CCS is the process by which carbon dioxide gas that would otherwise be released into the atmosphere is captured, compressed and injected into underground geologic formations for permanent storage. The Intergovernmental Panel on Climate Change estimates that fossil fuel power plants and large industrial facilities account for as much as 60 percent of global carbon emissions. Thus, broad-based deployment of cost-effective carbon capture and sequestration has the potential to make a massive impact on the world’s greenhouse gas levels.
ExxonMobil believes the greatest opportunity for future large-scale deployment of CCS will be in the natural gas-fired power generation sector. While CCS technology can be applied to coal-fired power generation, the cost to capture CO2 is about twice that of natural gas power generation. In addition, because coal-fired power generation creates about twice as much CO2 per unit of electricity generated, the geological storage space required to sequester the CO2 produced from coal-fired generation is about twice that associated with gas-fired generation.
ExxonMobil is conducting proprietary, fundamental research to develop breakthrough carbon capture technologies with an aim to reduce complexity, lower the cost and ultimately, encourage wide-spread global deployment of this crucial technology.
ExxonMobil’s long-term commitment to advancing CCS technology
For more than 30 years, ExxonMobil engineers and scientists have researched, developed and applied technologies that could play a role in the wide-spread deployment of CCS.
We have a history of proven results in a production process called Enhanced Oil Recovery (EOR), which involves injecting CO2 into a reservoir to extract “trapped” oil and gas that could not otherwise be produced. In the United States alone, more than 11 trillion cubic feet of CO2 have already been used in EOR projects.
ExxonMobil is working with partners on a number of CCS-related research projects, such as improved capture technology; reservoir flow modeling; geologic storage and integrity modeling; and assessing well seal integrity and storage capacity of oil and gas reservoirs, aquifers and coal beds for potential storage use.
We are constantly striving to find new and better ways to improve the CCS technology. Fore example, our 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.
With our long history of operational, technical and research experience in the technologies comprising CCS, ExxonMobil is uniquely positioned to lead the way in further technology development of this promising approach to reducing emissions.
Our involvement includes:
- Partnering with the European Commission and other companies on the CO2ReMoVe project that evaluated a range of technologies to monitor the injection and storage of CO2 from gas streams in fields around the world.
- Collaborative research at the International Energy Agency, Massachusetts Institute of Technology, Georgia Tech, University of Texas and University of Wyoming.
- Participation in U.S. Department of Energy Regional Sequestration Partnerships.
- Intensive internal research and development of CCS-related technologies and participation in demonstration projects.
- Co-founder of the Global Climate and Energy Project (GCEP) at Stanford University, a long-term research program designed to accelerate development of a range of commercially viable energy technologies that can lower GHG emissions on a global scale.
- ExxonMobil and FuelCell Energy, Inc. recently announced an agreement to pursue novel technology in power plant carbon dioxide capture through a new application of carbonate fuel cells, which could substantially reduce costs and lead to a more economical pathway toward large-scale application globally.
The carbon capture and sequestration process
Step 1: Capturing CO2
The first step in the CCS process is capturing, or separating, the CO2 from the fuel source used at power generation plants or industrial manufacturing facilities. Capture is the most costly and energy-intensive step of the CCS process.
ExxonMobil has extensive experience in separating CO2 from hydrocarbons through its natural gas processing facilities, which remove impurities from the gas before it is shipped via pipeline.
Most current capture technologies use a solvent to remove CO2 from the gas stream, but ExxonMobil’s Controlled Freeze Zone technology is based on the freezing and re-melting of CO2 in a modified distillation column. Controlled Freeze Zone technology reduces the cost and complexity of separating CO2 from natural gas and could have significant benefits for CCS systems, in part because there are no limits on CO concentration, and the CO2 is discharged under pressure, ready for re-injection.
Step 2: The transportation process
The second step is transporting the captured CO2 to the storage site – underground geologic formations such as depleted oil or gas reservoirs.
ExxonMobil Pipeline Company operates or has an interest in more than 12,000 miles (more than 19,000 kilometers) of pipeline in the United States, using the most advanced technology and extensive quality-control procedures to ensure the safety of its lines. The company’s integrity management program includes a wide range of testing and monitoring techniques – from hydrotesting to tools that travel through the pipeline to inspect for flaws or ongoing corrosion control. In addition to these inspection and maintenance measures, the company’s Operations Control Center monitors pipeline operations on a 24-hour basis.
ExxonMobil is currently involved in a number of research projects designed to test the integrity of steel and other materials when exposed to CO2.
Step 3: Injection and storage
The third and final component of CCS is injecting CO2 into underground reservoirs for storage. ExxonMobil is well versed in this area, due to the company’s long history of using water, natural gas and CO2 injection for EOR and sound resource management.
The company’s field-tested program of injection well integrity management includes mechanical testing, corrosion control programs and computer controlled systems.
ExxonMobil has extensive technological expertise in monitoring and ensuring the integrity of our fields. Our involvement in CO2 injection projects in the North Sea and LaBarge, Wyoming, gives the company first-hand knowledge and experience in this stage of the CCS process.