As the world continues down the path of the energy transition, there arises an opportunity to deliver new, clean energy and industry jobs with the potential to sustain economies well into the future. As fossil fuels continue to sustain the global energy mix, carbon capture and storage has emerged as a frontrunner in the race against climate change. This technology can be a key, cost effective option for reducing carbon dioxide emissions from industrial applications where deep emission reductions can only be achieved through CCS. The road ahead is challenging, but if policies are set to meet standards mitigating climate change, CCS is an additional tool to make significant and necessary contributions towards achieving net-zero emissions around mid-century.
- Greenhouse gases absorb and radiate heat from the sun. This allows for the average global temperature to remain around 60°F instead of below freezing. Carbon dioxide is the most abundant greenhouse gas, and while it absorbs less heat than methane or nitrous oxide it stays in the atmosphere longer. The 2019 average for atmospheric carbon dioxide was 409.8 ppmv, its highest level in 800,000 years.
- Carbon capture and sequestration (CCS) is the process of capturing carbon dioxide created during power generation and industrial processes in order to store it in subsurface reservoirs instead of releasing it into the atmosphere. Facilities equipped with CCS capability can generally capture 90% to 100% of produced CO2, compress and transport it, and inject it to be stored or used for enhanced oil recovery (EOR). Injection is common into former oil and gas reservoirs, deep saline formations, or coal beds.
- CCS has been used since 1977 in EOR applications, but the Department of Energy (DOE) has worked to incentivize its Fossil Energy’s Carbon Storage program since 1997. Tax credits for carbon sequestration are created through Section 45Q of the IRS code, and additional credits exist at the state level for California, Texas, Louisiana, Montana, and North Dakota.
- Globally an estimated 40 million metric tons of CO2 was captured and stored in 2019. Relative to the nearly 5 billion metric tons of CO2 produced in 2018 by the U.S. alone, additional CCS technology needs to be implemented to meet government and environmental group’s goals. There are currently 51 large scale CCS facilities globally, but more investment activity and construction of new plants has been underway this year.
- For CCS technology to make an impact on recent climate goals, the pace of development and deployment needs to increase substantially over the next several years. Focus will likely shift again to utilizing CO2 for hydrocarbon extraction while simultaneously storing the gas in a productive reservoir. While there are many methods to help reach global goals for carbon neutrality, CCS may be beneficial for industrial applications finding it difficult to decarbonize due to their industry and products manufactured.
This year will long be remembered as extremely challenging, due largely to the emergence and spread of the COVID-19 pandemic. The human toll has been awful, but the economic impact may take decades to overcome. As governments implement economic stimulus packages to lift nations out of recession and get people back to work, there arises a once-in-a-generation opportunity. This is to change course and re-build the global economy in a climate-friendly and environmentally sustainable manner. As the world continues down the path of energy transition, there arises an opportunity to deliver new, clean energy and industry jobs with potential to sustain economies well into the future. Countless companies in both the private and public sectors, in addition to a growing number of countries, have committed to net-zero emissions in the next few decades. Not only have many of these moves been welcomed, but they are claimed to be necessary as the future of this planet depends on actions taken today. It has been clear for some time that achieving net-zero emissions by mid-century and containing temperature increases to well below 2?C will require the rapid deployment of all available abatement technologies. This will include the early retirement of some emission-intensive facilities and the retro-fitting of others with technology like carbon capture and storage (CCS) . In the years to come, CCS will be a key pillar in the race against climate change as it has flexibility to remove emissions from industries difficult to decarbonize. Many of these industries manufacture products that will continue to be essential to daily life, and implementing CCS perfectly aligns itself with global goals of achieving net-zero emissions.
The Earth emerged from the last ice age with atmospheric carbon dioxide (CO2) levels of approximately 280 parts per million by volume (ppmv). By 2019 that level jumped to 409.8 ppmv . That means carbon dioxide levels today are higher than at any point in at least the past 800,000 years, as seen in Figure 1 below. It is often linked to climate change, but what is the significance of carbon dioxide in the atmosphere?
Carbon dioxide is a greenhouse gas which means it is a gas that absorbs and radiates heat. Thanks to the giant fireball millions of miles away, the Earth’s land and ocean surfaces continuously radiate thermal infrared energy, or heat . But, unlike oxygen or nitrogen that make up most of the atmosphere, greenhouse gases absorb that heat and release it gradually over time, much like the bricks in a fireplace after the fire goes out. Without this natural greenhouse effect, Earth’s average annual temperature would be below freezing instead of close to 60°F . The problem is, increases in greenhouse gases have tipped the Earth’s climate out of balance, trapping additional heat and raising Earth’s average temperature. Carbon dioxide is the most important of Earth’s greenhouse gases as it absorbs less heat per molecule than the greenhouse gases methane or nitrous oxide . However, it is far more abundant and it stays in the atmosphere much longer. Because of this fact, increases in atmospheric carbon dioxide are responsible for about two-thirds of the total energy imbalance causing Earth’s temperature to rise .
