Fossil Blog

Seismic Risk Won't Threaten the Viability of Geologic Carbon Storage

June 18th, by Bruce Hill, Ph.D., Senior Geologist. 


This week’s rumblings against carbon capture and storage (CCS) as a powerful means to mitigate global climate change come not from any natural geological source, but solely from an opinion piece published in this week's Proceedings of the National Academy of Science (PNAS) Perspectives.  Despite the arguments of two Stanford geophysicists, however, there is plenty of countervailing scientific evidence that CO2 from U.S. fossil power plants can be captured and safely stored.  While the opinion piece rightly raises the importance of rigorous site selection and site characterization for commercial scale storage, it falls far short in its analysis of the overall feasibility of storing commercial volumes of CO2.  Here’s why:


By analogy with recently experienced earthquakes resulting from brine injections, the authors attempt to cast doubt on the feasibility of large-scale geologic storage of carbon dioxide captured from industrial sources by pointing to the role of CO2 pressure buildup in the hosting formations in their potential to induce earthquakes and resulting fractures and faults. Their concern is not about the impacts of tremors nor large scale earthquakes that would let CO2 rush out, but instead, about the possibility that the induced seismicity could be accompanied by small scale fracturing that could migrate upwards and compromise the integrity of an overlying geologic seal.


What the article does not say is that for a brittle fault or fracture zone to reach the surface it would take crossing thousands of feet of rock and shale layers that may very well, in the process, accommodate the upwardly propagating stress like a plastic substance bending like taffy --instead of fracturing.  It also does not address the rate at which any CO2 affected by such small scale fracturing might migrate over time, and whether those volumes would be significant over the time scales necessary to combat global warming. Moreover, according to MIT geoscientist Ruben Juanes, there are no models or data that can predict seismicity from large-scale CO2 injections. Furthermore, CO2 injection technology is hardly new.  Approximately 1 billion tons of CO2 have been safely injected (and stored) in the process of enhanced oil recovery (EOR) in the U.S. since the late 1970s, with no reported seismic incidents.  In fact, there have been no earthquakes reported anywhere from saline CO2 injections either, according to the June 15 NAS report (Induced Seismicity Potential in Energy Technologies).


In the opinion piece, the authors paint, with a broad brush, a scenario of limited storage capacity for power plant CO2 generated in the Midwest's Illinois Basin--the U.S. locus of coal power generation. In their rush to judgment, the authors overlook numerous storage strategies that would complement local and regional storage in the Midwest:


  • Their contention is based on the unrepresentative example of the AEP Mountaineer pilot CCS project in West Virginia, combined with computer modeling of the Illinois basin done in 2009 by Lawrence Berkeley National Laboratory undertaken for a purpose other than to predict seismicity. The poor injectivity encountered in the Mountaineer project is not representative of the geology of the Mt. Simon Formation across the entire Illinois Basin. A better example is the continuing success at the ADM project underway presently in Decatur, Illinois.
  • An understanding of the three-dimensional subsurface geology is critical. In the Illinois Basin, there are other formations that have the potential to simultaneously store CO2. The University of Texas Bureau of Economic Geology Gulf Coast Carbon Center, has been investigating stacked storage in combination with EOR in brine formations below producing zones in Mississippi. Tight formations with low permeability and multiple seals above the Mount Simon Formation provide an additional layer of security.
  • Carbon dioxide can and will be pipelined to the Gulf Coast and Texas’ Permian Basin for enhanced oil recovery. Plans are underway for an extension CO2 pipeline that will extend Denbury Resources' existing "Green Pipeline" up into southern Illinois to tap into anthropogenic sources of CO2.  A 2011 NETL study suggests next-generation EOR in depleted US oilfields can accommodate an additional 20 billion tons of CO2. 
  • Pipelines could also carry CO2 to other formations in the offshore Gulf, Atlantic and Pacific Coasts where there are an estimated 500 billion to 7.5 trillion tons of storage capacity, according to DOE.
  • CO2 pipeline build-out has been studied by the research group Battelle for several international climate mitigation scenarios and suggests that the pace would be reasonable.  ARI, an energy resources consulting firm, estimates that three 800-mile pipelines could accommodate the CO2 from Midwest power plants for 30 years.
  • Brine water production and reinjection into other formations can relieve formation pressures that could potentially lead to rock failure.


