To a growing portion of the public, this is the existential question of our time: How do we significantly slash greenhouse gas emissions before it’s too late?
Solar? Wind? Nuclear? Reforestation? How about carbon capture and storage (CCS), what is in essence the process of separating carbon dioxide (CO2) from the air, or from gases produced in electricity generation and industrial processes, then injecting the captured CO2 into geological rock formations typically located several kilometers underground?
CCS features in three of the Intergovernmental Panel on Climate Change’s (IPCC) four primary pathways to limiting global warming to 1.5 degrees Celsius (1.5°C) with no overshoot — a best-case scenario to protect the planet from the very worst impacts of climate change, but one we’re currently nowhere near meeting. (Recent estimates put us on track for an increase of between 3-5°C by the end of the century.) Indeed, operational CCS projects are capturing carbon at a rate far behind where it will need to be within decades to meet those global emission reductions.
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Part of the problem is how these technologies are, in many respects, still very much in the developmental stage, despite the fact that the fossil fuel industry has been using them since the 1970s. Questions also surround just how meaningfully CCS technologies are currently contributing to carbon emission reductions. For example, CCS is being used to funnel CO2 back underground to stimulate oil fields that are running dry, in a process called enhanced oil recovery (EOR) — a way, say CCS skeptics, not so much of reversing course on global warming but of prolonging the life-blood of the fossil fuel industry. Strictly speaking, such technologies fall under the umbrella of carbon capture, utilization and storage, or CCUS.
“In terms of the actual efficiency of carbon capture, it’s not nearly as effective as people claim it is,” said Mark Jacobson, a professor of civil and environmental engineering at Stanford University who says anthropogenic global warming must be tackled by scaling up to 100 percent renewables as quickly as possible. His own research into two CCS projects, factoring in production and processing emissions, found they trapped only between 10-11 percent of net carbon emissions averaged over 20 years.
“It’s never better to capture carbon than it is to use that money to replace coal or gas,” Jacobson said.
The underlying discrepancies at the heart of CCS have spilled out into the political arena. In his Green New Deal outlined last year, former Democratic presidential candidate Bernie Sanders struck a red line through the possibility. “To get to our goal of 100 percent sustainable energy, we will not rely on any false solutions like nuclear, geoengineering, carbon capture and sequestration,” his proposal stated. On the flip side of that coin, Joe Biden and former presidential candidate Pete Buttigieg outlined plans that would accelerate development and deployment of CCS technologies.
“Understandably, there are concerns around some of the ramifications from CCS,” said Deepika Nagabhushan, director of the Clean Air Task Force’s (CATF) Decarbonized Fossil Energy program. CATF co-signed a letter last year to the Senate advocating legislation advancing the development of CCS projects.
“But the reality is that it would be very difficult – impossible, frankly — to meet some of these really ambitions temperature targets without exploring some of these technologies,” said Nagabhushan.
“Contain the Surge to Gas”
According to the Global CCS Institute, there are 51 CCS facilities globally, 19 of which are in operation and 32 in various stages of development, including construction. They include ammonia and ethanol production plants, as well as direct air-capture facilities. The CATF also maintains a database of more than 20 publicly announced projects as part of the 45Q tax credit program, which is awarded to new CCS projects in the U.S.
The holy grail of CCS is in the energy sector, the single largest source of global greenhouse gas emissions, and the CATF’s list of CCS projects includes several at coal plants and natural gas retrofits. As for what’s currently at play in the power sector, there are two large-scale CCUS power projects in operation in North America: the Petra Nova facility in Texas and the Boundary Dam plant in Canada, both of them coal power plants. But important questions hover over their overall carbon-capture efficiencies.
The Boundary Dam, for example, is designed to trap 1 million metric tons of CO2 a year, but has captured a total of only 2.2 million metric tons over four years, according to an Institute Energy Economics and Financial Analysis report from 2018. As for the Petra Nova plant, if broader factors — like the energy needed to power the carbon capture equipment and the extra oil generated through EOR — are calculated in, “it is possible the Petra Nova project could increase, rather than decrease, global CO2 emissions,” the report claimed.
As coal is becoming increasingly uneconomic — at least relative to cleaner power resources — the potential use of CCS in the power sector should be primarily focused on natural gas, said Rachel Cleetus, policy director with the Climate and Energy program at the Union of Concerned Scientists. Nevertheless, a continued push toward natural gas — the U.S. Energy Information Administration announced natural gas consumption recently set a record high — comes with its own set of problems, she added.