As seen in Figure 2, methane and nitrous oxide have increased their contributions to the heating imbalance as well as annual greenhouse gas index slightly over the past forty years, but both are shadowed by the increases from carbon dioxide. If the planet is to avoid the economic and human consequences of severe climate change, emissions of CO2 must be cut significantly. To do this, actions must be taken to curb CO2 emissions, improve energy efficiency, substitute high carbon-emitting fuels with lower carbon fuels, and develop and adopt alternatives to fossil fuels . As long as fossil fuels continue to provide most of the world’s total energy, an argument can be made to capture and sequester CO2.
What is Carbon Capture
Carbon capture and sequestration/storage (CCS) is the process of capturing carbon dioxide formed during power generation or industrial processes and storing it in subsurface reservoirs so it is not emitted into the atmosphere . As a result, CCS technologies have significant potential to reduce CO2 emissions within the global energy system, and have a vital, growing role to play in decarbonization around the world. Deploying CCS at a power plant or industrial facility generally entails three major steps: capture, transportation, and storage .
During the capturing process, several different technologies can be used to gather CO2 at the facility emitting pollutants into the atmosphere. Post-combustion carbon capture, which is the primary method used in existing power plants, separates CO2 from the exhaust of a combustion process . Pre-combustion carbon capture, which is largely used in industrial processes, involves gasifying fuel and separating out the CO2 . There are commercially available pre-combustion capture technologies used by industrial facilities; however, for power plants pre-combustion capture is still in early stages. This process may be less costly than other options, but it can only be built into new facilities. To retrofit an existing facility for pre-combustion capture would be exorbitantly costly. Lastly, there are oxy-fuel combustion systems where fuel is burned in a nearly pure-oxygen environment rather than regular air, resulting in a more concentrated stream of CO2 emissions, which is easier to capture .
Currently facilities with CCS can capture 90% to 100% of the CO2 produced, and after capture it is compressed into a fluid . From there it can be transported to an appropriate storage site, usually by pipelines, ships, and occasionally trains or other vehicles . Finally, the CO2 is injected into underground geologic formations where it is stored long term rather than being released into the atmosphere or used as a drive mechanism for enhanced oil recovery (EOR). Storage sites used for CO2 include former oil and gas reservoirs, deep saline formations, and coal beds.
History of Carbon Capture
Carbon dioxide capture technology has been used since the 1920s for separating CO2 sometimes found in natural gas reservoirs from the saleable methane gas. The true idea of CCS, capturing CO2 and preventing it from being released into the atmosphere, was first suggested in 1977 using existing technology in new ways . In the 1970’s, CO2 captured from a natural gas processing facility in Texas was piped to a nearby oil field and injected to boost oil recovery. This process, known as Enhanced Oil Recovery (EOR), has proven to be very successful. Millions of tonnes of CO2 – both from natural accumulations of CO2 in underground rocks and captured from industrial facilities – are now piped to and injected into oil fields across the nation every year . Due to the success of the process in the oilfield and its environmental benefits, since 1997 the Department of Energy (DOE) Office of Fossil Energy’s Carbon Storage program has significantly advanced the carbon capture and storage knowledge base through a diverse portfolio of applied research projects .
In the United States, multiple enacted policies aid and encourage the use of CCS technology. National tax credits for carbon sequestration are created through Section 45Q of the Internal Revenue Code . Adding to these national tax credits, several tax credits and other crediting mechanisms exist at the state level in California, Texas, Louisiana, Montana, and North Dakota. As a result, such credits have incentivized the use of CCS in industries far and wide. Gas processing facilities, which extract natural gas from underground reservoirs, often have to clean the CO2 from the natural gas in order to be able to sell it. These facilities therefore have to strip the CO2 before they have a usable commodity, and the carbon credits from the sale of CO2 are an added bonus. Power plants and steel mills that burn fossil fuels don’t have to capture CO2 in order to produce electricity or goods, and the capture process actually costs slightly more overall . Because of this, capturing CO2 from these facilities is purely done for emissions reduction reasons. EOR projects have a use for the CO2 captured in the earlier processes which gives the CO2 a value in monetary terms . The CO2 is often extracted from the reservoir along with the oil, but as it was expensive to purchase, will be separated and can be used again to produce even more oil. Eventually, when all the oil has been produced, the CO2 can be stored in the depleted oil reservoir – permanently preventing that CO2 from being released into the atmosphere and contributing to the greenhouse effect.
Carbon Capture In The Energy Industry
The story of carbon capture, utilization, and storage begins with oil and gas. Oil companies pioneered a process decades ago to isolate CO2 from plumes of mixed gases. Separately, in an effort to squeeze more oil out of the ground, the industry began injecting CO2 into porous subsurface rock . While the process helped mobilize more oil in the reservoir, the most significant policy support for the technology is the tax credit known as 45Q for capturing emissions. The emissions in almost all cases are then used to increase oil production . While there are countless oil companies capturing carbon dioxide, the industry has nearly monopolized the transportation and storage portion of the process where most of the carbon credits are applied.
