that are developing a pilot site for commercial scale carbon capture and storage in a saline aquifer. The inital pilot will sequester 1,000 tonnes per day in 2010, while the commercial phase could see 10,000 tonnes per day as soon as 2015.

Another Canadian initiative called the [http://www.ico2n.com 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.

In October 2007, the Bureau of Economic Geology at The University of Texas at Austin received a 10-year, $38 million subcontract to conduct the first intensively monitored, long-term project in the United States studying the feasibility of injecting a large volume of CO₂ for underground storage ["Bureau of Economic Geology Receives $38 Million for First Large-Scale U.S. Test Storing Carbon Dioxide Underground" [http://www.jsg.utexas.edu/news/rels/102407.html] ] . The project is a research program of the Southeast Regional Carbon Sequestration Partnership (SECARB), funded by the National Energy Technology Laboratory of the U.S. Department of Energy (DOE). The SECARB partnership will demonstrate CO₂ injection rate and storage capacity in the Tuscaloosa-Woodbine geologic system that stretches from Texas to Florida. The region has the potential to store more than 200 billion tonsVague|date=September 2008 of CO₂ from major point sources in the region, equal to about 33 years of U.S. emissions overall at present rates. Beginning in fall 2007, the project will inject CO₂ at the rate of one million tonsVague|date=September 2008 per year, for up to 1.5 years, into brine up to 10,000 feet (3,000 m) below the land surface near the Cranfield oil field about 15 miles (25 km) east of Natchez, Mississippi. Experimental equipment will measure the ability of the subsurface to accept and retain CO₂.

Currently, the United States government has approved the construction of what is touted as the world's first CCS power plant, FutureGen. On January 29, 2008, however, the Department of Energy announced it was withdrawing funding from FutureGen, as it had originally been proposed, casting considerable doubt on the future of the project and in the view of some effectively terminating the project.

Examples of carbon sequestration at an existing US coal plant can be found at utility company Luminant's pilot version at its Big Brown Steam Electric Station in Fairfield, Texas. This system is converting carbon from smokestacks into baking soda. [http://www.skyonic.com/theCompany.php Skyonic ] plans to circumvent storage problems of liquid CO2 by storing baking soda in mines, landfills, or simply to be sold as industrial or food grade baking soda. [http://www.greenfuelonline.com/index.html GreenFuel Technologies Corp.] is piloting and implementing algae based carbon capture, circumventing storage issues by then converting algae into fuel or feed.

In the Netherlands, an 68 MW oxyfuel plant ("Zero Emission Power Plant") is being planned and is expected to be operational in 2009 ["Demonstration project The Netherlands: Zero Emission Power Plant" [http://www.createacceptance.net/fileadmin/create-acceptance/user/docs/Demonstration_project_The_Netherlands.pdf] ] .

In the United States, four different synthetic fuels projects are moving forward which have publicly announced plans to incorporate carbon capture and storage.

American Clean Coal Fuels, in their [http://www.cleancoalfuels.com/cleancoalfuels_projects.html Illinois Clean Fuels] project, is developing a 30,000 Barrel Per Day Biomass and Coal to Liquids project in Oakland Illinois, which will market the CO2 created at the plant for Enhanced Oil Recovery applications. The project is expected to come online in late 2012.

Baard Energy, in their [http://www.baardenergy.com/orcf.htm Ohio River Clean Fuels] project, are developing a 53,000 BPD Coal and Biomass to Liquids project, which has announced plans to market the plant’s CO2 for Enhanced Oil Recovery.

Rentech is developing a [http://www.rentechinc.com/rentech-projects.htm#2 29,600 barrel per day coal and biomass to liquids plant in Natchez Mississippi] which will market the plant’s CO2 for enhanced oil recovery. The first phase of the project is expected in 2011.

DKRW is developing a [http://www.dkrwadvancedfuels.com/fw/main/Medicine_Bow-111.html 15,000-20,000 Barrel Per Day coal to liquids plant in Medicine Bow Wyoming] , which will market it plant’s CO2 for enhanced oil recovery. The project is expected to begin operation in 2013.

