Carbon Mitigation Initiative
CMI

CMI Technology

CMI Technology

CMI Technology studies 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 now also investigate storage in shales. A program on advanced batteries has begun.

Research Highlights – At a Glance

Michael Celia: The capture and belowground storage of carbon dioxide (CO2) emissions from power plants and other sources has the potential to mitigate climate change by preventing the release of these emissions into the atmosphere. The presence of abandoned oil and gas wells in areas that are otherwise suitable for geological storage may compromise storage integrity. Both CO2 and brine may leak out from old wells, potentially contaminating groundwater supplies and possibly leading to CO2 leakage into the atmosphere. The Celia group has combined modeling approaches with empirical data collection to estimate the risks of leakage along abandoned wells in the Wabamun Lake area of Alberta, Canada.

Howard Stone: Climate changes involve atmospheric motions, ocean flows, and evolution of ice on land and in the sea. These dynamics are necessarily interrelated; insights into individual processes can help to illuminate poorly understood aspects of global climate dynamics, such as factors affecting the maintenance of sea ice cover in the Arctic basin. Sea ice cover can impact fresh water fluxes, local ecology, and ocean circulation. The Stone group is providing simplified models for understanding the movement of ice through narrow straits, which can affect flow and mixing in the ocean.

Daniel Steingart: Building more energy-efficient systems depends on the ability to optimize and regulate the performance of energy-storing batteries. The Steingart group has developed a new type of zinc material that overcomes many of the limitations of zinc storage batteries. This material may be useful for long-term energy storage in grid-scale and electric vehicle applications.


Estimating Leakage of CO2 and Brine Along Abandoned Oil and Gas Wells
Principal Investigator: Michael Celia

At a Glance

The capture and belowground storage of carbon dioxide (CO2) emissions from power plants and other sources has the potential to mitigate climate change by preventing the release of these emissions into the atmosphere. The presence of abandoned oil and gas wells in areas that are otherwise suitable for geological storage may compromise storage integrity. Both CO2 and brine may leak out from old wells, potentially contaminating groundwater supplies and possibly leading to CO2 leakage into the atmosphere. The Celia group has combined modeling approaches with empirical data collection to estimate the risks of leakage along abandoned wells in the Wabamun Lake area of Alberta, Canada.

Research Highlight

Early research by the Celia group led to the development of models to estimate leakage risk along old wells with a focus on CO2 injection into deep saline aquifers.1-12 These models predict the movement of both CO2 and brine within the injection formation, leakage upward (or downward) of both fluids along old wells, and flows from leaky wells into other permeable formations along the vertical direction. While these models were applied to realistic field settings, such as the Alberta Basin in Canada,13,14 the models were always limited by a lack of data on properties of potentially leaky (old) wells, specifically effective permeability.

More recent work facilitated the estimation of effective permeability values for the leakage of both CO2 and brine along old wells. This work has included a program with BP and others as partners.15 The program involved reentering old wells and performing vertical interference tests (VITs) outside of the wells’ casings.16-19 The tests produced estimates of the effective behind-casing permeability for the sampled well regions. Data from a separate, ongoing field measurement program focusing on methane emissions from old wells has also produced estimates of effective permeabilities along the entire length of a set of leaking old wells in Pennsylvania.20

Subsequently, the Celia group combined the original modeling with the new data sets to produce quantitative estimates of expected leakage rates for a specific potential injection site in the Alberta Basin. The site is in the Wabamun Lake area, and the injection formation is the Nisku Formation (see Figure 2.1). The collective data from the measurement programs were used to define overall statistics for well permeabilities, and those statistics were applied to the old wells in the Wabamun Lake area. The model includes 11 permeable formations along the vertical direction, with a total of 1,146 old (potentially leaky) wells in an area of 2,500 square kilometers (see Figure 2.1). The efficient computational models developed earlier by the Celia team enabled the researchers to run 1,000 simulations of the problem, assigning different well permeability values based on statistics from the measured data sets. The mean leakage rate for the fraction of injected CO2 that reaches the shallow aquifers after 50 years of injection is less than 0.001%, and 95% of the results fall below 0.002%. The total amount of CO2 that leaks out of the injection formation, independent of whether it reaches the shallow zone, also stays well below 0.1% after 50 years. Moreover, the amount of brine that leaks is consistently much lower than the amount of CO2.

