The reduction of carbon emissions from power plants is one of the most challenging aspects of combating climate change. Basically, burning things to produce energy produces carbon dioxide, which traps heat in the atmosphere. As a result, global warming and other environmental changes occur.
In 2015, the Paris Agreement set the objective to keep the temperature of the planet below 35.6ºF (2ºC increase) with the further ambition to keep it below 34.7ºF (1ºC increase). For countries and corporations to meet this goal, they need to use "negative emission technologies" for carbon capture.
What is Carbon Capture and How Does it Work?
Carbon capture is the method of capturing carbon dioxide at the source of emission and then transporting it to a location where it can be stored or buried deep underground. CO2 can be captured in several different ways. The most common carbon capture and storage methods are:
Post Combustion: CO2 is removed from the waste gasses produced by fossil fuel combustion;
Pre-Combustion: During this process, the fossil fuel is converted to CO2 and hydrogen before being burned;
Oxyfuel: In this method, fossil fuels are burned in a completely oxygenated atmosphere to create CO2 and steam.
Carbon capture is a three-step process which seems straightforward at first…
Capturing CO2 at its source: In sizable industrial processing facilities, CO2 is separated from other gasses, such as those produced at coal and gas power plants.
Transport: After the carbon has been separated, it is compressed into a liquid form and transported to suitable storage sites via pipelines, roads, ships or other means of transportation.
Storage: Afterwards, the CO2 is pumped into deep underground rock formations, usually at least 1 km deep, for long-term storage.
With the widespread realization that global warming is a severe issue, carbon storage and capture technologies are rising to the fore, although some have been around since the 1980s in North America. Today the technology is preventing over 40 million tons of CO2 from entering the atmosphere.
Types of Carbon Removal and Technologies Explained
Through innovative technology, scientists are exploring new methods for storing and removing carbon from the atmosphere. In addition to removing carbon dioxide, researchers are now looking at ways to use it as a resource besides removal.
The primary carbon removal solutions are:
Nature-based Solutions
These solutions include reforestation and afforestation. Afforestation involves repurposing land use by establishing trees where none previously existed Reforestation involves reestablishing existing forests.
A further natural solution is to restore coastal and marine habitats. So that CO2 would remain out of the atmosphere for as long as possible.
High-tech Solutions
High-tech Solutions are direct air capture and bioenergy with carbon capture and storage (BECCS). In clean energy transitions, both of these solutions can help remove large amounts of carbon dioxide from the atmosphere.
Bioenergy with Carbon Capture and Storage (BECCS)
In BECCS, CO2 is captured and permanently stored after biomass is burned for energy. Biomass is burned in power plants (or mixed with fossil fuels), in pulp mills for the production of paper, in lime kilns for the production of cement and in refineries to produce biofuels derived from fermentation (ethanol) or gasification (biogas).
Using BECCS, it is possible to remove carbon from the atmosphere because biomass absorbs CO2 during growth and does not rerelease it during combustion. Carbon dioxide is instead captured and injected into deep geological formations, preventing it from entering the natural carbon cycle.
Direct Air Capture
Carbon dioxide can be permanently stored when captured from the atmosphere using direct air capture. Additionally, CO2 captured from the air can be used to produce beverages, foodstuffs, and synthetic fuels by blending them with low-carbon hydrogen.
However, since CO2 concentrations in the atmosphere are low, direct air capture technologies are more energy-intensive and costly than other CO2 capture technologies that extract CO2 from industrial facilities.
Hybrid Solutions
A combined solution might include;
Using enhanced root crops;
Sequestering carbon in the ocean;
Capturing and storing carbon in bioenergy;
Soil can be converted into carbon storage by adding biochar (charcoal made from biomass) to the soil. Biochar can last hundreds or thousands of years;
Enhanced weathering (for example, adding extremely fine mineral silicate rocks to soils to increase their capacity to absorb CO2) and ocean fertilization are less developed approaches that increase the capacity of the ocean to absorb CO2. A deeper understanding of enhanced weathering and ocean fertilization approaches is needed to determine their potential for removing carbon as well as their costs, risks, and trade-offs.
According to the World Resources Institute, the United States will be able to achieve the most significant cumulative carbon reduction at the lowest risk if it pursues all-of-the-above carbon reduction strategies. If one pathway does not meet the expectations, multiple options will provide the opportunity to meet the 2 Gt CO2 removal target by 2050.
In the United States, reforestation, afforestation, and agroforestry are significant feasible opportunities for removing carbon. The direct air capture method is a promising method of capturing atmospheric carbon dioxide, which is likely to be an important component of an overall carbon removal strategy.
Why is Carbon Capture Needed?
To combat climate change, carbon capture is essential. And for greenhouse gas emissions to be reduced, they must be implemented globally. At this point, although global warming cannot be stopped, it can be slowed.
With carbon dioxide levels exceeding 400 parts per million, we are experiencing the highest level of carbon dioxide in the past 400,000 years. As a result, carbon capture technologies can play a significant role in combating climate change. However, net zero is happening too slowly to limit the impact of emissions on a warming planet.
Progress is slow, and countries that are amongst the most prominent contributors are not committed to reducing carbon emissions at all. China, for example, only showed moves to be carbon neutral by 2060. And the biggest emitter, the US, has targets to reduce emissions by 50% by 2030. Without consensus on a global scale, there is little hope of winning the fight, which is why investors and entrepreneurs are encouraged by new technologies to remove carbon from the atmosphere, transport and store it.
What Challenges Are There with Carbon Removal?
Those opposed to carbon removal are concerned that the hype surrounding it is merely a distraction from what needs to be done, which is not to create emissions at all. Aside from this, the critical challenges to widespread carbon removal use are:
Cost of implementation: The carbon capture process is generally expensive because of its energy and deployment costs. However, researchers are working hard to reduce costs.
Transportation: Although CO2 won’t explode like natural gas, transporting it to storage and utilization sites in a liquified form requires investment in a lot of safe infrastructure plus there’s the issue of how much energy it requires to compress the gas and maintain high pressure and low temperature throughout the transportation process.
Storage: There is no way to predict what will happen to CCO2 trapped below Earth's surface in the distant future. It may be possible to make a big difference down the road by implementing reasonable regulations - and choosing quality storage sites. Leakages of CO2 can damage the environment and contribute to climate change if storage sites are not correctly monitored, managed, and selected. There is also concern for the impact of underground storage on marine life.
Now is the Time for Decisiveness and Action
Carbon capture is limited in Canada currently, there are only two major Carbon Capture, Utilization and Storage (CCUS) projects (one in Saskatchewan and one in Alberta), and it remains to be seen whether public funding will become available for further projects like this in the future. Alternatively, government mandates may either force carbon removal eventually, decide that a no emissions policy should be the primary approach, or it might be a combination of both. Whichever way, decisions need to be made quickly, and action needs to happen much more quickly than it is now.