Carbon Capture and Storage (CCS) a promising technology that can help mitigating carbon footprint

By integrating three individual technologies the oil and gas industry has used for decades -- capture, transportation and storage -- CCS could enable power plants and industrial facilities to achieve meaningful management of GHG, while maintaining their ability to produce much-needed energy and other products.

The United Nations Intergovernmental Panel on Climate Change (UNIPCC) estimates that these large facilities -- especially power generation plants -- account for as much as 60% of the world's total fossil fuel CO2 emissions. CCS technology can help address these emissions by (a) Separating CO2 from the flue gas (exhaust) from coal-fired power generation or combustion sources at other industrial facilities (b) Compressing the CO2 to reduce its volume and transporting it via pipeline to a storage site (c) Finally, injecting the CO2 into underground geologic formations, such as saline aquifers, depleted oil or gas reservoirs, or deep coal beds, where it can be stored indefinitely.

Coal-fired power plants present unique challenges for CO2 capture. First is size. While several CO2 capture technologies are currently operating on a scale of tens to hundreds of tons of CO2 captured per day, even a relatively small power plant of 200 megawatts (MW) would produce almost 5,000 tons per day at 90% capture. Second is the impact of impurities found in coal flue gas which are not found in other more consistent flue gas streams, such as those from natural gas combustion or from some chemical processes. Third is the challenge of cost. In a small application, the impact of a high cost per ton of CO2 captured may not have a major impact on the economics of the base process. However, because of the quantity of CO2 produced in coal combustion and the narrow margins that often exist in the electrical generating business, an energy-intensive CO2 removal process can significantly affect the economics of a power plant.

After the CO2 is removed from the flue gas stream, it must be compressed for transport and injected underground for long-term storage (sequestration). The total effort to capture and sequester CO2 can increase the cost of electricity from coal-fired power plants by 50-80%. Therefore, the challenge is not only to commercially demonstrate CCS on the scale required, but also to develop a more economical approach to CO2 capture for conventional coal-fired electric power plants.

For more than 30 years, Exxon Mobil engineers and scientists have researched, developed and applied technologies that could play a role in making CCS viable in commercial applications. For example, their patented 'Controlled Freeze Zone' technology is a single-step process that could more efficiently separate CO2 and other impurities from a natural gas stream. It has the potential to make CCS more affordable.

The earth has a fever that it just can't shake. Global CO2 emissions are currently at 4.4 tons per capita. Climatologists think that this number must be cut in half by 2050 to keep CO2 levels in the atmosphere around 470 ppm (parts per million) and therefore to limit the temperature to about 2°C.

Scientific evidence gathered by international researchers over the past several decades has increasingly linked excessive greenhouse gas (GHG) emissions -- especially those of carbon dioxide (C02) -- with global climate change. The paradox facing the world community is the primary source of CO2 emissions, fossil fuels (coal, oil and natural gas), also provide the vast majority of energy, especially electricity, needed to help power both developed and developing economies. Since 1971, abundant fossil fuels have generated, on average, two-thirds of the world's total electricity, and nearly 40% of this total has come from coal, according to the Organization for Economic Cooperation and Development (OECD).

According to a large part of the scientific community, emissions produced by man are increasing the concentration of greenhouse gas in the atmosphere, reinforcing the natural greenhouse effect, in this way causing an increase in the Earth's average temperature. Starting in 1750, the concentration of CO2 in the atmosphere has increased by more than 30% (from approximately 280 ppm to approximately 380 ppm), after having been essentially stable (at levels inferior to 280 ppm) for approximately 10 thousand years.

The scientific community has launched several alarms regarding the danger of climate change with reference to the increase in the sea level, the impact on water resources and biodiversity, the decrease of the glaciers and desertification. Scenarios of an increase in greenhouse gas emissions could result in even more dramatic consequences. It is estimated that if over the next few years, greenhouse gases are not significantly decreased; by 2050 the concentration of CO2 alone could increase by 15-30% with respect to 2005 levels. In this case, the temperature could increase on average by approximately 3°C with respect to the pre-industrial era. A temperature increase of this type could result in an average increase of sea levels of between 0.6 to 1.9 meters, simply due to the effect of the warming of the oceans.

