CO2 can also be captured at stationary areas and injected underground into geological formations—a process called geological sequestration. This technology captures the CO2 and other pollutants emitted when fossil fuels are burned. They are then compressed into a liquid and pumped deep beneath the Earth's surface into geologic formations. David Goldberg, a geophysicist at Columbia University's Lamont-Doherty Earth Observatory in Palisades, New York, has experimented successfully with this technique by pumping CO2 into basalt rock beneath the ocean floor. This is one method the IPCC has identified to mitigate global warming. The IPCC has suggested that offsetting CO2 emissions in this manner is one way to achieve an overall net reduction in greenhouse gas emissions. The IPCC has also estimated that worldwide it is possible to permanently store up to 1,100 gigatons of CO2 underground. As a comparison, worldwide emissions from large stationary sources such as urban areas is about 13 gigatons per year. Geological sequestration could store approximately 85 years of CO2 emissions from large stationary stores.
The IPCC endorsed this sequestration technology as safe and acceptable in 2005 because CO2 has been sequestered naturally in geologic formations for hundreds of millions of years with no ill effects. The IPCC has also supported the technology because there are several practical trapping mechanisms available that can keep the CO2 from moving around underground and eventually escaping.
According to the EPA, about 95 percent of the largest sources of CO2 emissions (coal-fired power plants, large cities) in the United States are within 50 miles (80 km) of a potential geologic sequestration site. In order to pursue this technology, the EPA is currently investigating geologic sequestration technology.
The method—also called geo-sequestration or geological storage— involves injecting CO2 directly into underground geological formations.
Storage sites that would qualify include old oil fields, unmineable coal seams, and saline aquifers.
The option of using old oil fields is an attractive option because CO2 has been injected into existing fields for the past 30 years in order to recover the last of the recoverable oil. Besides having already been done extensively and with the knowledge that the technology works, an additional benefit with these sites is that these formations already have an impermeable cap rock above them to keep the CO2 from escaping into the atmosphere (the same barrier that kept the oil underground for millions of years instead of leaking out onto the Earth's surface).
Unmineable coal seams are also considered to be safe and able to supply long-term storage. Saline aquifers are another formation considered as a possibility to store CO2 for a long period of time. According to the EPA, they have a large potential storage area associated with them, and they are relatively common geographically, which means that the CO2 would not have to be transported long distances, thereby lowering sequestration costs. The downside to saline storage sites is that they have not been used enough at this point to fully understand their positive or negative characteristics yet. Current research is being conducted in southeastern Saskatchewan, trying to determine whether the pros outweigh any cons.
According to a report in iStockAnalyst and The Paducah Sun, three energy companies along with the Kentucky Geological Survey are planning to test the feasibility of storing CO2 underground. The Western Kentucky Carbon Storage Foundation will be providing the resources to drill the test well. Peabody Energy (the world's largest coal company) and ConocoPhillips (the world's fifth-largest oil refiner) are looking into the possibility of building a coal gasification plant to produce a substitute for natural gas—the CO2 sequestration project is part of this larger project.
Rick Bowersox, chief geologist for the Kentucky Geological Survey, says, "We want to demonstrate the sequestration process prior to it being put into commercial use."
In response, Kentucky governor Steve Beshear says, "The importance of CO2 sequestration research for our state's and the nation's energy future cannot be overstated. Kentucky has been a strong sup porter of effects to develop partnerships and projects such as this one, and the results from this testing are crucial in our quest to develop and implement clean coal technologies and become a world leader in energy production."
Australia has also announced recent plans to try carbon sequestration in order to offset carbon emissions. Prime Minister Kevin Rudd announced in July 2008 a $5 billion plan to implement carbon sequestration by storing CO2 in deep subterranean strata and the adjacent seabed. Although he has been met with criticism, saying that carbon sequestration technology is too new and untried to invest that much money in trying, Rudd is an optimistic supporter of the technology, and he plans to move ahead.
Resources Minister Martin Ferguson agrees that there are "good arguments for implementing carbon sequestration." He believes it would encourage investment and commercialization of the technology and is a feasible way to allow the continued generation of carbon-based power while reducing the net overall impact.
Currently, the Commonwealth body Geoscience Australia has identified several areas that would be feasible for storage of greenhouse gases—areas in Victoria, Western Australia, and Southern and Central Queensland. As the project moves forward, however, it is meeting opposition from bureaucrats claiming that up to 15,000 jobs in the energy and production industries that do generate greenhouse gases could be lost.
