Study: carbon dioxide reacts quickly with underground rocks, makes safe geosequestration feasible
Storing carbon dioxide deep below the earth’s surface could be a safe, long-term solution to one of the planet’s major contributors to climate change. University of Leeds research shows that porous sandstone, drained of oil by the energy giants, could provide a safe reservoir for carbon dioxide. The study found that sandstone reacts with injected fluids more quickly than had been predicted - such reactions are essential if the captured CO2 is not to leak back to the surface.
Biopact tracks developments in research into geosequestration and carbon capture and storage (CCS), because these technologies can be coupled to bioenergy, resulting in carbon-negative fuels and energy (more here). Contrary to all other renewables, which are merely 'carbon-neutral', bioenergy coupled to CCS takes historic CO2 emissions out of the atmosphere (schematic, click to enlarge). Biopact is collaborating on an article on carbon negative bioenergy, to appear in Energy Policy.
Safe and durable storage of CO2 is one of the key requirements to make CCS practicable. The Leeds study adds to the growing body of science on how CO2 reacts with the geological elements and formations in which it would be stored. Results are published in the December issue of Geology.
The researchers looked at data from the Miller oilfield in the North Sea, where BP had been pumping seawater into the oil reservoir to enhance the flow of oil. The study covered samples of water pumped out from the Miller oilfield over a seven-year period. The data is routinely collected by BP to assess whether water-borne chemicals are liable to cause costly problems of scale to the drilling equipment. The Leeds scientists compared these with the composition of the water that was there before and the water that was injected. This showed that minerals had grown and dissolved as the water travelled through the field.
Significantly, PhD student Stephanie Houston found that water pumped out with the oil was especially rich in silica. This showed that silicates, usually thought of as very slow to react, had dissolved in the newly-injected seawater over less than a year. This is the type of reaction that would be needed to make carbon dioxide stable in the pore waters, rather like the dissolved carbonate found in still mineral water.
The study gives a clear indication that carbon dioxide sequestered deep underground could also react quickly with ordinary rocks to become assimilated into the deep formation water:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: carbon capture and storage :: geosequestration :: carbon-negative :: bio-energy with carbon storage :: climate change ::
The work was supervised by Bruce Yardley, Professor in the School of Earth and Environment at the University, who explained: “If CO2 is injected underground we hope that it will react with the water and minerals there in order to be stabilized. That way it spreads into its local environment rather than remaining as a giant gas bubble which might ultimately seep to the surface.
“It had been thought that reaction might take place over hundreds or thousands of years, but there’s a clear implication in this study that if we inject carbon dioxide into rocks, these reactions will happen quite quickly making it far less likely to escape.”
Although extracting CO2 from power stations and storing it underground has been suggested as a long-term measure for tackling climate change, it has not yet been put to work for this purpose on a large scale. “There is one storage project in place at Sleipner, in the Norwegian sector of the North Sea, and some oil companies have actually used CO2 sequestration as a means of pushing out more oil from existing oilfields,” said Prof Yardley.
In the UK the Prime Minister has recently announced a major expansion of energy from renewable sources and the launch of a competition to build one of the world's first carbon capture and storage plants. The Leeds study suggests the technique has long-term potential for safely storing this major by-product of our power stations, rather than allowing it to escape and further contribute to global warming.
Stephanie Houston worked on the project as part of an Industrial Case Studentship, funded by the Natural Environment Research Council and BP. Her work was supervised by Professor Bruce Yardley, who is based in the Institute of Geological Sciences within the School of Earth and Environment at the University of Leeds.
References:
Stephanie J. Houston, Bruce W.D. Yardley, P. Craig Smalley, and Ian Collins, "Rapid fluid-rock interaction in oilfield reservoirs", Geology, Volume 35, Issue 12, (December 2007), pp. 1143–1146.
Eurekalert: Planting carbon deep in the earth - rather than the greenhouse - November 26, 2007.
Article continues
Biopact tracks developments in research into geosequestration and carbon capture and storage (CCS), because these technologies can be coupled to bioenergy, resulting in carbon-negative fuels and energy (more here). Contrary to all other renewables, which are merely 'carbon-neutral', bioenergy coupled to CCS takes historic CO2 emissions out of the atmosphere (schematic, click to enlarge). Biopact is collaborating on an article on carbon negative bioenergy, to appear in Energy Policy.