Image 1: Pic. CCS Technology

Experts from the UNIPCC to the IEA (International Energy Agency) have identified carbon capture and storage as a necessary technology to combat climate change.

Mountaineer in the U.S. represents the first small-scale demonstration project to integrate both carbon capture and storage, and American Electric Power may receive $334 million in federal funds to scale up the project to capture 20% of the plant's CO2 emissions. The proposed plant would first turn coal into gas, and the gas combusted to spin a turbine to produce electricity. The result of this technology -- known as integrated gasification combined cycle (IGCC) -- is expected to be the removal of roughly 90% of the CO2 and almost all of the sulfur dioxide and nitrogen oxide from the power plant's emissions. Mountaineer has captured and stored more than 3,000 metric tons of CO2 in the Copper Ridge dolomite formation since Oct. 1, 2009 and the company aims to capture as much as 100,000 metric tons a year in the future. "As with any new technology, it's had its ups and downs," says Gary Spitznogle, the project's manager at AEP.

The U.S. Department of Energy estimates that such an IGCC plant would produce electricity at a cost of $103 per megawatt-hour, compared to just $63 per megawatt hour for a pulverized coal-fired power plant without CO2 capture. That math would change if the U.S. Congress one day places a price on carbon dioxide. Various U.S. national laboratories and research universities -- as well as the companies commercializing the technology -- are striving to reduce that cost further, to as low as just $10 per metric ton of CO2 captured, says CO2 sequestration project leader Rajesh Pawar of Los Alamos National Laboratory in New Mexico.

Despite the costs, utilities are moving forward with carbon capture and storage at existing and new coal-fired power plants. The primary driver seems to be the reality of governments eventually placing a cost on carbon dioxide emissions, both in the U.S. and throughout the world.

The U.S. Company Duke Energy has partnered with China's Huaneng Group to develop carbon capture and storage technology and is considering a plan to capture 18% of the CO2 from its planned 630 megawatt, $2.35 billion IGCC plant in Edwardsport, Ind.

The Chinese government is partnering with its largest coal supplier, Australia, to build several demonstration projects, including one in Beijing that uses an amine scrubber to capture CO2 from a power plant that produces both heat and electricity. And ground has been broken on China's version of FutureGen, dubbed GreenGen. The 650-megawatt, IGCC power plant is now under construction and could begin storing CO2 in depleted oil fields near the city of Tianjin as soon as 2015.

Oklahoma-based Tenaska aims to build a $3.5 billion IGCC power plant in Taylorsville, Ill. that would capture 50 % of its CO2 emissions, and the Erora Group is planning a similar power plant in Henderson County, Ky. Existing power plants are also getting into the act, including the Southern Company, which plans to add its own chemistry set -- known as amine scrubbers, which employ a different compound to capture the CO2 -- to a power plant near Mobile, Ala.

CCS projects also are moving ahead in Europe. In the vineyards of Jurancon in southeastern France, a project to integrate both CO2 capture and storage is now complete. Recently, an old oil-fired boiler there was converted to burn natural gas in pure oxygen -- so-called oxyfuel -- and thereby create a relatively pure stream of CO2 that can be siphoned off and stored. The Lacq project will transport roughly 60,000 metric tons of CO2 per year 17 miles to a depleted natural gas field for storage.

The engineering firm, Alstom, which supplied the technology at Lacq, has installed an oxyfuel boiler for a coal-fired power plant in Germany, known as Schwarze Pumpe. That plant also demonstrates, however, one of the main challenges of carbon capture and storage: acceptance from the people who would have to live over the stored CO2. Plans to store the greenhouse gas from Schwarze Pumpe in a nearby natural gas field have foundered on resistance from the local government. A similar CO2 storage effort by Shell in the Netherlands has also been stopped by public resistance from the town of Barendrecht. Residents there fear a leak or declining property values as the ground deep beneath their feet literally fills up with CO2.