Also reported in July 2008 by Scientific American News, volcanic rocks buried deep beneath the ocean off the coast of the Pacific Northwest (California, Oregon, and Washington) may prove to be one of the best places yet to store CO2.
David Goldberg, a geophysicist at Columbia University's Lamont-Doherty Earth Observatory, says that pumping greenhouse gases deep into basalt rock in the region is a workable solution to offset increasing amounts of CO2 in the atmosphere. The volcanic rock has proven desirable because at 8,850 feet (2,700 m) below the ocean surface the liquid CO2 is heavier than the water above it, ensuring that leaks would never be able to bubble to the surface. In addition, CO2 mixes with the volca-nically warm water and undergoes a chemical reaction within the basalt itself to form carbonate compounds called chalk, which permanently locks up the greenhouse gases into a mineral form. For deposits in the ocean bed, the additional layer of 650 feet (200 m) of marine sediment on top of the basalt layer acts as another barrier.
According to Goldberg, "You have three superimposed trapping mechanisms to keep your CO2 below the sea bottom and out of the atmosphere. It's insurance on insurance on insurance."
In this project alone, it is estimated that at least 229 billion tons (208 billion metric tons) of carbon could be stored in the basalt formations of the Juan de Fuca Plate (a major plate in the Earth's plate tectonic system) 100 miles (160 km) off the United States's West Coast. This would represent the equivalent of 122 years of all U.S. emissions of 1.9 billion tons (1.7 billion metric tons) each year.
M. Granger Morgan of Carnegie Mellon University, who is a carbon sequestration expert, says, "On the one hand you wouldn't want to bet the future of U.S. climate policy on it until one has done more work, but on the other hand, it looks quite promising."
Goldberg is also looking at the issue globally and says there are other formations worldwide similar to this tectonic plate in the Pacific Northwest that could be used for CO2 sequestration. One promising site in Iceland began testing in 2008. The project involves the capture and separation of fuel gases at the Hellisheidi Geothermal Power Plant, the transportation and injection of the CO2 gas fully dissolved in water at elevated pressures at a depth between 1,312-2,625 feet (400-800 m), as well as the monitoring and verification of the storage. A comprehensive reservoir characterization study, currently in progress, must be completed before the CO2 injection can occur. This includes soil CO2 flux measurements, geophysical survey, and tracer injection tests. The results from the tracer tests are showing significant tracer dispersion within the target formation, which suggests that there is a large surface area available for chemical reactions. The pilot project's large available reservoir volume and surface area in combination with the relatively fast CO2-water-rock reactions that occur in basaltic rocks look like they may allow safe and permanent geologic storage of CO2 on a large scale. According to Goldberg, "The volumes of storage we're talking about are huge and the problem is huge. The prize is very large here with this option. It's worth a serious look."
The Midwest Regional Carbon Sequestration Partnership claims that a porous rock filled with saltwater that underlies much of the Midwest could permanently store half of the greenhouse gases released in the next century by industries in Ohio and neighboring states. Because of this, they are currently involved in a large-scale test injection of CO2 into the rock layer, known locally as the Mount Simon Sandstone formation.
The goal of this project is to compress and inject 1 million tons (907,185 metric tons) of CO2 from a new ethanol plant in Greenville. The gas would be injected into a chamber to a depth of 3,000 feet (914 m) from 2010 to 2014.
This project would offset the Andersons Marathon Ethanol LLC-Ohio's largest ethanol plant—which will produce 110 million gallons of ethanol from 43 million bushels of corn each year. Generating more than 250,000 tons of CO2, almost the entire amount of CO2 would be injected underground.
Debra Crow, spokesperson for Andersons Marathon Ethanol LLC, says, "We're interested in being a good corporate citizen and helping with any kind of research that can improve the environment."
The U.S. Department of Energy is providing $61 million in funding for the Greenville project. Not everyone sees it in a positive light, however. According to Nechy Kanter of the Sierra Club, "The government should place a higher priority on improving energy efficiency and supporting green technologies such as wind and solar. Carbon sequestration is 'highly experimental and highly expensive,' and can't be undertaken without taxpayer support. We don't want polluting sources counting on sequestration and then it not come through."
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Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.