Figure 2.1
Figure 2.1. Maps showing (a) the location of the Wabamun Lake area, (b) the locations of existing wells within the 2,500-square-kilometer study area, and (c) the depth of each well, with permeable formations shown along the vertical direction.

All results to date indicate that leakage from the Nisku Formation should be expected to be very low, assuming the properties of the old wells in this area can be estimated from the statistics derived from different sets of well data (which do not involve wells from Alberta). The amount of brine that leaks into shallow aquifers is much lower than the amount of CO2, indicating that shallow drinking water supplies should be safe from any significant leakage of CO2 or displaced brine. While a broader analysis using these leakage models is ongoing, the overall conclusion is not expected to change.

References

  1. Nordbotten, J., M.A. Celia, S. Bachu, and H.K. Dahle, 2005. Semianalytical Solution for CO2 Leakage through an Abandoned Well. Environ. Sci. Technol., 39(2): 602-611. doi:10.1021/es035338i.
  2. Nordbotten, J., M.A. Celia, and S. Bachu, 2005. Injection and Storage of CO2 in Deep Saline Aquifers: Analytical Solution for CO2 Plume Evolution during Injection. Transport Porous Med., 58(3): 339- 360. doi:10.1007/s11242-004-0670-9.
  3. Nordbotten, J.M., and M.A. Celia, 2006. Similarity Solutions for Fluid Injection into Confined Aquifers. J. Fluid Mech., 561: 307-327. http://dx.doi.org/10.1017/S0022112006000802.
  4. Nordbotten, J.M., D. Kavetski, M.A. Celia, and S. Bachu, 2009. Model for CO2 Leakage including Multiple Geological Layers and Multiple Leaky Wells. Environ. Sci. Technol., 43(3): 743-749. doi:10.1021/es801135v.
  5. Nordbotten, J.M., and M.A. Celia, 2012. Geological Storage of CO2: Modeling Approaches for Large-scale Simulation. Hoboken, NJ: John Wiley and Sons.
  6. Celia, M.A., and J.M. Nordbotten, 2009. Practical Modeling Approaches for Geological Storage of Carbon Dioxide. Ground Water, 47(5): 627-638. doi:10.1111/j.1745-6584.2009.00590.x.
  7. Celia, M.A., J.M. Nordbotten, B. Court, M. Dobossy, and S. Bachu, 2011. Field-scale Application of a Semi-analytical Model for Estimation of CO2 and Brine Leakage along Old Wells. Int. J. Greenhouse Gas Control, 5(2): 257-269. doi:10.1016/j.ijggc.2010.10.005.
  8. Celia, M.A., S. Bachu, J.M. Nordbotten, and K.W. Bandilla, 2015. Status of CO2 Storage in Deep Saline Aquifers with Emphasis on Modeling Approached and Practical Simulations. Water Resour. Res., 51(9): 6846-6892. doi:10.1002/2015WR017609.
  9. Bandilla, K., M.A. Celia, J.T. Birkholzer, A. Cihan, and E.C. Leister, 2015. Multi-phase Modeling of Geologic Carbon Sequestration in Saline Aquifers. Ground Water, 53(3): 362-277. doi:10.1111/ gwat.12315.
  10. Gasda, S.E., J.M. Nordbotten, and M.A. Celia, 2009. Vertical Equilibrium with Sub-scale Analytical Methods for Geological CO2 Sequestration. Computat. Geosci., 13(4): 469-481. doi:10.1007/s10596- 009-9138-x.
