Can we bury global warming?*

Combating climate change is perhaps the biggest environmental challenge of our generation – a looming existential threat to global society as we know it. Dramatic changes in Earth’s climate will cause disputes over shortened water, energy, and food supply, and injuries and deaths from rising sea levels, heat waves, and other extreme weather events. Greenhouse gases such as carbon dioxide are widely believed to be the major cause. While many efforts today focus on transforming infrastructure to emit less carbon dioxide through technologies such as renewable energy and sustainable design, these efforts may not be enough. Removing carbon dioxide from the atmosphere may be necessary to meet climate change targets such as the 2-degree limit agreed upon in the Paris talks.

There are several ways in which we can remove carbon dioxide, a major greenhouse gas, from the atmosphere. For example, we can plant forests – natural “carbon sinks.” Another way is to pump carbon dioxide underground with carbon capture and storage (CCS) techniques. The concept is simple: if the carbon dioxide is deep underground rather than in the atmosphere, it cannot act as a greenhouse gas and contribute to climate change. The details in the implementation of CCS, however, are far from simple, perhaps explaining why it’s not a prominent climate change mitigation technology on the scales of renewables, advanced energy storage systems, or even forest carbon sinks, despite CCS being touted by climate change experts, including Princeton professors, as key to avoiding global warming.

CCS is not a new technology. The first Carbon Capture and Sequestration Technologies Program at MIT was initiated in 1989. CCS soon started finding success as a means to remove CO2 from emissions sources ranging from gas processing and ethanol production to enhanced oil recovery fields. Notable projects include the Sleipner West field in Stavanger, Norway, which opened in 1996. Spurred by a carbon tax, the field includes the world’s first offshore CCS plant, still running today. More recently, the Weyburn-Midale CO2 Monitoring and Storage Project, which began in 2000 and ended in 2011, successfully injects CO2 from a coal gasification site in North Dakota to an enhanced oil recovery site in Canada. In enhanced oil recovery, the injected carbon displaces oil, thereby increasing oil production rates – allowing oil companies to make more money and CCS to be economically feasible. This brief history of carbon capture and storage suggests that it is very gradually becoming a technology capable of removing emissions from coal power plants. Whether it can safely, economically, and effectively bury global warming is yet to be determined.

CCS will only make real progress in emissions reduction if applied on a large scale, eliminating emissions from a major source of carbon emissions, coal power plants. Compared to the sixteen non-power plant CCS projects currently operating or under construction, there are only two currently operating power plant CCS projects (with a few more under construction and dozens more in the planning phase). But recent news about the largest current project, SaskPower’s Boundary Dam 3 in Saskatchewan, Canada, could stall the progress of these future projects. According to a recent New York Times article, “the project has been plagued by multiple shutdowns, has fallen way short of its emissions targets, and faces an unresolved problem with its core technology.” The good news is that with every malfunction, management gains valuable experience and makes tangible improvements to the plant (in March 2016 the plant reached 67% capacity), but the problems have also called for “tens of millions of dollars in new equipment and repairs.”

CCS will only make real progress in emissions reduction if applied on a large scale, eliminating emissions from a major source of carbon emissions, coal power plants.

The current debate over CCS is less about its technological feasibility and more about its potential impact. Supporters of CCS see the world as hugely dependent on a grid of aging fossil fuel power plants that will be operational for years to come. In order to meet climate change targets such as the 2-degree limit agreed upon in the Paris talks, supporters say that CCS is a necessary technology to cut emissions during the inevitable decades-long transition period from fossil fuels to renewables. Opponents of CCS argue that investing in CCS is a waste of resources when investment should be in renewable energy, energy storage, and infrastructure redesign – areas that reject current fossil fuel dependence altogether.

Even with current technology, there is also much risk in CCS because so much about deep earth is unknown. There is potential for CO2 leakage back into the atmosphere and damage to the environment and ecosystems. Moreover, the current practice of enhanced oil recovery potentially defeats the original purpose of CCS. It is used to produce more oil, a fossil fuel that can release emissions from cars, planes, and other forms of emissions production that CCS isn’t currently compatible with. CCS would need to move away from enhanced oil recovery, either through increased efficiency or subsidies, to really fulfill its purpose. Ultimately, despite the risks and opposition, CSS could still present the solution necessary to bury global warming a little more than six feet under(ground).

*The title is a reference to Professor Robert Socolow’s 2005 article published in Scientific American that argues that geologic carbon sequestration is, conditionally, a feasible means of avoiding global warming.

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