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Environment

Carbon Dioxide Capture and Storage

Sally M. Benson^a1 and Franklin M. Orr Jr.^a1

^a1 Stanford University, USA

Reducing CO₂ emissions from the use of fossil fuel is the primary purpose of carbon dioxide capture and storage (CCS). Two basic approaches to CCS are available.^1,2 In one approach, CO₂ is captured directly from the industrial source, concentrated into a nearly pure form, and then pumped deep underground for long-term storage (see Figure 1). As an alternative to storage in underground geological formations, it has also been suggested that CO₂ could be stored in the ocean. This could be done either by dissolving it in the mid-depth ocean (1–3 km) or by forming pools of CO₂ on the sea bottom where the ocean is deeper than 3 km and, consequently, CO₂ is denser than seawater. The second approach to CCS captures CO₂directly from the atmosphere by enhancing natural biological processes that sequester CO₂ in plants, soils, and marine sediments. All of these options for CCS have been investigated over the past decade, their potential to mitigate CO₂ emissions has been evaluated,¹ and several summaries are available.^1,3,4

Sally M. Benson can be reached at Stanford University, Global Climate and Energy Project, 4230 Jerry Yang and Akiko Yamazaki Environment and Energy Bldg., 473 Via Ortega, Stanford, CA 94305, USA; tel. 650–725–0358, and e-mail smbenson@stanford.edu.

Benson is a research professor in the Energy Resources Engineering Department in the School of Earth Sciences at Stanford University, and the executive director of the Global Climate and Energy Project. She received her MS and PhD degrees from the University of California in materials science and mineral engineering. Benson joined Stanford in 2007 after working at Lawrence Berkeley National Laboratory in a number of capacities, including Earth Science Division Director, Associate Laboratory Director for Energy Sciences, and Deputy Director for Operations.

Franklin M. Orr, Jr. can be reached at Stanford University, Global Climate and Energy Project, Yang and Yamasaki Environment and Energy Building, Rm. 324, 473 Via Ortega, Stanford, CA 94305–4230, USA; tel. 650–725–6270, fax 650–725–9190, and e-mail fmorr@stanford.edu.

Orr is the Keleen and Carlton Beal Professor in Petroleum Engineering in the Department of Energy Resources Engineering and director of the Global Climate and Energy Project at Stanford University. He holds a PhD degree from the University of Minnesota and a BS degree from Stanford University, both in chemical engineering. Orr joined Stanford in 1985 and served as dean of the School of Earth Sciences from 1994 to 2002. His research interests include multiphase fow in porous media, CO₂ sequestration, and reduction of greenhouse gas emissions from energy use. In addition, Orr is a member of the National Academy of Engineering.