 Fossil fuels power our daily lives. They provide energy for our homes, our vehicles and our businesses. But burning fossil fuels produces carbon dioxide (CO2), a greenhouse gas believed to contribute to climate change. As demand for these fuels continues to grow, controlling emissions will require technology that can deal with large volumes of carbon dioxide.
ConocoPhillips, like many companies, is exploring possible solutions. One that potentially can reduce CO2 emissions is carbon capture and storage (CCS).
“ConocoPhillips understands the impact of carbon emissions on climate change, and we are doing many things to reduce our carbon footprint and to develop technologies to reduce carbon emissions,” said Stephen Brand, senior vice president, Technology.
CAPTURE AND STORAGE
Carbon capture and storage is the gathering and underground injection of carbon dioxide. According to Cal Cooper, science fellow, Environmental Technology, CCS is similar to conventional gas production.
“It’s the gas business in reverse,” Cooper said. “It’s something the industry knows how to do.”
To store carbon dioxide, it is injected into carefully selected sites where it remains indefinitely. It can be stored in saline reservoirs, depleted oil and gas reservoirs, or possibly in coal seams. Expert models predict that CCS has the potential to remove about 25 percent of annual global CO2 emissions by 2050, about 6.4 billion tonnes per year.
But before it can be injected, it must be separated from gas streams. So far, collecting carbon dioxide from the air has proven to be difficult because there’s only a small concentration (less than 400 parts per million) in air or flue gas. It can, however, be captured more cost effectively from process streams in facilities where the CO2 stream is more concentrated.
BUILDING EXPERTISE
Separating and injecting carbon dioxide, the essential processes for CCS, are not new to the oil industry. For years, companies such as ConocoPhillips have been injecting CO2 into oil reservoirs to push oil toward the well, allowing for additional oil recovery. The process is known as enhanced oil recovery (EOR). More than 40 million tonnes of CO2 per year have been injected into the Permian Basin as part of EOR projects. In Prudhoe Bay, Alaska, a natural gas recycling plant has safely and reliably injected CO2 for about 30 years as part of a gas cap maintenance program.
ConocoPhillips is developing several new projects that could include CCS. For example, it currently is developing several large gasification projects that each have the potential to capture and store up to 5 million tonnes of CO2 per year. At the Lost Cabin gas plant in Wyoming, Conoco Phillips has solicited bids for the purchase of carbon dioxide, which currently is vented, from the plant.
ConocoPhillips is working with other organizations to develop CCS technology. In the San Juan Basin, the company, in coordination with the Department of Energy, is experimenting with CO2 injection rates into a coal formation. The first carbon dioxide injection test well already is drilled, and CO2 injection will begin soon. The company also leverages research-spend by participating in consortiums, such as the CO2 Capture Project, that accelerate research by sharing costs and expertise among major energy companies.
CHALLENGES
 Despite the availability of technology to implement CCS now, there are a number of challenges.
First, there is no value for carbon. Companies are wary about investing money in something that has no current or predictable future value. Second, a regulatory framework that would govern long-term storage is lacking. Third, current capture technology is energy-intensive and very costly. Because the process itself uses a lot of energy, companies will need to store even more CO2 to offset the amount produced to get the energy to capture it.
“We need to start now to capture and store carbon dioxide,” Cooper said. “The infrastructure and regulatory framework needed to facilitate carbon capture and storage cannot be built overnight.”
COMMITMENT TO CHANGE
ConocoPhillips is committed to finding pragmatic and sustainable solutions to address the environmental impacts of climate change. Aside from having a strong climate change position, the company is joining other groups that have similar goals.
In 2007, the company joined the United States Climate Action Partnership, a group of businesses and leading environmental organizations that have come together to call on the federal government to quickly enact strong national legislation to require significant reductions of greenhouse gas emissions.
The company also joined the World Bank’s Global Gas Flaring Reduction partnership, a public-private partnership of governments, state-owned companies and major international oil companies committed to minimizing the wasteful practice of burning natural gas – also known as gas flaring – and reducing greenhouse gases to mitigate the impact of climate change.
“Climate change is a global concern, and it will take collaboration to find the most efficient and cost-effective solutions,” Brand said. “It’s a new research world, and the company is hard at work understanding unique technologies that could have a huge impact on the industry in the present and well into the future.”
Before the use of carbon capture and storage to reduce CO2 emissions can be widespread, several obstacles will need to be overcome. ConocoPhillips is undertaking research to develop possible solutions.
“CCS may not be the complete answer to climate change concerns, but it is an important bridging technology,” said Sabrina Watkins, manager, Environmental Technology. “Individuals, corporations and governments each have the creativity and innovation to bring to bear near term reductions in CO2 emissions and long-term changes in how the world uses energy.”
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In pre-combustion, fossil fuel is converted into a carbon dioxide and hydrogen mixture. The CO2 then is extracted from the mixture and stored, and the hydrogen is used as power. The second technique is oxyfuel capture. Fossil fuels are burned in oxygen instead of air. This creates an exhaust stream comprised of CO2 and steam. The carbon dioxide then is captured by condensing the stream. The
third option is post-combustion capture. Solvents, such as amines, are used to separate CO2 from the exhaust gas. Since each amine absorbs CO2 at a certain temperature and pressure, carbon dioxide can be removed by varying the exhaust’s temperature and pressure.
Graphic courtesy of U.N. Intergovernmental Panel on Climate Change |
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