Different CO2 uses lead to different levels of emissions reductions, depending on whether the CO2 is permanently stored or if it is used to displace fossil fuels in underground reservoirs. One of the primary uses of CO2 is for enhanced oil recovery (EOR), a method of oil extraction that uses CO2 and water to drive oil up the well, improving oil recovery and sequestering the CO2 underground, as seen in the figure above . Since only some of the carbon dioxide is left in the ground, the rest will be produced and must be re-processed to be used again. Selling CO2 for EOR and other uses can provide revenue to capture facilities, incentivizing further implementation of CCS technologies. Figure 4 shows a high-level representation of the process used during CO2 EOR operations.
In the year 2000, several major oil and gas companies, including Shell and ConocoPhillips, formed the Carbon Capture Project, whose goal is to help “develop next generation technologies that will reduce the costs of CCS and make CCS a practical and cost-effective option for reducing or eliminating CO2 emissions, resulting from the use of fossil fuels” . The initiative made CCS mainstream and a viable option to remove harmful greenhouse gasses from being emitted into the atmosphere. Carbon Capture Coalition, which is a 2018 rebranding and expansion of the National Enhanced Oil Recovery Initiative, further popularized CCS and allowed CCS for EOR to represent the only carbon capture technology that exists at scale . While enhanced oil recovery does manage to sequester most of the injected CO2 permanently, carbon dioxide harvested during the capture phase represents only 15% of what the industry currently uses, the rest comes from natural gas . That being said, why not have the captured CO2 provide additional benefits other than removing greenhouse gases from the atmosphere? Once the CO2 is removed, if it is going to be put into the ground, it might as well help produce a resource the world will continue to need into the foreseeable future as energy demand increases on an annual basis.
Future of Carbon Capture
In all cases where fossil fuels are the source of energy, CO2 is inevitably produced. If policy and incentives are to prevent this CO2 reaching the atmosphere, CCS will be absolutely essential. In 2019, the Intergovernmental Panel on Climate Change (IPCC) released a special report on the impacts of global warming of 1.5 °C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty . The report (IPPC 1.5 SAR) shows that recent trends in emissions and the level of international progress towards the Paris Agreement deviate from a track consistent with limiting warming to well below 2°C. “Without increased and urgent mitigation ambition in the coming years, leading to a sharp decline in greenhouse gas emissions by 2030, global warming will surpass 1.5°C in the following decades, leading to irreversible loss of the most fragile ecosystems, and crisis after crisis for the most vulnerable people and societies” . So what does this mean for CCS?
According to the Global CCS Institute’s 2019 Status Report, 40 million metric tons of CO2 from plants currently in operation are captured and stored each year . For context, the United States alone emitted over 5 billion metric tons of CO2 in 2018 . This must increase at least 100-fold by 2050 to meet the scenarios laid out by the IPCC’s 1.5 SAR as somewhere between 350 and 1,200 gigatonnes of CO2 will need to be captured and stored this century . Globally, there are 51 large-scale CCS facilities in operation or under construction, including power plants capturing at least 800,000 metric tons of CO2 annually and other industrial facilities capturing at least 400,000 metric tons of CO2 annually . In the United States alone, there are 10 large-scale operational facilities. Luckily CCS is again growing this year and the sustained lift in activity around CCS and the increased investment in new facilities is exciting and encouraging. There is much more work to do. In every part of the CCS value chain, substantial progress is being made. New, more efficient and lower-cost capture technologies across a range of applications are changing the outlook for one of the most significant cost components of the CCS value chain.
Carbon dioxide is a greenhouse gas that holds a huge hand in global warming, and technology is available to be utilized that can combat climate change. This is the opportunity the global pandemic and CCS have provided. With the world desiring to move towards a clean energy future and national governments worldwide implementing economic stimulus packages to lift their nations out of recession, CCS is a unique opportunity to re-grow the global economy in a climate-friendly and environmentally sustainable manner. For CCS to make the maximum contribution to emissions reductions, the pace of development and deployment needs to increase substantially to get projects up and running in time to meet global targets. CCS has the potential to make a big difference to greenhouse gas emissions, but action needs to be taken swiftly to allow the impact to take effect before temperatures rise and the cost of tackling climate change increases. Furthermore, CCS will allow for sustained benefits of using hydrocarbons to generate energy as focus shifts to a carbon-constrained world. This technology can be a key cost effective option for reducing carbon dioxide emissions from industrial applications where deep emission reductions can only be achieved through CCS. The road ahead is challenging, but if policies are set to meet standards mitigating climate change, CCS is an additional tool to make significant and necessary contributions towards achieving net-zero emissions around mid-century.