Carbon Capture and Geologic Sequestration (CCS) involves capturing carbon dioxide (CO2) from power generation and industrial processes, transporting the CO2 to an area with suitable geology, and injecting it into deep geologic formations, sequestering the CO2 underground for hundreds to thousands of years. Geological formations suitable for CO2 sequestration include oil and gas fields, saline aquifers, and deep coal seams. The goal is to avoid the atmospheric release of CO2 by sequestering the captured CO2 emissions approximately one kilometer underground.
Because injected CO2 will initially be more buoyant than the brine in the geological formation, injected CO2 will have the tendency to move upwards and spread laterally within the subsurface. After CO2 injection ceases, CO2 trapped in the rock matrix will gradually become less mobile and more secure as CO2 dissolved in the brine and slow geochemical reactions convert it to minerals like calcium carbonate. Thus, an effective geologic sequestration site will keep large volumes of a buoyant fluid underground for centuries to millennia and effectively occupy the pore space in perpetuity.
Several CCS projects are underway in Norway, Algeria, and Canada and more are planned in the United States, China, Australia, and other European countries. Four CCS projects are currently active, each injecting roughly 1 million metric tonnes of CO2 per year. Two projects involve injecting CO2deep below the seafloor into deep gas formations – the Sleipner natural gas field in the North Sea, about 250 kilometers off the coast of Norway; and the Snovhit natural gas field in the Barents Sea. A third project in In Salah, Algeria, involves injecting captured CO2 into a land-locked deep gas formation. Finally, the Weyburn-Midale CO2 project in Saskatchewan, Canada, involves injecting CO2 into depleted oil fields in order to increase reservoir pressure and oil fluidity – the better to extract additional oil from the fields, while trapping the CO2underground. In order for CCS to be implemented as a major climate change technology, however, projects will need to move to the large-scale commercial stage and inject and sequester billions, not millions, of tonnes of CO2 each year. Experts estimate such technology could be ready on a commercial scale by 2015 and in widespread use by 2020 (other estimates say 2030).
The U.S. Department of Energy (DOE) has funded numerous regional carbon sequestration partnerships with the aim of long-term research and development of the technology as well as several, anticipated large-scale pilot projects. Moreover, the American Recovery and Reinvestment Act (President Obama’s 2009 stimulus bill) provided an additional $3.4 billion for CCS demonstration projects, increasing federal support for CCS by 70 percent to more than $8 billion. Such funding, plus additional economic incentives and regulatory requirements (including an adequate price on CO2 emissions) will be necessary for industry to begin building “carbon-capture ready” plants than can be used to support capture and sequestration technology when it comes on line. Such plants are necessary because adding CO2 capture capability cannot be done feasibly or effectively as an “end-of-pipe” modification.
With regard to storage, a 2007 DOE report estimates that geological resources are likely sufficient to allow sequestration of more than 3,600 billion metric tonnes of CO2 from power plants and other industrial sources across the U.S. and Canada. Compared with the approximately two billion tonnes of CO2 emitted from coal-fired power plants annually in the United States, such estimates would indicate that storage capacity is plentiful. Indeed, federal energy personnel have testified in Congress that at the current rate of energy production and use, the United States and Canada have the capacity to store all CO2 emissions they produce over the next 175 to 500 years. These are only rough estimates, however, and may overstate the amount of actual storage capacity available.
Despite its significant potential to have a real impact on climate change, CCS is not without risks. First are the environmental risks associated with the continued use of coal. These include the adverse effects from mountaintop removal of coal, acid mine drainage, land subsidence, air pollution, and acid rain. Second, with regard to risks associated with the capture and storage of CO2, initial buoyancy flow could drive CO2 upwards through undetected faults or abandoned boreholes. High concentrations of CO2 (greater than 30 percent) can cause immediate death from asphyxiation while prolonged exposures to concentrations of CO2 (above 3 percent) may cause a variety of negative health effects. Slow CO2 seepage into the near subsurface could harm flora and fauna and potentially cause local disruptions of ecology or agriculture. Even if the CO2 remains in the subsurface it can displace saline groundwater into potable aquifers, contaminate hydrocarbon resources, or cause subsurface pressure changes. While these risks likely will be small with well-managed sites, they cannot be ignored and will require the creation of complex regulatory structures governing site selection, injection of CO2, storage, closure, and post-closure care into perpetuity. Third, some climate risks are associated with CCS. If CCS becomes part of forthcoming state or federal CO2 cap-and-trade systems, incorporating CCS into industrial operations will result in credits for reducing CO2 through CCS technology. It is very possible, however, that if significant quantities of CO2 injected into the subsurface prematurely leak back into the atmosphere, it could limit the long-term climate benefit, thus significantly compromising GHG reduction efforts and the viability of the cap-and-trade system.
