Many things have changed since the first large-scale carbon capture project in 1972. Fueled by the relentless pursuit of climate action, the evolution of carbon capture technologies has been transformative.
In the previous article, we discussed nature-based Carbon Sequestration, and this multiple-part series will explore CCUS and answer your most-asked questions. We will cover how carbon capture works, industrial processes, advantages and disadvantages, scalability and most importantly, “Is carbon capture and storage a good idea?”
What is Carbon Capture, Utilization and Storage in Simple Terms?
CCUS technologies start with capturing carbon dioxide from significant point sources, such as coal power plants. The captured carbon dioxide is then transferred to be used in various applications or injected deep underground into geological storages that trap CO2 permanently.
How does Carbon Capture Work?
CO2 capture is essential to several industrial processes, and commercial technologies developed have been around for several decades. The most advanced and widely adopted technology is chemical absorption. Power generation, fuel transformation and industrial production facilities often use this process.
In Chemical Absorption, the Gas stream that emanates from combustion plants (Flue Gas) is placed in contact with a chemical solvent that absorbs the CO2 of the gas stream. Afterwards, the solvent and carbon dioxide solution is heated to release the solved carbon dioxide to be compressed and stored.
Another widely used carbon capture method is Physical Separation. In this process, the post-combustion gas stream is passed through a solid material that traps the carbon dioxide. After that, similar to the former method, by change of conditions, the CO2 is released to be stored.
Additionally, many other technologies are continually being created and refined as the search intensifies for the most effective solutions to carbon capture.
Utilization and Storage: What is Captured Carbon Used For?
The CO2 captured can be used in various industries ranging from food and beverages to oil and natural gas. However, the biggest challenge is transporting the gas captured to utilization sites. The two main methods for large-scale transport include pipeline and ship. On the other hand, for short distances and small volumes, CO2 can also be transported by truck or rail, significantly increasing costs and emissions.
As mentioned, Carbon capture has been around since 1938. However, the initial application wasn’t to reduce emissions. In these projects, the captured CO2 is injected into oil reservoirs to increase the pressure of the oil wells and increase oil production, known as enhanced oil recovery (EOR).
At first, EOR sounds like a wasted effort. After all, the carbon captured and stored produces more oil, and the additional oil will result in more emissions. Yet, in reality, EOR has played a crucial role in adapting carbon capture and storage (CCS).
In EOR, an average of 500kg of CO2 is required to produce a barrel of oil, and each barrel results in 400 kilograms of CO2 emissions. If done correctly, EOR reduces emissions by storing an additional 100kg in storage sites.
For storing carbon in oil reserves to have the most impact, some crucial requirements must be met.
- The source of CO2
Most EOR processes use CO2 from natural underground deposits to minimize expenses. Practically, extracting already stored carbon to be stored again in oil reserves. Therefore, for EOR to positively influence climate change, the oil industry must be obliged to source its carbon from anthropogenic sources (sources that are caused by human activities).
- Who Claims the Reduction
The carbon captured and stored can only be used to reduce the emissions of one entity. Assume 1 tonne of CO2 is captured from a power generation facility and used in an EOR facility. Only one can claim the environmental benefit to prevent double accounting.
- Permanence
It is vital for the environment that the carbon emissions are permanently stored. Specific steps should be taken to ensure and demonstrate the permanency of CO2 storage. These steps include identifying suitable geological formations of the reservoirs, providing proper sealing of abandoned wells, and monitoring and field surveillance to detect potential leakage.
How effective is carbon capture and storage?
In recent years, CCUS has been the most advertised solution to remove carbon from the atmosphere. From direct air capture to EOR projects, they all claim carbon capture is the key to solving climate change. To Answer this question, we must carefully examine CCUS applications and compare the pros and cons of carbon capture.
What are the advantages of CCUS?
- Mitigating Emissions in Existing Infrastructure
Heavy industries, such as cement, steel, and chemical production, can incorporate CCUS technologies into existing facilities and capture the emitted emissions. Although this solution is costly, the alternative is an extra 600 billion tonnes of emissions by 2070.
- Unavoidable Emissions
Many Hard-to-Decarbonize Industries adopt Net Zero strategies to reduce their emissions, and eventually, they encounter an unavoidable portion of emissions that can not be reduced any further. Only the adaptation of CCUS technologies can reduce This unavoidable portion of emissions.
- Cleaner Fossil Fuels
Following climate-effective Enhanced Oil Recovery (EOR) requirements, CCUS may provide a solution to cleaner or carbon-negative fossil fuels.
What are the Cons of CCUS?
- Costly and Time Consuming
CCUS projects have proven to be highly costly, and even with enough resources, these projects take years to be operational. CCUS facilities currently capture almost 45 Mt CO2 globally and are projected to increase to 250 Mt CO2. However, according to Sustainable Development Scenario, CCUS deployment would remain substantially below what is required in the Net Zero Scenario.
- Energy Penalty
Energy Penalty is the answer to “Why can’t they put carbon capture tech on top of coal plants?” Capturing CO2 requires a substantial amount of energy, reducing the overall efficiency of the power plant or industrial process fitted with CCUS.
- Perpetuates Fossil Fuel Dependence
The idea that we can continue using fossil fuels and emit billions of tonnes of CO2 per year, and CCUS will remove it from the air and bury it (CO2) underground, sounds too good to be true. Unfortunately, it is.
The heavy dependence on CCUS and abandoning the transition to Renewable energy won’t solve fossil fuel dependence or the climate change crisis. While CCUS has a role in reducing emissions, this technology mustn’t become a justification for avoiding the transition toward a sustainable, renewable energy future.
In Conclusion
While CCUS has notable benefits, particularly in reducing CO2 emissions and enabling cleaner use of fossil fuels, these need to be weighed against significant challenges such as high costs, energy penalties, and potential risks associated with storage. The role of CCUS in the future energy system will largely depend on how these challenges are addressed and how it fits into a broader strategy of emission reductions and transition to renewable energy.
In our next blog, we will delve deeper into the pros and cons of Carbon Capture, Utilization and Storage and answer the question, “Can carbon capture facilities reverse climate change?”