  11. Gasda, S.E., J.M. Nordbotten, and M.A. Celia, 2011. Vertically-averaged Approaches for CO2 Migration with Solubility Trapping. Water Resour. Res., 47(5): W05528. doi:10.1029/2010WR009075.
  12. Gasda, S.E., J.M. Nordbotten, and M.A. Celia, 2012. Application of Simplified Models to CO2 Migration and Immobilization in Large-scale Geological Systems. Int. J. Greenhouse Gas Control, 9: 72-84. doi:10.1016/j.ijggc.2012.03.001.
  13. Celia, M.A., J.M. Nordbotten, B. Court, M. Dobossy, and S. Bachu, 2011. Field-scale Application of a Semi-analytical Model for Estimation of CO2 and Brine Leakage along Old Wells. Int. J. Greenhouse Gas Control, 5(2): 257-269. doi:10.1016/j.ijggc.2010.10.005.
  14. Nogues, J.P., B. Court, M. Dobossy, J.M. Nordbotten, and M.A. Celia, 2012. A Methodology to Estimate Maximum Probable Leakage along Old Wells in a Geological Sequestration Operation. Int. J. Greenhouse Gas Control, 7: 39-47. doi:10.1016/j.ijggc.2011.12.003.
  15. Crow, W., J.W. Carey, S. Gasda, D.B. Williams, and M. Celia, 2010. Wellbore Integrity Analysis of a Natural CO2 Producer. Int. J. Greenhouse Gas Control, 49(2): 186-197. doi:10.1016/j.ijggc.2009.10.010.
  16. Crow, W., J.W. Carey, S. Gasda, D.B. Williams, and M. Celia, 2010. Wellbore Integrity Analysis of a Natural CO2 Producer. Int. J. Greenhouse Gas Control, 49(2): 186-197. doi:10.1016/j.ijggc.2009.10.010.
  17. Gasda, S.E., J.M. Nordbotten, and M.A. Celia, 2008. Determining Effective Wellbore Permeability from a Field Pressure Test: A Numerical Analysis of Detection Limits. Environ. Geol., 54(6): 1207- 1215. doi:10.1007/s00254-007-0903-7.
  18. Gasda, S.E., J.M. Nordbotten, and M.A. Celia, 2012. Application of Simplified Models to CO2 Migration and Immobilization in Large-scale Geological Systems. Int. J. Greenhouse Gas Control, 9: 72-84. doi:10.1016/j.ijggc.2012.03.001.
  19. Duguid, A., R. Butsch, J.W. Carey, M. Celia, N. Chuganov, S. Gasda, T.S. Ramakrishnan, V. Stamp, and J. Wang, 2013. Pre-injection Baseline Data Collection to Establish Existing Wellbore Leakage Properties. Energy Procedia, 37: 5661-5672. doi:10.1016/j.egypro.2013.06.488.
  20. Kang, M., E. Baik, A.R. Miller, K.W. Bandilla, and M.A. Celia, 2015. Effective Permeabilities of Abandoned Oil and Gas Wells: Analysis of Data from Pennsylvania. Environ. Sci. Technol., 49(7): 4757-4764. doi:10.1021/acs.est.5b00132.

Modeling Ice Bridges to Refine Predictions of Ocean Dynamics
Principal Investigator: Howard A. Stone

At a Glance

Climate changes involve atmospheric motions, ocean flows, and evolution of ice on land and in the sea. These dynamics are necessarily interrelated; insights into individual processes can help to illuminate poorly understood aspects of global climate dynamics, such as factors affecting the maintenance of sea ice cover in the Arctic basin. Sea ice cover can impact fresh water fluxes, local ecology, and ocean circulation. The Stone group is providing simplified models for understanding the movement of ice through narrow straits, which can affect flow and mixing in the ocean.