What People are Fighting About
CCS has both its detractors and supporters within the environmental community. Greenpeace released a report in May 2008 entitled “False Hope,” in which it contends that CCS wastes energy, creates unacceptable risks of leakage, is too expensive, undermines funding for more sustainable solutions to potential climate change, carries significant liability risks, and cannot be implemented in time to avoid dangerous climate change. Greenpeace argues instead for investing in renewable energy technologies and increased energy efficiency that can begin to reverse climate change today. Other environmental groups, however, such as Environmental Defense Fund, Natural Resources Defense Council, World Resources Institute, and the Nature Conservancy, see CCS as a necessary technology to help mitigate the effects of climate change. As one environmental organization representative put it, CCS “is a terrible idea that we desperately need.”
Outside the environmental nonprofit community, one finds an equally significant range of views on the merits of CCS. Those who deny the fact of climate change may see CCS and other climate change technologies as an unnecessary expenditure of government and private resources. Some in industry view CCS as a way to acknowledge the problem of climate change while allowing the world to continue to use coal long into the future. Others see it as a transition technology that allows the world to make dramatic reductions in CO2 emissions—and broker politically viable climate agreements—while we seek to develop alternatives to coal and fossil fuels. Yet others oppose CCS because of potential risks to human health and the environment, the moral and ethical issues associated with injecting pollutants into the earth, and the fact that CCS enables the continued use of coal and may reduce the incentives and funding needed to transition to a more sustainable energy future.
A Progressive Perspective
The risks of CCS must be weighed against the risks of rejecting CCS as a climate change strategy. A 1998 study estimated that in order to avoid dangerous changes to our climate, we will need at least as much net new carbon-free energy online by 2050 as the sum of global energy produced currently. Thus, the question becomes, if CCS is not deployed to avoid future CO2 emissions, what other technologies could fill the gap?
Hydroelectric generation represents roughly 7 percent of current U.S. electricity needs and all of the other renewable sources combined represent less than 3 percent of the nation’s electricity. Even accounting for rising fossil fuel prices and increasing technology-forcing policies such as renewable energy standards, the Energy Information Administration (EIA) estimates non-hydropower renewable energy will remain less than 10 percent of the total U.S. electricity generation by 2030. While other estimates show a higher potential percentage of renewable energy available in the next decades from wind, solar, and biomass, it remains unlikely that these energy sources can on their own replace the use of coal in the United States, which today relies on coal for 50 percent of its electricity needs. The same is true for international energy consumption: the rest of the world relies on coal for more than 50 percent of its electricity needs. Another alternative, nuclear power, currently provides the most carbon-free energy in our system. Although there have not been any new orders for nuclear power plants in the United States since the 1970s, new policy incentives and the need for climate-friendly energy technology may foster increased interest in nuclear energy in the coming decades. Even while the EIA predicts an increase in nuclear power, it warns that the industry’s future remains highly uncertain because “plant safety, radioactive waste disposal, and the proliferation of nuclear weapons” continue to raise significant concerns. Illustrative of this point is the fact that the United States, after decades of negotiation, has yet to find a solution for its existing nuclear waste, much less additional waste from added nuclear capacity.
While there are clear reasons to be concerned about the risks associated with large scale deployment of CCS, it is not clear that any alternatives are either less risky or sufficient to stabilize GHG concentrations while still meeting worldwide energy demands. As a result, there are good arguments that CCS technology development should be pursued, along with other non-coal-based alternatives, so that all options remain open for reducing CO2 emissions as soon as possible. This basic assumption, that a diverse portfolio of low-carbon energy technologies that includes coal with CCS is necessary to reach climate goals, is also reflected in the strategic plans of countries currently regulating CO2 emissions. The Intergovernmental Panel on Climate Change (IPCC) notes that the opportunity cost of not pursuing CCS as part of the problem may simply be too high, and some estimates suggest that using the technology could save tens of billions to trillions of U.S. dollars when compared to other climate strategies.
The critical requirement in going forward with CCS, however, will be to ensure that appropriate regulation, legal remedies, and funding mechanisms are put in place, to ensure that CCS is developed in a manner that minimizes the risk of harm to human health, the environment, and the climate. For instance, some in industry and government have argued that the federal government or states should accept ownership of sequestered CO2 and indemnify CCS operators for any associated harm. This approach, however, eliminates industry incentives to engage in good site selection and responsible risk management throughout the lifetime of CCS projects. A better approach is to use existing tort and environmental statutory liability to the extent they apply, but at the same time develop a comprehensive federal regulatory program governing CCS and then place on top of it a funding system consisting of industry-financed insurance, bonding, selected damage caps (for early pilot projects only), and pooled federal funding that would provide protection for both CCS operators and those potentially harmed by CCS. Such a system can go a long way in decreasing the risks of climate change while managing the risks of CCS.