Massachusetts Institute of Technology (MIT) has researched how microorganisms acclimate and adapt to high partial pressures of CO2 associated with geological carbon storage of supercritical CO2. In its supercritical state, CO2 has the high-density characteristics of a liquid yet behaves like a gas by seeking to fill all the available pore space within the storage medium. An enabling technology for geological carbon storage is the development of reservoir-sealing mechanisms and leak remediation strategies, should they be needed. Biofilm barriers—an aggregate of microorganisms in which cells adhere to each other or a substrate—hold promise as a geologic carbon storage leak mitigation tool. However, establishing such barriers in situ (e.g., following hydrocarbon reservoir decommissioning) requires that biofilm-producing strains remain active underhigh-pressure CO2 conditions (Figure 1).
This project has identified and developed microbial strains capable of activity in supercritical CO2 environments. MIT has characterized the diversity of bacteria capable of surviving in a supercritical CO2 atmosphere and is investigating the molecular mechanism of microbial survivability and stress response in supercritical-CO2-tolerant bacteria through physiological, genomic, and transcriptomic (ribonucleic acid) profiling.
The overall goal of the Department of Energy’s (DOE) Carbon Storage Program is to develop and advance technologies that will significantly improve the effectiveness of geologic carbon storage, reduce the cost of implementation, and prepare for widespread commercial deployment between 2020 and 2030. Research conducted to develop these technologies will ensure safe and permanent storage of carbon dioxide (CO2) to reduce greenhouse gas (GHG) emissions without adversely affecting energy use or hindering economic growth.
Geologic carbon storage involves the injection of CO2 into underground formations that have the ability to securely contain the CO2 permanently. Technologies being developed for geologic carbon storage are focused on five storage types: oil and gas reservoirs, saline formations, unmineable coal seams, basalts, and organic-rich shales. Technologies being developed will work towards meeting carbon storage programmatic goals of (1) estimating CO2 storage capacity +/- 30 percent in geologic formations; (2) ensuring 99 percent storage permanence; (3) improving efficiency of storage operations; and (4) developing Best Practices Manuals. Developing and deploying these technologies on a large scale will require a significantly expanded workforce trained in various carbon capture and storage (CCS) technical and non-technical disciplines that are currently under-represented in the United States. Education and training activities are needed to develop a future generation of geologists, scientists, and engineers who possess the skills required for implementing and deploying CCS technologies.
The National Energy Technology Laboratory (NETL), through funding provided by the American Recovery and Reinvestment Act (ARRA) of 2009, manages 43 projects that received more than $12.7 million in funding. The focus of these projects has been to conduct geologic storage training and support fundamental research projects for graduate and undergraduate students throughout the United States. The training and projects can be categorized under one or more of the DOE Carbon Storage Program’s five Technology Areas: (1) Geologic Storage and Simulation and Risk Assessment (GSRA), (2) Monitoring, Verification, Accounting (MVA) and Assessment, (3) CO2 Use and Re-Use, (4) Regional Carbon Sequestration Partnerships (RCSP), and (5) Focus Area for Sequestration Science. This research effort identified microbial species that are able to survive in a carbon storage environment in the presence of supercritical CO2.
Overall the project will make a vital contribution to the scientific, technical, and institutional knowledge base necessary to establish frameworks for the development of commercial-scale CCS. Project research has advanced knowledge of microbial populations that can persist in carbon storage reservoirs following CO2 injection and helps to better understand the activities the microbes mediate. These microorganisms hold potential as agents for biofilm barrier engineering due to their tolerance and growth under high-pressure CO2 conditions. This type of biofilm technology contributes to the Carbon Storage Division’s Programmatic goal of ensuring 99 percent storage permanence. In addition, this project offered students an opportunity to gain vital skills relating to the permanent storage of CO2 in the subsurface that allows for the implementation of CCS on a commercial-scale.
The goal of this research project is to identify and develop strains capable of microbial activity under supercritical CO2 in order to develop technologies that can form sealing mechanisms that can be deployed if leakage occurs at a geologic CO2 storage site. This type of technology could also be used as proactive mitigation through remediation/plugging of abandoned well-bores. The specific objectives of this project are to:
Characterize the growth requirements and optima of a biofilm-producing supercritical-CO2-tolerant microbial consortium isolated from hydrocarbons recovered from the Frio Ridge, Texas carbon storage site.
Evaluate the ability of this consortium to grow cores under simulated reservoir conditions associated with supercritical CO2 injection.
Isolate and characterize individual microbial strains from this group of microbes.
Investigate the mechanisms of supercritical CO2 tolerance in isolated strains and the consortium through (meta)genome-enabled studies.
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