There are several pilot and demonstration projects currently proceeding in Canada as a means to understand the potential for a reduction in CO2 emissions using CCS technology. Among them is the IEA GHG Weyburn-Midale CO2 Monitoring and Storage Project. This project stands out as the world's first measurement, monitoring and verification program in connection with CO2 Enhanced Oil Recovery (EOR) operations. It is the planet's largest CO2 injection operation, and as of January 1, 2010 had 17 million tonnes of CO2 underground.

"Even with the most optimistic projections on renewables and nuclear, you still have 60% fossil fuels by 2030 with massive emissions," says Philippe Paelinck, director of CO2 business development at Alstom. "If CCS technology is not accepted by the public, we will not be able to arrive at the necessary levels of emissions -- and those are zero for the power sector by 2050."

After all, the coal-fired power plants already built or planned in just the first 10 years of the 21st century would end up emitting more carbon dioxide in the next 25 years -- 660 billion metric tons -- than the 524 billion metric tons that have been emitted since the dawn of the Industrial Age in 1751, notes George Peridas of the Natural Resources Defense Council. And the UNIPCC estimates that a properly selected storage site would safely stow away 99% of the CO2 generated by a coal-burning power plant for at least 1,000 years. But even if all that CO2 is captured and stored, coal will not be entirely clean, whether because of the impacts of the mountaintop removal mining that provides some of the fuel or the toxic ash that burning coal leaves behind.

With a rising population linked to an increased energy demand, India is expected to become one of the top three CO2 emitters in the world by 2030; it is currently ranked sixth. Out of the country's present installed electricity generation capacity of around 140GW, roughly 70% is generated by thermal power plants, mostly from coal. This capacity is likely to be increased significantly in the next 10-20 years; India has plans to upgrade and extend its current fleet of power plants by investing in 13 more efficient coal-fired Ultra-Mega Power Plants (UMPPs), which would entail a further 52GW of installed capacity coming on line starting in 2012.

In India, now there is a lively debate about whether CCS should be deployed in the country. It is expected that coal will play a significant role in providing energy and electricity in India until 2050, at least, despite measures to significantly increase the role of other energy sources. Although CCS is not seen as an immediate priority for Indian Government or industry, survey respondents do expect it to become more important in the future, particularly for industry. Thus, it is appropriate to consider whether CCS is a technically feasible option for India and, if so, whether and when it should be used?

Although there are some significant challenges, it seems likely that introducing CO2 capture at Indian power plants could be technically feasible especially in locations where it is considered appropriate to apply 'capture ready' concepts for new build plants before CCS is deployed. Identifying both suitable storage sites and routes for transporting captured CO2 safely to these sites also requires careful consideration. One important factor in shaping views on whether CCS is an appropriate option for India is the proposed timing of any deployment of possible projects. In particular, survey respondents typically suggest that it is necessary for developed countries to demonstrate CCS at commercial scale before any commercial-scale CCS projects in India are considered.

In fact, most survey respondents suggested that any consideration of deployment of CCS in India should be within an appropriate international framework, including measures for knowledge-sharing and technology-transfer that consider local conditions carefully. The importance of establishing reasonable methods to help with early engagement on CCS between India and developed countries was also noted by some respondents. For example, one respondent suggested that consideration should be given to establishing local knowledge/training centers within India. Survey respondents also suggested that it was reasonable for developed country governments to contribute to financing of both initial projects and wider deployment of CCS in India. This could partly be through international finance institutions such as the World Bank, the International Monetary Fund and the Asian Development Bank.

To conclude, advanced CCS technologies are innovative and transformational; they are aimed at providing cost-competitive technology options for controlling C02 emissions and enabling the continued use of fossil fuels in a carbon-constrained world. They can help provide policymakers the basis for meeting their national economic, energy, and environmental needs. They will be most effectively utilized as part of a portfolio response to CO2 emission mitigation that includes wider use of renewable and nuclear energy and increased energy efficiencies. Given current projections regarding atmospheric C02 buildup and climatic temperature increases, the global objective should be to begin large-scale commercial deployment within the next decade, and in the meantime focusing an unprecedented international level of cooperation and research toward this goal.

The groundwork has already been established for worldwide cooperation and collaboration; progress has been made, but there is still much to do.