CMI Technology explores the integration of intermittent renewable energy (wind and solar) into electricity grids, as affected by carbon policy and renewable energy policy—including the evolving roles for energy conversion in conjunction with carbon dioxide (CO2) capture and storage. Capture studies include both biological and fossil fuel inputs. Storage studies emphasize leakage pathways and also investigate storage in shales. Work also continues that is directed toward maximizing energy storage in batteries.
Research Highlights – At a Glance
Michael Celia: In order to have a significant impact on the carbon problem, very large amounts of captured CO2 need to be injected underground, with quantities reaching gigatonnes of CO2 per year by mid-century. The Celia group has developed models for large-scale injection, including pressure responses and associated pressure management schemes, and applied these to realistic injection scenarios in the Illinois Basin of North America, with simulated basin-wide injection rates exceeding 200 Mt CO2/ yr. Results indicate that if carbon capture and storage is to be implemented at the scale required to impact the carbon problem, such basin-wide analyses will need to be performed and appropriate management of pressure developed and implemented.
Ian Bourg: The objective of this initiative is to resolve the physics of soil carbon storage. The carbon storage capacity of soils is known to increase significantly with clay content, and in particular with the content in swelling clay minerals (smectites), but the cause of this relationship remains unknown. Using atomistic-level simulation methodologies, the Bourg group was able to model fully flexible clay particles surrounded by water and interacting with dissolved organic compounds. These results will enable more accurate Earth System Model predictions of the soil carbon sink and inform practical strategies for enhancing this important carbon sink.
Daniel Steingart: We are studying a fundamental question in battery research – whether apparently negative and inevitable physical phenomena in an electrochemical cell, such as corrosion and anisotropic growth, can be exploited for benefit. We use various imaging techniques to examine the deposition and removal of plate metals during cell operation and in conditions that emulate practical usage patterns.
Full-scale Basin-wide CO2 Injection with Pressure Management
Principal Investigator: Michael Celia
At a Glance
In order to have a significant impact on the carbon problem, very large amounts of captured carbon dioxide (CO2) need to be injected underground, with quantities reaching gigatonnes of CO2 per year by mid-century. The Celia group has developed models for large-scale injection, including pressure responses and associated pressure management schemes, and applied these to realistic injection scenarios in the Illinois Basin of North America, with simulated basin-wide injection rates exceeding 200 Mt CO2/yr. Results indicate that if carbon capture and storage is to be implemented at the scale required to impact the carbon problem, such basin-wide analyses will need to be performed and appropriate management of pressure developed and implemented.
The capture and belowground storage of carbon dioxide emissions from power plants and other sources has the potential to mitigate climate change by preventing the release of these emissions into the atmosphere. In order to have any significant impact on the carbon problem, very large amounts of captured CO2 need to be injected underground, with quantities reaching gigatonnes of CO2 per year by mid-century. This will require tens to hundreds of millions of tonnes of CO2 to be injected into a given sedimentary basin.
Earlier research by the Celia group, and others, led to the idea that very large-scale injection of CO2 may need to be coupled with brine production and other measures to control pressure buildup in the injection formations.1-11 To illustrate the impacts of very large-scale injection, a new study simulates pressure buildup in the Illinois Basin associated with injection of CO2 into the Mount Simon Formation. Figure 2.1.1. shows the increase of pressure associated with injection of close to 200 Mt CO2/yr, assuming 54 different on-site injection locations, and using a computational model that includes 11 geological layers and covers approximately 300,000 km2.
Figure 2.1.1. Onsite injection scenario after 50 years of continuous injection without pressure management. Left panel: CO2 plumes in the injection formation. Right panel: Pressure increase and area of review (AoR, hatched area) in the injection formation. Total AoR is close to 200,000 km2. From Bandilla and Celia12.
The Area of Review (AoR) is defined as the area where, by EPA regulation, pressure increase is sufficient to require site characterization and monitoring. The total AoR for this injection scenario is close to 200,000 km2. Not only is this a large area, but many of the individual injection sites have AoRs that overlap with those from neighboring injection sites, thereby complicating the determination of responsible parties in the event of a leakage event or other problem. In addition, the large pressure build-up has a number of associated risks including possible leakage of brines from the injection formation to shallow drinking water aquifers (this is the basis of the EPA definition for AoR) as well as increased potential for induced seismicity.