Taken together, the weight of evidence suggests that CCS technology is viable and that a combination of storage options will provide capacity for large volumes of captured CO2. Whether all the carbon dioxide emitted by industrial activities in the U.S. and around the world can be captured and stored remains to be seen, but CCS is viable and has an essential important role to play in reducing greenhouse gases. With numerous small-scale CO2 injections and four decades of EOR under our belt, now is the time to invest in the understanding of large-scale geologic storage, rather than abandon it.




Fracking and Geologic Carbon Storage Can Safely Coexist



June 7th, 2012 by Bruce Hill, Ph.D. Senior Scientist / Geologist





A recent paper by Princeton researchers published in Environmental Science and Technology questions the compatibility of hydraulic fracturing (“fracking”) and geologic carbon storage and has received an unwarranted amount of attention. Despite the conclusions of the paper, the overwhelming evidence suggests that geologic storage can indeed coexist safely with other subsurface activities, including oil and gas extraction and shale gas operations. Here’s why:

The study is based on the simplistic assumption that where there is any overlap between a geologic carbon storage site and a shale gas site, the two activities are incompatible. Their claim rests on the assumption that a shale gas formation would necessarily be required to function as a “seal” to prevent escape of the CO2 stored in a geologic storage formation below it. In their paper, the authors represented this point with the following map that erroneously crosses off the geologic CO2 storage where there is shale gas production across most of the sedimentary basins in the U.S:

Map from Elliott and Celia 2012
Map from Elliott and Celia 2012

The problem is that, by adopting these simple assumptions, Princeton team overlooked the third dimension – depth — and the thousands of feet of physical separation of the formations and attendant geologic complexity that typically exists below. Sedimentary basins do not consist of just two simple layers, i.e., the CO2 reservoir and the cap rock/shale gas layer. Instead, sedimentary sequences typically consist of thousands of feet of bedrock, with multiple layers of shale, sandstones, limestones (that may also be “tight” or largely impermeable). In fact, because CO2 must be injected in a fluid-like “supercritical” state, instead of as a gas, sequestration must take place a depths of over one-half mile. In the Illinois basin, for example, near the heart of the coal power industry, the nation’s biggest source of manmade CO2, carbon stored in deep saline aquifers there would have to travel upwards through multiple impermeable shale layers and other formations comprising nearly 7,000 feet of rock—over four times the height of the Sears Tower in Chicago– to reach the surface.

So the authors drew the false conclusion that one would necessarily exclude the other, given that these operations can safely co-exist where there are thousands of feet of vertical separation between carbon storage and shale gas zones with multiple confining zones in-between as our schematic diagram below (roughly based on ISGS generalized IL basin geology) clearly illustrates:


To reject the safety of geologic carbon storage based on a two-dimensional overlap of projects is like saying that two airliners cannot fly in the same airspace even though they may be vertically separated by thousands of feet. There is no unavoidable collision risk there. Similarly, in most sedimentary basins, unavoidable conflict between GS and fracking would be far lower than represented in this paper. So until the analysis is done in three dimensions–incorporating site-specific subsurface geologic data–the conclusions of this study are premature at best and highly misleading at worst.

All that said, there is an important take-home from this report: regulators should pay close attention to the interplay of shale gas and geologic storage development activities. Just as airliners operating in the same airspace need air traffic controllers, subsurface activities such as geologic storage and shale gas operations require geologic review, ongoing monitoring, and regulatory oversight to avoid conflicts. With sensible safeguards, it is likely that CO2 storage reservoirs can, in many areas, safely coexist in the same space with conventional and unconventional oil and gas operations, including shale gas production and hydraulic fracturing.

Lastly, as a practical matter, there is little reason to believe that shale gas activity will impede the development of carbon capture and storage technology. The Department of Energy (DOE) in 2012, estimated that U.S. geologic formations can provide 500 years of storage for North American CO2 emissions — 2 to 20 trillion metric tonnes. (U.S. annual power sector emissions are 2.4 billion tons.) A considerable portion of this estimated storage capacity is offshore where shale gas extraction would not be realistic. Furthermore, this analysis doesn’t take into account the DOE estimate of 120 billion tons of U.S. CO2 storage capacity in depleted petroleum-bearing formations that have contained oil and natural gas for millions of years. Finally, the Safe Drinking Water Act mandates that geologic storage operators must complete a comprehensive three-dimensional study of the geology and risks before CO2 injection and storage in saline aquifers can be initiated. The bottom line is that shale gas operations and hydraulic fracturing should pose no impediment to development of geologic carbon storage capacity in the U.S.





