Harnessing the full potential of carbon capture: embracing the synergies between CCS and CCU technologies
Introduction
Carbon Capture and Storage (CCS) and Carbon Capture and Utilisation (CCU) are essential parts of the global energy transition, alongside renewables-based electrification, bioenergy and hydrogen. While CCS refers to the process of capturing CO2 and storing it permanently underground, CCU considers the conversion of the extracted CO2 into valuable products, such as fuels and chemicals.
In the current public debate, there appears to be a perception that these techniques are competing, reflected for example in how certain governmental funding mechanisms support one over the other. In fact, CCS and CCU are complementary, each offering unique benefits that, when combined, can significantly accelerate progress towards a sustainable future.
Reducing emissions with CCS
CCS will play a fundamental role in the fight against climate change, particularly for reducing emissions in sectors that are difficult to decarbonize, such as cement production. In short, CCS involves capturing CO2 emissions generated by power plants or industrial processes, transporting it to a suitable storage site, and permanently injecting it deep underground (into geological formations, such as saline aquifers or depleted oil and gas reservoirs) for long-term containment. This process prevents CO2 from being released into the atmosphere, thereby mitigating its contribution to global warming.
Evolution of Carbon Capture technologies
CO2 capture has been in operation for many decades. As early as the 1930s, the oil and gas industry started using a process called 'gas sweetening' to remove sour gases, including carbon dioxide and hydrogen sulphide, to improve natural gas quality and make it less corrosive and harmful to the environment. The most widely adopted, and still frontrunning, process is ‘amine scrubbing’, involving chemical absorption using a type of amine solvent.
In the United States, full-chain CCS has been operating since the early 1970s. US natural gas plants have effectively captured and stored over 200 million tons of CO2. In Europe, the first large-scale CCS project, known as the Sleipner Project, began in 1996 in the North Sea. Each year, about 1 million tonnes of CO2 are stored at Sleipner.
CCU: Turning emissions into resources
CCU technologies include various chemical production processes, ranging from established methods like methanol and Fischer-Tropsch syntheses to more emergent techniques such as alcohol-to-jet conversion. These technologies convert captured CO2 into valuable products such as synthetic fuels, chemicals, and building materials, turning carbon emissions into an economic opportunity and offering a path to sustainable growth.
One of the key advantages of CCU is its potential to be carbon-neutral or even carbon-negative. By using biogenic CO2 and green hydrogen, a closed carbon loop can be created. This allows the carbon emitted during product use to be captured and reused, effectively reducing net carbon emissions. Additionally, CCU has the potential to decrease raw material consumption and facilitate the shift towards a circular economy. Finally, offering solutions to separate industrial production from fossil fuels, CCU addresses the critical aspects of supply chain security and resilience.
The success of this pathway depends on its economic feasibility, influenced by factors such as the cost of renewable electricity, technology efficiency, and market demand for the produced materials. Advances in technology and well-designed supportive policies play a key role in enhancing the economic attractiveness of CCU.
The power of synergy
While CCS and CCU both have distinct objectives, substantial benefits can be obtained by combining the two technologies:
Reducing emissions at the source: CCS captures carbon emissions at their source, preventing their release into the atmosphere. By integrating CCU with CCS, these captured emissions can be utilised to produce valuable products, partly offsetting the costs of CCS deployment.
Economic viability: CCU technologies often face challenges related to cost and market demand. Integrating CCU with CCS can help overcome these hurdles by providing a steady supply of CO2 feedstock, reducing production costs, and fostering a market for CCU products.
Enhanced sustainability: Together, CCS and CCU offer a more sustainable approach to emissions reduction. CCS prevents CO2 emissions from contributing to climate change, while CCU reduces the reliance on fossil resources by producing valuable products from captured CO2.
Policy and regulatory support: Combining CCS and CCU allows policymakers to develop comprehensive climate strategies. By incentivizing both technologies, governments can create a more inclusive approach to emissions reduction, fostering innovation and investment in the carbon management sector.
Conclusion
CCS and CCU should not be viewed as competing technologies but complementary elements of a holistic strategy to combat climate change. CCS effectively reduces emissions at their source, while CCU transforms CO2 into valuable resources. When integrated, these technologies can amplify each other, providing a multi-faceted approach to reducing carbon emissions, enhancing economic sustainability, and furthering innovation.
Content contributor
Jonas Alin, Project Director, Liquid Wind