One way to reduce pressure build-up, and thereby the AoR, is through the use of brine production wells. Such wells need to be close enough to the injection to have an impact on the pressure response, but far enough away to avoid any early CO2 breakthrough. If the volume of brine extracted matches the volume of CO2 injected, then the pressure responses associated with each injection well can be controlled and the pressure build-up is highly localized. A strategy of 100% volume matching reduces the overall AoR from around 200,000 km2 to less than 20,000 km2 while eliminating overlapping AoRs (Figure 2.1.2.).
Figure 2.1.2. Pressure increase and AoR in the injection formation for the onsite scenario after 50 years of continuous injection with 100% brine production. Total AoR is about 18,000 km2. From Bandilla and Celia12.
Production of brine carries its own set of challenges, however, related to the use and disposal of the brines. While earlier collaborative work with Lawrence Livermore National Laboratory5,6,10 studied the possible use of heat from produced waters as well as desalination options, these utilization options appear to be limited in the Illinois Basin due to the relatively low temperatures and high salinities. Therefore disposal of the produced water becomes an issue. We have considered reinjection of the produced brines into formations above the injection formation (that is, above the Mount Simon Formation), with fractions ranging from 25% to 100% of the extracted water. In these cases, pressure increases in the overlying formations need to be analyzed and potential AoRs need to be computed for those injection operations.
Also, as in our earlier analysis of the Basal Sandstone formation in western Canada13, we considered off-site injection at regional centers, as opposed to on-site injections. This requires pipelines to transport the CO2 to the best locations for injection, but the result is a smaller and more easily managed pressure response. Even without brine extraction, this strategy reduces the overall AoR by about 30%. Adding brine extraction then allows for much larger reductions in AoR values, similar to the on-site results. The use of regional centers chosen for optimal injection properties also solves the problem of excessive pressure buildup at injection locations where subsurface properties are not conducive to large-scale injection, which happens at several of the on-site locations, affecting approximately 25% of the total CO2 injected.
Overall, if carbon capture and storage is to be implemented at the scale required to impact the carbon problem, these kinds of basin-wide analyses will need to be performed and appropriate management of pressure developed and implemented.
1 Bandilla, K. W., M.A. Celia, T.R. Elliot, M. Person, K.M. Ellett, J.A. Rupp, C. Gable, and Y. Zhang, 2012. Modeling carbon sequestration in the Illinois Basin using a vertically-integrated approach. Comput. Visual Sci., 15(1): 39-51. doi:10.1007/s00791-013-0195-2.
2 Birkholzer, J. T., A. Cihan, and Q.L. Zhou, 2012. Impact-driven pressure management via targeted brine extraction—Conceptual studies of CO2 storage in saline formations. Int. J. Greenh. Gas Con., 7: 168-180. doi:10.1016/j.ijggc.2012.01.001.
3 Bourcier, W.L., T.J. Wolery, T. Wolfe, C. Haussmann, T.A. Buscheck, and R.D. Aines, 2011. A preliminary cost and engineering estimate for desalinating produced formation water associated with carbon dioxide capture and storage. Int. J. Greenh. Gas Con., 5(5): 1319-1328. doi:10.1016/j. ijggc.2011.06.001.
4 Buscheck, T.A., J.M. Bielicki, M.J. Chen, Y.W. Sun, Y. Hao, T.A. Edmunds, M.O. Saar, and J.B. Randolph, 2014. Integrating CO2 Storage with Geothermal Resources for Dispatchable Renewable Electricity. Enrgy. Proced., 63: 7619-7630. doi:10.1016/j.egypro.2014.11.796.
5 Buscheck, T. A., T.R. Elliot, M.A. Celia, M.J. Chen, Y.W. Sun, Y. Hao, C. Lu, T.J. Wolery, and R.D. Aines, 2013. Integrated geothermal-CO2 reservoir systems: Reducing carbon intensity through sustainable energy production and secure CO2 storage. Enrgy. Proced., 37: 6587-6594. doi:10.1016/j. egypro.2013.06.591.
6 Buscheck, T. A., Y.W. Sun, M.J. Chen, Y. Hao, T.J. Wolery, W.L. Bourcier, B. Court, M.A. Celia, S.J. Friedmann, and R.D. Aines, 2012. Active CO2 reservoir management for carbon storage: Analysis of operational strategies to relieve pressure buildup and improve injectivity. Int. J. Greenh. Gas Con., 6: 230-245. doi:10.1016/j.ijggc.2011.11.007.