Germany

The German industrial area of Schwarze Pumpe, about 4 km south of the city of Spremberg, is home to the world's first CCS coal plant. The mini pilot plant is run by an Alstom-built oxy-fuel boiler and is also equipped with a flue gas cleaning facility to remove fly ash and sulphur dioxide. The Swedish company Vattenfall AB invested some 70 million Euros in the two year project which began operation September 9, 2008. The power plant, which is rated at 30-megawatts, is a pilot project to serve as a prototype for future full-scale power plants. [citation| title= Germany leads 'clean coal' pilot| url=http://news.bbc.co.uk/2/hi/science/nature/7584151.stm| date=2008-09-03| publisher=BBC News] [citation| title=Access all areas: Schwarze Pumpe| url=http://news.bbc.co.uk/2/hi/science/nature/7584155.stm| date=2008-09-03| publisher=BBC News] 240 tonnes a day of CO₂ are being trucked 350 kilometres (210 miles) where it will be injected into an empty gas field. Germany's BUND group called it a "fig leaf". For each tonne of coal burned, 3.6 tonnes of carbon dioxide is produced. [ [http://news.yahoo.com/s/afp/20080909/bs_afp/germanywarmingemissions 'Emissions-free' power plant pilot fires up in Germany] ]

Australia

The federal Resources and Energy Minister Martin Ferguson has opened the first geosequestration project in the southern hemisphere. The demonstration plant is near Nirranda South in South Western Victoria. (coord|35.31|S|149.14|E) The plant is owned by the CO₂ Cooperative Research Centre. It is funded jointly by government and industry. It aims to store 100,000 tonnes of carbon dioxide extracted from a gas well. Carbon dioxide-rich gas is extracted from a reservoir via a well, compressed and piped 2.25km to a new well. There the gas is injected into a depleted natural gas reservoir approximately two kilometres below the surface. [ "First carbon storage plant launched" [http://news.sbs.com.au/worldnewsaustralia//first_carbon_storage_plant_launched_544064] ] [ "Seeking clean coal science 'only option'" [http://news.theage.com.au/seeking-clean-coal-science-only-option/20080402-237d.html] ] This project is tiny by world standards as BP's Algerian plant is storing 1,000,000 tonnes each year.Fact|date=September 2008.

This plant does not propose to capture CO₂ from coal fired power generation. There is no project anywhere in the world storing CO₂ stripped from the products of combustion of coal burnt for electricity generation at coal fired power stations.

Limitations of CCS for power stations

ee also

*Biochar
*Carbon cycle re-balancing
*Carbon dioxide sink
*CO2 sequestration
*FutureGen
*Lake Nyos A possible hazard resulting from a large scale release of CO2
*Low-carbon economy
*Mitigation of global warming
*Solvay process industrial process used in the production of soda ash (sodium carbonate)
*Terra preta

References

* [IPCC, 2005] "IPCC special report on Carbon Dioxide Capture and Storage". Prepared by working group III of the Intergovernmental Panel on Climate Change. Metz, B., O.Davidson, H. C. de Coninck, M. Loos, and L.A. Meyer (eds.). Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 442 pp. Available in full at [http://www.ipcc.ch/pdf/special-reports/srccs/srccs_wholereport.pdf www.ipcc.ch] (PDF - 22.8MB)
*"Environmental Challenges and Greenhouse Gas Control for Fossil Fuel Utilization in the 21st Century". Edited by M. Mercedes Maroto-Valer "et al.", Kluwer Academic/Plenum Publishers, New York, 2002: "Sequestration of Carbon Dioxide by Ocean Fertilization", pg 122. by M. Markels, Jr. and R.T. Barber.
*Nobel Intent: Carbon Dioxide Lakes in the Deep Ocean, September 19, 2006 @ 11:08AM - posted by John Timmer http://arstechnica.com/journals/science.ars/2006/9/19/5341
*Solomon, Semere. (July, 2006). Carbon Dioxide Storage: Geological Security and Environmental Issues Case Study on the Sleipner Gas Field in Norway. The Bellona Foundation. Retrieved November 7th, 2006, from http://bellona.no/filearchive/fil_Paper_Solomon_-_CO2_Storage.pdf
* ICO2N - The Vision [http://www.ico2n.com/docs/tech/ICON%20Vision.pdf]