Safe and durable storage of CO2 is one of the key requirements to make CCS practicable. The Leeds study adds to the growing body of science on how CO2 reacts with the geological elements and formations in which it would be stored. Results are published in the December issue of Geology.
The researchers looked at data from the Miller oilfield in the North Sea, where BP had been pumping seawater into the oil reservoir to enhance the flow of oil. The study covered samples of water pumped out from the Miller oilfield over a seven-year period. The data is routinely collected by BP to assess whether water-borne chemicals are liable to cause costly problems of scale to the drilling equipment. The Leeds scientists compared these with the composition of the water that was there before and the water that was injected. This showed that minerals had grown and dissolved as the water travelled through the field.
Significantly, PhD student Stephanie Houston found that water pumped out with the oil was especially rich in silica. This showed that silicates, usually thought of as very slow to react, had dissolved in the newly-injected seawater over less than a year. This is the type of reaction that would be needed to make carbon dioxide stable in the pore waters, rather like the dissolved carbonate found in still mineral water.
The study gives a clear indication that carbon dioxide sequestered deep underground could also react quickly with ordinary rocks to become assimilated into the deep formation water:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: carbon capture and storage :: geosequestration :: carbon-negative :: bio-energy with carbon storage :: climate change ::
The work was supervised by Bruce Yardley, Professor in the School of Earth and Environment at the University, who explained: “If CO2 is injected underground we hope that it will react with the water and minerals there in order to be stabilized. That way it spreads into its local environment rather than remaining as a giant gas bubble which might ultimately seep to the surface.
“It had been thought that reaction might take place over hundreds or thousands of years, but there’s a clear implication in this study that if we inject carbon dioxide into rocks, these reactions will happen quite quickly making it far less likely to escape.”
Although extracting CO2 from power stations and storing it underground has been suggested as a long-term measure for tackling climate change, it has not yet been put to work for this purpose on a large scale. “There is one storage project in place at Sleipner, in the Norwegian sector of the North Sea, and some oil companies have actually used CO2 sequestration as a means of pushing out more oil from existing oilfields,” said Prof Yardley.
In the UK the Prime Minister has recently announced a major expansion of energy from renewable sources and the launch of a competition to build one of the world's first carbon capture and storage plants. The Leeds study suggests the technique has long-term potential for safely storing this major by-product of our power stations, rather than allowing it to escape and further contribute to global warming.
Stephanie Houston worked on the project as part of an Industrial Case Studentship, funded by the Natural Environment Research Council and BP. Her work was supervised by Professor Bruce Yardley, who is based in the Institute of Geological Sciences within the School of Earth and Environment at the University of Leeds.
References:
Stephanie J. Houston, Bruce W.D. Yardley, P. Craig Smalley, and Ian Collins, "Rapid fluid-rock interaction in oilfield reservoirs", Geology, Volume 35, Issue 12, (December 2007), pp. 1143–1146.
Eurekalert: Planting carbon deep in the earth - rather than the greenhouse - November 26, 2007.
Article continues
Monday, November 26, 2007
Environmental researchers propose radical 'human-centric' map of the world
Professor Erle Ellis of UMBC and Professor Navin Ramankutty of McGill assert that the current system of classifying ecosystems into biomes (or 'ecological communities') like tropical rainforests, grasslands and deserts may be misleading because humans have become the ultimate ecosystem engineers. To take this into account, they propose an entirely new model of human-centered 'anthropegenic' biomes in the November 19 issue of the journal Frontiers in Ecology and the Environment.
Existing biome classification systems are based on natural-world factors such as plant structures, leaf types, plant spacing and climate. The Bailey System, developed in the 1970's, divides North America into four climate-based biomes: polar, humid temperate, dry and humid tropical. The World Wildlife Fund (WWF) ecological land classification system identifies 14 major biomes, including tundra, boreal forests, temperate coniferous forests and deserts and xeric shrublands.
For their part, Ellis and Ramankutty propose a radically new system of anthropogenic biomes - dubbed 'anthromes' - which describe globally-significant ecological patterns within the terrestrial biosphere caused by sustained direct human interaction with ecosystems, including agriculture, urbanization, forestry and other land uses. Now that humans have fundamentally altered global patterns of ecosystem form, process, and biodiversity, anthropogenic biomes provide a more contemporary view of the terrestrial biosphere in its human-altered form (map, click to enlarge; you can view the 'anthromes' in Google Earth, Google Maps and Microsoft Virtual Earth here.)