Research Highlight

Ice bridges are stationary, rigid structures composed of sea ice, which are commonly formed in the many straits and channels throughout the Canadian Arctic Archipelago. Under certain conditions, the ice bridges are stable and span the width of the strait, connecting the two neighboring landmasses. These ice bridges appear seasonally and persist for several months, impacting both the local climate and ecology in two significant ways. First, since they are solid structures spanning the strait, they inhibit the flow of sea ice from colder regions into warmer waters. Second, by regulating the motion of ice, they affect the dynamics of flow and mixing in the ocean, thus influencing ocean salinity and regulating the transport of gases and nutrients that are crucial for ecological processes (e.g., the growth of photosynthetic plankton that form the base of marine food chains).

While ice bridges are regularly and predictably observed in the field, the precise mechanical conditions under which they form are not well understood. Improved models for predicting the dynamics of ice bridges would lead to a fuller picture of global changes in sea ice. Failure to form an ice bridge during a particular season can, for instance, result in an irrecoverable loss of sea ice through flow into warm oceans and subsequent melting. The Stone group seeks to provide simple predictors for the conditions required for the formation and maintenance of ice bridges and to study the physical mechanisms involved in the bridge formation process.

Although most studies of ice flows implement numerical models, the mechanics community has a long history of developing simplified models for studying flow in narrow geometries. The Stone group is drawing upon these techniques, developing a model that includes the role of mechanical stresses in response to wind, which is more central to ice bridge formation than other secondary processes such as the rotation of the Earth, or ice melting and freezing. This model will provide oceanographers and climate scientists with simple tools by which to understand the complex dynamics of sea ice, while speaking more broadly to the scientific community on problems of global importance. Preliminary work has focused on developing a theory to predict the flux of ice expected in situations without ice bridges, which agrees well both with field measurements and large-scale computational models. The theory also makes predictions for the critical ice thickness (defined to account for the wind stress, the compressive strength of the ice, and the channel width) beyond which the flow becomes entirely arrested, which is also consistent with numerical studies.

The Stone group’s current efforts are focused on modeling the process by which the flow becomes arrested, eventually leading to the formation of an ice bridge. Such behavior also arises in other engineering and science problems, such as the flow of granular materials, including soil, in confined geometries, which suggests a broader scope for understanding other physical and geological processes.

In the future, the group aims to build an experimental laboratory model of ice flow. Ice bridge formation on the surface of the ocean may result from collisions between floating masses of ice as they flow through a strait. The experimental model would examine the flow of a large number of floating rigid objects (not necessarily ice) through a narrow channel as a representation of the geophysical system. The model will serve to validate the theoretical aspects of the work, as well as illuminate features of the complex mechanical behavior of ice at the geophysical scale. A long-term goal is to understand the eventual breakup of ice bridges using a model that incorporates processes such as ice melting and water flow.

Figure 2.2
Figure 2.2. (A) Map showing the Nares Strait between northwestern Greenland and Ellesmere Island, Canada. The Nares Strait is a site for seasonal ice bridge formation. Source: Environment Canada, Government of Canada. (B) Satellite image indicating the location of a stable ice bridge in the Nares Strait, marking the boundary between (a) the ice sheet and (b) open water in the strait (data taken May 25, 2001). Greenland and Ellesmere Island are marked (c) and (d), respectively. Image adapted from: Dumont, D., Y. Gratton, and T. E. Arbetter, 2009. Modeling the dynamics of the North Water Polynya ice bridge. J. Phys. Oceanogr., 39: 1448–1461. http://dx.doi. org/10.1175/2008JPO3965.1.

Short Circuits for Better Batteries
Principal Investigator: Daniel Steingart

At a Glance

Building more energy-efficient systems depends on the ability to optimize and regulate the performance of energy-storing batteries. The Steingart group has developed a new type of zinc material that overcomes many of the limitations of zinc storage batteries. This material may be useful for long-term energy storage in grid-scale and electric vehicle applications.