7 Buscheck, T. A., Y.W. Sun, Y. Hao, T.J. Wolery, W. Bourcier, A.F.B. Tompson, E.D. Jones, S.J. Friedmann, and R.D. Aines, 2011. Combining brine extraction, desalination, and residual-brine reinjection with CO2 storage in saline formations: Implications for pressure management, capacity, and risk mitigation. Enrgy. Proced., 4: 4283-4290. doi:10.1016/j.egypro.2011.02.378.
8 Buscheck, T. A., J.A. White, S.A. Carroll, J.M. Bielicki, and R.D. Aines, 2016. Managing geologic CO2 storage with pre-injection brine production: a strategy evaluated with a model of CO2 injection at Snøhvit. Energy Environ. Sci., 9(4): 1504-1512. doi: 10.1039/C5EE03648H.
9 Cihan, A., J. Birkholzer, and M. Bianchi, 2014. Targeted Pressure Management during CO2 Sequestration: Optimization of Well Placement and Brine Extraction. Enrgy. Proced., 63: 5325-5332. doi:10.1016/j.egypro.2014.11.564.
10 Court, B., K.W. Bandilla, M.A. Celia, T.A. Buscheck, J.M. Nordbotten, M. Dobossy, and A. Janzen, 2012. Initial evaluation of advantageous synergies associated with simultaneous brine production and CO2 geological sequestration. Int. J. Greenh. Gas Con., 8: 90-100. doi:10.1016/j.ijggc.2011.12.009.
11 Lindeberg, E., J.F. Vuillaume, and A. Ghaderi, 2009. Determination of the CO2 storage capacity of the Utsira formation. Enrgy. Proced., 1(1): 2777-2784. doi:10.1016/j.egypro.2009.02.049.
12 Bandilla, K.W., and M.A. Celia, 2017. Active pressure management through brine production for basin-wide deployment of geologic carbon sequestration. Int. J. Greenh. Gas Con., in review.
13 Huang, X., K.W. Bandilla, M.A. Celia, and S. Bachu, 2014. Basin-scale modeling of CO2 storage using models of varying complexity. Int. J. Greenh. Gas Con., 20: 73-86. doi:10.1016/j.ijggc.2013.11.004.
14 Bandilla, K.W., and M.A. Celia, 2016. Active Pressure Management through Brine Production for Basin-wide Deployment of Geologic Carbon Sequestration. Int. J. Greenh. Gas Con., in review.
Resolving the Physics of Soil Carbon Storage
Principal Investigator: Ian Bourg
At a Glance
The objective of this initiative is to resolve the physics of soil carbon storage. The carbon storage capacity of soils is known to increase significantly with clay content, and in particular with the content in swelling clay minerals (smectites), but the cause of this relationship remains unknown. Using atomistic-level simulation methodologies, the Bourg group was able to model fully flexible clay particles surrounded by water and interacting with dissolved organic compounds. These results will enable more accurate Earth System Model predictions of the soil carbon sink and inform practical strategies for enhancing this important carbon sink.
Soil are a vast pool of carbon (2,400 gigatonnes of carbon, integrated from the surface to 2 m depth), roughly three times larger than the atmosphere and 240 times current annual fossil fuel emissions. A 0.4% annual increase in global soil carbon content would, on its own, entirely offset global fossil fuel emissions. According to Earth System Models, soil carbon content will increase significantly over the 21st century. The magnitude of this increase is poorly known (it may range from 0.01 to 0.15% annually) because of a lack of understanding of the fundamental mechanisms that control the rate of microbial degradation of soil organic matter. A 0.02% annual increase in the global soil carbon content would add 25 GtC to the soils, which is a stabilization “wedge” as defined by Pacala and Socolow (2004). Conversely, soil carbon losses have historically led to significant anthropogenic carbon dioxide emissions. The US’s Great Plains lost almost 4% of their soil organic carbon over the last 30 years, and decreases of similar or greater magnitude have been estimated for other regions.
The carbon storage capacity of soils is known to correlate with soil clay content, and in particular with the content in swelling clay minerals (smectites), but the cause of this relationship remains unknown. Clay minerals contribute predominantly to the specific surface area and cation exchange capacity of soils, suggesting that organic molecules may become chemically shielded from microbial degradation by attachment to clay surfaces. Clay minerals also strongly influence the hydraulic permeability of porous media, suggesting that they may slow the degradation of soil organic matter by modulating soil microbiology and/or hydrologic permeability.
