Sustainable Carbon Cycles
What are sustainable carbon cycles and why are they important?
The concept of Sustainable Carbon Cycles describes the use of Carbon in our manufacturing processes and products in such a way that it contributes to reaching the climate neutrality goals.
To reach these goals, the chemical industry can rely on a broad array of complementary technologies and efficient processes. It includes feedstock choices or deploying technologies like Carbon Capture and Utilisation (CCU), Carbon Capture and Storage (CCS) and chemical recycling.
How sustainable carbon cycles can help us on our way to climate neutrality
When working towards the climate goals identified in the Paris Agreement and assessing progresses, it is important to consider the amount of CO2 already present in the atmosphere as well as the generation of additional CO2 emissions through feedstock and power choices. As an increasing CO2 concentration in the atmosphere plays a role in the rising of global temperatures, to reach the goals of the Paris Agreement it is important that “cumulative CO2 emissions are kept within a budget by reducing global annual CO2 emissions to net zero at the medium to long term.” ”
So, by thinking in terms of “atmospheric carbon budget,” it is possible to determine the “carbon” impact of any action performed by any actor on the climate goals identified in the Paris Agreement.
Indeed, every decision, every undertaken action where carbon is involved has an impact on this budget; and the impact can be positive, negative, or neutral. More specifically, there can be three main changes in the atmospheric carbon budget:
- CO2 can be removed from the atmosphere; in this case, the balance would be negative as the amount of CO2 in the atmosphere is reduced; which means we have a positive impact on the environment.
- AdditionalCO2 emissions in the atmosphere can be avoided; in this case, the balance would be zero and our impact neutral.
- More CO2 can be emitted; in this case, it means additional CO2 emissions are added to the atmosphere lowering the remaining budget and this could hamper achieving the Paris Agreement goals.
The chemical sector needs, and will need in the future, carbon molecules as a raw material for our products. However, by working towards establishing sustainable carbon cycles we have the opportunity to get the carbon we need from different sources, ultimately controlling the impact we have on the atmospheric carbon budget.
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The main four sources of carbon are:
using carbon from plants
CO2 exists naturally in the atmosphere. Plants capture CO2 through photosynthesis while growing. We can use the carbon content of biomass as feedstock to produce chemical products. In case the carbon of the products will be emitted after use, we would still have CO2 neutral balance . Tomorrow, when the economic system is even more circular, we will be able to keep biogenic carbon in the loop by reusing it over and over again. In this case, we would approach a carbon removal situation, keeping the carbon stored in the products, the so-called “carbon removal pool”. If we combine the use of biogenic carbon with CCS, we will have CO2 removed from the atmosphere.
using carbon from the atmosphere
Once scaled-up and powered with low-carbon energy, technologies like Direct Air Capture (DAC) could help us use carbon that is already in the atmosphere to create our products. In an maximized circularity scenario, we would approach a removal by keep the carbon in the “carbon removal pool”. Also in this case, if combined with CCS and powered with low-carbon energy, this option could result in a carbon removal.
using carbon from industrial processes
Industrial processes from different sectors emit CO2. If this CO2 stream is captured at the very emission source via Carbon Capture and Utilisation (CCU) technology, then we can transform it into feedstock and bring it back into the economic in a circular way. The first immediate benefit of this approach is avoiding additional CO2 emissions in the atmosphere. If we combine this with Carbon Capture and Storage, we could reach a net-zero emissions, or even remove CO2 if the CCS technology is powered with low-carbon energy and the carbon comes from biogenic sources.
using carbon that in previous lifecycles of manufactured products came from fossil sources
Some of the carbon molecules currently present in our economy originally come from fossil sources. By making them circular, we can reduce their overall footprint. For example, technologies like chemical recycling can help us recycle “used” carbon into new feedstock. In this way, “old” carbon can then be reused to create new chemical products and be kept in so called “carbon chemical pools,” in which it will be “trapped” (or stored) for years or decades.
Additional mitigation measures
While recycling carbon and avoiding emissions is the first course of action, this will not be enough to reach climate-neutral by 2050. The deployment of additional technologies such as Carbon Capture and Storage (CCS) will help us to address remaining “hard-to-abate” emissions. Carbon Capture and Storage can help us have a substantial impact on our atmospheric carbon budget by increasing our ability to remove CO2 from the atmosphere, hence going above and beyond “simple” emission avoidance.
Last but not least, access to cheap and abundant low-carbon energy is pivotal to realise the sustainable carbon cycles in a fully sustainable way.