Research Highlight

Zinc is a low-cost, abundant material, and its strong reducing potential combined with stability in water give it a high energy density. These properties have made zinc an excellent choice of anode material in a wide range of battery designs for more than 200 years. However, zinc also presents some challenges for use in a storage battery.

During charging, zinc undergoes morphological changes, and may produce dendrites—microscopic conductive fibers that can short-circuit a battery. Zinc also exhibits low utilization during discharge. Low utilization is related to a combination of corrosion and passivation effects: zinc oxide formed during standard operation and/or corrosion will block remaining reaction sites if not considered in the battery design.

To overcome these challenges, the Steingart group has created a hyper-dendritic zinc morphology with a high surface area that allows for rapid discharge in a free-standing system with no binding material or conductive additives, while still maintaining significantly higher utilization levels than typical zinc morphologies. At rates of 2.5 amperes per gram of material, the high-density zinc has a utilization level approximately 50% higher than typical zinc granules or dust. Tuning the electrolyte with specific additives further increases the utilization level of the material at high-rate discharge by up to 30%.

Zinc has many favorable characteristics for large-scale energy storage: high volumetric energy density, low cost, low toxicity, global abundance, and chemical compatibility with water-based electrolytes. Silver-zinc batteries have been successfully used as primary and secondary cells in a range of demanding applications, including those requiring large scale, high power and high energy density. These include critical military applications, such as guidance systems for torpedoes and missiles.

However, zinc electrodes present some significant challenges, and anode failure is a key factor in the reduced cycle life of these batteries. These challenges include morphology changes and dendrite growth during deposition, which can lead to problems such as the short circuit of a cell, and poor utilization efficiencies during the discharge step, which is a dissolution reaction, arising mainly from corrosion and passivation effects. As such, typical zinc utilization levels are limited to 60% or lower. Careful engineering and materials science can extend the cycle life of the electrode; however, these issues still present a major limitation for secondary batteries using a zinc electrode.

Over the last year the Steingart group has furthered engineering of a zinc morphology formed in a counterintuitive manner, generating zinc that produces dendrites “on purpose.” The dendrites are about 30 nanometers long; at the length scales critical for batteries, they create reliable foams at the micron scale. Many properties of these foams are superior to those of standard zinc particles and plates—including energy utilization, power density, and cycle life. In the next year the Steingart group will further explore the fundamental basis for this improvement, and will work to build new types of batteries that take advantage of the hyper-dendritic zinc.

Figure 2.3.1
Figure 2.3.1. Formation of hyper-dendritic zinc over a period of four minutes. The zinc was formed at a potential of -2.0 V vs. an HgO reference electrode. Note that the sharp features shown at t=0 are “smoothed over” by t=222s. Time in seconds is indicated in the upper left corner of each image.

Such batteries can be operated and built in a variety ways. The way in which the battery is formed is counterintuitive, in that dendrites are grown, on purpose, so aggressively that the growth front becomes even and predictable at the micron scale even though it is rough at the nano scale. In previous work, the group also showed that short circuits in zinc batteries are not a safety concern, as the short-circuit product is simply zinc oxide. Because short circuits are no longer a concern, the battery may be designed to “short circuit” occasionally to regenerate.

If this design is successful, batteries will be able to hold more energy and last longer, with the compromise that the enhanced surface area my lead to more battery self-discharge due to corrosion, and that the structure is still dynamic and may have to be reformed occasionally. Some batteries utilizing hyper-dendritic zinc may be built for around $30 per kilowatt-hour. At such prices, the marginal cost of storage becomes reasonable for long-term (3- to 10-hour) power on a daily basis. Current batteries are designed such that round-trip efficiency is very high, but the cost is at least $150 per kilowatt-hour.

Figure 2.3.2
Figure 2.3.2. Scanning electron microscope images of electrodeposited dendritic zinc in alkaline solution at various voltages. Note that the characteristic size of the fundamental zinc hexagons decreases as a function of overpotential, so that the initial dendrites are on the order of 10 μm wide, but the final hexagons produced at -2.0V are on average 50 nm wide—200 times smaller.