A key breakthrough in this initiative in 2016 is the ability to model, using atomistic-level simulation methodologies developed by the Bourg group over the last two years, fully flexible clay particles surrounded by water and interacting with dissolved organic compounds. As a first test of this methodology, the group simulated the adsorption of dissolved gases (noble gases, methane, CO2, or H2) on smectite clay particles (Gadikota et al., 2017). These simulations (Figure 2.1.), which solve Newton’s equations of motion for systems of about 100,000 atoms using semi-empirical models of all relevant interatomic interactions, require about two weeks of time on hundreds of parallel processors. The main challenge is to develop models of these interatomic interactions that accurately predict the properties of real clay-water systems, a research area in which the Bourg group is actively involved, in collaboration with synchrotron scientists at two US National Laboratories. The simulations are carried out on the Cori supercomputer of the US Department of Energy, the world’s fifth fastest computer.
According to Earth System Models, soil carbon content will increase significantly over the 21st century. The magnitude of this increase is poorly known (it may range from 0.01 to 0.15% annually) because of a lack of understanding of the fundamental mechanisms that control the rate of microbial degradation of soil organic matter. A 0.02% annual increase in the global soil carbon content would add 25 GtC to the soils, which is a stabilization “wedge” as defined by Pacala and Socolow (2004).
The results show that clay minerals, despite their well-known hygroscopic nature, have a significant hydrophobic character at the atomistic scale. This local hydrophobicity exists because the random distribution of negatively charged sites (mostly isomorphic substitutions of Al by Mg) in the clay structure gives rise to uncharged “patches” on the clay surface, i.e., localized regions where the clay surface is hydrophobic because it carries no exchangeable cations (Na+ ions in Figure 2.1.). The affinity of different dissolved gases for the clay surface further shows unexpected variations related to the size and shape of the adsorbing molecules and the structuring of interfacial water by the clay surface. Results obtained with dissolved gases and preliminary results obtained with uncharged organic compounds suggest that organic molecules containing aromatic rings and/or heteroatoms (O, N, S) should have a significantly greater tendency to attach to (and become physically shielded by) clay surfaces.
The Bourg group is building upon these simulation methodologies to investigate the mechanisms of soil carbon storage through two research efforts. The first effort (carried out under the auspices of CMI) focuses on developing a fundamental knowledge of the thermodynamics of adsorption of a range of organic molecules representative of soil organic matter on smectite clay minerals. The second effort (supported by the US Department of Energy) focuses on developing new constitutive relationships for the impact of clay minerals on the permeability of soils. The two research efforts are independent (and carried out by different team members), but their results inform each other.
In addition to providing an advanced understanding of carbon cycling in soils, this initiative will enable more accurate representations of the interaction of organic or hydrophobic compounds with clay surfaces in other areas, for example, in basin modeling, CO2-enhanced oil recovery, and the remediation of soils contaminated by organic contaminants. Results on the adsorption of dissolved gases on smectite surfaces shed light on long-standing questions associated with the use of noble gases as tracers of fluid migration in the subsurface.
Chan, Y., 2008. Increasing soil organic carbon of agricultural land. Primefacts, 735. New South Wales Department of Primary Industries.
Gadikota G., B. Dazas, and I.C. Bourg, 2017. Molecular dynamics simulations of the solubility of gases (CO2, CH4, H2, noble gases) in water-filled clay interlayer nanopores. J. Am. Chem. Soc., in preparation.
He Y., S.E. Trumbore, M.S. Torn M.S., J.W. Harden, L.J.S. Vaughn, S.D. Allison, and J.T. Randerson, 2016. Radiocarbon constraints imply reduced carbon uptake by soils during the 21st century. Science, 353(6306): 1419-1424. doi:10.1126/science.aad4273.
Pacala, S., and R. Socolow, 2004. Stabilization Wedges: Solving the Climate Problem for the Next 50 Years with Current Technologies. Science, 305(5686): 968-972. doi:10.1126/science.1100103.
Sulman, B.N., R.P. Phillips, A.C. Oishi, E. Shevliakova, and S.W. Pacala, 2014. Microbe-driven turnover offsets mineral-mediated storage of soil carbon under elevated CO2. Nat. Clim. Change, 4: 1099-1102. doi:10.1038/nclimate2436.
Exploiting Negative Phenomena to Maximize Energy Storage in Batteries
Principal Investigator: Daniel Steingart
At a Glance
We are studying a fundamental question in battery research—whether apparently negative and inevitable physical phenomena in an electrochemical cell, such as corrosion and anisotropic growth, can be exploited for benefit. We use various imaging techniques to examine the deposition and removal of plate metals during cell operation and in conditions that emulate practical usage patterns.
