Carbon Capture and Disposal
This figure shows the existing set of power plants in the US mapped to known potential reservoirs for geologic disposal of carbon, including coal seams, saline formations and basalt formations.
Fossil fuels form the backbone of the present global energy system, and current resources are more than adequate to fuel the global energy system for the century ahead. Like all energy forms, its use stems from its economic competitiveness. The contribution of fossil fuels in the future global energy system depends on technology. Key issues include the ability of technology to make unconventional oil and gas resources available and the availability of technologies to remove and dispose of carbon in reservoirs permanently isolated from the atmosphere. Consider the development path needed to realize the potential of carbon capture and disposal technologies. Phase I of the GTSP demonstrated the potential contribution that carbon capture and disposal could play in atmospheric stabilization. The PNNL IA research team demonstrated a wide array of options ranging from the capture of carbon in soils to the chemical capture of carbon in stack gases and its subsequent transport and disposal in permanent reservoirs. If available, carbon capture and disposal technologies could store hundreds of billions of tons of carbon by the end of the century.
Scientists at PNNL are studying the flow and chemical reaction processes of CO2 at high pressure in basalt and sedimentary rock formations to assess the potential of these formations to permanently sequestor CO2.
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Many questions must be addressed if carbon disposal technology is to be deployed widely. Permanent disposal of carbon in various reservoirs must be demonstrated if carbon capture is to be an effective option in the future. The availability of various reservoirs, their proximity to emissions sources, and their retention capability will become important determinants of the role of carbon disposal technologies. Loss rates of one percent per year are inconsistent with stabilization of the concentration of greenhouse gases and could constitute an emissions source of billions of tons of carbon per year by the end of the century (Edmonds, Kim and Smith 2002; Dooley 2002).
Environmental regulation will also impact the future role of carbon capture. Regulation frequently becomes more stringent over time. Future requirements for reservoirs will be more stringent than initial requirements. Evolving regulation will require an examination of technology responses that range from the use of CO2 in economically attractive applications, such as for tertiary recovery of liquids and gases and as a flush gas for coalbed methane at one extreme, to complete mineralization at the other. A significant amount of research is required to move from the theoretical potential to the deployment of specific technologies capable of capturing and permanently isolating billions of tons of carbon per year from the atmosphere. In Phase II of the GTSP the PNNL IA team will address these questions.
While technology may be global, its deployment will always be regional and local. In GTSP Phase I studies explored differences between regional technology deployments against a background of limited greenhouse gas emissions. In GTSP Phase II these studies will be expanded and deepened to explore pathways by which advanced energy technologies can migrate and to determine which technologies show particular promise. This will involve identifying and modeling the variety and distribution of global reservoirs for the disposal of carbon.