Carbon Capture and Sequestration
A waste product of burning fossil fuels to release their energy is carbon dioxide, whose concentration in the atmosphere partially sets Earth’s climate. One intriguing strategy for continued use of fossil fuels without forcing climate changes is to capture carbon dioxide at its industrial sources, and then to store it in a form or a location that keeps it out of the atmosphere. While the concept is attractive, there are numerous technological challenges, which Cornell research teams are tackling. Exploration has also begun of the even more challenging possibility that it may prove necessary to capture carbon dioxide from the general atmosphere in addition to capturing it from concentrated point sources.
Capturing carbon dioxide gas from the complex mixture of gases emitted from a power plant is the first challenge, as traditional industrial approaches are expensive. Emmanuel Giannelis’ and Fernando Escobedo’s research groups, parts of the KAUST-Cornell Center for Energy and Sustainability, are investigating new classes of solid sorbents that would be both efficient and could be recycled, to repeatedly capture carbon dioxide, which would reduce the cost. They take a combined approach, developing through theory and experimentation new nanoscale hydrid materials that capture the carbon dioxide from a gas. They are also exploring means to transform the carbon dioxide waste into useful products, such as biodegradable polymers or solid carbonates that could be used as substitutes for cement or aggregate.
If useful bi-products cannot yet be synthesized then, once captured, the challenge is to safely store the carbon dioxide where it cannot escape to the atmosphere. Several other Cornell researcher groups are exploring the safe storage of carbon dioxide. Rocks hold one large category of storage sites for carbon dioxide: just as oil and gas originate in fluid-filled pore spaces in rocks and can be released via wells drilled into the rock, the reverse can be done: carbon dioxide can be pumped into subsurface rocks to flow into those pores. Major questions include: where are there good storage sites; how much can be injected, are there particularly safe and efficient injection strategies? Once injected, can the migration of carbon dioxide be monitored effectively and inexpensively? Teresa Jordan’s group examines the suitability of rock formations to be storage sites near New York State power plants. Louis Derry’s and Lawrence Cathles’ research groups experiment with the flow of carbon dioxide through pore spaces. Donald Koch and Abraham Strook’s research group examines how the rate and steadiness of pumping changes the efficiency of flow of carbon dioxide through the pores. Christine Shoemaker’s group improves the numerical modeling tools utilized to predict the flow of carbon dioxide in the subsurface system.