In our first full year working with the Carbon Mitigation Institute we posed a fundamental question in energy storage research: can apparently inevitable physical outcomes in a cell such as corrosion and anisotropic growth be exploited for benefit rather than suppressed and avoided?
In a closed electrochemical cell, the maximum energy density is achieved when the lightest possible electrochemically active components are paired with the largest possible potential window. While this demands use of a heretofore unrealized fluoride compound as an oxidizing agent, it also requires use of metallic lithium as a reducing agent. Metallic lithium has been used successfully as a primary metal anode for half a century, but its use as a secondary anode has been limited by both the chaotic nature of its redeposition during a charging cycle and the possibility of an explosion when there is an uncontrolled short circuit. Its application as a secondary anode is feasible only where performance requires a minimal safety factor.
Building upon our previous studies of the growth of zinc at potentials beyond the onset of reactant starvation, we have spent the last year establishing the laboratory infrastructure required to examine the deposition and removal of plate metals while the cells are operating (Figure 2.3.). This includes optical microscopy, electrochemical acoustic analysis, and transmission X-ray microscopy.
Figure 2.3. 3D reconstruction (left) and 2D image (right) of zinc dendrites that have maximized cycle life and energy density.
We have imaged lithium and zinc with all of these methods, and we are beginning our second year with stability analysis of plate metal systems deposited and removed in various regimes that emulate practical usage patterns. We now have further evidence that better utilization of the active material is achieved with asperities that are pre-grown at the correct length scales rather than the flat structures dictated by conventional design.
Although flat structures are easiest to imagine being “predictable,” in actuality the complex competition between nucleation and growth during crystal growth quickly turns a flat surface into a rough structure. Instead, by starting with a rough structure that is “sympathetic” to the length scales natural to a given growth rate, more of a metal anode can be used reliably.
Going forward this year, we want to test the limits of how much of this rough scaffold can be utilized before the effect is no long present, and what impurities might be leveraged to act as scaffold.
Park, J.H., D.A. Steingart, S. Kodambaka, and F.M. Ross, 2017. Electrochemical Electron-Beam Lithography: Write, Read and Erase Metallic Nanocrystals on Demand, in revision.
Schneider, N.M., J.H. Park, J.M. Grogan, S. Kodambaka, D.A. Steingart, H.H. Bau, and F.M. Ross, 2017. Nanoscale evolution of interface morphology during electrodeposition, in review.
Bandilla, K.W., and M.A. Celia, 2016. Geological Sequestration of Carbon Dioxide. In The Handbook of Groundwater Engineering, 3rd Edition. Eds. J.H. Cushman, and D.M. Tartakovsky. Boca Raton: Taylor and Francis Group, 657-690.
Bandilla, K.W., B. Guo, and M.A. Celia, 2016. Applicability of Vertically Integrated Models for Carbon Storage Modeling in Structured Heterogeneous Domains. GHGT- 13 Conference, Lausanne.
Guo, B., K.W. Bamdilla, J.M. Nordbotten, M.A. Celia, E. Keilegavlen, and F. Doster. 2016. A Multiscale Multilayer Vertically Integrated Model with Vertical Dynamics for CO2 Sequestration in Layered Geological Formations. Water Resour. Res., 52(8): 6490- 6505. doi:10.1002/2016WR018714.
Guo, B., Y. Tao, K.W. Bandilla, and M.A. Celia, 2016. Vertically-integrated Dual-porosity and Dual-permeability Models for CO2 Sequestration in Fractured Resevoirs. GHGT-13 Conference, Lausanne.
Guo, B., Z. Zheng, K.W. Bandilla, M.A. Celia, and H.A. Stone, 2016. Flow Regime Analysis for Geological CO2 Sequestration and Other Subsurface Fluid Injections. Int. J. Greenh. Gas Con., 53: 284-291. doi:10.1016/j. ijggc.2016.08.007
Guo, B., Z. Zhong, M.A. Celia, and H.A. Stone, 2016. Axisymmetric Flows from Fluid Injection into a Confined Porous Medium. Phys. Fluids, 28: 022107. doi:10.1063/1.4941400.
Huang, X., K.W. Bandilla, and M.A. Celia, 2016. Multi-physics Pore-network Modeling of Two-phase Shale Matrix Flows. Transport Porous Med., 111(1): 123-141. doi:10.1007/ s11242-015-0584-8.