Rahman, F. A., Aziz, M. M. A., Saidur, R., Bakar, W. A. W. A., Hainin, M. R., Putrajaya, R., & Hassan, N. A. 2017. Pollution to solution: Capture and sequestration of carbon dioxide (CO 2) and its utilization as a renewable energy source for a sustainable future. Renewable and Sustainable Energy Reviews, 71, 112-126.
Air pollution and the role of carbon dioxide in climate change
Every modern convenience requires energy. From the lights we use in our homes to the cars that we use for transportation, each requires large amounts of energy to run. Currently the majority of this energy is supplied by burning fossil fuels. And while there are countless benefits to having this energy available, it comes at the price of harmful air pollution produced during the burning of these fuel sources. This air pollution contains several greenhouse gases that trap heat in the atmosphere, which leads to overall warming of the atmosphere and climate change. The most abundant greenhouse gas that is produced is carbon dioxide, known as CO2 in its chemical formula. While maintaining and planting trees helps to take excess CO2 out of the air, there are not enough plants to naturally capture and store all the carbon dioxide currently emitted. Looking to alleviate the excess CO2 emissions being released into the atmosphere, focus has turned towards new advances in technology to capture and store CO2 from the air using what is called carbon capture sequestration (CCS) technology.
What is carbon capture sequestration (CCS) technology?
The vast majority of CO2 entering into the atmosphere is from the burning of fossil fuels at large scale power plants. Carbon capture sequestration (CCS) technology removes CO2 from emissions at the time they are generated at a facility. CO2 is able to be taken out through physical and chemical processes in which it is either integrated into a liquid or solid, or filtered through a membrane. In all methods, CO2 is converted into a gaseous, liquid, or solid state and then transported via trucks or pipelines for long term storage in rock deep below the earth’s surface or deep in the ocean. Typically, old oil fields are used for storage on land. While CCS technology is beneficial in preventing CO2 emissions from entering the atmosphere, there are challenges with this technology.
Challenges of CCS technology
The main challenge of CCS technology is that there are still a lot of uncertainties and gaps in the knowledge about its use. Mainly there are risks and costs associated with storing the captured CO2. Questions remain about the effects of storing the captured CO2 underground as well as the storage capacity and long-term reliability of these underground reservoirs. This technology is of little use if the stored CO2 will eventually leak out or cause other unintended negative consequences for the environment. Further, capturing and storing the CO2 requires additional energy and financial costs. Because of the challenges with CCS technology, methods of using the captured CO2 instead of just storing it are needed. A promising solution is converting the captured CO2 into biofuel. In doing so, it is a much more sustainable approach to the pollution problem than simply storing it. If used as biofuel, it could generate an energy source without increasing the need for fossil fuels.
Looking towards the future
The use of captured CO2 as a biofuel could be a sustainable source of energy given the vast amount of CO2 currently produced by large industrial facilities. It could potentially also be a better alternative to how biofuel is currently produced. Currently, biofuels are typically made from the fermentation of crops. An argument against this way of producing biofuels is that generating energy in this manner could cause land needed for biofuel crops to compete with land needed for food production. Thus, converting captured CO2 into biofuel could be a solution to making both CCS and biofuel technology more sustainable with less impact on the environment. The need for more sustainable energy sources is high, given that current rates of fossil fuel consumption are on pace to exhaust these resources within the next 50 years. The technology of CCS is still developing and still has technological, economic, and environmental concerns to address. In its current setup, it has a lot of risks and uncertainties. With the combination of utilizing the captured CO2 as a biofuel, the technology has the potential to help lessen the impact of human activities contributing to climate change.