“Our view is that we really need to contain the surge to gas, otherwise we’re going to get locked into a pathway that will result in either a surge in emissions, CO2 and methane, or a lot of stranded assets in the natural gas sector,” Cleetus said.
For this reason, the CCS projects of the future need not focus so much on the power sector as on a broad menu of heavy carbon-producing industries, said Cleetus. “Think cement, iron and steel,” she said, adding that right now, industrial CCS applications come with other concerns such as decreased efficiency and increased water usage. “We have proof of concept, but we’re still far from scaling up.”
Indeed, CCS will have to be scaled up fast for it to play its part in effectively curbing global warming. The International Energy Agency’s (IEA) sustainable development scenario holds the global temperature rise to below 1.8 °C. It’s also well within the trajectory of the various scenarios the IPCC proposed in 2018 providing a 50 percent chance of limiting the global temperature rise to 1.5 °C.
This IEA sustainable development scenario requires that by 2030, 350 million metric tons of CO2 (MtCO2) is captured per year. But system limitations mean that the CCS facilities currently in operation capture an estimated 96 MtCO2 per year only, according to the Global CCS Institute. This is a little more than a quarter of where it needs to be within 10 years. Zeroing in on individual facilities, the Petra Nova and Boundary Dam plants combined capture 2.4 MtCO2 per year, according to the IEA.
Interestingly, there’s enough available geological space in the world’s nearshore continental margins — the shallowest parts of the ocean abutting the coastline — to hold enough greenhouse gas emissions to reach an IPCC goal of six to seven gigatons of sequestered carbon dioxide a year by 2050, according to a study published last year in Nature Scientific Reports. This could be achieved by drilling between 10,000 to 14,000 injection wells worldwide in the next 30 years, the report finds.
Of course, such a goal faces tremendous obstacles, not least of all the massive investments needed to develop and build the requisite infrastructure, including pipelines. There would also have to be market incentives to persuade companies to trap and simply squirrel carbon away underground rather than using it for something like EOR. That said, the CATF argues that EOR can act as a stepping stone toward such a goal.
“Looking at the whole picture of what’s needed to achieve ambitious climate goals or to achieve net zero emissions by 2050, we do have to find ways to commercialize CCS for hard-to-decarbonize sectors where possible,” Cleetus said. “We also have to ensure strong legal, environmental and social safeguards for this technology.”
“It’s Just a Pyramid Scheme”
That CCS isn’t where it needs to be isn’t due to lack of investment — indeed, billions have been spent on carbon capture research and development over the years, some of it on expensive boondoggles. The Bush administration greenlit in 2003 what was then a billion-dollar state-of-the-art coal gasification and carbon capture facility, but cancelled the project in 2008 after massive cost overruns. The Obama administration tried and failed to revive the project.
The most infamous, however, is the Kemper coal power plant in Mississippi, a $7.5 billion coal-gasification and carbon capture project that was abandoned after massive cost overruns and delays. The plant is now the world’s most expensive natural gas power plant. However, the project’s financial failures, CATF argues, was the result of trying to develop a “first-of-a-kind” coal-gasifier, “which is completely separate from the carbon capture equipment installed on the plant.”
Indeed, CCS technologies will need road-testing through deployment for them to work more efficiently, said Nagabhushan. “Every project will be different, I can’t stress this enough,” she said. “It depends on so many factors what costs that plant will incur.”
In that respect, the political pendulum appears to be swinging in CCS’s favor — at least in the near term. A coalition of industry, labor and environmental groups recently pushed successful legislation that revamped the 45Q tax credits, increasing the amount of federal money available to companies undertaking CCS or CCUS projects. Individual states like California have woven CCS into their emissions reductions targets. Meanwhile, carbon capture costs are decreasing. According to the Energy Department, it cost $80 to capture a metric ton of carbon in 2012. Today, it costs around $50 per metric ton, while by 2030, the projected cost is $30.
Nevertheless, the urgency of the situation — greenhouse gas emissions hit a record high last year — requires a wholesale pivot away from fossil fuels. “You have biofuels. Nuclear power. Coal and carbon capture. They all claim that they can do things, and all they need is another billion dollars to solve it,” said Jacobson. “It becomes a part of what people assume is working, whereas really, it’s just a pyramid scheme.”