External links

* [http://www.ipcc.ch/ipccreports/srccs.htm Intergovernmental Panel on Climate Change] IPCC Special Report on Carbon Dioxide Capture and Storage (CCS).
** [http://www.greenfacts.org/en/co2-capture-storage/index.htm Scientific Facts on CO2 Capture and Storage] , a peer-reviewed summary of the IPCC Special Report on CCS.
* [http://www.jsg.utexas.edu/carboncapture/carbonsequestration.html Carbon Sequestration News] Recent news articles on CO₂ capture and storage.
* [http://www.cou2.com/ COyou2 Personal Carbon Capture] Can carbon capture and storage technology be used as an individual solution to climate change?
* [http://www.beg.utexas.edu/environqlty/co201.htm Gulf Coast Carbon Center] University of Texas at Austin research center that investigates geologic storage of anthropogenic carbon dioxide in the Gulf Coast region.
* [http://pangea.stanford.edu/~mhesse/NewsLinks.html Stanford University] Collection of recent news articles on CO₂ capture and storage.
* [http://www.bigskyco2.org/ The Big Sky Carbon Sequestration Partnership] The Big Sky Carbon Sequestration Partnership (BSCSP)
* [http://climatechangeaction.blogspot.com/search/label/ccs Webcasts, Reports and Articles] Relevant Climate Change Action Posts
* [http://www.fossil.energy.gov/programs/sequestration/index.html DOE Fossil Energy] Department of Energy programs in carbon dioxide capture and storage.
* [http://www.epa.gov/climatechange/emissions/co2_gs_tech.html U.S. Environmental Protection Agency] Overview of Geologic Sequestration of CO₂.
* [http://www.epa.gov/climatechange/emissions/co2_geosequest.html U.S. Environmental Protection Agency - Regulating Geologic Sequestration of CO₂ ] U.S. EPA page outlining EPA's role in regulating geologic sequestration of CO₂.
* [http://assets.opencrs.com/rpts/RL34307_20080415.pdf] US Congressional Research Service report: "Regulation of Carbon Dioxide (CO2) Sequestration Pipelines: Jurisdictional Issues (Updated April 15, 2008) by Adam Vann and Paul W. Parfomak.
* [http://assets.opencrs.com/rpts/RL33971_20080117.pdf] US Congressional Research Service report: "Carbon Dioxide (CO2) Pipelines for Carbon Sequestration: Emerging Policy Issues" by Paul W. Parfomak and Peter Folger.
* [http://www.co2captureandstorage.info/ CO₂ Capture and Storage] International Energy Agency Greenhouse Gas Research Programme (includes CSS project summaries)
* [http://www.co2geonet.com CO2GeoNet] European Network of Excellence on CO₂ Geological Storage
* [http://www.netl.doe.gov/technologies/carbon_seq/core_rd/storage.html CO₂ Capture and Geologic Storage] National Energy and Technology Laboratory summary of worldwide projects
* [http://www.ico2n.com] ICO2N - Canadian Carbon Dioxide Capture and Storage initiative
*
* [http://www.geos.ed.ac.uk/sccs/ Scottish Centre for Carbon Storage] Current Carbon Capture and Storage Research being undertaken in Edinburgh, Scotland.
* [http://www.co2storage.org.uk/ UK Carbon Capture and Storage Consortium] Overview of the UK academic consortium focused on researching issues related to Carbon Capture and Storage.
* [http://www.worldcoal.org/pages/content/index.asp?PageID=476 Storing CO₂ Underground]
* [http://www.ceem.unsw.edu.au/content/documents/Diesendorf_Coal-Geoseq.pdf Can geosequestration save the coal industry?]
* [http://www.co2storage.org.uk/ UK Carbon Capture and Storage Consortium] Overview of the UK academic consortium focused on researching issues related to Carbon Capture and Storage.
* [http://www.co2sinus.org/index_en.html CO2SINUS] CO₂ Storage in in situ Converted Coal Seams - Research Project at the RWTH Aachen University.http://www.berr.gov.uk/whatwedo/energy/sources/sustainable/ccs/ccs-demo/page40961.html