What is Carbon Sequestration

Carbon sequestration is the continuous process of capturing and storing carbon, mainly in the form of carbon dioxide, in a carbon pool or carbon reservoir. In some cases, this process becomes a carbon sink when the carbon pool can capture more carbon than it can release.

How does Carbon Sequestration Benefit the Environment

By continuously capturing and storing carbon, this process reduces the amount of carbon dioxide in the atmosphere and is an effective method to combat climate change and harmful effects to the environment. 

In broader terms, one of the carbon sequestration methods also paves the way for a more sustainable and environmentally friendly waste management solution. 

Carbon rich soil from the sequestration process also helps to boost soil structure and health leading to a more fertile land. It will improve agricultural activity and the land will also be less prone to erosion.

Carbon Sequestration vs Carbon Capture

While carbon sequestration and carbon capture are similar and sometimes used interchangeably with each other, they are different and distinct in their own measures. The table below highlights the key differences and similarity between the two processes: 

Carbon Sequestration Methods

Carbon sequestration exists in both natural and technological forms. More specifically, natural carbon sequestration is the capture and storage of carbon by natural processes while technological carbon sequestration is driven by employing artificial methods to collect and/or separate the carbon from the environment. 

Biological Carbon Sequestration

Biological carbon sequestration is the capture and storage of carbon dioxide by continuous processes that is happening on a natural basis. 

For example, photosynthesis, agricultural improvements and sustainable green management such as reforestation. The plants absorbed CO2 from the environment for its growth. 

Ocean Carbon Sequestration

Ocean carbon sequestration involves a solubility and biological pump which are defined as: 

1. A solubility pump is a physicochemical process that converts carbon dioxide in the air into organic matter to be stored within the ocean floor, essentially trapping carbon on the ocean floor for thousands of years due to the low temperature, high pressure and slow decomposition. 

2. A biological pump is a natural sequestration of carbon from the atmosphere by the ocean, to be stored within the ocean, essentially trapping carbon in sea to be used by the living organism within the sea. 

Both pump logics are workable because of the highly favourable conditions that the ocean provides the sequestration process with – low temperature and high pressure for carbon to dissolve in water and trapping it within the ocean ecosystem. 

Geological Carbon Sequestration

Geological carbon sequestration is the storage of carbon underground in geological formations such as depleted oil and gas reservoirs or unmineable coal mines. 

A special property of carbon dioxide is that it can exist as a supercritical fluid when compressed to high pressures. 

This unique property allows for carbon dioxide to be transported and injected underground for storage, essentially trapping it in a geological pool. 

Technological Carbon Sequestration

Technological carbon sequestration involves using artificial but precise and calculated solutions to capture and store carbon from industrial sources. 

Various engineering techniques from utilising unique state properties and proprietary information allows for a sophisticated method of sequestration, when otherwise not allowed by the abovementioned sequestration methods, to still allow for the benefits of carbon sequestration. 

A very fundamental example would be to tap on the acidity of carbon dioxide and the use of a relative base to remove carbon dioxide, thereby extracting carbon dioxide and storing it in other less environmentally detrimental forms.

Biochar for Carbon Sequestration

Biochar is a carbon-rich material produced by the pyrolysis of biomass in the absence of oxygen. It is a technological carbon sequestration whereby the carbon in the material is transformed into a stable form that can last for thousands of years.

Besides storing carbon in the ground, the porous nature of biochar also helps to improve the soil’s health. It is able to retain water and at the same time, the porous nature is able to hold nutrients for a longer period of time. In fact, it can be impregnated with the nutrients or fertiliser before the biochar is stored and buried in the soil. 

Moreover, the stable nature of biochar allows carbon credit to be claimed as a revenue stream for biochar projects. Being carbon neutral or carbon negative is a long term sustainability objective of various countries and companies. The carbon credits from the biochar is a way in achieving the long term sustainability objective.

It is understood that the process of producing biochar through pyrolysis is still emitting greenhouse gases. However, the pyrolysis process is able to use the energy from the feed materials to sustain its process. The waste, that would otherwise be sent to landfills which will decompose and emit methane which is 26 times more carbon intensive than CO2, is processed such that not all the carbon is released into the environment. The biochar produced will retain some of the carbon and the process is widely accepted as a carbon negative process.

Anergy’s HTP in Carbon Sequestration

Anergy’s High Temperature Pyrolysis (HTP) is able to convert waste into biochar and energy in the form of syngas or heat or electricity.

The higher operating temperature of the HTP allows the biochar produced to be more stable with the less volatiles in the biochar. As such, higher carbon content is generally produced in the biochar from the HTP process. 

The superior quality of the biochar could potentially yield a higher economic return. With the right feedstock and optimal operating conditions, the biochar produced could be used as coke replacement in the steel making industry or even used as water filtration.

Contact Us to find out more about Anergy’s HTP technology.