Clean Air Task Force hosts Shanghai Electric Delegation



November 18, 2011 by Pamela Hardwicke, Special Projects Facilitator


On November 10 through November 18, the Clean Air Task Force hosted a China delegation of Shanghai Electric company engineers and executives to tour US national laboratories and research institutions to learn about US efforts in clean technology.


The delegation’s first stop was the Midwest Geological Consortium Sequestration’s Illinois Basin Decatur Project, which is the first U.S. large demonstration-scale injection of CO2 from a biofuel production facility in Decatur, Illinois.


Next up on the tour was the Gasification Technologies Institute, a non for profit research and development (R&D) organization that focuses on new energy solutions and is headquartered in Chicago, IL. Delegates got the chance to meet with R&D directors and tour the GTI facility.


The delegates taking a tour of GTI


We then went on to the National Renewable Energy Laboratory (NREL) in Golden, Colorado. NREL is a research and development facility of the U.S. Department of Energy (DOE) for renewable energy and energy efficiency.


The last stop on our delegation tour was the Lawrence Livermore National Laboratory (LLNL) in San Francisco, CA. LLNL is a national security laboratory that aims to ensure the safety, security, and reliability of the U.S. nuclear deterrent and reduce threats to national and global security. Delegates got the opportunity to tour the National Ignition Facility also known as NIF. NIF aims to bring self-sustaining nuclear fusion into reality.



The delegation tour at LLNL with Tomás Díaz de la Rubia, Deputy Director for Science and Technology and Julio Friedmann, Deputy Director for Energy and Environmental Security, Global Security Principal Associate Directorate



This tour not only introduced  a manufacturing leader in China to some of the most highly esteemed research institutions in the United States, but will also most likely help to lay the groundwork for future clean energy collaborative efforts between the US and China.







Underground Coal Gasification – Coming Soon to Wyoming?


November 2nd, 2011 by Mike Fowler, Climate Technology Innovation Coordinator


After years of talk, things are starting to get real: developers are looking at pioneering underground coal gasification (“UCG”) projects in Wyoming. Some may see these projects as first steps to finally producing truly clean energy from coal, while others may perceive them as unnecessary, risky experiments. What’s the truth? Let’s explore the issues.



First, some unpleasant facts. Fossil fuel use has increased dramatically across the globe (China’s coal power plant fleet, most of it built in the last 10 years, is now more than twice the size of ours in the US) and appears likely to continue to mushroom (in South Asia alone there are 600 million people – roughly twice the population of the US – waiting for access to electricity). Even in the center of Europe, Germany, in its rush to move away from nuclear power, is considering building more coal power instead. And in the US, where coal usage has declined slightly, another plain fossil fuel – natural gas – has taken up the slack, with limited greenhouse gas advantages.


Many environmentally-minded people suggest that civilization should move away from fossil fuels (and nuclear power) entirely. But when experts do the math, they find that proposals to power civilization exclusively with sun, wind, and waves are just what they sound like – a seaside vacation, and unfortunately not a plausible solution to our global climate crisis. In California, a recent study highlights the difficulty in meeting even a 60% greenhouse gas emission reduction target through copious application of renewable power, since wind and sun must be complemented by natural gas or something else during the roughly two-thirds of the year when they aren’t available.



In this context, carbon capture and storage (CCS) technology has an important role to play in treating the emissions of CO2 at the source, just as sulfur scrubbers have helped reduce acid rain in the past. We know CCS will work with fossil fuels to provide baseload power, because the components of CCS systems have been used at commercial scale for decades in industry. Unfortunately, though, CCS currently increases the costs of utilizing fossil fuels, and consumers are generally reluctant to shoulder this additional burden, especially during challenging economic times. This is where UCG comes in.


Underground coal gasification is the process of injecting air (or oxygen) through a well into a deep coal seam to support chemical reactions that convert the coal to ‘syngas’ (a gaseous fuel primarily containing hydrogen and carbon monoxide). This syngas is then extracted through additional wells, and can be used to fuel a power plant. CCS can be applied to UCG by removing carbon from the syngas using conventional processes (read more here) and sequestering the CO2 geologically (more here). But in the case of UCG, the costs for this may be significantly lower because there is no need for coal handling and processing equipment, no need to construct a massive steel gasifier, and the raw gas may be considerably cleaner to start with (some sulfur and quite a bit of inorganic material may stay below ground, for example).