Humans have become ecosystem engineers, routinely reshaping ecosystem form and process using tools and technologies, such as fire, dams, irrigation or plantation, that are beyond the capacity of any other organism:
energy :: biomass :: bioenergy :: biofuels :: ecology :: biosphere :: biomes :: anthromes :: anthropocentric :: sustainability :: realism :: romanticism ::
This exceptional capacity for ecosystem engineering, expressed in the form of agriculture, forestry, industry and other activities, has helped to sustain unprecedented population growth, such that humans now consume about one third of all terrestrial net primary production, move more earth and produce more reactive nitrogen than all other terrestrial processes combined, and are causing global extinctions and changes in climate that are comparable to any observed in the natural record.
Clearly, humans are now a force of nature rivaling climate and geology in shaping the terrestrial biosphere and its processes. As a result, the vegetation forms predicted by conventional biome systems are now rarely observed across large areas of Earth's land surface.
The researchers argue human land-use practices have fundamentally altered the planet. Their analysis was quite surprising, said Ramankutty. Less than a quarter of Earth's ice-free land is wild and 'pristine', and only 20% of this is forests; more than 36% is barren, such that Earth's remaining wildlands account for only about 10% of global net primary production. More than 80% of all people live in the densely populated urban and village biomes that cover approximately 8% of global ice-free land. Agricultural villages are the most extensive of all densely populated biomes; one in four people lives within them. Ramankutty concludes that when one is studying a 'pristine' landscape, one is really only studying about 20% of the world.
If we want to think about going into a sustainable future and restoring ecosystems, we have to accept that humans are here to stay. Humans are part of the package, and any restoration has to include human activities in it. Man has become a 'geo-engineer' with often catastrophic consequences for nature. But his unsurpassed capacity to manage ecosystems also holds the key to utilizing these systems in a sustainable way.
Maps and classes
Viewing a global map of anthropogenic biomes shows clearly the inextricable intermingling of human and natural systems almost everywhere on Earth's terrestrial surface, demonstrating that interactions between these systems can no longer be avoided in any significant way.
Anthropogenic biomes are not simple vegetation categories, and are best characterized as heterogeneous landscape mosaics combining a variety of different land uses and land covers. Urban areas are embedded within agricultural land, trees are interspersed with croplands and housing, and managed vegetation is mixed with semi-natural vegetation (e.g. croplands are embedded within rangelands and forests).
For example, Croplands biomes are mostly mosaics of cultivated land mixed with trees and pastures, and therefore possess just slightly more than half of the world's total crop-covered area (8 of 15 million km2), with most of the remaining cultivated area found in Village (~25%) and Rangeland (~15%) biomes. While Forested biomes are host to a greater extent of Earth's tree-covered land, about a quarter of Earth's tree cover was found in Croplands biomes, a greater extent than that found in Wild forests (~20%).
Romanticism versus realism
Part of the enduring fascination for 'virgin' ecosystems stems from a romantic, eurocentric view of nature. Environmentalists and activists often draw on this vision, with at times truly perverse effects: the people who actively work and live in these 'pristine' natural environments are sometimes reduced, idealised and 'naturalised' to the status of people living in 'perfect harmony' with nature, like other species. When these 'indigenous' people break the romantic vision projected onto them, environmentalists tend to look at them as destructive forces and 'enemies'. And there the debate often ends.
The new, radically human-centric view on ecology reopens these debates and offers a space for negotiation that may allow stakeholders to transform their often antagonistic relationship into one of a dialogue based on realism instead of romanticism.
Sustainable ecosystem management must develop and maintain beneficial interactions between managed and natural systems: avoiding these interactions by simply negating them is no longer a practical strategy. Though still at an early stage of development, anthropogenic biomes offer a framework for incorporating humans directly into realistic models and investigations of the terrestrial biosphere and its changes, providing an essential foundation for ecological research in the 21st century.
References:
Ellis, Erle and Navin Ramankutty, "Putting people in the map: anthropogenic biomes of the world", Frontiers in Ecology and the Environment, November 26, 2007, DOI: 10.1890/070062
Ellis, Erle and Navin Ramankutty; Mark McGinley (Topic Editor). 2007. "Anthropogenic biomes." In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). [Published in the Encyclopedia of Earth November 26, 2007; Retrieved November 26, 2007]
View the biomes in Google Earth, Google Maps and Microsoft Virtual Earth.
Article continues
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