Technology Publications

Bandilla, K., M.A. Celia, J.T. Birkholzer, A. Cihan, and E.C. Leister, 2015. Multi-phase Modeling of Geologic Carbon Sequestration in Saline Aquifers. Ground Water, 53(3): 362- 277. doi:10.1111/gwat.12315.

Celia, M.A., S. Bachu, J.M. Nordbotten, and K.W. Bandilla, 2015. Status of CO2 Storage in Deep Saline Aquifers with Emphasis on Modeling Approached and Practical Simulations. Water Resour. Res., 51(9): 6846- 6892. doi:10.1002/2015WR017609.

Edwards, R.E.J., M.A. Celia, K.W. Bandilla, F. Doster, and C.M. Kanno, 2015. A Model to Estimate Carbon Dioxide Injectivity and Storage Capacity for Geological Sequestration in Shale Gas Wells. Environ. Sci. Technol., 49(15): 9222-9229. doi:10.1021/ acs.est.5b01982.

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): 23-141. doi:10.1007/ s11242-015-0584-8.

Kang, M., E. Baik, A.R. Miller, K.W. Bandilla, and M.A. Celia, 2015. Effective Permeabilities of Abandoned Oil and Gas Wells: Analysis of Data from Pennsylvania. Environ. Sci. Technol., 49(7): 4757-4764. doi:10.1021/acs. est.5b00132.

Kim, H., Z. Zheng, and H.A. Stone, 2015. Noncircular stable displacement patterns in a meshed porous layer. Langmuir, 31(20): 5684- 5688. doi:10.1021/acs.langmuir.5b00958.

Lai, C.-Y., Z. Zheng, E. Dressaire, J.S. Wexler, and H.A. Stone, 2015. Experimental study on penny-shaped fluid-driven cracks in an elastic matrix. Proc. R. Soc. A, 471: 20150255. http://dx.doi.org/10.1098/rspa.2015.0255.

Wang, H., Y. Ren, J. Jia, and M.A. Celia, 2015. A Probabilistic Collocation Eulerian- Lagrangian Localized Adjoint Method on Sparse Grids for Assessing CO2 Leakage through Wells in Randomly Heterogeneous Porous Media. Comput. Meth. Appl. Mech. Eng., 292: 35-53, 2015. doi:10.1016/j. cma.2014.11.034.

Zheng, Z., I. Griffiths, and H.A. Stone, 2015. Propagation of a viscous thin film over an elastic membrane. J. Fluid Mech., 784, 443- 464. http://dx.doi.org/10.1017/jfm.2015.598.

Zheng, Z., B. Guo, I. Christov, M. Celia, and H. Stone, 2015. Flow Regimes for Fluid Injection into a Confined Porous Medium. J. Fluid Mech., 767: 881-909. http://dx.doi.org/10.1017/ jfm.2015.68.

Zheng, Z., H. Kim, and H.A. Stone, 2015. Controlling viscous fingering using timedependent strategies. Phys. Rev. Lett., 115: 174501. http://dx.doi.org/10.1103/PhysRevLett. 115.174501.

Zheng, Z., L. Rongy, and H.A. Stone, 2015. Viscous fluid injection into a confined channel. Phys. Fluids, 27: 062105. http:// dx.doi.org/10.1063/1.4922736.

Zheng, Z., S. Shin, and H.A. Stone, 2015. Converging gravity currents over a permeable substrate. J. Fluid Mech., 778: 669-690. http:// dx.doi.org/10.1017/jfm.2015.406.

<< Previous  |  Table of Contents  |  Next >>

 
Feedback: cmi@princeton.edu
Last update: April 05 2016
BP Princeton Environmental Institute © 2017 The Trustees of Princeton University
CMI is sponsored by BP.