Although UCG is a novel technology, preliminary CATF analyses indicate that the cost of producing UCG power WITH CCS close to the cost of producing power from a conventional coal power plant without CCS. Our analysis is summarized in the figure below. If these costs prove true, this could be a game-changer for CCS utilization, especially in the developing world.


comparison across technologies

UCG has other potential advantages as well. The coal that fuels the process is not mined, reducing the surface impact of the energy source. And the spatial footprint of UCG operations could be significantly less than the footprint necessary to extract an equivalent amount of energy from coal bed methane and similar technologies. Also, a UCG project may be a net producer of water, as opposed to net consumer, depending on the circumstances of an individual project. For these reasons and more, there is cause to believe that UCG could hold considerable promise as a cost-effective path to cleaner coal.



UCG is not without its risks, however. There have been several dozen small UCG trials since the 1950s, and in a handful of cases groundwater contamination and surface subsidence resulted. Based on this history, communities likely will be cautious about proposals for new UCG projects in their area. But several points are important here: UCG cannot result in underground coal fires (1000 feet or more below the surface, only oxygen intentionally supplied through a well will support combustion); properly done, UCG won’t result in surface subsidence (in part because of the depth); and finally, new site screening and operational methodologies and technologies promise greater site isolation (and hence groundwater protection) than in previous trials.



There is a lot yet to learn about the pioneering UCG projects in Wyoming. Many risks and benefits depend on site details. Transparency on the part of developers and permitting authorities will almost certainly be important for local communities evaluating the projects. But the big picture remains: if we can bring down the costs of CCS, we have a much better chance of preventing climate change. CATF analysis suggests that UCG, operated safely, could be a critical part of that global effort.




No More Fossil Energy Without Carbon Capture

July 19th, 2011 by Kurt Waltzer, Carbon Storage Development Coordinator, and Conrad Schneider, Advocacy Director

This posting originally appeared in the National Journal’s Energy and Environment Experts blog.



We have no choice but to develop low carbon coal technology. By 2015 China will have more than 950GW of coal power – three times the level in the U.S. Unlike plants in the U.S. though, the vast majority of the Chinese coal plants are brand new and will likely be around for half a century or more. India is right behind. If these new coal plants do not capture and store their carbon emissions, it’s game over for having any hope of fighting climate change.


Scientists now say that we need to virtually zero out our carbon emissions from the production of electricity by mid-century. To have any shot, we must rapidly commercialize low carbon fossil technologies, including carbon capture and storage (CCS). But the announcement by American Electric Power to shelve its project at Mountaineer is another example of how our policy to move this technology has been ad hoc and woefully inadequate.


Its not like the technologies that make up CCS are new. Carbon capture for industrial facilities has been around for decades. And the oil industry has injected and stored over a billion tons of CO2 since the mid 1970s as part of its efforts to recover additional oil from depleted oil fields.


But we’ve failed to adopt the necessary regulations and incentives to push these technologies together (carbon capture AND storage) to drive deployment and lower costs. In part, this is because CCS has been rejected by those who believe that that climate change can be “solved” with renewables and efficiency and by the deniers who find it difficult to even acknowledge the existence of climate change.


In AEP’s recent announcement on Mountaineer, CEO Mike Morris noted that without greenhouse gas regulations, its impossible to recover the cost of installing carbon controls, despite the fact that the smaller scale CCS pilot at Mountaineer validated the technology.


We need a responsible approach to climate that recognizes CCS is essential for all fossil fuels (i.e., coal and gas). The U.S. can play a key role in CCS deployment and cost reduction in the following ways: First, the Obama Administration should propose strong new source performance standards in September that send the clear signal that CCS must be deployed on future and existing fossil power plants over a reasonable period of time. Second, the Department of Energy should reform programs like the Clean Coal Power Initiative so that award recipients receive enough funding to move projects forward. Finally, Congress should adopt significant incentives for CCS – Senators Lugar, Conrad, Bingaman, and Rockefeller have each developed a package that will encourage industry to take the necessary steps.


We can do this – all it takes is the right regulations, sufficient incentives, and the political will to see it through. Because if we don’t, pure and simple — we just won’t avoid the worst consequences of global climate change.